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Canadian meteorites: a brief review1
Graham C. Wilson and Phil J.A. McCausland
Abstract: We present a brief overview of Canadian meteorites with a focus on noting significant recent falls, finds, and re-search developments. To date, 60 Canadian meteorites have received official international recognition from the Nomencla-ture Committee of the Meteoritical Society, while at least 13 more are “in process” for submission to the MeteoriticalBulletin, that organization’s official database of the world’s meteorites. The 60 meteorites (44 finds and 16 falls since therecognition of the Madoc iron in 1854) include 25 irons, 3 pallasite stony-irons, and 32 stony meteorites. The latter include14, 11 and 3 H, L and LL chondrites, 2 carbonaceous chondrites and 2 enstatite chondrites, but no achondrites. The mostintensively researched meteorites are Tagish Lake (C2 ungrouped) and Abee (EH5), followed by Bruderheim (L6) andSpringwater (pallasite). Bruderheim, a 1960 fall, is widely distributed, being the most massive reported Canadian meteoriteat 303 kg total known weight (TKW). Seven Canadian meteorites exceed 100 kg TKW, 36 are between 1 and 50 kg, and17 are <1 kg. Recent years have seen the addition of the Tagish Lake, Buzzard Coulee and Grimsby meteorite falls, all ofwhich have well-determined fireball trajectories and therefore well-known orbits, a striking Canadian addition to the handfulthat are known worldwide. The discovery of the Holocene Whitecourt iron impact crater is similarly a significant recent de-velopment in understanding the impactor flux. The lessons learned on meteorites can be applied to newly recovered samplesfrom the Moon, Mars, asteroids, and comets.
Résumé : Nous présentons une brève vue d’ensemble des météorites canadiennes tout en ciblant les plus récentes chutesimportantes, les trouvailles et les résultats de la recherche. À ce jour, 60 météorites canadiennes ont été officiellement recon-nues par le comité de nomenclature de la Meteoritical Society, alors qu’au moins 13 autres sont « en traitement » pour êtresoumises au Meteoritical Bulletin, la base de données officielle de cette organisation pour les météorites mondiales. Les60 météorites (44 trouvailles et 16 chutes depuis la reconnaissance de la météorite ferreuse Madoc en 1854) comprennent25 météorites ferreuses, 3 pallasites mixtes et 32 météorites pierreuses. Ces dernières comprennent 14, 11 et 3 chondrites H,L et LL, 2 chondrites carbonées et 2 chondrites à enstatite, mais pas d’achondrites. Les météorites les plus étudiées sontcelles du lac Tagish (C2 non groupée) et d’Abee (EH5), suivies de Bruderheim (L6) et de Springwater (pallasite). Brude-rheim, une pluie météorite à grande distribution, datant de 1960, est la météorite canadienne la plus massive, avec un poidstotal connu de 303 kg. Sept météorites canadiennes ont un poids total connu de plus de 100 kg, 36 pèsent entre 1 et 50 kget 17 ont un poids inférieur à 1 kg. Au cours des dernières années, les chutes des météorites du lac Tagish, de Buzzard Cou-lee et de Grimsby, toutes avec des trajectoires bien déterminées de globes de feu et donc des orbites bien connus, ont étédes ajouts canadiens remarquables à la poignée de météorites connues mondialement. La découverte du cratère d’impact dela météorite ferreuse Whitecourt (datant de l’Holocène) constitue aussi un développement important récent dans la compré-hension du débit des impacteurs. Les leçons apprises sur les météorites peuvent être appliquées à des échantillons nouvelle-ment récupérés de la lune, de Mars, des astéroïdes et des comètes.
[Traduit par la Rédaction]
IntroductionThe history of modern meteorite research in Canada argu-
ably dates to the time of recognition of the first meteorite inthe country 13 years prior to Confederation, near Madoc,southern Ontario in 1854. The 167.5 kg single mass of ironmeteorite was acquired by William Logan, first director ofthe fledgling Geological Survey of Canada (Hunt 1855). The4th edition of the Natural History Museum catalogue of me-teorites (Graham et al. 1985), lists only 46 authenticated me-teorites for Canada, the world's second-largest country.
The official catalogue of the world’s meteorites is nowpublished on-line as the Meteoritical Bulletin, and (as ofearly 2012) lists 60 officially recognized Canadian meteor-ites. These we focus on here, though it may be noted thatmany years can pass between the first recovery of a meteoriteand its recognition as such by science. Even then, a properclassification must be carried out, and a suitable amount ofmaterial deposited with a recognized scientific depository(such as a major museum or university department active inmeteorite research). The first author of this paper has main-
Received 27 January 2012. Accepted 16 May 2012. Published at www.nrcresearchpress.com/cjes on 2012.
Paper handled by Associate Editor Richard Leveille.
G.C. Wilson. Turnstone Geological Services Limited, P.O. Box 1000, Campbellford, ON K0L 1L0, Canada.P.J.A. McCausland. Department of Earth Sciences, Western University, London, ON N6A 3K7, Canada.
Corresponding author: Graham C. Wilson (e-mail: [email protected]).1This article is one of a series of papers published in this CJES Special Issue on the theme of Canadian contributions to planetarygeoscience.
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tained a modest database of these official meteorites plusother finds “in process”, the latter currently numbering 13 to15 (most of these are listed at: http://www.turnstone.ca/cana-met4.pdf, 10 April 2012) — which we hope will be added tothe true tally before long.Before considering the 60 meteorites, and describing the
significance of a few, we should first answer two questions,namely: (1) why study meteorites? and (2) what does Canadagain from its meteorites, and vice versa?
The importance of meteoritesQuite recently, meteorites were still rare. The total, histori-
cal worldwide haul of meteorites consisted of one or morefragments from some 2000 distinct meteorite finds or wit-nessed meteorite falls (e.g., the 2611 “reasonably authenti-cated meteorites” of Graham et al. 1985). This last total didnot include the growing number of recoveries from the colddeserts of Antarctica, and preceded the impressive recoveriesfrom the hot deserts of North Africa and the Middle East inthe past two decades.The Meteoritical Bulletin (with 98 published editions
through 2010, and now available as on-line updates alone)cited, as of 17 January 2012, some 41 714 valid entries, and12 128 provisional names. This explosive growth of the mete-orite inventory, roughly a 20-fold increase in a quarter-century,has been accompanied by a steady growth in the science ofmeteoritics, and associated fields of observational small-body astronomy, cosmochemistry, and astrobiology. Thefield has long been at the forefront of developments in geo-chemical and mineralogical analysis of small and valuablesamples, particularly in clean sample handling, mass spec-trometry, and electron microscopy (e.g, Mason 1963; Clay-ton 1993; Bogard 1996).A multidisciplinary approach to a well-defined problem,
such as the documentation and interpretation of a photo-
Fig. 1. The Springwater main-group pallasite, showing coarserounded olivine in metal (kamacite) with minor iron–nickel phos-phide (schreibersite) at the metal–silicate interface. Note metric scalebar in centimetre, subdivided to millimetres.
Fig. 2. The Dresden (Ontario) H6 (S2) chondrite, displaying theclassic contrast, in a freshly recovered fragment, of black meltedglassy fusion crust ≤1 mm thick around the pale, metal-flecked,silicate-dominated interior. Coin diameter = 23 mm.
Fig. 3. A photomicrograph of the Red Deer Hill L6 (S3) chondrite.A glassy shock melt vein, up to 0.25 mm thick, containing abundantmicron-scale troilite (FeS) globules. Coarse troilite, as a typicalaggregate of recrystallized polygonal domains (best seen in cross-polarized reflected light), occurs left of the vein, while a smallangular grain of white kamacite, and minor patches of secondaryoxide (goethite) are visible to the right. Nominal magnification 200×,long-axis field of view 0.4 mm, in plane-polarized reflected light.
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Fig. 4. Field photo of site location EG-06 in the Tagish Lake C2 chondrite strewnfield, recovered in April 2000 from the frozen lake surface(Hildebrand et al. 2006). The dark carbonaceous chondrite was heated during the daytime and tended to melt and disaggregate into the icewithin distinctive melt holes. In this view, one of the meteorite-bearing melt holes has been chainsawed out of the ice as a keystone block andtipped onto its side for viewing. The meteorite can be seen inside the ice block, having descended and formed a dark pancake of material~10 cm below the snow-covered top of the block. Some dark debris can be seen to have continued downward along small holes much deeperinto the ice.
Fig. 5. The Grimsby H5 chondrite 21.9 g fragment “HP-1” as it was discovered two weeks after the 25 September 2009 fall, resting lightly ona grassy field in the west end of Grimsby, Ontario. This is one of only 13 pieces recovered from the fall. Note the dark, millimetre thickfusion crust and incipient rusting of FeNi metal on the fractured surfaces (McCausland et al. 2010). This fragment of Grimsby is evidentlypart of a larger, post-ablation individual that survived the fireball, but its sister fragments have not to date been found. Coin diameter =23 mm.
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graphed meteorite fall, can provide interesting opportunitiesfor a diverse scientific team (e.g., Brown et al. 2000).Although there is now an almost unlimited supply of themost abundant classes of chondritic meteorite, the recogni-tion of rare classes of igneous (achondritic) meteorites, someof them attributed to parent bodies such as the Earth’s moon,Mars, and asteroid 4 Vesta, means that the sample-conserva-tive approach to analysis of small samples remains valid. Thestudy of meteorites, particularly with the parallel evolution ofgeochemistry to handle the requirements of the Apollo andLuna sample-return programs in the late 1960s and early1970s, has had concrete benefits, in terms of widely applica-ble technologies and also specific contributions to materialsscience, discovery of new minerals, and a refinement of ourpicture of the evolution of the solar system (McSween 1999;Hutchison 2004).Since the productive 1969 fall of the Allende carbonaceous
chondrite in Mexico, it has become clear that the most “prim-itive” early constituents of the solar nebula are preserved incertain meteorite classes that have escaped significant meta-morphism or aqueous alteration, casting light onto an epochthat predates the Earth’s oldest known rocks by hundreds ofmillions of years. Presolar grains of phases such as graphite,diamond, SiC, and corundum offer glimpses into a remotepast, right back to the origin of the chemical elements (nucle-osynthesis), in a generation of stars that predated our Sun.Meteorites provide also a wealth of clues to the origins andevolution of their parent bodies, ejection of the meteoroidfrom the parent body, and cosmic ray interactions with themeteoroid prior to its fall through Earth’s atmosphere (Hutch-ison 2004).
Meteorites in Canadian scienceThe 60 officially-sanctioned meteorites in Canada that
were found or seen to fall before being recovered are listedin order of class and name in Appendix A Table A1. Notethat one of the Canadian attributions of Graham et al.(1985), the Leeds iron, has been discredited, recognized byscientific detective work as a synonym of the large Tolucairon from Mexico (Kissin et al. 1999).The largest public collections in Canada, as of 2012, in-
clude: the National Collection, curated at the Geological Sur-vey of Canada in Ottawa; the University of Alberta atEdmonton; and the Royal Ontario Museum in Toronto. Thelatter may be smaller in numerical terms, but has a very ac-tive acquisitions program and a remarkable diversity of therarer achondritic classes of meteorite, including many speci-mens from the hot deserts of North West Africa (the num-bered NWA series) and some notable Canadiana, includingthe recently unearthed main mass of the Springwater palla-site. The National Collection (Herd 2002; Herd et al. 2010)has the widest selection of Canadian meteorites, and morethan 2700 samples of over 1100 meteorites. It has someiconic samples (e.g., the main masses of Madoc, Abee, andSt-Robert). Other collections include: the University of Calgary(Tagish Lake and Buzzard Coulee falls); Planétarium de Mon-tréal; University of Western Ontario; and smaller collections atthe University of British Columbia, Queens and elsewhere.The evolution of meteorite research in Canada since 1950
has proceeded in part via a number of small, very modestly-funded academic groupings with a soupcon of government
cachet, under various acronyms such as ACOM, MIAC, andADWG. The Associate Committee on Meteorites, and itssuccessors the Meteorites and Impacts Advisory Committee(to the Canadian Space Agency) and Astromaterials Disci-pline Working Group, have all benefitted from a range of sci-entific expertise, in fields of physics and astronomy,mineralogy, geology and geochemistry (e.g., Millman andMcKinley 1967). Peter Millman suggested establishing an ar-chive of mainly-Canadian fireball events at the first ACOMmeeting in 1960. The archive recounts 2129 Canadian fire-balls reported from 1962 to 1989, plus 410 US and six otherfireball reports (Beech 2005, 2006). Another product ofACOM was the MORP (Meteorite Observation and RecoveryProject from 1971 to 1985) that focused on the three Prairieprovinces and recorded 795 fireball events. Based on MORPdata, ACOM undertook some epic adventures, notably recov-ery of the Innisfree fall of 1977 (Halliday et al. 1978, 1996).Within its modest financial bounds, MIAC also sponsored
unsuccessful attempts to locate meteorites in sub-Arctic andArctic settings such as Devon and Baffin islands. A muchgreater degree of success with finds has attended the PrairieMeteorite Search initiative, run by the University of Calgary,Campion College at the University of Regina, and the Uni-versity of Western Ontario, which has sent summer studentsinto communities to solicit samples from the public. The ini-tiative brought to light substantial additional material fromthe Red Deer Hill find, and as many as 13 previously un-known finds, although most of these have yet to reach offi-cial status in the Meteoritical Bulletin.Notable orbital information has been reconstructed after
the fact for a number of documented falls in Canada, includ-ing Shelburne (van Drongelen et al. 2010), Dresden(McCausland et al. 2006), Abee (Marti 1983), and St-Robert(Brown et al. 1996). Detailed contemporaneous follow-upanalyses of public photographic and video records from fire-ball events have allowed for the determination of useful or-bits for Tagish Lake (Brown et al. 2000) and BuzzardCoulee (Milley et al. 2010; Brown et al. 2011). Increasinglysophisticated dedicated camera networks have permitted orbi-tal reconstructions with minimal observer error (Halliday et al.1996; Weryk et al. 2008). Canadian fireball network meteoriterecoveries so far include Innisfree (Halliday et al. 1978, 1981)and Grimsby (Brown et al. 2011). Worldwide, several fireballcamera networks, along with the careful analysis of fortuitouslyrecorded meteorite-dropping fireball events, have to date led tothe reliable reconstruction of just 14 pre-atmospheric meteor-oid orbits (Brown et al. 2011), of which four are fromCanadian falls.
Recently highlighted Canadian meteoritesHere is a quick chronological survey of a dozen selected
Canadian meteorites, including some of the most exten-sively-researched examples, with emphasis on the subjects ofrecent research in Canada. This is a vade mecum, a basic in-troduction, and much more could be said. Indeed, Whyte(2009) has provided an excellent historical overview of 14 ofthe meteorites recovered in the province of Alberta, plusnotes on two more recent finds.Shelburne (1904 fall) provides a classic case of a fireball
event, witnessed on a summer evening, with numerous ob-servers and the rapid recovery of two multi-kilogram frag-
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ments in farmland in southern Ontario (see recent synthesisby McCausland and Plotkin 2009; van Drongelen et al.2010). It illustrates the vastly greater likelihood of meteoriterecovery in the well-tended farmlands and populous areas ofCanada, as in the Prairie provinces and southern Ontario andQuebec, versus the sparsely settled regions of the westernmountains, boreal forest, and sub-Arctic to Arctic regions.Shelburne is a veined and brecciated L5 chondrite, a fine rep-resentative of one of the most abundant meteorite classes,well-distributed in public and private meteorite collectionsworldwide (McCausland and Plotkin 2009).Springwater (1931 find) was the first (Nininger 1932) and
by far the largest of three pallasite finds in Canada in the20th century. Recent searching has yielded more material,and the main mass (53 kg) is now in the collection of theRoyal Ontario Museum. It is the fourth-most-cited Canadianmeteorite, in part because pallasites are an uncommon class,with less than 100 representatives, and because the originalfind was substantial (67.6 kg). Besides olivine and kamacite(a relatively Ni-poor Ni–Fe alloy), Springwater is notable forits content of phosphate minerals. Like Brenham, an historicKansas find, Springwater is famed for its rounded olivinegrains (Fig. 1). See Yang et al. (2010) for a recent synthesisof ideas on pallasite petrogenesis.Dresden (Ontario) (1939 fall), like Shelburne before it, is a
fine example of the fall and recovery of an ordinary chon-drite. The fascinating human history of the meteorite is re-counted by Plotkin (2006). This historic stone (Fig. 2) isaffirmed as a brecciated H6 (S2) chondrite by a recent re-examination of the 40 kg main mass and several other smallindividuals, with a measured bulk specific gravity (3.48) andaspects of mineral chemistry and bulk composition (total Fecontent is 28.0% and elemental abundances are quintessentialH-chondrite, except for low S, with 1.90 wt.% Ni, 0.36 wt.%Cr, and 0.10 wt.% Co; McCausland et al. 2006).Abee (1952 fall) is an enstatite chondrite, a grouping that
includes some of the most chemically reduced stony meteor-ites. It has seen a level of research unrivalled until the arrivalof the Tagish Lake carbonaceous chondrite, 48 years later,being described in ∼130 articles. The single large mass, animpressive 107 kg egg-shaped body, was retrieved from adeep hole in a farmer’s field following a widely observedevening twilight fireball (Dawson et al. 1960; Whyte 2009).The metal- and enstatite-dominated, dense and brecciatedmeteorite is the largest enstatite chondrite known, and socame to be widely distributed and the subject of a multidisci-plinary consortium effort (Marti 1983 and references therein).The mineralogy is very exotic by terrestrial standards, includ-ing graphite and diamond, and other reduced phases scarcelyever found on Earth, such as the sulphides oldhamite, ninin-gerite, and keilite (Shimizu et al. 2002).Bruderheim (1960 fall) remains, at 303 kg, the largest
documented fall or find on Canadian soil (Folinsbee andBayrock 1961; Whyte 2009). An L6 chondrite, it was recov-ered rapidly from a very productive strewnfield 50 km north-east of Edmonton (Folinsbee and Bayrock 1961), and wasdistributed widely for research. Bruderheim has thus beenwell studied as a freshly-recovered representative of an abun-dant class of stony meteorite. Rare gases, halogens, rare-earthelements, the light elements Li and B, and radionuclides suchas 14C are all well-documented in the case of Bruderheim
(Jull et al. 2000), making the meteorite an oft-used referencestandard. The 1960 Bruderheim fall was seminal for Cana-dian meteoritics, being instrumental in the growth of the Uni-versity of Alberta’s diverse meteorite collection (by trades)and in the establishment of the National Research Council’sAssociate Committee on Meteorites (ACOM) as a coordinat-ing scientific body for the study of fireball reports and mete-orite falls in Canada (Millman and McKinley 1967; Whyte2009).Peace River (1963 fall) is an L6 chondrite with shock melt
veins, and rare achondritic clasts (see Herd 2012). It is espe-cially noted for its evidence of high-pressure extraterrestrialshock events (Price et al. 1983), generating high-pressurepolymorphs of otherwise familiar silicate phases, such aswadsleyite and ringwoodite (after olivine) and majorite (afterorthopyroxene). The mineral wadsleyite was first discoveredin a Peace River shock vein (Price et al. 1983). Brief opticalstudy reveals that other Canadian meteorites like Red DeerHill (L6, Fig. 3) may show similar textural or mineralogicalevidence of impact events.St-Robert (1994 fall) arrived in spectacular style, northeast
of Montreal, depositing fragments of crusted H5 chondriteacross an 8 km × 3.5 km strewnfield (Brown et al. 1996;Hildebrand et al. 1997). Several fragments of St-Robert werestudied for noble gas isotopic ratios and short-lived cosmo-genic radionuclides, formed by cosmic ray irradiation of theparent meteoroid during its journey to Earth (Leya et al.2001). From these data, St-Robert is ascertained to have hada relatively simple cosmic ray exposure (CRE) history, hav-ing been liberated as a ∼90 cm diameter meteoroid from alarger body at 7.8 Ma, a common CRE age amongst H chon-drites that likely represents a H chondrite small body breakupevent (Leya et al. 2001). Poirier et al. (2004) reported a pre-cise Pb–Pb age of 4566 ± 7 Ma (2s) for St-Robert chon-drules, and a mineral–whole-rock Pb–Pb age of 4565 ±23 Ma (2s), indicating that the Pb–Pb system was undis-turbed in the early history of the H chondrite parent body.St-Robert is a particularly useful example of a ‘typical’ H5chondrite with a relatively simple, well known history fromits early history on the H chondrite parent body through itsdelivery to the Earth. There is sufficient St-Robert in Cana-dian collections to permit fresh study and re-evaluations,such as of physical properties, density, and porosity(McCausland et al. 2011).Tagish Lake (2000 fall) is a C2 ungrouped carbonaceous
chondrite that appears to be unique; within 12 years it hasbecome arguably the most-researched Canadian meteorite. Itsrecovery is a remarkable story of the arrival of friable primi-tive material that landed fortuitously on the frozen surface ofTagish Lake in northern British Columbia (Brown et al.2000; Hildebrand et al. 2006). Its recovery is eerily similarto that of the 1965 Revelstoke meteorite, the smallest knownCanadian fall, also a fragile primitive carbonaceous chondrite(CI1). Revelstoke was discovered some two weeks after itsfall, when two beaver trappers, crossing a frozen lake onsnowshoes, noted blackened snow (Folinsbee et al. 1967).Multiple, pristine frozen fragments of Tagish Lake werefound on its eponymous, frozen lake (Fig. 4) ten days after abrilliant fireball was witnessed over a huge region. Laterdedicated searching of the ice surface before the spring 2000breakup defined a strewnfield at least 16 km long, consisting
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of more than 420 fall locations (Brown et al. 2000; Hilde-brand et al. 2006). The remarkable fall was soon awarded itsown consortium study (Brown et al. 2002 and referencestherein). Tagish Lake ranks among the most primitive andfriable meteorites ever studied, a heterogeneous accretionarybreccia with high microporosity of ∼40% and a bulk specificgravity of just 1.66, a large range of unequilibrated olivinecompositions (Fo71–100), magnetite, carbonates, and organiccompounds (Zolensky et al. 2002; Izawa et al. 2010a,2010b). Tagish Lake is a repository of prebiotic organic mat-ter with origins in the solar nebula as well as from parentbody aqueous alteration processes, and has become a signa-ture pristine planetary material for developing sample han-dling protocols (Zolensky et al. 2002; Herd et al. 2011).Infrared reflectance spectra of Tagish Lake (which contains4%–5% carbon and has been subject to aqueous alteration onits parent body) are consistent with its derivation from anouter main belt D-type asteroidal parent body (Hiroi et al.2001; Izawa et al. 2010a), possibly representing materialmore primitive than is found in other classes of meteorite.Southampton (2001 find) is the most recent Canadian pal-
lasite find, discovered by an observant passer-by on a beachon the shore of Lake Huron, west of Owen Sound. The mainmass of this beautiful meteorite has been preserved at theRoyal Ontario Museum, and the pallasite has been the sub-ject of recent research (see Kissin et al. 2012). At the timeof its discovery it was just the 52nd pallasite known to sci-ence.Whitecourt (2007 find) is a IIIAB iron meteorite that has
the distinction of being one of very few meteorites in theworld known to be associated with its own impact crater,some 36 m wide and 6 m deep in glacial till (Herd et al.2008; Kofman et al. 2010). Whitecourt was discovered byhunters who were curious about the closed bowl structureand explored the local ground with metal detectors, correctlysuspecting it to be an impact crater. A follow-up systematicstudy found innumerable mostly small (<5 cm) shrapnel-likeshards, similar to fragments from a minority of other irons,such as Sikhote-Alin and Gebel Kamil (Kofman et al. 2010).The “total known mass” recovered is necessarily an approxi-mation. The structure, and thus the impact of the iron mete-oroid, is established to be less than 1100 years old, and itrepresents a size of impactor that is usually missed in the ter-restrial impact record (Herd et al. 2008).Buzzard Coulee (2008 fall) arrived as the climax to a spec-
tacular (magnitude –20) fireball event on 20 November 2008.The meteoroid, estimated mass 10 tonnes, entered the atmos-phere at a low velocity of 14 km s–1 (an average velocitywould be 20 km s–1), enabling it to penetrate to an altitudeof just 12 km above surface before shattering to produce afine meteorite shower of black crusted fragments, the largestfound to date weighing 13 kg (Hildebrand et al. 2009). Initialclassification of Buzzard Coulee is H4 (S2, W0). More than40 kg (>130 fragments) were recovered before the first seri-ous seasonal snow cover interfered with recovery on Decem-ber 6th (Kulyk 2009; Weisberg et al. 2009) and there aremost likely some thousands of fragments, TKW (total knownweight) >200 kg.Grimsby (2009 fall) is an H5 chondrite (McCausland et al.
2010), the 14th meteorite fall with an instrumentally meas-ured pre-atmospheric orbit indicating an origin in the main
belt asteroids (Brown et al. 2011). This fall event is notablythe first to incorporate Doppler weather radar as an essentialscientific component in the analysis of the behaviour of fall-ing meteorite fragments. Grimsby is a fall with small recov-ered mass (215 g recovered from 13 fragments as of early2012) in a mixed urban and agricultural area at the west endof Lake Ontario (Fig. 5). Grimsby made headline news forhuman interest as a “hammer” that struck, amongst otheranthropogenic targets, a vehicle windshield and a garage(McCausland et al. 2010).
ConclusionsVast by land mass but small by population, the recovery
rate per square kilometre in Canada is very low (Beech2003), yet some very special falls and finds have been recov-ered. With such a small number of meteorite recoveries, it isnot surprising that some of the rarer meteorite classes, in-cluding all the achondrites (a broad chemical and textural va-riety of primary igneous and derived brecciated lithologies)are not, as yet, represented (Appendix A Table A1).Future meteoritical research in Canada will likely include
some advanced projects as well as some inevitable associatedspadework. The advanced programs will include continuedoptimization of fireball tracking networks to aid in impactorflux determination and possible meteorite recovery (Weryket al. 2008; Brown et al. 2011), and additional advances intechniques for materials characterization of the payloads ofsample-return missions (Herd et al. 2011; McCausland et al.2011). The lessons learned on meteorites will in the nextgeneration be applied, in all probability, to newly recoveredsamples from the moon, Mars, asteroids, and comets.Less glamourous, but nevertheless of great educational im-
portance, the spadework includes public interaction, a featureof the Canadian meteorite community since ACOM days.Public education via presentations, Web sites and social me-dia, museum displays, and field visits to current and histori-cal meteorite strewnfields are all important (Plotkin 2006;McCausland and Plotkin 2009). It is a common perceptionthat meteorites are “manna from heaven”, and every re-searcher soon develops a repertoire of stories concerning“meteorwrongs” and members of the public who occasionallyare suspicious of any demythologizing of their preciousfinds. Much more frequently, finders of prospective meteor-ites are genuinely curious about their finds and open to learn-ing about meteorites.We consider the best approach to be to engage the curious
public, and (in most cases) explain not only that their mate-rial is not a meteorite, but what it actually is, and discuss thespecific features that attracted their attention in the first place.Almost invariably, possible meteorite enquiries become ex-cellent opportunities to educate the very people who aremost curious about their surroundings. A small investmentof meteorite education can pay large dividends in elevatinginterest in the real wonder of science and possibly lead tothe recovery of future meteorites. Good illustrated referencebooks to have on hand are those of Norton (1994) and Nor-ton and Chitwood (2008).Once a meteorite has been recovered, classification using
standard techniques can be conducted (see, e.g., Dodd 1981;Hutchison 2004), with a view to submitting a type specimen
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to a meteorite research institution as soon as possible to ena-ble long-term availability of research sample from the mete-orite, and submitting a brief descriptive report for theconsideration and approval of the Nomenclature Committeeof the Meteoritical Society.
AcknowledgementsWe thank past and present members of the Meteorite Im-
pact Advisory Committee (MIAC) and the AstromaterialsDiscipline Working Group (ADWG) for stimulating discus-sion, and all those sample preparators who struggle to pro-vide excellent polished thin sections for meteorite research!Reviews by Martin Beech and Michael Higgins were mosthelpful in improving this work. The second author gratefullyacknowledges financial support from the Centre for PlanetaryScience and Exploration (CPSX) at Western University.
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Appendix AAppendix A begins on the following page.
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Table A1. Canadian meteorites — approved (60) and listed in Meteoritical Bulletin.
Meteorite Class Region Ni%Metal Fa%Oliv History Date TKW (kg) RefsMINLIB EarliestChondrites (32)Revelstoke CI1 BC — — Fall 1965 0.001 15 1967Tagish Lake C2 ungrouped BC — 0–29 Fall 2000 11.0 132 2000Blithfield EL6 Ont — — Find 1910 1.83 20 1922Abee EH5 Alta — — Fall 1952 107 131 1960Beaver Creek H4 BC — 19 Fall 1893 14 22 1963Buzzard Couleea H4 Sask — 17.8 Fall 2008 200 11 2008Redwater H4 Alta — 19 Find 2009 0.230 0 2010Skiff H4 Alta — 18 Find 1966 3.54 7 1980Wood Lake H4 Ont — 19 Find 2003 0.35 3 2004Grimsby H5 Ont — 18 Fall 2009 0.215 10 2009Riverton H5 Man — 20 Find 1960 0.103 2 1976St-Robert H5 Que — 19 Fall 1994 25.4 26 1994Wynyard H5 Sask — 18 Find 1968 3.479 4 1980Belly River H6 Alta — 20 Find 1943 7.9 11 1953De Cewsville H6 Ont — 18 Fall 1887 0.340 3 1900Dresden (Ontario) H6 Ont — 20 Fall 1939 47.7 21 1939Great Bear Lake H6 NWT — 19 Find 1936 0.04 2 1963Vulcan H6 Alta — 20 Find 1962 19 9 1967Shelburne L5 Ont — 24 Fall 1904 18.6 20 1904Vilna L5 Alta — 25 Fall 1967 0.00014 5 1973Blaine Lake L6 Sask — 26 Find 1974 1.896 5 1978Bruderheim L6 Alta — 24 Fall 1960 303 89 1961Catherwood L6 Sask — 25 Find 1965 3.92 10 1973Ferintosh L6 Alta — 26 Find 1965 2.201 4 1984Homewood L6 Man — 25 Find 1970 0.325 5 1976Kinley L6 Sask — — Find 1965 2.44 6 1971Kitchener L6 Ont — 26 Fall 1998 0.202 12 1998Peace River L6 Alta — 23 Fall 1963 45.76 39 1967Red Deer Hill L6 Sask — 26 Find 1975 25.0 6 1978Holman Island LL(?) NWT — 29 Find 1951 0.552 8 1963Innisfree LL5 Alta — 27 Fall 1977 4.58 30 1978Benton LL6 NB — 31 Fall 1949 2.84 7 1964Achondrites (0)Irons (25)Fillmore IA Sask 7.18 — Find 1916 0.200 3 1971Mayerthorpe IA Alta 7.19 — Find 1964 12.61 6 1971Midland IA Ont 8.37 — Find 1960 0.034 4 1971Osseo IA Ont 6.51 — Find 1931 46.3 14 1938Annaheim IA-ANOM Sask 7.74 — Find 1916 11.84 13 1921Bernic Lake IAB Man 6.53 — Find 2002 9.8 5 2004Burstall IAB Sask 6.57 — Find 1992 0.359 5 1998Hagersville IAB Ont 6.89 — Find 1999 30.0 5 2001Lac Dodon IAB Que 8.64 — Find 1993 0.800 4 1995Penouille IAB Que 9.40 — Find 1984 0.072 3 1995Torontob IAB Ont 7.04 — Find 1997 2.715 5 1997Bruno IIA Sask 5.79 — Find 1931 13 9 1936Edmonton (Canada) IIA Alta 5.37 — Find 1939 17.34 6 1969Chambord IIIA Que 7.53 — Find 1904 6.6 5 1963Iron Creek IIIA Alta 7.72 — Find 1866 145.93 15 1886Madoc IIIA Ont 7.52 — Find 1854 167.5 26 1855Manitouwabing IIIA Ont 7.34 — Find 1962 38.6 16 1964Welland IIIA Ont 8.77 — Find 1888 8.16 23 1891Whitecourt IIIAB Alta 8.11 — Find 2007 200 7 2008Kinsella IIIB Alta 8.78 — Find 1946 3.72 4 1978Thurlow IIIB Ont 9.92 — Find 1888 5.5 5 1900Millarville IVA-ANOM Alta 9.78 — Find 1977 15.636 6 1979
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Note added to proof
1. A 61st Canadian meteorite was accepted in MeteoriticalBulletin 101, on 23 August 2012: this is the Lone IslandLake IAB-sLL iron, Manitoba, 7.62% Ni in metal, a findin 2005, TKW 4.8 kg, 3 references, 2005 onwards.
2. As of Met. Bull. 101, 23 August 2012, the official worldtally of approved meteorite names rose to 43 973. In jud-ging the qualities of a meteorite display, it may be helpfulto remember the approximate proportions of the majorclasses. In round figures, seven out of eight meteoritesare the most-common, ordinary chondrites (H, L and LL,88%); 5% are achondrites (of which 55% are in the "ves-toid" HED clan); 4% are less-common to rare chondrites,primarily eight subclasses of carbonaceous chondrite, plusthe enstatite chondrites; >2% are irons; and <1% are pal-lasite and mesosiderite stony-irons.
ReferenceKissin, S.A., and Wilson, G.C. 2006. Toronto, a new Canadian
meteorite. Meteoritics & Planetary Science, 41(S8): A243–A246.doi:10.1111/j.1945-5100.2006.tb01001.x.
Table A1 (concluded).
Meteorite Class Region Ni%Metal Fa%Oliv History Date TKW (kg) RefsMINLIB Earliest
Skookum IVB YT 17.13 — Find 1905 15.88 19 1915Garden Head IRANOM Sask 16.96 — Find 1944 1.296 6 1971Gay Gulch IRANOM YT 15.06 — Find 1901 0.483 8 1915Stony irons (3)Giroux Pallasite Man 10.3 11 Find 1954 4.275 12 1967Southampton Pallasite Ont 9.47 12.5 Find 2001 3.58 4 2002Springwaterc Pallasite Sask 12.6 18 Find 1931 167.6 62 1932
Note: All 60 meteorites are listed in the Meteoritical Bulletin, but individual details may be drawn from the wider meteoritic literature. The various fallsand finds are listed by the province or territory where they were recovered: Alberta, British Columbia, Manitoba, New Brunswick, Northwest Territories,Ontario, Quebec, Saskatchewan, and Yukon Territory. No recoveries have yet been reported for Newfoundland, Nova Scotia, Prince Edward Island, and theTerritory of Nunavut. Classification: two key factors are included: the percentage of nickel in bulk metal (irons and stony irons) and the mole proportion offayalite (100 – Mg #) in olivine. Total known weight (TKW) is reported using the best available data, but in the newer falls (e.g., Buzzard Coulee) andfinds (e.g., Whitecourt) the quoted values should be taken as minima. As an indication of the extent of research and general interest, the number of recordsciting each meteorite in Graham C. Wilson’s unpublished MINLIB bibliographic database are quoted. Published titles on Canadian meteorites, appearing asrecords in the MINLIB database, may be viewed in an on-line chronological–alphabetical bibliography at http://www.turnstone.ca/canmetbib.htm
aThe Buzzard Coulee TKW is now believed to be in excess of the nominal 200 kg noted here, in >1000 fragments.bThe Toronto iron (Fig. A1) was identified in that city and classified at the University of Toronto and Lakehead University, but the true provenance may
never be known — an earlier find in rural Quebec is suspected but unverifiable.cThe TKW includes the original 67.6 kg from the 1930s and a nominal 100 kg from recent finds.
Fig. A1. The Toronto iron, in the uncut 2.7 kg mass, a find of un-certain but probable Quebec provenance (Kissin and Wilson 2006).
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