Journal of the

Association of Teachers .of Geology

VOLUME 1

NUMBER 2

JULY 1976

Contents

LETTERS 30

RESOURCES REPORTS Book Reviews 32

ARTICLES Geological Curators

33 Group Interpretation of

textures in igneous 35 rocks

NEWS Regional round-up 43 Curriculum developme"t

proposa Is 44 Geology in-service

courses in Avo" 45

SHOPFLOOR Simulation of igneous

textures 46 Crystal models 47 Workshop on teaching

palaeontology 51

DIARY 57

COMMENT 60 Cert. of Education:

Foundation Which way for secondary

Geology?

COVER PICTURE

- see page 46

GEOLOGY teaching

LETTERS Comments are invited from ATG members on the Associations policy, the contents of GEOLOGY teaching, or any other matter concerning geological education. Points raised in correspondence from members can be put to other individuals or organisations for reply and further discussion, as the following letters concerning 'University-geology' show.

Dear' Sir,

The most interesting article by Geoffrey Brown on the historical development of Geology in the 6th forms of schools, in the March 1976 issue of GEOLOGY teaching rightly underlined the dichotomy between many university geology departments and the schools. For too long these departments have exhibited a b1inkered attitude to the development of the subject in the schools, largely by geographers. •

It is surely time for a reappraisal of many university geology courses, for they are far too narrowly based. The excellent courses offered in geology by the Open University have given a lead. Cour ses similar to these should be made more widely available in higher educa­tion for 'A' level students whose interest in geology has been stimulated in the schools, but who may not necessarily have the science 'A' levels which so many departments require.

Dear Sir,

Yours faithfully,

Brian J. Edwards Head of Geology Department Queen Mary's Grammar School, Sutton Road, Wa1sa11, Staffordshire.

Thanks for the opportunity to see Brian Edwards' letter about liaison between schools and univer­sities and the development of geology in schools.

I'm not familiar enough with university geology courses at large to comment on how many of them, if any, are too narrowly based nor am I certain quite who would do the reappraising that Mr. Edwards mentions. Those that I am acquainted with seem to me to be very good -and successful in that they attract students already in university to transfer to geology from other honours courses. The Committee of Heads of University Geology Departments would, I am sure, be happy to encourage liaison between departments and the schools of their region. The A.T.G., too, has always been eager to foster links between teachers at all levels, and it has, I think, been by no means unsuccess­ful. Such liaison to my certain knowledge already exists in several parts of the country. In several of the larger cities the civic museum runs a Schools Service which involves consultation and liaison with the local university. This arrangement can be highly successful in involving both parts of the dichotomy Mr. Edwards mentions, and museum staff are these days commendably enthusiastic to help.

I acknowledge that the Open University has produced some excellent texts and courses but it aims to serve a rather special category of

student. At some universities rather similar courses are available for non-degree students. At Bristol, for example, there is the Certificate Course in Geology run by the Departments of Extra-Mural Studies and of Geology, and it covers two years of study. Short "topping-up" courses on recent develop­ments in the earth sciences have also been organized for geology teachers from schools. No doubt there is plenty of scope for other developments in similar vein. It should be recognised, however, that because of recent cuts in university financing many departments are short-staffed and unable to offer courses outside their formal degree teaching.

University teaching in geology was the target for many criticisms and brickbats a few years ago. Some of these criticisms were warranted no doubt, but there has undoubtedly been much improvement in course content and in the standard and style of teaching; and it's not entirely due to the much-mentioned "Revolution in the Earth Sciences". The British B.Sc. degree is well regarded in most quarters and of course the maintaining of a high standard of training to degree level concerns university teachers most. Recruiting good potential undergraduates from schools may be a secondary concern but in many departments this and contacts with schools is the special responsibility of one member of staff of a geology department.

There is a further point that rather worries me. For national examinations at secondary level there must be a syllabus to which most schools adhere, but the universities are by no means so required to conform and it may seem that the degrees of our three dozen or so universities all resemble each other too closely. From what I have seen of our universities, the geology degree syllabus for the first year at one tends to look much like that of all the others and may only differ to an appreciable extent from its fellows for successive years. The universities could perhaps do more to vary their approaches to the subject and to vary the range of topics offered to their honours students. No doubt the differences in emphasis and in areas of interest between university degree courses will emerge more clearly in the next few years. The important differences which ought to exist between geology courses at universities and polytechnics are also likely to be discussed and clarified. Boundaries between school, university, polytechnic or other kinds of course remain blurred. The A.T.G. and other bodies, formal and informal, which now exist to promote the teaching of our subject will, I hope, be able to involve teachers at all levels in discussions on these topics.

30

Fewer university staff now view the teaching of geology in schools with the misgivings that were common a few years ago. Many, however, are still suspicious of geography teachers teaching geology at sixth form level. More geology-trained teachers are, however, now employed and the growth of their numbers is welcome. However, I would agree that there is plenty of room for improving the links between university geology departments and schools. Perhaps we could hear more from those who, like Mr. Edwards, feel that something further could be done, and perhaps they would be prepared to say what.

Yours faithfully,

Professor D.L. Dine1ey, Department of Geology, Queen's Building, University Walk, Bristol BS8 1TR

Dear Sir,

I write in response to your note on page 2 of GEOLOGY teaching Vo1.l concerning in-service training courses. A course that would have met my needs as a teacher of geology was that which the Dept. of Adult Education and Extramural Studies at the University of Leeds was due to run between 12th and 15th April 1976. I was not able to enrol as it clashed with my own field­work in North Wales, but nonetheless I heard with surprise that it had to be cancelled, having only received 14 enro1ments by March 11th­si~ short of the required number. The plan for this course, whereby members would have chosen two out of the five topics to study in detail during four days would have ensured that a sound knowledge was gained. I would like to emphasise the value of "being involved" in the study, rather than listening to a series of lectures.

Yours faithfully,

Peter J. Perkins

Head of Geography & Geology, Bicester School.

Please write in with ideas - or offers to run -in-service courses. In view of the current financial climate, perhaps they should be organised by local teachers groups in collabor­ation with nearby higher educational establish­ments so that accommodation costs can be eliminated.

Dear Sir,

Will you consider continuing the publ­ication of the very useful lists of new books, films etc which appeared in the Association's now-discontinued Circular?

I found the lists invaluable in setting up an A level geology course here. They are the primary source of my information on books and films.

Yours faithfully,

Derek J Gobbett

Solihull Sixth Form College Widney Manor Rd Solihull West Midlands 891 3JG

The list will appear ogain in the September issue. Ed.

31

New from Pergamon Press T HE GEOLOGICAL EVOLUTION OF THE BRITISH ISLES T.R. OWEN, University College of Swansea, Wales

This book outlines the geological history and evolution of the British Isles and its surrounding sea areas. New information concerning Britain's evolution has emerged from the recent exploration of the seas around Britain in the search for oil and gas and much of this new information has been incorporated. The book will serve university and college students, sixth·form pupils in geology and will also be valuable to students in the allied d isciplines such as geography, oceanography, and civil engineering.

CONTENTS: Iniroduction. "Iapetus" - the first Atlantic Ocean. "Even Further Back ... ?". The old red sandstone continent. From coral seas to mountain chains. From new red sandstone deserts to chalk seas. The final mOUlding. ISBN 0 08 0204619 250 x 176mm 160pp ISBN 0 08 0204600 f 93 illustrations

OTHER GEOLOGY TITLES FROM PERGAMON ALLUM Photogeology & Regional Mapping ANDERSON & OWEN Structure of the British Isles BROWN et.1 Geological Evolution of Australia & New Zealand KEEN An Introduction to Marine Geology PRICE F.ault and Joint Development in Brittle & Semi-brittle Rock SIMPSON Geological Maps SPRY Metamorphic Textures YORK & FARQUHAR The Earth's Age & Geochronology f = hard wearing soft flexicovers or special student editions

All The Above Titles Are Available On Inspection.

$11.00 $ 5.00

8.75 4.50 9.75 6.50

13.75 7.50

10.00 5.00 9.80 5.00 7.00 3.50

16.00 8.00

· 8.25

£5.50 £2.50 f

£4.35 £2.25 f £4.90 £3.25 f £6.90 £3.75 f £5.00 £2.45 f £4.90 £2.45 f £3.50 £1.70 f £8.00 £3.95 f £3.95 f

An inspection copy of any book suitable for use as a course text for students will gladly be sent without obligation to academic staff to consider it for adoption. Copies may be retained for a period of 60 days from receipt and returned if not suitable. When a particular title is adopted, or recommended for adoption for class use, and the recommendation results in a sale of multiple copies, the inspection copy may be ret.ained with our compliments. If after examination the lecturer decides that the book is not suitable for adoption but would like to retain it for his personal library, then our Educators' Discount of 10% is allowed off the invoiced price.

UNIVERSITY OF KEElE

A one year full-time course leading to an

M.Sc (EDUCATION)

offered by the Department of Education in con­

junction with the Department of Geology. It

combines CURRICULUM STUDIES and RESEARCH

TRAINING in SCIENCE EDUCATION with the study

of RECENT DEVELOPMENTS in GEOLOGY and is

recognised by the DES for the purposes of secondment.

Opportunities also exist for studies leading to an

M.A. or M.Sc. or Ph.D. by thesis in either

GEOLOGICAL EDUCATION or GEOLOGY on a

part-time or full-time basis.

Further particulars and application forms from:

The Registrar, University of Keele, Newcastle,

Staffs. ST55BG

32

Reviews and notes about books, eq'uipment, specimens and audio -visual aids, etc.

BOOK REVIEWS

THE WORLD OF ROCKS AND MINERALS by Anita Mason; Osprey Ltd ., 1976 . £3 . 25

This book was published last month; it is one of many of this type, It sets out to catalogue many different min era ls, and in this it succeeds in a v ery attractive and easi ly-r ead format, but it fails to justify its title, and it is unlikely to be of much us e to the teacher of Geo l ogy in the classroom.

The book begins with a twelv e -pa ge introduction to minera ls and rocks, not likely to add much to the knowledge of geology teachers, although it would be valuable for a total newcomer to the h obby of mineral collecting, who would see m to be the most likely prospective readers. The introduction me nti ons Man's hist orical association with minerals; distinguishes between rocks, minera ls and crystals quite c l ear ly; discusses th e way minera ls form fuention ing th e various classes of rocks, and the occurrence of minera ls in relation to thes e c lasses - the only discussion of rocks as such in th e book) and a Is 0 summa rizes the proper t i e~ used t o id e ntify minerals (some of th em , at l east) . It makes no attempt to be a laborator y guid e, but it does detail the procedures used in cu tting, polishing and setting stones .

Th e main part of the book consists of 10 8 pag es of photographs with notes, one mineral (or variety) is shown on each pag e . The photographs are very attractive, and the notes concise and well laid out, giving th e basic diagnostic properties of each min er al; indeed, these notes might well be enough for the a-level candidate, b1Jt h ow many a-level candidates need to know 108 min e ral s? Some omi ss ions in the notes are c h emica l formulae (compositions are given in words on ly) and crystal systems, Details of how eac h can be cut ar e given, howeve r. One ecampl e of missed opportunity to make an int eres ting point i s the treatment of fluor­spar and blue-john. These are given separate pages, although it is made clear that the second is a vari ety of th e former but no e xplanation for th e differences is made, even though coll ec tors would s ur ely like to know that the blue -john results from the geologi ca l peculiarities of Tr e ak Cliff? One useful feature i s the well-researched information on the occurrence of th e mine rals. This book is therefore unlike ly to find a pIa ce in any course, but cou ld be of use in the sc h ool library, as a way of inspiring younger chi ldr en _ th ere would be many ' oohs ' at th e very attractive ;ictures (the jacket notes sta t e that they ar e mostly of 'supe rb specimens of a standard rar e ly come across'). Even if A-l e v e l candidates n eeded to kn ow about Liriconi t e, they would want mor e about the composi ti on than 'Hydrat ed arsenate of aluminium and copper'. They would also like to see some relation s hip between min e rals -

which are in fact grouped, more or less, by compos i ti on, but this is not es peci ally clear. Pupils are perhaps more likely to refer to a well-presented book of this type than to the rather dry 'Rutley', but the price could be much lower if the obscure minerals were removed; perhaps many collectors do want a book of this sort, but it seems to join many that have missed the possibility of serving a need in school geology courses.

Peter Whitehead

THE PRACTICAL STUDY OP CRYSTALS, MINERALS AND

ROCKS

Revised edition 1974 . McGraw Hill (London) 245 pp " £3.45 paperback, ISBN 07 084035 O.

The revised version and the original edition of the book, as the authors state in their preface, are based on a first-year undergraduate course c urrently being taught at the University of Edi nburgh. There is, as a result, a strmg bias toward morphological crystallography, and the first half of the book is given over to a very c l ea r and amply illustrate d exposition of this topic. The second half is devoted to an equally well illustrated and lucidly explained account of rock forming minerals and chapters dealing with the three principal classes of rocks in t erms of thei r physical and optical features, thin section textures, mod e and environment of formation. The dis~ussion of each subject is presented in a logical order and written in a way which makes the reading easy, while the text figures and the half tone plates are very clear, numerous and appropriate to the text ,

PIELD EXCURSIONS IN SOUTH-EAST ENGLAND

Field Studies for Schools Volume 11

Edited by Alice Coleman and Clare T , Lukehurst; Rivingtons, London, 1974. xii + 1 88 pp., Cloth 73, ISBN 0280 022910 O.

Tw en ty-four traverses are described; the majority are in Kent and the remainder in East Sussex. The book follows th e established format of this ser i es, and has far more to offer the geographer than the geologist. The background informati on of each traverse shows the relationship of human or physical geography to th e local geology, The Ramsgate and Pegw ell Bay study is one of the few with an accompanying field sk e tch. The Folkestone Study of the cliff and scarp is the most valuable t o the geologist, although the Borden to Bearst ed traverse provides a useful summary of the the(. ri es of dry valley formation.

33

GEOLOGICAL CURATORS GROUP

Mike Jones, Secretary of the Geological Curators Group, explains the objectives and activi ties of a Group concerned both with the storage, cataloguing and use - by teachers and researchers - of geological specimens.

Geological collections whether of specimens, maps, archives or any other material are an important part of our scientific heritage, which in the British Isles is entrusted to a great variety of institutions. These include not only our great national museums but also several hundred local authority and many university and college museums. Important geological material also exists in a number of society and other private collections.

Unfortunately, the historical processes which brought this about did not always ensure that collections were endowed with financial and other support in proportion to their importance. In the local authority sphere in particular one finds that some of the finest collections are the responsibility of authorities that are unable or unwilling to maintain them satisfact­orily. This situation is compounded by the lack of any statutory req~irement for museum provision; consequently collections can be denied the facilities and care necessary for their preservation, or sold, or even used as hardcore for municipal roads ~ Fortunately few adopt this latter extreme, although many - for a variety of reasons - adopt a level of care which inevitably leads to a steady decline in the scientific and educational value of the material. In the last resort only public, scientific and educational opinion stands between the preservation or destruction of many of these irreplaceable collections.

The formation of the Geological Cu~tors' Group in 1974, and its subsequent affiliation to the Geological Society of London was to a large extent a reaction against the situation described above. The Group facilitates on the one hand, corporate representation regarding the future of geological collections and of geology in museums in this country, and on the other, liaison between those responsible for the curation and deployment of collections. Affiliation to the Geological Society will aid development of the essential scientific element in museum work, whilst a close relationship with the Museums' Association caters for professionally orientated interests of individual members of the Group.

We have always felt that the Group should cater not only for the curator a'nd museum technician, but also for the user of collections: researchers, teachers, students and amateur geologists. Regretab1y, the requirements of the user are in many museums of little consequence when decisions affecting collections are made, largely because of the vicious circle which exists between use and facilities. Inadequate facilities lead to low demand reSUlting in difficulty in justifying the improvement of facilities. Teachers, apprecia­tive of the enormous potential which museums have as education services could do much to remedy this situation. The A.T.G. and the Geological Curators Group could usefully coopera te on this iss ue •

The aim, already emphasised, of providing representation on the future of collections is

ot course only one aspect, albeit important, of the Group's activities. It also exists to further every aspect of geology within the museum context and has a correspondingly wide range of interests to meet this objective.

Of particular importance is the need to obtain up to date information on the collections which exists in the British Isles; consequently a comprehensive nationwide survey was launched in 1975. Over a thousand questionnaires were sent to every institution known or thought likely to have a collection of geological material. To date over 400 returns have been made. The fifty or so categories of information requested are being processed at the Ulster Museum, Belfast and will allow for the first time an evaluation of the scale, importance and condition of geological collections in the British Isles. If any readers know of collections not likely to have been included and wish to contribute to the survey, they should contact Mr. p. Doughty, Keeper of Geology, Ulster Museum., Botanic Gardens, Belfast BT9 5AB.

The Group has also been involved in preparing documentation standards for geological specimens as part of a national museum docu­mentation scheme. This scheme, organised by the Information Retrieval Group of the Museums Association (IRGMA) is intended to encourage standardisation of specimen records, and also provides for future computerisation of data.

Of particular relevance to the teaching profession is the proposed National Geological Site Recording Scheme. This being developed by the Group in close cooperation with the Nature Conservancy Council and with the advice of the Working Party on Field Facilities in Geological Education, and by liaison with a variety of other interested bodies. Records of geological sites are already maintained by many museums as a necessary aid to the management of collections and the provision of information and advisory services. The scheme proposes to co-ordinate and enlarge these efforts to ensure, as far as is practicable, a national coverage which will:

• standardise records sufficient to facilitate efficient information retrieval

• provide a nationwide information service on geological sites for both conservation and user purposes.

Such a scheme must involve the fullest possible consultation with all interested parties, and so many meetings and discussions have been held over the past 18 months. A report summarising the main recommendations will be published in July and will be made generally available for comment and criticism.

Plans for providing expert assistance to museums possessing important collections but lacking specialist staff have been prepared and negotiations for the finance necessary to implement this are also in progress. The

34

objectives behind this scheme are perhaps more difficult to achieve than any other so far attempted by the Group. It is not anticipated that there will be any major developments on this front until experience indicates the most effective procedures to adopt. However, it remains our most important long term objective.

information on exchange facilities. Inventories of type, figured and cited specimens in museums which have not otherwise been published are an important feature. Special issues, such as one concerned with site recording are also published from time to time.

Finally, in order to facilitate the exchange of ideas and to record and disseminate information, the Group has a varied programme of meetings, often arranged jointly with other bodies, and publishes a thrice yearly newsletter. This publication has assumed proportions more appropriate to a journal due to the volume of information forthcoming. Substantial articles, concerning important collections and collectors are the main feature of most issues, backed up by articles and reports on curatorial and technical matters, accounts of meetings and

With such a varied and wide ranging field of interest the Group has a substantial and ever increasing membership drawn from many walks of life. Overseas membership is also increasing steadily. The widening of horizons to which this diversity in membership inevitably leads is a welcome force within the Group and hopefully the teaching profession will make a significant contribution in this respect. Those interested in membership should contact Mike Jones, Secretary (GCG), Clo Earth Sciences Section, Leicestershire Museums, 96 New Walk, Leicester LEl 6TD.

Continued from page 45 Geology in-service courses in Avon

In addition to fieldwork, there ha's been a visit to see the educational facilities at . the National Museum of Wales, a seminar on crysta­llography and a workshop on teaching resource materials. It is hoped that such .courses not only help teachers to learn about local field­work sites and other facilities, but also promote liaison between teachers at different schools and colleges.

Apart from the provision for CSE and GCE geology teachers, there are meetings and courses for primary and lower secondary teachers. These are designed to help teachers with little or no knowledge of ·geology and serve to introduce the subject, as well as looking at teaching ideas and resource materials. A new development in

GEOLOGISTS' ASSOCIATION

this area is the encouragment of geology in environmental studies, particularly in first year secondary courses. This is linked to a new museum display on local geological history which is nearing completion. Apart from short courses for teachers, there will be support for this development by the provision of specimens, fossil casts, · transparencies and information sheets.

Further details or information about the Avon in-service training courses can be obtained from Andrew Mathieson, Assistant Organiser (Geology), Schools Department, City Museum & Art Gallery, Queens Road, Bristol, BS8 lRL.

The Association is publishing separately some of the major review papers which have appeared recently in the Proceedings. The following are at present available:

R. OXBURGH, 'The Plain Man's Guide to Plate Tectonics', ~. Geol. Ass., 1974, Vol.85, 299-357. Price 75p inc. postage & packing.

W.G. CHALONER & M.E. COLLINSON, 'An illustrated key to the commoner British Upper Carboniferous plant compression fossils' ~. Geol. Ass. 1975, Vol.86, 1-44, Price £1 inc. postage & packing.

D.V. AGER, 'The geological evolution of Europe', Proc.~. Ass. 1975, Vol. 86, 127-54. Price 75p inc. postage & packing.

S. MOORBATH, 'The geological significance of Early Precambrian rocks' Proc. ~. Assoc. 1975, Vol. 86, 259-279. Price 75p inc. postage & packing.

Available soon:

J.D. BELL 'The Tertiary intrusive complex of the Island of Skye'.

R.C. SELLEY, 'The habitat of North Sea oil and gas'.

Available from: Dr. P. Wa lla.ce Publications Secretary, Geologists' Association, Department of Geology, Imperial College, London SW7

Please mak e cheques payable to Dr. P. Wallace.

35 THE INTERPRETATION OF CRYSTALLIZATION AND VESICUIATION TEXTURES IN IGNEOUS ROCKS

by W. J. Phillips

A geologist regards a mineral as an inorganic substance which possesses two fundamental characteris tics.

1. A mineral possesses a characteristic chem ­ical composition which may vary within certain limits.

2. A mineral possesses an ordered arrangement of the atoms of which it is formed, and this results in the development of plane surfaces known as faces. If the mineral has been able to grow without interference, the faces may intersect to produce distinctive geometric forms known as crystals.

In contrast a melt such as a lava flow, is a liquid within which there is an almost com­pletely random arrangement of the atoms which are in continuous motion. When a melt cools it loses energy. As the energy of motion of its atoms decrease it is less easy for individual atoms to move abput and for the liquid to flow. The viscosity of a liquid is a measure of the resistance to flow, and clearly during cooling the viscosity increases . If the rate of cooling of a lava is relatively high, the viscosity may become so great that the liquid appears to be mechanically rigid at normal temperatures and over short periOds of time. The melt is then said to have consolidated as a glass and it can be regarded as a greatly cooled liquid with an extremely high viscosity. Rocks composed of glass (e.g. pitchstone) characteristically show conchoidal fractures.

While it is probably true that over a long period of time the atomic positions in a liquid are com­pletely random, at any instant some atoms may be arranged with regard to their neighbours exactly as they would be in a crystal structure. Thus the instantaneous structure of the liquid might be one in which some atoms form part of

Vein ca vi t y

Successive st ages of growth indicated by zones of inclusions

Layer of sphalerite ~ with galena (black)

Surface on which quart z nucleated

Vein wall

a crystal-like structure called a cluster, with some distance between it and neighbouring clusters as illustrated in two dimensions in figure 1. Due to the random translational move-ments of the atoms in the liquid these clusters of atoms disperse as easily as they form.

Fig.1 . The structure of a liquid.

• • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • . . .-.-. • • • • •• / I • • • .-.-.-. • • • • ./. • • I • ./ ... / • • • '. . . . • I / • • • '.-.-./ • .-.-. • • • • • cluster

• • • • • • • • •

However, if during the cooling of a melt some clusters continue to grow in size they are called nuclei from which crystal forms develop. In a melt the crys tals grow outwards from an approx­imately central nucleus and dis tinctive growth zones can be seen in some crystals in thin sections of igneous rocks. Macroscopic growth zones can be seen frequently in crystals which have nucleated on vein walls and grown into cavities, figure 2. The sides of the quartz crystals have been modified by the interference of adjacent crystals but the terminal faces of the crystals and the successive growth zones have well deve loped crystal forms because they were in contact with the aqueous solution which flowed along the vein and from which the crystals grew.

_-==-_===-_ cm

When an igneous rock texture is studied I an estimate of the number of nuclei that d~veloped in a unit volume of the melt may be obtained simply by plotting the approximate centres of the crys tals. Figure 3 is a photograph (magni­fication x2) of a piece of rock called a grano­diorite which has a coarse grained texture com­posed of interlocking crystals of quartz (vitreous Ius tre) I felds par (grey) and biotite (black). It can be seen that the granodiorite had fractured and the s pace is now filled by a light coloured I fine grained rock composed of intergrown crystals of quartz and feldspar. This rock is an aplite and it occupies a vein in the granodiorite.

Assume first of all that the minerals started to crystallize at approximately the same temper­ature and that the rates of crystallization were approximately constant. Figure 4 represents the approximate number of nuclei of crystals occurring in areas of equal size. It can be

£19 ~ a r----:-----:------:-"'!'1

Granodior ite

deduced from figure 4a that there was a relatively small number of nuclei per unit volume in the magma from which the granodiorite formed I so that generally the crystals did not come into contact and interfere with each others develop­ment until they were relatively large in size. Consequently I the coarse grained texture of too granodiorite was formed. In contrast the number of nuclei per unit volume of the aplite vein I figure 4b I was relatively large so that these crystals came into contact when they were relatively small in size I thus producing the fine grained equigranular texture.

Clearly it may be concluded that the different grain sizes of equigranular igneous rock textures de pends on the number of crys tal nuclei that formed in the melt. It is appropriate therefore to consider the results of experimental studies of the rates of formation of nuclei in melts.

Aplite

EXPERIMENTAL STUDIES OF THE RATES OF CRYSTAL NUCLEATION IN MELTS

When crystals of a pure substance are present within a melt of the same composition there is a temperature called the equilibrium temperature I

at which the crystals do not change in size either by further growth (crys tallization) or by melting. The crys tals are therefore in equilibrium with the melt.

Consider the cooling of a melt containing no crystals. When the temperature falls to the equilibrium temperature I the melt would be in equilibrium with its crystals if they existed I but no crystals will form at this particular temper­ature because no cha nge is possible under equil­ibrium conditions.

36

At any temperature below that of equilibri"um I

some crystals could form spontaneously in the melt. However I it can be demonstrated easily by experiment that melts may be cooled to temp­eratures well below the equilibrium temperature without the formation of crystals. This con-dition is called undercooling or supercooling I

and the amount of undercooling is indicated by the temperature difference measured below the equilibrium temperature. An undercooled melt is said to be metastable because crystals will grow immediately the process of crystallization has been initiated .

Why is it that an undercooled melt does not crys tallize spontaneous ly?

The explanation for the de layed s tart of crys tal growth in melts is that the stability of a crystal in a melt de pends on the curvature of the clus ter surface . A small cluster of atoms tends to form a spherical group at the surface of which the forces that may bind another atom to the cluster are relatively weak I figure Sa. If by chance a cluster becomes larger in size I its surface will become less convex. An atom coming in contact with the surface of a larger cluster will have a greater number of neighbours which provide bond­ing forces and so makes it less likely that the atom becomes detached from the cluster I figure Sb.

Above the equilibrium temperature the trans­lational energy of the atoms in the melt is so great that the clusters are constantly forming and dispersing. Below the equilibrium temp­erature the translational energy is sufficiently low that there is a chance that some atoms may become attached to a cluster and remain there. Consequently I a certain number of clusters may by chance attain a size much larger than the majority of clusters. If a cluster of atoms con­tinues to grow in size it is said to be a nucleus which will grow to form a crystal.

Fig:..-ll. TEMPERATURE

Equilibrium Tem~erature

I I I

Small amount + of undercooting

RATE OF NUCLEATION

+ : Release of latent heat

Granodiorite texture ....... L.....lo.J""-..DIlIU>........I.Q.:.......J

37

Fig:.2L 0 0

0 0 0

0 0

0 0 0

o 0

Fig:....2JL "'./bonds

0 ----=:7·~nds

o 0 0 0

0 0 0 0 0 0 0

0 0 0 0 0 0

0 0 0 0 0 0 0

0 0 0 0 0 0

Experimental studies of metallic and silicate melts show that if the temperature of the melt is lowered in order to obtain a small amount of undercooling I the number of nuclei which form is very small per unit volume. This is repre -sented graphically in figure 6a. Since the movement of the atoms is more restricted in the crystal structure I energy in the form of heat is released during crystallization. Crystallization is an exothermic process and the heat released is known as latent heat. A certain amount of undercooling is required in order to initiate nucleation but once crystal growth starts the temperature rises to the equilibrium temperature and crystal growth may slow down and stop. The continued growth of the crystals in a melt therefore requires the removal of heat by con­duction or radiation to the surroundings.

If only a small number of nuclei form per unit volume of the melt as represented by figure 6a I a coarse grained equigranular texture will de­velop . At a greater amount of undercooling the number of nuclei formed per unit volume is much greater and this is represented graphically in figure 6b. The reason that a greater number of nuclei form at lower temperatures is that there is a greater chance that clusters will develop to a critical size and so become nuclei.

TEMPERATURE

RATE OF NUCLEATION

+ I I I Release of I latent heat

I

Large number of nuclei

Aplite texture ~~~~~~~

Once nuclei form, crystallization will proceed as heat is lost to the surroundings until the melt is converted into a mass of interlocking crystals the size of which will depend on the number of nuclei formed per unit volume of the melt.

What can be deduced about the likely amount of undercooling that gave rise to the aplite vein in figure 3?

The relatively large number of crystals per unit volume indicates that a -relatively large number of nuclei formed and it can be deduced that the melt from which the aplite crystallized experi­enced a greater amount of undercooling than the melt from which the granodiorite crys tallized.

38

If the rate of cooling is extremely rapid there may not be sufficient time for clusters to grow into nuclei. This is due to the decrease in the motion of the atoms which is reflected by the very great increase in the viscosity, and so the melt con­solidates as a glass.

HOW LONG DOES IT TAKE FOR A SHEET INTRUSION TO CRYSTALLIZE?

Estimates of the rate of cooling of sheet like bodies of magma have been made by J. C. Jaeger (19S7). Jaeger assumed that cooling of the magma took place by conduction into the wall rocks which were originally at zero temperature. In the example which is considered here it is assumed that the magma was intruded at a liquid­us temperature of 10000C and that crystallization

o was completed at 800 C. The effect of the re-lease of the latent heat of crystallization, which is of the order of 100 calories per gram of melt, was taken in account.

The change in temperature with time for points at specified distances from the contact of the sheet were calculated. The results of the calculations are plotted graphically in figure 7a, as temper­ature/time curves. The numbers on the curves represent distances from the contact measured as fractions of the thickness of the sheet in­trusion (D) in metres. For example the top O.SD curve represents the rate of cooling at the centre of the sheet assuming that no liquid flow occurred after intrusion. The lower O. SD curve represents the change in temperature of the country rock at a distance from the contact equal to half the thickness of the sheet, and it can be seen that it is estimated that the temperature at o this point rises. slowly to about 400 C and then decreases at an even slower rate . At the contact of the sheet the magma cools rapidly to about 600

0C while the temperature of the country rock

rose rapidly to 6000

C and then cooled gradually. The time scale depends on the square of the thick­ness of the sheet. The curves are of particular interest because they provide estimates of the time taken for a sheet intrusion of specified thickness to crystallize.

How long would it take for layers of crystalline rock to form at the contact and extending one tenth of the thickness from the contact of a dyke with thickness D = 10 metres?

Study the temperature/time curve for the point O.lD in from the contact in figure 7a. At what time after intrUSion would crystallization cease assuming the final crystallization temperature to

o be 800 C? The curve AB represents the change in temperature from 10000C to 800

0C at a point

O.lD from the contac~ and the estimated time of reaching B is O.OOlD , so that if D = 10m, the outer layer equal to one tenth of the thickness will crys tallize in O. I years, about five weeks.

How long would it take for one half of the sheet to crys tallize ?

The rate of crystallization of a point O. 2SD from the contact is given by the line AC in figure 7a, and the estimated time of completion of crystall­ization up to a dis tarce O. 2 SD on each side of the sheet is O.OOSD ,which for D = 10m would be approximately O.S years.

How long would it take for a sheet 10m in thick­ness to crystallize completely?

The rate of crystallization of the centre of the sheet is represented by the line AE in figure 7a, and the estimated time of c0:r2Pletion of crystal­lization at 800

0C is 0.012SD , so if D = 10m

the es timated time of completion of crys tallization is l. 2 S years.

Figure 7b is a temperature/distance graph on which the curves represent temperature profiles at particular times after intrusion. The temper­ature profile after an outer layer of the dyke equal to one tenth of its t2ickness has crys tal­lized, is labelled O. OOID on figure 7b. The temperature profiles after one half, and the whole

sheet have c¥stallized are labelled O. 00SD2

and O. Ol2SD respectively in figure 7b. Clearly the rate of cooling would be greatest at the con­tact and smallest at the centre of the sheet.

What are the two reasons for the decrease in the rate of cooling within the sheet?

.E.ig "la Rates of a sheet intrusion (after Jaeglli

CO 1000-A~0

.OO-l~-,·~l.l·2.

600- (-1--:·~11 O§i~~~lii~~~::J 400- ~. -/ ·3

200- --- ·50

I

1. As the temperature of the country rocks rises and the melt cools, the temperature gradient decreases as illustrated in figure 7b. , and this results in a decrease in the rate of heat lost by conduction.

2. Since the crystallization process is exo­thermic, the release of latent heat also reduces the rate of cooling towards the centre of the sheet.

39

In a relatively thin sheet intrUSion in contact with cold country rocks, what would be the likely ef­fects of the varying rates of cooling at different dis tances from the contact?

1i\-U-J-*-'--L-I.--w....L.JjItl:-:':~T~':-'::~--L-I.....LJ..~~J.....L-'-'-'-"-'·'04 0' Very rapid cooling of the magma at the contact

600-

400-

200-

0- .50 .40 Centre Contact

DISTANCE Country rocks

may result in its consolidation as a glass because there would be insufficient time for nuclei to form. Some distance from the contact the rate of cool­ing may have decreased sufficiently so that many nuclei formed and developed a fine grained tex­ture. Towards the centre of the sheet the still lower rate of cooling may be accompanied by the formation of fewer nuclei per unit volume and hence a slightly coarser texture. However, tex­tural variation will depend on the thickness of the. sheet so that very thin sheets may consolidate entirely as glass. The absence of glass or fine grained rocks at the margin of an intrusion would indicate that rapid cooling did not occur.

What is the most likely explanation for the lack of rapid cooling at the margin of an intrusion?

It is likely that the country rocks were at a re­latively high temperature so that rates of cooling and hence rates of nucleation were relatively low, thus allowing the development of coarse grained textures at the margins of deep seated intrusions.

PORPHYRITIC TEXTURE

Figure 8 is a photograph (mag. X 2) of a rock com­posed of large well developed crystals of feldspar and biotite embedded in a mass of tiny crystals. The large crys tals are called phenocrys ts and the mass of smaller crystals is called the ground mass . Rocks of this kind are said to have a porphyritic texture. This particular rock is called a por-phyrite and it is similar in chemical and mineral­ogical corn position to the granodiorite.

How did the porphyritic texture form and what is the explanation for the well developed shapes of the phenocrys ts ?

The small number of phenocrysts per unit volume indicates that these crystals grew from a small number of nuclei, and therefore it can be inferred that they developed as the result of a small amount of undercooling. After nuclea tion the tern pera­ture probably increased to the value of the equil­ibrium temperature and the growth of the pheno­crysts continued as heat was lost from the melt into the surroundings. The well developed forms of the phenocrysts indicates that crystal growth occurred in a melt without interference from adjacent crystals.

The fine grained 'ground mass indicates that after a period of growth of the phenocrysts a large

40

number of nuclei formed per unit volume, and this is diagnos tic of a relatively large amount of under­cooling. Since the rate of transfer of heat from the melt to its surroundings will decrease as the temperature of the surroundings increases, it can

be inferred that the reason for the high rate of nucleation was that the melt containing the pheno­crysts moved into a new low temperature environ­ment where the rate of heat loss and amount of undercooling increased. This situation would arise if the partly crystallized melt flowed up to fill a fracture in colder rocks and so consolidate as a dyke or sill, or if the melt flowed onto the surface, as a lava flow. Thus porphyritic tex­tures are common in lavas and in dyke rocks.

POIKILITIC AND PORPHYRITIC TEXTURES IN LARGE INTRUSIONS

In the preceding discussion it was assumed that the different minerals had similar equilibrium temperatures and rates of nucleation. In reality the different minerals forming an igneous rock are likely to have different equilibrium temper­atures.

Consider the crystallization of a gabbro composed of augite and plagioclase crystals. A common texture in gabbro, illustrated in figure 9a, con-s is ts of rela ti vely numerous la ths of plagioclase (white) many of which are enclosed by less numer­ous larger irregular crystals of augite (lined). The term poikilitic texture is used to describe the enclosure of randomly oriented crystals in a large crys tal, and the particular kind cons idered here is sometimes also called an ophitic texture. An

9b

estimate of the relative abundance and distribu­tion of nuclei in two dimensions may be obtained by plotting the approximate centres of the crystals as in figure 9b. This distribution of nuclei may be interpreted as a result of the different number of nuclei of the two minerals that formed at a particular amount of undercooling as illustrated in figure 9c.

Porphyritic textures composed of very large ortho­clase phenocrysts in a coarse grained granite cannot be explained by two rates of undercooling and nucleation. It is more likely that due to the abundance of the components of orthoclase in the magma, nucleation and growth of this feldspar occurred long before the other minerals began to grow.

Poikilitic texture Dis tribut ion of nuclei

Temperature of nucleation

()

•

Nucleation rate of Plagioclase

Q

'" Plagioclase

Augite

"

" <>

• " ~

~

•

Nucleation of

VESICULATION

Lavas frequently contain cavities known as ves­icles which were produced by the separation and expansion of small bubbles of gas consisting largely of steam but also containing CO

2, HCI,

NaCI and H2S. Subsequently crystalllzation on

the margins of the vesicles and crystal growth in­wards may have produced globular masses known as amygdules and the rock is then said to be amygdaloidal.

Dalton's law of partial pressures states that at constant temperature the total pressure exerted by a mixture of gases in a definite volume is equal to the sum of the individual pressures which each gas would exert if it occupied the same total volume alone. The solubility of each volatile component in a magma of certain com­position and at a particular temperature, depends es·sentially on the partial pressure of the volatile component. However, it will be sufficient here to regard the vapour pressure of the volatile com­ponents as the total pressure of the volatile com-ponents. At depth it can be assumed that the load pressure exceeds the vapour pressure and that the magma is undersaturated in the volatile components. This is illustrated graphically in figure 10 which should be read from the bottom upwards in the direction of the ascending magma. If the magma rises at constant temperature to shallower depths the load pressure decreases and eventually it will be less than the vapour pres­sure of the volatile components. Under these conditions the magma is now supersaturated in the volatile components and bubbles of a gaseous phase may separate in the magma.

The kinetics of nucleation of gas bubbles are very similar to the kinetics of crystal nucleation which have been considered above, but the supersatur­ation of the volatile components at cons"tant temp­erature depends on the pressure.

Fig. 10 - --

A liquid is always attempting to attain its lowest energy state by reducing its surface area, while in contrast the higher energy gaseous phase al­ways fills the container that is available. Thus when a gas phase separates in a magma, the gas is confined to spherical bubbles and there is an excess pressure inside the bubble even at equil­ibrium with the liquid in order to support the spherical interface. The excess pressure (p) inside a gas bubble is given by the relationship

2s p

r

where s is the surface tension and r is the radius of the bubble.

It can be assumed that the surface tension (s) be­tween the silicate liquid and the gas in the bubble has a constant value. Consequently the forma­tion of a bubble nucleus with a very small radius requires a very high excess pressure. Once the bubble has formed volatile components diffuse in­to the bubble so the radius increases and the excess pressure (p) decreases to an equilibrium value, figure 10. The high excess pressure re­quired for bubble nucleation is analogous to the undercooling required for crys tal nucleation, and the reduction of the excess vapour pressure to an equilibrium value after bubble nucleation is anal­ogous to the release of latent heat after crystal nucleation and growth until the equilibrium temp­erature is approached.

What effect will the nucleation and growth of bubbles have on the temperature of the vesicul­ated magma?

r- +~ ~ Glass ~ "( ~ shards ~ ..... .t..

DEPTHO~r-____ P_R_E_S_S_U_R_E ________________ _ km

2

3

l,

5

pressure in gas bubbles

""E:----, Excess vapour pressure

" " " " " , "

" ,

required for bubble nucleation

',Load pressure '~ depth x densit y x g ,

" Vapour pressure of volatile components in magma

1 _ Magma

Whereas the change from the liquid phase to a lower energy crystal phase is an exothermic pro­cess releasing latent heat, the separation of a higher energy gaseous phase is an endothermic process because energy is required :

1. to form the liquid/gas interface 2. to provide the increased translational

energy of the atoms in the gas phase, and

3. to allow the growth and expansion of the gas bubbles until the excess vapour pressure has reduced to the equilibrium value.

Vesiculation produces a significant increase in volume and consequently it frequently results in the extrusion of the vesiculated magma as lava fountains (Phillips, 1971) or high temperature foams which give rise to the nulle ardente.

DIARY - continued £rom page 59

S333 Earth Science Topics and Methods

10 Landslips 0730 Thurs 1 July2 1240 Sun 4 July

11 Tunnelling 1240 Sun 18 July 1240 Sat 24 July Techniques

12 Porphyry Copper 1355 Sat 7 Aug 1240 Sun 8 Aug Deposits

13 Mining in 1355 Sat 21 June 1240 Sun 22 Aug Cornwall

14 Cratering on 1240 Sun 5 Sept 1700 Thurs 9 Sept the Moon

15 Geologist on 1240 Sun 19 Sept 1700 Thurs 23 Se pt the Moon

16 Methods for 1240 Sun 3 Oct 1700 Thurs 7 Oct Mars

42 Since vesiculation is an effective means of cool­ing a crystal free magma' it commonly results in the consolidation of the silicate liquid as a glass thus forming the extremely low density pumice or the glass shards characteristic of disintegrated vesiculated lava.

References

Jaeger, J.G. 1975. The temperature in the neighbourhood of a cooling sheet. Amer. J. Sci. v. 255. p. 306-318.

Phillips, W.J. 1971. Dynamic models of oceanic volcanic activity. Geology. v. 3, p. 15-40.

YHA. GEOLOGY CLUB

Field trips £or the remainder o£ 1976

July 17-21 Ludlow, Shropshire

September 17-19 Ox£ord

October 15-17 Linton, Yorks Dales

November 5-7 Eyam, Derbyshire

Dec 31- Jan 2 AGM, Boggle Hole , Yorks

See page 44 £or details o£ the YHA. Geology Club

THE CITY OF LIVERPOOL COLLEGE OF HIGHER EDUCATION

GEOLOGY Courses in BA Honours BA General BEd Honours BEd Ordinary

The planned BA Honours degree in Environmental Sciences o££ers GEOLOGY and PHYSICAL GEOGRAPHY as one o£ the major options £or second and third year.

Common £irst year £or all degree programmes.

Geology may be studied with two o£ a wide range o£ subjects, including: Environmental Science, Physical Education, Geography, Biology, Art, Music, Sociology, Psychology.

Further details £rom: J D Crossley, Geology Dept The City o£ Liverpool College o£ Higher Education The Hazels, Prescot, Merseyside, 134 1NP

Note: We shall continue to recrui t un-: i~ 1~lid­Octo!::>er

NEWS REGIONAL ROUND - UP

Over the last few years, local groups of geology teachers have been formed in several areas of the country. They take a variety of forms, and the following is a summary of only some of their activities.

KEELE SCIENCE AND TECHNOLOGY CENTRE, GEOLOGY GROUP.

Organiser: D.E. Thompson, Institute of Education, University of Kee1e, Kee1e, North Staffs.

The centre arranges meetings on a local and regional basis; local meetings (nominally for teachers within 40 km) include updating lectures (such as 'Bunter Pebble Beds' and 'Physical Properties of Seismic Waves'), sessions on resources (such as 'Geophysics and geotectonics') and discussions on examinations. On a regional basis, for teachers within 80 km, sessions in the form of in-service courses are organised, such as one-day meetings on 'Plate Tectonics' and 'Sedimento10gy', together with field courses to a variety of areas, specifically designed to aid teachers to teach in the field.

SUSSEX AND SURREY GEOLOGY TEACHERS

Organiser: K.M. Harvey, Farnham College, Morley Road, Farnham, Surrey GU9 8LU

A pair of groups that work together, the Sussex and Sur rey Teachers have held a swop session, a trip to Bogner to examine the London Clay, and a demonstration of acetate peels, fossil casting and embedding. New members would be very welcome, as this is a new venture; ATG members seem very scattered in this area, so many may not have heard of the groups. Please get in touch.

THE GIDLOGY TEACH ERS OF MERSEYS!DE AND or STRICT

Secretary: J.D. Cross1ey, City of Liverpool College of Higher Education, Liverpool Road, Prescot, Merseyside L34 1NP

This group, with support from the University of Liverpool as well as C.F. Mott College, holds courses such as 'Rock Textures', and is engaged in building up a list of fieldwork for the Merseyside area. They are also building up resources and exchanging specimens, and intend to involve themselves in a whole variety of curriculum development and co-operation. Use of college facilities to prepare specimens is also made possible through the group.

WALSALL GEOLOGY TEACHERS' WORKING PARTY

Secretary: N.W. Dutton, Darlaston Comprehensive School, Herberts Park Road, Wednesbury, West Midlands, WSlO 8QJ

This group meets three times a term in the Walsall Education Development Centre or in schools. A guide to field studies in the area was published last year, and an improved second edition is planned for next year. The group has held a lecture for pupils, when Emlyn Evans of the

National Museum of Wales spoke on 'Minerals'. It has liaised wit~ Aston University, and is engaged in improving resources at the E.D.C. for geology and has campaigned against the West Midlands County Council in an effort to preserve a local quarry (unsuccessfully - but some 10ng­term concessions at the site may be possible). A survey of the status of the subject in Wa1sal1 schools is carried out each Autumn - a growth of 8.7% in pupils taking Geology courses was recorded between September 1974 and September 1975.

STOCKPORT GIDLOGY TEACHERS ASSOCIATION

Treasurer: J.E. Sidde11ey, Stockport School, Mile End Lane, Stockport SK2 7AF (Tel. 061-483-3622)

The Sixth Form Conference held by the Association was mentioned in 1h e April issue of 'GIDLOGY teaching'; the group meets every six weeks at Pend1ebury Hall Teachers Centre, and has strong support from Manchester University. A variety of meetings to update teachers are held, and the group is at present surveying the local position of the subject in schools. Attempts have been made to bring pressure to bear in order to improve the position of the subject, but lack of money is, as usual, the restricting factor.

SANDWELL GEOLOGY TEACHmS GROUP

Secretary: G.A. Hardwick, Rowley Sixth Form College, Hawes Lane, Row1ey Regis, Sandwe11, West Midlands.

The Sandwe11 group meets once or twice per term, and has acted mainly as a stimulus to the sharing of resources and ideas. For example, schools have circulated guides to field sites, and lists of material that are available on loan have been produced. The group is particularly concerned with helping schools just beginning to teach Geology. Meetings are held at West Bromwich or Warley Teachers Centres, and often are combined with meetings of the Geography panel. One plan for the future is to arrange a joint field excursion to help schools with small groups. The secretary would be glad to hear from anyone in the area with ideas and enthusiasm.

SHEFFIELD GEOLOGY TEACHERS GROUP

Convener: Dr. F. Spode, Dept. of Geography and Environmental Studies, Sheffield City Polytechnic, Tot1ey, Sheffield, S17 4AB

The survey of field localities mentioned in the last 'Round-up' is well under way, and a watch is also being kept on sites involved in land­scaping by the City Engineers, with a view to conserving exposures. Two field meetings have been organised, at Parkwood Springs on May 26 and at Upper Fulwood on June 28. In addition, Mr. B. Stevens is keeping the group informed about the development of Science syllabuses containing a geological element, in his capacity as Science Adviser. The group meets about twice a term, at the Melbourne House Teachers Centre.

43

HERTFORDSHIRE GEOLOGY TEACHERS GROUP

Chairman: Mrs. P.A. Wi1son, Kings Lang1ey Comprehensive School, Love Lane, Kings Lang1ey, WD4 9AN

WANTED in Nottingham area!

Tim Co1man of Forest Hills College, Car1ton Rd., Nottingham is keen to establish a local geology teachers group, and would like to hear from other teachers in the area who would like to participate in the kind of activities described above in the reports from othe r ATG groups.

LOCAL ADVISERS

As well as local groups, various LEAs have advisers, or inspectors for Geology; in Mid Glamorgan, Mr. T.G.L. Hopkins, the Geography adviser, has organised courses for Geology teachers in the area, and in Lincolnshire the responsibility is shared by the Social Science adviser, Mrs. L. Brabben, the Environmental Education Adviser, Mr. D. Ge1icher and Mr. S. Warmeth who is Science Adviser. We would be interested to hear from any areas where courses etc. are held, even if there is as yet no formal Group.

Information about all Group meetings, both reports after the event and advance notices, would be very welcome for future editions. Send to: P.S. Whitehead, 15 Daisy Bank Cresc., Wa1sa11, West Midlands, WS5 3BH.

In addition to the above, two further groups a re active.

THE BIRMINGHAM GEOLOGICAL ASSOCIATION FOR SCHooLTEACHmS

44

Secretary: J.L. Robertson, Golden Hillock Comprehensive School, Golden Hillock, Road, Sparkhi11, Birmingham B11 2QG

NORTHmST GEOLOGY TEACHERS ASSOCIATION

Secretary: K.M. A11ett, King Edward VI High School, Cottingwood Lane, Morpeth, Northumberland, NE61 1DN

Regional Round-up would be glad to hear from these groups.

YHA Geology Club

The YHA Geology Club was started nearly two years ago. Its policy is to organise field trips at the lowest possible price, based on Youth Hostels, and including travel arrangements (including using group fare schemes on British Rail). The Club have already run trips to Shropshire, the Yorkshire Wo1ds, L1andovery, Devon and Derbyshire. Members are of all ages and sexes, but most are in the 11-18 age range, and have a common interest in geology and hostelling. The current annual subscription is 90p, which includes the cost of four newsletters a year, and the chance to join weekend and longer trips, and purchase geological equipment. ATG members might wish to encourage their pupils who are YHA members to obtain further information from Chris Darmon, 49 Studfie1d Road, Sheffield S6 4ST. See page 42 for future events

OTHER NEWS GEOLOGY CURRICULUM DEVELOPMENT PROPOSALS GO

THROUGH SCHOOLS COUNCIL MILL

One of the principle recommendations of the Schools Council's Geology Curriculum Review Working Group (SCGCRWG) was that there should be investment in the development of new curriculum materials. The Report of the Group is to be published by the Schools Council as Working Paper 58 late this year or early next. It recommends a major development aimed at the 14-16+ age range, with some further geological materials allied to the Science 5-13 project. The Group, prior to its disbanding last year, delegated the task of preparing a 14-16+ proposal to five of its members. In the event, an individual submission to the Council has now superceded the 5-13 proposal. Both these curriculum development proposals are described below.

Geological aspects of the environment for 8-13 age range

This proposal pre ceded the Report of the SCGRWG and has been devised by Geoffrey Brown of University College, Aberystwyth. Although it does not concur with their recommendation that the needs of the younger pupil would best be served by designing additional materials to be attached to the end of Science 5-13, it is not in conflict with this view. For the approach to the learning process and to the "Objectives in Mind" would follow Science 5-13 closely. However, the development in this field is so unique and important that it needs to be able

to develop its own phi10sopby and its own working strategies, free from the constraints which may be imposed by any existing structure. As members of ATG's Primary Group are fully aware, there is a growing recognition by teachers in primary schools of the value and the need to include geological knowledge as part of their environmental work and geological topics in the form of projects are appearing in increasing number and variety. Although these developments are very encouraging, it must be said that the level of geological content and the standard of work does vary widely. This is hardly surprising, for to find a teacher of this age group who has a geological background and who is confident in handling the material, is a rare event. In consequence, incorrect concept formation and dubious facts are often communic­ated to pupils, which can only be regretted. For example, the size of the popular Dinosaurs can, as a collective group, vary from 'as big as mountains' to 'as big as this classroom' and they are frequently associated with prehistoric man; scratches and irregularities on stone are mistaken for fossils and labelled 'Ammonite'; while 'Flint' recurs as a convenient name for smooth pebbles. Perhaps even more significant is the fact that many teachers include geology unwittingly in their environmental studies or fail to recognise and to develop their local potential. In other words, this growing interest and enthusiasm for geology on the part of primary teachers deserves encouragement but it must be guided along correct geological lines.

THE ASSOCIATION OF TEACHERS OF GEOLOGY

COURSE AND CONFERENCE LEEDS 1976

III

TIME TABLE

FRIDA Y lOth SEPTEMBER

16.00

18.00

18.45

20.00

21.15

21.30

Registration opens

Sherry reception

Dinner

Charles Morris Hall

Charles Morris Hall

Lecture, Dr EH Francis (Assistant director IGS, Leeds) '''Geol survey" to "IGS'" Rupert Beckett Lecture Theatre, Arts Block

Introduction to Demonstration J

Demonstration of combined slide projector -microfiche reader - polarising microscope

SATURDAY 11th SEPTEMBER

08.00

09.00

10.15

11.30

12.45

13.50

18.00+

18.45

20.00

Breakfast

Earth Sciences buildin~ (as map) Lab. Session I films e c.

Lab. Session IT

Lab. Session ITI

Lunch

Excursions -

Coaches Return

Earth Sciences building Primary group; discussion, introduced by CHR Halfyard; and review of exhibition material

11.15 General demonstrations and films Classroom C

Coaches depart from front of Henry Price Bldg

Dinner Charles Morris Hall

Lecture, Professor MR House (University of Hull), 'Life and death of ammonites' Rupert Beckett Lecture Theatre, Arts Block

SUNDAY 12th SEPTEMBER

08.00 Breakfast

1) 09.00 Primary Group Discussion, introduced by D. B. Hardman

2) 09.00

10.15

11.00

11.15

11.45

13.00

Teaching Lab 1

'Examining and examination syllabuses in geology for GCE' by RJ Whittaker (JMB, Manchester), and discussion; chairman, Professor EK Walton

R.B .L. T. Arts Block

Open forum: chairman Dr WJ Phillips, President-elect R.B.L. T. Arts Block

Coffee

Ninth Annual General Meeting R.B.L. T. Arts Block

Presidential address by the retiring President - Professor DV Ager "The teaching of Palaeontology" R.B.L. T. Arts Block

Lunch Charles Morris Hall

Conference ends

THE ASSOCIATION OF TEACHERS OF GEOLOGY

President

Professor DV Ager

Secretary

A1un J Thomas

Treasurer

J Myers

IV

Dept of geology and oceanography University College Singleton park

National Museum of Wales Cardiff CF1 3NP

148 Hempstal1s lane Newcastle-under-Lyme ST59NR

Swansea SA2 8PP

NINTH ANNUAL GENERAL MEETING

To be held at 11.15 on Sunday 12 September 1976 in the Rupert Beckett lecture theatre, university of Leeds -

AGENDA

1. Apologies for absence

2. Minutes of Extraordinary General Meeting (13.9.75 Swansea)

3. Minutes of Eighth Annual General Meeting (13.9.75 Swansea)

4. Matters arising

5. Treasurer's report

6. Secretary's report

7. Editor's report

8. Nominations to Council 1976-77

Officers

President 1976-78 President-Elect Retiring President Secretary 1976-79 Asst. Secretary Treasurer Asst. Treasurer Editor A sst. Editor

Dr. W. J. Phillips Prof. E. K. Walton Prof. D. V. Ager D.S. Scott Dr. J.D. Weaver J. Myers PW Williams Dr. R.C.L. Wilson DB Thompson

Ordinary Members

L.J. Allchin 1974···77 R. Bradshaw C • R. S tevenson Ms J Pugh 1975-78 T. Shipp H.M. Wailer DB Hardman1976-79 P Kennetl PS Whitehead

(retiring members - AJ Thomas secretary; JC Cummings, VR Paling, F Spode)

9. any other business

It was with this need in mind that this preposal was placed befere the Scheels Ceuncil fer censideratien, initially in the Spring ef 1975. The aim is to. preduce sets ef teaching packages er werk kits en basic geelegical themes, which can be used by teachers within the centext ef their lecal envirenmental studies. It is envisaged that groups ef class teachers situated in centrasting envirenments (urban as well as rural) sheuld werk clesely with geelegical 'experts', and preduce teaching materials en a variety ef such themes. These Wo.uld be so. designed as to. be subsequently adaptable fer use by teachers in general, pro.viding info.rmatio.n and guidance o.n co.ntent and metho.d.

Such a teaching package Wo.uld include, teaching no.tes o.n · content, explanatio.n o.f geo.lo.gical co.ncepts, identificatio.n ef links with other subjects, wo.rksheets, o.verhead transparencies, display material, no.tes en experiments and field exercises, sets o.f specimens, etc.

As a result o.f this wo.rk it is ho.ped that the participating teachers Wo.uld acquire a wo.rking knewledge and the necessary skills required to. use the materials co.rrectly and effectively. Fundamental to. the develo.pment o.f this pro.ject, Wo.uld be a precess ef self-generatio.n in which design teams Wo.uld be given the resPo.nsibility ef pro.mo.ting these packages to. teachers in o.ther lo.calities, thus leading to. further lo.cal develepment and resulting in supper.t materials grewing in number and variety.

The preposal has successfully nego.tiated Scho.o.ls Council's initial 'screening pro.cedure', and if successful as a 'Ro.und 2' prepo.sal, wo.rk sho.uld begin at Aberystwyth in January 1977. The pro.ject will pro.vide a seund geelegical feund­atien fer yeunger pupils and previde a stimulus fer the subjects develepment as envisaged in the 14-16+ preject described belew.

Geological curriculum development for the 14-16+ age range

This prepesal is being prepared by Vin Davis, David Thempsen, Stephen Hannath, Pat Wilson and Chris Wilsen as a fellew-up to. the SCGCRWG's activities. The main purpese ef this preject will be to. begin to. put into. effect the recemmendatiens o.f the SCGCRWG cencerning beth the preductien ef new teaching materials in geolo.gy, and the need to. re-o.rientate existing geelegy syllabuses tewards an experimental science appreach, rather than a descriptive appro.ach to. the subject.

The 14-16+ materials will net enly be suitable fer GCE '0' Level, and CSE ceurses, but also. fer use by pupils starting geelegy in the sixth ferm (as an additio.nal '0' level, er in the future as an 'N' subject), er studying geelegy as part ef a nen-examinable general science ceurse. The pessibility ef cellaberating with an Examination Bo.ard to. preduce a cemmen '0' level/CSE exam fer the preject materials will be investigated. Additienally, seme ef the co.urse medules (such as Earth Physics) will be ef use to. pupils taking ether science subjects.

The preject materials will be greuped into. medules, the study time ef which will vary between feur weeks and ene term. Each mo.dule will centain cere materials, with eptienal extra materials fer the mere able pupils.

45

Apprepriate specimens and apparatus will be previded o.r specified, as will assessment materials in erder to. influence examinatio.n beard practices in the future. The nature o.f the medules is still being debated. They ceuld be 'tepic-based', with themes such as 'Matter, Minerals and Reeks', 'Physics ef the Earth', 'Geo.lo.gy o.f Natural Disasters'; er alternatively 'Cencepts' ceuld previde themes I;uch as 'Matter', 'Energy', 'Interactien and Change', 'Life' and 'Time'. A suggestien was made at a recent meeting ef the Scheels Ceuncil's Science Cemmittee that beth appreaches be tried and evaluated as part ef the preject's wo.rk.

Efferts will be made to. premete the pro.ject amo.ngst teachers during its productien phase in erder to. aveid the difficulties experienced by ether Curriculum Develepment prejects in gaining acceptance by the prefessio.n. Indeed, preductio.n o.f each course medule will be under­taken by a greup ef teachers, an academic adviser, and supervised locally by a 'Medule Directer'. The geegraphical lecatien and membership ef these 'Mo.dule Teams' will be representative of the variety o.f epportuni ties (and difficulties) fer teaching geelegy in different parts ef the ceuntry. Cellaberation with lecal teachers greups and museums with scheel geelegy services will be established. The preductien phase ef the preject will be preceded by a survey ef teachers, beth to. identify their needs fer new curriculum materials in geelegy, and to. identify possible members ef the Medule Teams.

The preposal is currently at the 'Reund I' stage ef censideratien by the Scheels Ceuncil, and ceuld begin eperatiens early in 1977 if all the hurdles are successfully negetiated! If these prepesals de ceme to. fruitien, scheel level geelegy will receive a majer 'shet in the arm' -a geal that many have been working tewards fer the last few years - spurred en by the enthusiasm ef geelegy teachers who. have already intreduced the subject into. scheel curricular by a blend ef passien, skill and even cunning!

GEOLOGY IN-SERVICE COURSES IN AVON

A series ef in-service ceurses are erganised fer Aven geelegy teachers by the Scheels Department ef Bristel Museum under the directien er the L.E.A. humanities adviser.

There are ever 50 scheels and celleges in Aven where CSE er GCE geelegy is taught. Currently there are feur day er half-day in-service sessiens each term fer these geelegy teachers. The majerity ef the meetings are arranged in scheel time, but seme are at half-terms er are after scheel. Most ceurses are fieldtrips to. lecal geelegical sites, and whever pessible these are led by teachers who. have used them. Thus, field teaching techniques can be discussed as well as examining the geelegy ef the lecalities. Two. ceurses have been based en the L.E.A. field studies centre in the Ferest ef Dean and have been jeintly erganized with the help ef the warden ef the centre. Duplicated infermatio.n abeut sites visited is circulated to. all teachers who. cannet attend meetings.

Continued on page 34

SHOPFLOOR AN EXPERIMENTAL SIMULATION OF THE FORMATION OF SIMPLE IGNEOUS TEXTURES

Peter Whiteheadkdescribes the use of salol (phenyl salicylate) to demonstrate crystallization from magmas. The method can be used to show how grain size depends on degree of supercooling, and may be used as a projected demonstration, or as a class experiment. The technique is a modification of that described by Mee ~ (1971).

Equipment

To demonstrate the crystallization, a projection microscope is needed (I borrow one from the Biology Department). The following items are also necessary: several slides, a test tube, a teat pipette, a glass beaker, a supply of very hot water, a small electric fan and a refrigerator (science department or home economics) or plenty of ice in a thermos flask. The salol is sold by BDH Chemicals Foo1e, Dorset, at about £3 for 250 g.

Method

Well in advance of the demonstration or class experiment, put most of the slides in the r~frigerator to cool. If the lesson is being held a long way from the refrigerator, the slides can be carried in a thermos flask, or a small expanded polystyrene box, preferably surrounded by crushed ice.

The salol should be melted in a water-bath. Either heat the test-tube of salol in a beaker of water over a bunsen burner or (if no gas is available) take very hot water into the lesson in a flask.

The projection microscope should be set up with the fan aimed at the space between the lamp and the stage in order to carry away the hot air before it can affect the temperature of the slides. When ready to start the experiment, take out half of the slides from the refrigerator or cold box.

A room-temperature slide should be put on the stage of the microscope, and, using a low-power objective (about 4x) the microscope should be focussed. Using the teat pipette, take a drop of liquid salol from the test-tube, and after allowing it to cool for a few seconds in the pipette, put it onto the slide. Crystallization should begin within a few seconds, and will be complete within about half a minute.

Replace the slide with one which was taken out of the cold box at the beginning of the demonstration. Repeating the experiment will produce a 'rock' with finer grains. Finally, take a slide straight from the refrigerator or cold box, and repeat again. This will give a very fine texture.

As the melting point of salol is only 43 0 C, pupils can safely use it to carry out the experiment for themselves. However, the heat from a microscope lamp is likely to affect the cooling (the slide warms up so rapidly that crystallization often will not take place without seeding), so it is best if they observe the process either with the naked eye or by means of a hand-lens, but the resultant 'rocks' can be examined under microscopes. However, if a projecting microscope is available, it is well worth using it, as the growth of the crystals is most spectacular.

Whether done as a class experiment or as a demonstration, most of the salol can, with care, be recovered.

Theory

An outline of the theory of grain size/supercooling relations is given by John Phi11ips in this issue of GBJLOGY teaching ', and in an Open Universi ty text (523- Course Team, 1971).

It should be noted that all salol 'rocks' are, of course, monominera1ic.

Ref e rences '

MEE, A.J.~. (1971) Science for the Seventies - Book 1 Teachers' Guide. Heinemann. 208 pp.

523- COURSE TEAM (1971) Geology: Block 1, Earth Materials. Open University Press, 83 pp.

* Blue Coat Church of England Comprehensive School, Birmingham Street, Wa1sa11, West Midlands.

Cover picture

Results of Salol experiment: upper picture shows coarse texture produced by slow cooling at room temperature; lower picture shows the effect of rapid cooling on a co1der slide. In both cases, the salol was photographed between two slides as a thin film to avoid depth of focus problems. The radial pattern, is due to elongate air bubbles included during the growth of the crystals.

46

47

CRYSTAL MODELS

W.M. Herbert describes methods for preparing crystal models for class and demonstration use.

DOING IS UNDERSTANDING

The principle that 'Doing is understanding' cannot always be followed in the teaching of geology. Some concepts must, unfortunately, be accepted as an act of faith by oUr pupils - very few of us can spare the time, money or courage to arrange personal experience of, say, volcanic eruptions or earthquakes. We partly compensate for this by introducing as much 'real' geology as we can into the classroom in the form of specimens, and few would deny that a proper understanding of rocks, minerals and fossils cannot be attained without personal handling and close observation of the objects in question.

There is nowhere more true than in the study of crystals. No amount of listening to a sermon on axes of symmetry can . equal in value the experience of holding a crystal and rotating it between finger and thumb to count for oneself the repetitions of a particular aspect; no two­dimensional drawing can test a pupil's knowledge of forms as well as an actual crystal (which has a back as well as a front:).

The problem, of course, is the availability of specimens. No doubt we all have our own prize items in our school collections, but rarely will we have sufficient numbers of the same crystal­type to equip a class, and real crystals have the annoying habit (sic) of not looking exactly like the book says they should - an important defect when one is teaching basic principles. The need is for class-sets of crystal models, augmented by larger demonstration models, and the purpose of this article is to suggest how these may be made cheaply by the teacher or, if the lesson time can be spared, by the pupils themselves.

Handling Models

Those of us who teach in Wales enjoy the excellent loan facilities offered by the Schools Service of the National Museum of Wales. In the present context, their sets of crystal models are of great value, but two drawbacks exist . Firstly, the sets contain only one specimen of each model, and secondly, the demand for the sets is 50 great that one cannot always depend upon having one at the right time, that is, when lessons in crystallography would be most appropriate in one's planned course. The solut­ion which I have adopted is to make my own crystal models in unlimited numbers by casting them in plaster.

The mould

Permission having been obtained from the Museum's Schools Service Officer in Geology (who happens to be the ATG Secretary:), the hard plastic models in the loan sets were used to make moulds out of Vinamo1d. This product is probably known to most of our members by now, but, for those who have not yet met it, Vinamo1d is a rubbery substance which can be melted by shredding it into a container which is then placed over a low heat. An old saucepan over a gas ring has served this purpose for me, but it should be

pointed out that this process is somewhat anti­social, since the smell is unpleasant - as even one's best friends are quick to point out.

The original model is fastened with double­sided Se110tape to the base of a container such as a small cake-tin. Two or three moulds may be poured at the same time as one unit, or the mould may be restricted by a 'dam' of cardboard held across the container by Plasticine. The melted Vinamo1d is then carefully poured in to cover the moje1(s), avoiding air bubbles. After overnight cooling, the solidified block of Vinamo1d is removed from the container and the model extracted from the mould by flexing the Vinamo1d. The polygonal opening into the mould now corresponds to the face which was stuck to the container base.

Vinamo1d may be obtained from Vinatex Ltd., Devonshire Road, off Butter Hill, Carsha1ton, Surrey, at a cost of £2.15 for 5 lb. This is a reasonable quantity with which to try one's first twenty or 50 moulds.

The cast

The ideal casting medium would · be free-flowing and quiCk-setting to give a hard, preferably opaque finish. (Transparent models are perhaps more attractive, but the time and care needed to exclude bubbles and produce a fine finish make the idea impractical, when one is thinking of production almost on an assembly line basis.) After considerable trial and error, I have returned to the first material I tried - plaster of Paris. Fibre-glass resin gave a hard product, but tended to 'craze' and bubble-exclusion was difficult; plaster additives such as Vinamu1 reduced the brittleness of the product, but made the final sandpapering of the model difficult because the p1as~er became 'rubbery'.

Plaster of Paris is easy to mix to a thin creamy consistency (a food mixer quickly prepares a large quantity for mass production), it pours well, it sets to 'extractable' hardness in less than thirty minutes, it can be sanded easily to remove blemishes (especially from the open face of the mould), and it is cheap. Its one dis­advantage lies in the softness of the finished product. One answer to this is mentioned below, but, if any members discover a plaster additive or a different casting medium wh·ich would produce the above advantages plus hardness, I should be grateful if they would pass on the information via GEOLOGY teaching.

The actual pouring of the cast is a very simple operation. If a large number of moulds are to be filled, the job has to be done quickly because the plaster begins to 'go off' within minutes of mixing. Otherwise, one need only take care to pour smoothly and continuously, filling the mould to overflowing. Passing the edge of a straight knife-blade over the top of the mould then removes the surplus plaster while it is still liquid. After the setting time has elapsed (thirty minutes is ample), the cast is removed by flexing the mould open and pressing

from below. At this stage, the model will still be quite soft, and overnight drying should be allowed before proceeding to the next stage.

The finish

After any blemishes have been removed by stroking the model over very fine glass-paper, my models are coated with a substance called P1asta1ac. This is a white, creamy liquid which is painted on with an ordinary artist's brush (washable in water) and which dries quickly to form a slightly glossy plastic film. This greatly reduces the vulnerability of the model to scratching, flaking or chipping, and has the added advantage of making the model non-porous and waterproof. This means that felt pens may be used to mark crystal faces, planes of symmetry, axis' emergence points, etc., all the marks then being removable with the wipe of a damp cloth.

P1asta1ac is produced by Norgine Ltd., 26-28 Bedford Row, London WC1R 4HJ. Unfortunately, their accounting system does not permit the sale of P1asta1ac direct to education authorities -it is a medical product distributed to hospitals and dental laboratories. My use of P1asta1ac has been made possible by the kindness of the marketing manager in supplying sample bottles, but he has intimated that, ' if sufficient enquiries reach him from schools, he may well be able to initiate supplies direct to LEAs.

To date, I have prepared class sets (ten to fifteen models) of some twenty different crystal forms or combinations of forms. The convenience of having these sets at hand during theory lessons and in practical sessions has been inestimable. One can even allow one's 'crystals' (no longer irreplaceable) to be taken away for homework! I am confident, too, that our mock GCE practical examinations will now have a wi~er scope in their crysta110graphy content.

DJM)NSTRATION ftDDELS

The plaster models are ideal for class handling, but are too small to be seen by all the class when held up by the teacher. For demonstration purposes, therefore, larger models are required­something like 6 in. to 9 in. longest dimension seems suitable, this being large ' enough to be seen and small enough to be held in one hand (whilst the other points out the required features).

Such models, beautifully produced in glossy board, are obtainable commercially; but my first enquiry about their cost was sufficient to set me thinking about self-help once more. Once the initial decision was made, the advantages other than cheapness quickly became obvious. Within the limits of one's patience and skill, any desired combination of forms may be demonstrated, one has control over size and colour, and cryst­a110graphic axes may be included or omitted.

I have gradually built up a set of twenty large demonstration models, made of cardboard. Some of the simpler forms are very easy to construct, but as non-right angles creep in, so the design of the cut-out becomes more difficult. I achieved some measure of success with these more complex models largely by experiment, and it is the hope that I may help minimise other members' trials and errors that the following suggestions are offered.

48

Materials

Cardboard is the easiest suitable material to work with. The thickness is a matter of personal choice, but something a little stouter than a postcard serves well; anything thicker, such as strawboard, tends to make ugly corners. Cutting out is preferably done with a knife and straight edge, and a sharp blade is essential for scoring the folds. Any quick-drying adhesive, such as balsa cement, is suitable for joining the edges. On most of my models, all folds and joins were reinforced after the assembly was completed with strips of gummed brown paper; this had the added advantage of concealing bad joins.

The cut-out

The accompanying diagrams show the shapes of the 'nets' of several models (solid lines are cut, broken lines are scored). Each net is paired with a drawing of the finished model and, in each, one of the edges is marked X. In the construction of a model, one should first decide how big the finished article is to be, assigning a dimension to edge X in the perspective drawing. The net should then be enlarged until the line X reaches the required dimension, ideally by projecting the net through an epidiascope on to the vertically mounted sheet of cardboard.

The nets do not show the tabs which will be necessary for gluing edges together. These may be added by following the rule "attach tabs to a1 terna te edges around the perimeter of the net", but there is one exception. Having decided by inspection of the net which face will be the last to be secured, one should leave this face free of tabs. The tabs which have been omitted should then be added to the ,edges which they would have met (again located by inspection), so that a 'platform' of tabs is built up to which the last face may be stuck. Care should be taken t~at the angle at the shoulder of each tab on the net is small enough to allow the folding of the model. For example, where two edges meet at right angles, the tab shoulders should be less than 450 •

The finish

Colouring of the model greatly improves its appearance, helps to hide patched-over mistakes and often increases its usefulness. My own models are coloured according to the crystal system; others might be colour coded to indicate crystal forms. Emulsion paint has been found very suitable. It is dense and easily applied, the brushes are easily cleaned, and one tin of white plus a selection of powder colours (from the Art Room) for mixing gives an unlimited range of tints.

The decision to add or omit crysta110graphic axes is again a personal one. I decided to include them and found that eighth inch dowell­ing served for the purpose, threaded through holes drilled in the appropriate spots, clipped off to protrude about 1! in. at each end, secured with a blob of adhesive, and painted with black lacquer. Locating the third axis in an eighth inch hole in the centre of the last face (from inside) is one. way of spending a long winter eveningt

The uses

I have found my own demonstration models partic­ularly useful since they duplicate the handling models used by the pupils. With the class equipped with plaster models and the teacher holding up a large cardboard version of the same crystal, very few of the concepts in crystall­ography are not more easily conveyed. In the early 'teaching' stage, features pointed out on the large model can be located on the smaller ones; later, in the 'practice' stage, when the pupils are identifying the forms present in a plaster model, the cardboard one is used to confirm or refute their attempts. And, because the model is a large one, a straight edge can be laid along a face to demonstrate its intercepts with the crystallographic axes. Having been designed on a rule-of-thumb basis, the large

models would no doubt fail any rigorous tests of interfacial angles, but for demonstration purposes they have proved invaluable.

49

In conclusion, I must emphasise that the purpose of this article is to pass on information which may help colleagues who have felt the need or ais aids in teaching crystallography, but who may have thought that the expense precluded any real solution to the problem. All the facts and opinions stated have been obtained by trial and error, and I would appeal to any other members who have found their own solutions to classroom problems to share their findings through the medium of GBOLOGY teachinl that our communal trials and errors may be minimised.

Only a small selection of model outlines can be shown. If there is a sufficient demand, the Association will arrange to have the complete set of 20 models printed on card and sold at a modest price.

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AUGITE

51 WORKSHOP ON TEACHING PALAEONTOLOGY

A repo~t by Chris Wi lson

The third of a series of joing meetings organised by the Earth Sciences Education Methods Group (affj liated to the Geological Society of London, and specialists sub­groups, or associatio~s) was held at the University of Glasgow on 22nd and 23rd May. The p'Jrpose of these meetings is to exchange ideas on teaching the sub­disciplines of gealogy, which may range from a discussion of the underlying philoiOphy determining the content of courses, through visual aids, to piactical work and fieldwork. The previous two meetings involving the Volcanic Studies Gro:JP and the Tectonic Studies Group were dominated by displays of pra::tical materials, but this meeting, which was excellently organised by Dr. lan Rolfe and his colleagues on behalf of the Educatio~ Methods Gro'Jp and the Palaeontological Association, consisted mostly of lectures, with coffee and tea taken amongst exhibits of various materials. The latter included sales of fossi I casts, demonstrations of stereo photography, exhibits of student project work a'1Cl labo~atory manuals, and even one author soliciting the sales of his books on dinosaurs.

UNIVERSITIES (29 returns)

First year courses

Mean in 3 year courses*: 22 returns Mean in 4 year courses (Scotland): 6 returns Maximum in all courses Minimum in all courses

Palaeontological contribution to degrees

The meeting opened with a review of the palaeonto­logi ca I componen t of degree courses gi ven by Dr. J.D. Lawson of the University of Glasgow. Dr. Lawson had written to :Jniversity and polytechnic geology deportments to obtain informatio~ on the relevant weighting given to palaeontology in their courses. He intended the results of his enquiries to serve as a bosis on which to plan the revision of palaeontological classes at Glasgow. During the meeting he provided a handout summarising his findings, the key points of which are given in the following tables.

The result suggests that polaeontology forms about one fifth of geology degree courses. First yeor courses ranged in style from the systematic treotment of groups, coupled with drawing 150 specimens, to a more radical palaeoenvironmental approach in which the groups were treated as they were encountered in a historical geology course. Dr. Lawson commented that poly­technics appeared to adopt a more modern approach, playing down systematics, and suggested that perhaps universities had something to learn from them. Many first year courses faced the difficulty of providing

Hours

Lectures Labs Total

15 26 41 7 11 18

33 59 82 6 8 14

*Typica11y consisting of general pa1aeo. 4 lectures, plus one hour on each of 8 major groups, plus 3 lectures on vertebrates and minor groups, with lab sessions roughly in proportion.

Post first year courses (excluding options)

Mean 3 year courses: 23 returns Mean in 4 year courses: 6 returns Maximum in all courses Minimum in all courses

Lectures

48 49 90 20

Hours

Labs

80 95

200 20

Typically about 3 lectures on each of biva1ves, brachiopods, corals and grapto1ites, 3.5 on trilobites, 4 on cepha10pods and echinoderms, 2 on gastropods, and approximately 9 on general pa1aeo, plus: other topics:-

Number of departments

Total

128 144 290

40

Teach Do not teach

Offer Option

Ay.. Lecture hours

Minor groups (sponges, hryozoa, worms) Pa1aeobotany Vertebrates Pa1aeoeco10gy Micropa1aeonto10gy Trace fossils Projects Statistics

18 12

9 18 20

9 7 specified 8 specified

7 11 18

6 5

17 (commonly courses

7 3 3 ?

in options)

4 7

13 9 8 ?

52 POLYTECHNICS (9 returns)

No honours geology courses in sample, included combined Science, B.Ed., Dip.Ed., civil engineering etc; 4 returns mentioned modular course structure.

First year courses*

means max min

* Courses similar to university first year courses

Post first year courses (pre option*)

means max min

* 3 returns mentioned options

enough specimens for large .numbers of students that took their first year courses. Later in the meeting one contributor suggested how this problem could be tackled (see below).

Dr. Lawson's survey showed that Rhona Black's 'Elements of palaeontology' was the best selling book for first year courses, but that some departments sti II use Woods, Morley Davis or Swinnerto:'l! Later courses used Raup and Stonley's 'Principles of Palaeontolqgy' (13 replies), Shrock and Twenhofel's 'Principles of invertebrate palaeontology' (12 replies), British Museum Fossil Guides (9 replies), and Moore Lallicker & Fisher's 'Invertebrate Fassi Is' (8 replies), plus a variety of others.

In the discussion of Dr. Lawson's contribution, the problem of compartr~entalisation within departments was raised, wi th a suggestion that it led to competition for timetable space between sub-disciplines of geology. This topic seemed to induce a defensive posture amongst some contributors, who seemed to feel that there was a need to justify the retention of their subject in geology degree curricula. This theme cropped up again -in other discussions. There often seemed to be a need to justify the inclusion of palaeontology at all, and such a justification had not been raised in the discussion sessions at the previous two Workshop meetings.

Needs of Industry

Dr. Bob Cummings, of Robertson Research International Limited, gave an account of the services palaeontology cO:Jld provide for industry. He suggested that many people have a biased view, considering that palaeo­ntology was just used to put an age label on samples. But it can do more: the studies of the way in which fossils are preserved can trace the a Iteration history of some rocks, indicating compaction, and studies of the mineralogical and chemical changes that take place as . material is fossilised are important in estimating the source potentia I of parti cu lar hori zons for oi I. Pa laeo­ecological work aids palaeogeographic interpretations which help to determine facies geometry, thus assisting in the location of host rocks hydrocarbons. Studies of biological assemblages present in rocks lead to conclusions concerning the hydrocarbon source potential, and can even predict the engineering properties of clays.

Hours

Lecture Lab Total

10 15

7

18 30 12

28 45 19

35 54 20

55 108

25

90 162

45

Dr • . Cummings was the only contributor to suggest what the final product of a degree course should be in terms of the characteristics of potentially employable graduates. He said he was basically looking for staff who Here enthusiC!~~: On the academic side, they should have a general geological awareness so that they could fit into multi-disciplinary projects that were the 'bread and butter' of commercial operators. Thus they shou Id have:

• a general palaeontological background with a degree of specia lism

• a command of various palaeontological techniques such as borehole logging and geophysical interpretation

Dr. Cummings suggested that there was more needed in graduates than just knowledge and intellectual skills; he also looked for:

• graduates whose personalities suits them to working with others

• who are adaptable to new pro!:>lems and working situations

• who can innovate, often quickly

• who are willing to travel

• who have a commercial awareness

Dr. Cummings said that he thought that Bri tish graduates were genera lIy inferior, having a rather parochial outlook to geology and to life in general. Sadly this general theme 9f student characteristics, especially in terms of the skills and attitudes they should develop during their degree cO"Jrses, did not recur during the meeting, save for a brief discussion of a need to train students to write reports.

Dr. Cummings also stated that he felt current efforts by the Natural Environment Research Council to estimate manpower requirements were a useless exercise; one could only plan one or two years ahead in industry.

During the discussion following Dr. Cummings' contri­bution, the problem of fitting new components into

courses was raised. Some felt it could be regarded as bastardising the teaching of palaeontology if courses were tailored more to the needs of industry. There seemed to be a misunderstanding about including course materials to increase "general awareness" of the student without teaching the last word on a particular topic. Again, the obsession with the knowledge content of courses seemed to stifle the discussion.

Much of the remainder of the meeting was taken up with acco'Jnts of individuals approaches to teaching palaeontology. Dr. Ron Austin of Southampton gave an account of his use of self instructional tapes, visual materials qnd specimens to solve the problem of providing practical work to large (200) first year classes. The tapes are used in carrells in a laboratory situation, so that students have free access at times to suit themse Ives.

The audience response to something different from the conventional lecture practical situation was predictable. How can you check the work is done? (Look at students work in their course manual.) It's too costly {about £50 ·~o, cassette tape recorder}. You cannot update it (you just edit in new bits). Dr. Austin manfully faced up to his critics and suggested thot the system could even be used for aspects of specialist courses such as micropalaeontology, where the use of one or two high quality microscopes could be maximised. .

Dr. Peigi Wallace gave an account, illustrated by a film, of experimental work in a flume tank involving real and model fossils. The purpose of the experiment in which student participated, wos basically to make fossils 'come alive' for students, encouraging them to observe and interpret the way in which the morphology of the organism might be related to current flow and other factors.

Dr. Ingham of the Huntarian Museum at Glasgow described a short (15 hour/5 week) project course for third year honour students at Glasgow. Although the students sometimes spent too much time on the work, it moti voted them to become fami I iar with bibliographic work, various physical preparation techniques, taxonomic methods, and to communicate their findings. The briefing in all these techniq~-es wo. given to students during the course, who at the same time studied independently, or in small groups, material available from the Hunterian Museum, o~ sometimes specimens collected during field classes. The accounts of some of the projects were on display during the Workshop, and were testament to the success of the project work -but Glasgow University regulations prevent this aspect of the degree studies being credited towards the final degree result. As this type of student training is likely to produce the kind of graduate that Dr. Cummi ngs requires, it seems sad thot some university regulations lag so far behind the desires of staff, students and prospective employers.

Dr. George Farrow made a plea for the no man's land between po laeoecology and sedimentology to be considered, suggesting that students should be aware that fossils were once part of living communities, only fragments of which are now preserved for study. He stated in his abstract that palaeoecology should come as a c li max to on honours course . But I sti II wonder, even after an enjoyable day in the Solway Firth looking at modern tidal flats with Dr. Farrow, whether such an appro-.Jch is equally appropriate to starting palaeonto­logical studies, from school level upwards. One does

not find bivalves on one part of the tidal flats, and 53 crustacea on another - so why start with systematics? There was some discussion of how, whether, or when systematics should be included in courses. No consensus emerged, save that some was necessary, but nonetheless it was the palaeantol03ical teachers achilles heel. But, then look at all those rock names that the petrologists burden their students with .•...

Dr. lan Rolfe spoke about the Museum's role inpalaeonto­logical teaching. Museums, he said, are not just specimen warehouses, and not like libraries either, for specimens, unlike books, need labelling as well as cataloguing. He felt that hi~ own Museum (the Hunterian Museum), although it looned over 3,000 specimens a year, shou Id change its role to take the subject to the public.

The afternoon session was enlivened by the 'Billy Graham' of the palaeontological world, Professor Sylvester Bradley. He harangued audience on the 'triangulation of palaeontology'. He suggested - na, he proclaimed-that palaeontology had three components. Interest in the subject usually started with an artistic interest in collecting identifying and classifying. He suggested that in the early days of geology this almost amounted to witchcraft, with Buckman identifying strata by their fossil contents, but unable to pass on his skill to others. The subject then developed into a technology, but to Professor Bradley, the techniques involved induction as much as physical preparation. This led into a quick tour of the philosophy of science including descriptions of the theses of Kuhn and Popper. The audience revelled in Professor Brad ley's stimu lating, and some­times outrageous remarks, and unfortunately it is impossible to adequately convey the content of the presenta tion by the wri tten word.

Your reporter hod the unenviable task of following Professor Sylvester-Bradley, and outlined some points about testing and evaluation. The discussion, as so often happens with this subject, was more concerned with personal anecdotes about somebody else's assessment system, rather than including more objective statements that scientists usually make when discussing their "pure" research. But that is perhaps the difference between attitudes to teaching and research.

The meeting was concluded by Professor T. N. George, speaking for the last time in the Department Lecture Theatre, which wa, about to be demolished. He said he had been taught palaeontology by Professors Truman and Woods; the former was a romantic and exciting instructor, but the latter a :lead Iy systemati st. But there was no doubt about who taught him more palaeontolo3Y -it was Professor Woods. '

The second d::Jy of the meeting was devoted to excursions to demonsttrate the teaching of palaeontol03Y either in the field or at a museum.

The Workshop meetings arranged by the Earth Science Education Methods Group and various specia list groups seem to be the only opportunity for large numbers of teachers in higher education to get together to talk about hON they teach their subject, rather than to discuss their research results. After attending three such meetings, I hove the impression that the p::Jrtici­pants are pleasantly surprised by the amount they get out of the meetings, and wonder whether there is scope foo' a wider collaboration that could also involve schools in some way in the fu ture .

GEOLOGY

with

GEOGRAPHY

at

of Higher Education

Applications for 1976 Department of Science (GT1),

College of Higher Education, Park Square, Luton, Beds. LU1 3JU.

Telephone: 34111 Ext. 278

TEACHERS - - - -

ONE OF THE BEST ROCK PROCESSING LABORATORIES IN THE COUNTRY IS NOW AT YOUR DISPOSAL.

Logitech of Scotland manufacture the thin rock section making system which is now "standard" in U. K. Geological Science laboratories. Our own laboratory is, of course, no exception and, though we say it ourselves, we do operate rather efficiently.

The facilities of our laboratory are now yours for the asking. If you want sample material processed to ..... .

lapped Bulk Specimens Lapped Thin Sections

Polished Bulk Specimens Polished Thin Sections

.... we will be delighted to help. We also have a range of Scottish rocks avail­able in bulk and thin section forms.

So if you want help with teaching aids or project support, please contact us -we are so efficient that even school budgets can stand our prices.

LfZlGITECH LTD Lomond Estate, Alexandria Dunbartonsh ire G8:;J OTL SCOTLAND

Telephone : (0389) 53764 Telegrams: Logitech Alexandria

54

55

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56

COURSES N

GEOLOGY .leading, ,to the following degrees :-

B.Sc. (HONOURS) CNAA DEGREE IN ENGINEERING GEOLOGY AND GEOTECHNICS

This course will give Chartered Engineer (C. Eng.) status to a graduate after the satisfl;lctory completion of a period in industry.

After a first year basiccourse in geology and engineering the undergraduate will receive a thorough training in Geology, Rock and Soil Mechanics, Hydrogeology, Economic Geology, Exploration Geology and Geophysics.

B.Sc. and B.Sc. (HONOURS) CNAA DEGREE IN SCIENCE

The full time degree enables a student to follow either a single subject programme in geology or a joint subject programme involving geology and one other subject.

A variety of other joint subject programmes is offered within the Science degree scheme and six other subjects are available as alternative programmes . .

Recent graduates h~ve found employment, in the UK and abroad, as:­mining and exploration geologists with the large mining companies; engineering geologists with consultant and contracting civil engineering firms; exploration geologists with the oil companies; gover~ment geologists with national surveys; geologists with specialist geological and geophysical companies.

- Other graduates have proceeded to do further research and yet others have found positions as teachers of geology.

For further details of courses and applicati,on forms please contact :-,. ,

THE REGISTRAR, PORTSMOUTH POLYTECHNIC, ADMISSIONS OFFICE, ALEXANDRA HOUSE, MUSEUM R0AD, PORTSMOUTH, POl 200.

a PORTSMOUTH .. ( POLYTECHNIC

Depo rtment of Geology

57

DIARY MEETINGS AND EXCURSIONS BM

CN CGS DA EGS EM(;

British Museum (Natural History) Croydon Nat. Hist. Soc. Cumberland Geological Society Devonshire Associa tion Edinburgh Geol. Soc.

Key to initials used

Types of even t

C E F L S

Course Fie Id excurs ion Film(s) Lecture Symposium/Conference

East Midlands Geol. Soc. FC Fie Id Cen tre

Field Studies Council Geologists Association Geological Museum, South Kensington Geological Society of London Hertfordshire Group of Geology Teachers Harrow & Ruislip Geological Society Manchester Geol. Assoc.

T Tour (usually of a museum)

FSC GA GM GS HGTG HRGS MGA NHN WGT YGS

Nat. Hist. Soc. of Northumbria Walsall Geol. Teachers Working Party Yorkshire Geological Society

J U L Y

L 2

L 2

E 3

E 3

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E 4

C 6 - 8

S 8

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E 10 - 11

E 11

E 16 - 26

C 17 - 24

C 17 - 24

C 19 - 23

C 20 _ 22

T 21

C 21 - 28

GA

BM

DA

NHN

EGS

MGA

EMG

BM

WGT

CN

YGS

GA

FSC

BM

BM

FSC

The Geology of Morocco by Prof. D.V. Ager, Dr. G. Kelling & Dr. R.T.J. Moody. Geol. Soc. Apartments, Burlington House. 6.00 pm

The Ice Age. Place: B.M. (Nat. Hist.) 3.00 pm

Cornish minerals in Truro Museum + China Clay in St. Austell area Details from Mrs. Elfrida Jones, Lower Cooks, Woodbury Salterton, Exeter, EX5 IPR

Geology of the coast between Berwick & Siccar. Details from J. Lee, Dept. of Geol., University of Newcastle-upon-Tyne.

Lower ORS sediments & volcanics of Perth Motorway cutting & Sidlaw Hills. Details from Excursion Sec., WGW Harper, 13 Craigmount Grove North, Edinburgh EHl2 8BX

Ramshaw Rocks & Dave Gorge led: Dr. N. Aikenhead & E.A. Francis. Contact: J.A. McCurdy, 9 Hayling Road, Sale, Cheshire M33 lGN,

Igneous Rocks of Charnwood Forest. Details from Mrs. D.M. Marow, 54 Cyprus Road, Mapper ley Park, Nottingham NG3 5EB

Finding out about the seashore - ecology, Contact: John Stidworthy, Education Section, B.M. (Nat. Hist.)

(1) General business (2) Discussion of Policy stateme nts ( 3 ) Demo­nstration of some practical geology in an integrate d science course. 4.30 pm, Place: Blue Coat Comp. School, Birmingham St., Walsall"

Warnham Quarry (Weald Clay) + Gault at Small Dole. Contact: Arnold Shaw 39, Wordsworth Drive, Cheam, Surrey.

South Pennines - On 10th Ramshaw Rocks on Leek-Buxton Road (SK 022.625) 10.15 am. On 11th at th e Minery Standard on 85056 near Whister (SK 2382.6020) 10.30 am.

River Westbourne: from source to estuary (tracing one of London ' s underground rivers) Led: E.S. Hillman. Details: Miss M. Pugh, Dept. of Geology, Imperial College, Prince Consort Rd., London SW7 2BP

Geology of N.E. England. Contact: Secretary, Dr. M.E. Tucker, Dept. of Geology, University of Newcastle upon Tyne NEl 7RU

Basic Geology of N'umberland & Cumbria: organised by University of Durham. Details: Mrs. A.P. Lewis, 32 Old Elve t, Durham DHl 3JB

Basic Ge ological Mapping and Map Interpr e tation organised by University of Durham. Details from: Mrs. A.P. Lewis, 32 Old Elvet, Durham DHl 3JB

Rocks, Fossils & Scenery. Contact: Juniper Hall Field Centre, Dorking, Surrey RH5 6DA

Course for 4th and 5th formers. Finding out about fossils. Details: John Stidworthy, Education Section, B.M. (Nat. Hist .)

Toe Evolution of Man. 3.00 pm, BM (Nat. Hist .)

Geology & Scenery of the Pembrokeshire Coast. Details from Dale Fort Field Centre, Haverfordwest, Dyfed.

C

C

C

C

C

E

E

C

C

C

C

C

C

A

L

C

C

E

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C

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21 - 28

21 - 28

21 - 28

23 - 25

23 - 30

24 - 31

24

24 - 31

24 - 31

28 - 4 Aug

28 - 4 Aug

28 - 4Aug

30 - 3 Aug

U G U S T

3

4 - 11

4 - 11

6 - 8

7

10

13 - 15

13 - 17

13 - 20

17

19

20

FSC

FSC

FSC

FSC

EMG

NHN

FSC

FSC

FSC

BM

FSC

GA

CN

BM

FSC

BM

BM

BM

E 20 - 3 Sep GA

L

E

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27

28

30

S E P T E MBE R

E

E

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4

6 - 14

10 - 11

BM

CiA

BM

GA

YGS

Introduction to Geology and Landscape. COntact: The Drapers' Field Centre, Rhyd-y-Crenan, Betws-y-Coed, Gwynedd.

Dynamic Geomorphology. Contact: Malham Tarn Field Centre, Settle, Yorks. BD24 9PU

Fossils Workshop. Contact: Orielton Field Centre, Pembroke, Dyfed.

Geology of Rutland. Book through: Brian Threlfall, Vaughan College, St. Nicholas Circle, Leicester LEl 4LB (Field Course).

Geology for Beginners. COntact: Preston Montford Field Centre, Mortford Bridge, Shresbury SY4 lDX

Edinburgh area. Contact: Mrs. D.M. Marow,_ 54 Cyprus Road, Mapperley Park, Nottingham.

The Whin Sill in Northumberland. Details: J. Lee, Dept. of Geology, University of Newcastle upon Tyne.

Field Course. Basic Geology of N'humbria & Cumbria, organised by University of Durham. Details: Mrs. A.P. Lewis, 32 Old Elvet, Durham DHl 3JB

Petrology - the study of rocks; University of Durham. Details from Mrs. A.P. Lewis, 32 Old Elvet, Durham DHl 3JB

Rock, Fossils & Minerals. Contact: The Leonard Wills Field Centre, Nettlecombe Court, Williton, Taunton, Somerset TA4 4HT

Geology & Scenery of the Pembroke shire Coast. Contact: Dale Fort Field Centre, Haverfor dwest, Dyfed.

Geology & Scenery of the Pembr okeshire Coa st. Contact: Orielton Field Centre, Pembroke, Dyfed.

Geology for Geography Teachers. Contact: Malham Town Field Centre, Settle, Yorks. BD24 9PU

Sea Stars & Urchins. 3.00 pm. Place: B.M. (Nat. Hist.)

Geology & scenery of the Yorkshire Dales. Contact: Malham Tarn Field Centre, Settle, Yorks. BD24 9PU

Field Course. The Geology of Pembrokeshire. Details: Principal, College of Adult Education, Cavendish Street, All Saints, Manchester MI5 6BP

Inferior Oolite from Oxfordshire to Somerset.

Chalk & Lower Greensand of N. Weald. 10.15 am, Clandon Station.

Evolution of Vertebrates. 3.00 pm. B.M. (Nat. Hist.)

Building Materials from the Earth. Contact: Juniper Hall Field Centre, Dorking, Surrey, RH5 6DA

Techniques in physical geography for A level teachers. Contact: Malham Tarn Field Centre, Settle, Yorks. BD24 9PU

Scenery & geology of Shropshire. Contact: Preston Montford Field Centre, Montford Bridge, Shrewsbury SY4 lDX

Life between the Tides. 3.00 pm. B.M. (Nat. Hist.)

Coral Reefs. 3.00 pm. B.M. (Nat. Hist.)

The Story in the Rocks. 3.00 pm. B.M. (Nat. Hist.)

Morocco. Organising Director: Dr. R.T.J. Moody, School of Geology, Kingston Polytechnic, Penrhyn Road, Kingston on Thames, Surrey.

Volcanoes. 3.00 pm B.M. (Nat. Hist.)

Middle Lias Dorset. Leaders: Dr. J.R. Senior & Prof. M.R. House.

Dinosaurs. 3.00 pm, B.M. (Nat. Hist.)

Barton, Hants. Led: J.J. Hooker.

Cantabrian Mountains N.W. Spain. Details from Dept. of Extra Mural Studies, University College, 38-40 Park Place, Cardiff CFI 3BB

Pleistocene Geology of Holderness and the Yorkshire Wolds. Details from Dr. J.A. Catt, Pedology Dept, Rothamsted Experimental Station, Harpenden, Herts. AL5 2JQ

58

E 11

E 11

E 12

E 12

E 18 - . 20

L 22

S 23

E 25

E 25

BROADCASTS

DA

G\

E/vG

MGA

\'KiT

CN

NHN

Berwyn Hills - led by Dr. P.J. Brench1ey. Contact: J.A. McCurdy, 9 Hay1ing Road, Sale, Cheshire M33 1GN

Taw - Torridge Estuaries - P1eistocene. Leader: Dr. R.B. Beck. Details: Mrs. E1frida Jones, Lower Cooks , Wood bury Sa1terton, Exeter EX5 1PR

Stra tigraphica1 relationships within the Lincolnshire Limestone Leader: M. Ash t on.

Huddersfield area. Details from Mrs. D.M. Marow, 54 Cyprus Road, Mapper1ey Park, Nottingham NG3 5EB

Carboniferous sediments of Settle district. Details from W.G.W. Harper 13 Craigmount Grove North, Edinburgh EH12 8BX

The Sub-Drift rock head surface between Manchester & Liverpool -R.F. Grayson. 6.30 pm. Dept. of Geology, University cf Manchester (Wi11iamson Building)

Wa1sa11 Group Meeting. General Business. 1st meeting of new term. 4. 30 pm. Education Development Centre, Wolverhampton Road, Wa1sa11.

59

Fullers Earth Works Nutfie1d Surrey. Contact: Arno1d Shaw, 39 Wordsworth Drive, Cheam, Surrey.

Coal Measures north of Druridge Bay (N'humber1and). Details: J. Lee, Dept. of Geology , University of Newcast1e-up6n-Tyne.

Watch out for programmes covering the Viking lander missions to Mars. We do not have details of programmes that will be transmitted in the general services of the BBC and ITV, but you may like to watch the Open University ProQramme on Mars (5333 TV15) OPEN UNIVERSITY TV; .

S100 Science: A Foundation Course 22 The Earth : Its Shape.

Internal St ructure and Composition

23 The Ea rth 's Magnetic Field

24 Major Features of the Earth 's Surface

25 Cont inental Movement and the Sea· Floor Spreading

26 Earth History I

27 Earth History 11

S23- Geology 10 Plate Tectonic

Processes

11 Earth H ,story -Clomates of the Past

0830 Sun 18 July

0830 Sun 1 Aug

0830 Sun 8 Aug

0830 Sun 15 Aug

0830 Sun 22 Aug

0830 Sun 29 Aug

1150 Sat 3 J ul v

1150 Sat 17 J ul v

1215 Sat 24 July

1840 Tues 3 Aug

1840 Tues 10 Aug

1840 Tues 17 AlIg

1840Tues 24Aug

1840 Tues 31 Aug

1725 Mon 5 Ju i\

11 50 Sat 24 J u Iv

52-3 Environment Water 1 1 50 Sat 7 Aug

2 A Case Study of 1150 Sat 21 Aug the Gower Coast

3 Rivers 1150 Sat 4 Sept

4 A Case Study of 1150 Sat 18 Sept' Windermere and Troutbeck

5 A Case Study of the 11 50 Sat 2 Oct Cwm Idwal and Nant Francon Area. North Wales

6 Conservation in the 1 01 0 Sat 1 6 Oct New Forest

3 This programme may be at 1355 (liberal asse mbly)

S2-4 Geophysics 5266 The Earth's Physical Resources

Ideas for the Future 1150 Sat 10 July 1905 Fri 16July Changing Gravity 1150 Sat 31 July

2 Cyprus : A Geol>hysical 1150 Sat 14 Aug

82-2 Geochemistry Case Study Part 1 : The Idea before Plate Techtonics

Geochemical Analysis 0730 Man 9 Aug 2 1905 Fri 13 Aug 3 Cyprus: A Geophysical 1150 Sat 28 Aug Case Study Part 2 :

2 Silicates 0730 Man 23 Aug 2 1815 Fri 27 Aug A New Significance 3 The Geochemical 0730 Man 6 Sept 2 1815 Fri 10 Sept 4 Cyprus : A Geophysical 11 50 Sat 11 Sept

History of the Earth Case Study Part 3 : 4 Phase Diagrams 0730 Man 20 Sept2 1815 Fri 24 Sapt The Formation of

Oceanic Crust 6 Origins of Igneous 0730 Man 4 Oct 2 1815 Fri 8 Oct

5 Earthq uakes 1150 Sat 25 Sept Rocks and Metal Ores

8 Geochemical 0730 Man 18 Oct 2 1815 Fri 22 Oct 6 Questions 1150 Sat 9 Oct Survaying

2 BBCl

Continue d o n page 42

1725 Man 9 Aug

1725 Man 23 Aug

1725 Man 6 Sept

1725 Mon 20 Se pt

1725 Man 4 Oct

1840 Man 18 Oct,

1725 Man 2 Aug

1905 Wed 18 Aug

1725 Tues 31 Aug

1725 Man 13 Sept

1725 Man 27 Se pt

1725 Man 11 Oct

CERTIFICATE OF EDUCATION: FOUNDATION

On July 8th, the Schools Council's governing body will meet to discuss the proposals for a common 16+ examination. It seems likely that they will approve the proposal, in which case Mr. Mulley will have to dec ide whether, and wh e n to implement it. At the earliest, the new exam could be in operation in 19 81. What do geology teachers (school and higher education) feel about the propbsals? Would the re-consideration of syllabuses that would be necessary when amalgamating GCE and CSE reduce some of the current disturbing diffe rences (see Geology 6, 17-27) between both the subject content and examination practices of the various Boards?

The Schools Council's Joint Examination Sub-Committee has suggested that the new exam should be available in three modes, with Mode 1 entirely devised by the Board, Mode 11 having exams set by the Board but t es ting a teacher designed syllabus, and Mode III with teachers s etting their own exam under th e Board's supervision and moderation. Und e r such a scheme, teach ers could choose (and d e sign) a geology course better suited to their local environment', and the chang e to a new system might enable - at last - pupils fieldwork to be adequately assessed and contribute a fair proportion of marks to the final result.

However, some geology teachers may have doubts about the new 16+ exam. If Mode III syllabuses and exams proliferate, how will standards compare across the country? And who will do all the moderating?

Write to GEOLOGY teaching with y our views about the Common 16+ exam, and, since the exam season is now virtually over, why not comment to us on your e xperience of this year's GCE and CSE?

WHICH WAY FOR SECONDARY GEOLOGY?

Secondary geology teachers are from a variety of baCkgrounds, but probably the majority have a geographical bia s . Is the physics or chemistry specialist , who also teaches geology a rarity? And what of the specialist geology graduate - more are entering the teaching profession. Modern geology certainly has more in common with chemistry, physics and biology than the rather qualitative approach still charact e ristic of some syllabuses. Not only is there a need to shift the emphasis of geology teaching towards the general approach es to science teaching, but geology can contribute something to integrat e d science (see Shopfloor and John Phillips' article in this issue). Geology is a naturally integrated science, so perhaps more lower school science should be taught via an e arth s c i ence course, rather than isolated bits of chemistry, physics and biology. What do you think, secondary teachers?

SEE CENTRE COLOUR PAGES FOR ANNUAL CONFERENCE PROGRAMME AND BOOKING FORM

Th e re wi ll be no 'r eminders ' post e d this yea r

GEOLOGY feacHing,

P~l5mt-i~8' .t1udrter Iy' by the Association of Teachers of Geoloay, Dept. of Earth Sciences, The Open University, Milton Keyn8$, MK7 6AA, U. K. Tel: (0908) - 63228

Opinions and comments in this issue are the personal views of the authors and do not necessari Iy represent the views of the Association.

Contr·iDufi6ns 'for the next issue of GEOLoGy teachtrig 'wi'llbe welcome, and should be sent to the Edi tor I from whom notes for contributors are ova i lab le.

Editorial Subcommittee

Chris Wils~:1 (Editor) JererTiy Clulow (Advertisipg) Stephen Hannalh (Primary

School GeoloflY) Dick Mayhew (Reviews)

so book NOW!

John PhI.Hips (Hi~!EdifCatidn~ Frant<"'5'po3e (Primary S"'e~'

Geology & Teacher Training) Robin Stevenson (Diary & News) David Thompson (Resources,

Teacher Training, Examin':' ations)

Peter Whitehead (Secondary School Geology, local T eocher Groups)

Design T yptng Richard Hoyle linda Skyte

60