Tertiary basins of Spain the stratigraphic record of crustal kinematics Edited by PETER F FRIEND AND CRISTINO J. DABR IO

CA.\1BRIOGE U~IVERSITY PRESS

GG zr:;-t¡o

Tertiary basins of Spain

¡he stratigraphic record of crustal kinematics

EDlTED BY

PETER F, FRIEND Depamnem Df Eanh Sciences, University af Cambridge

A:ND

CRISTINO J, DABRlO Departamento de Estratigra{ia. Facultad de Ciencias Geológicas ana Instituto de Ge.%!!ia Económica, CSIC, Universidad Complutense, .Hadrid, Spain

CAMBRIDGE Ul'>IVERSI'lY PRESS

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© Cambridge University Press 1996

Fint published 1996

Printed in Great Brltain at the tJnlversity Press, Cambridge

A catalogue rCfordjor rhis book is avaifabie from tite British U/m.'!T.:

Library al CQngress calaloguinp: in pubJication daw

Tertiary basins of Spain : the stratigtaphic record of crustal kinematics ¡ edited by Peler F. Friend and Cnstina J, Dabno.

p. cm, - (World and regional geology series) Indudes bibliographical refen:nces. SBl';0521461715 1. Geo1ogy, Stratigraphic Teniary. 2. Geology, SttuclUral Spain. 3. Basins (Geology) -- Spain, L Friend, P.F JI. Dabrio. CrisiÍno J. lII. Series, QE691 T465 1995 551.7'8'0946 - oc20 9,;·21724 CIP

IS.BN O 521 46171 5 r:.ardback

SE

G6 Mineral resources of the Tertiary deposits of Spain

MA GARCIA DEL CURA. CJ. DABRJO AND S. ORDÓÑEZ

Abstrae!

Spam is the most self-sufficlcnt country for mincrals in thc

El!. A major proportion of these Spanish mmeral resources has been oblained from Tertiary materiaL-. The mab materi:l!s exploited in Tertiary basins have been: brDwn coal and iignitcs. pútassium salts, sodium salts (sulphates and chlorides), diálOmitc. sepiolitc and othcr absorbent days, bentonites. cc!cstinc. pumícc and also dimension (buHding-) stones and ccramícs. portland cement and plaster fa\\' material:;.

PlrZl1-Ag and gold alunite vokanogenic ores, related tú Nco­gene volcanism, bcsides Au-placers ha ve: been mincd from Roman times, Minor Cu and Mn occurrences are 3.1,,0 rev1éwed,

The brow!I coal mines of Galician basins havc providcd aU th::." sígnificant productíon of Spain: more than 17 \tft. Low-t¡uali:y

Oligocene lignitcs in thc castern pan of the Ebro Basin and Ba[earic

Islands are less important from tbe econOm:C point oC view. Other occurrences ~lre in the Guinzo de Limiú. Guadix Baza. GranacJ (Arenas de! Rey) and Aleoy basins.

Introouction

The esrimated value of mmeral production (oíl and gas exdudedl :n 1990 ir: Spain was about S4325 mimon, which repre~

sented over JD/e of the coun-:.ry"s Gross NationaJ Product. Wíth a le\'e: of sU!,ply CS:lmalcd al 3S:~!o of ¡he dornest;c consumption of minenl rav.'< ma:erials, Spain i5 thc most $e!r~sufficient country in

the EU (Mañ.ana. 1991;. Jn 1 990 the wholc prOductlOT: ofbrown coal (20.9 Mt), p01<¡ssium

salts (O,7B Mt). sodium sulpha:e ')al1$ (0,71 :Vi:). ac:r.lOmtcs (0.!5

MIJ. sepiolite-attapulgíte (0.56 Mt). diatorr:.itc (92 ktL cclcstine (SO kt}. and pumice was extracteJ fmm Tertiary rocks fíTGE, I 99:j" The T ertiary basÍns also provldc a largc proponi0n of hgnites. natural stones, locludíng commerdal marbks, ceramlc raw mater­

ia!s. cerncnt rav,· material;; (1irne5tone. c!¡:lYs and gypsum), aggre­g2tes (crushed Jímcstone anó basaH) and gypsum for plastcr m2nufacturc.

Tnis chapter presentsa reviev.' oftnc most important mines, both ac~r'.'e anO biSl0ricaL 2nd occurrences locateo m or rc!ated tü the

The Spanish Tertiary basins (continental ~ind marine, (Oligo- se¿imcntary rocks oftheTcn:ary baSlllf> in SpallL

cene~Mjocene) are fiUed by thick evaporites in which are ootained porassium sal/s and sodium salts (sulp}w[cs and chlorides). The

Montevives celestine mine ¡~ locuted in thc cvaporitic unit of the

Granada basin (Mioccnc), and provides all orlhe Spanish celestinC"

production. Spain tS the world's third largesl produccr of celestine. The Madríd basin and tbe minor Calatayud basín suppl)! I.he

whole ofSpanish sepiolifc production. Tbe :nost important Spanish attapu{gite production 1S obtained ftom the El Cuervo rr.ine (Sevilhl

and Cádil provlncesj. The genesis of the Cabo de Gata benumih deposns is thought to be by hydrothermal altcration and halmyrol­Sts or Neogene volcanic roch, The !\1acnJ basin hcntonitcs ami

'pink days' have been interpreted as HU early diagenetic:. cven edaphic MgMrich, attapulgitization ofillitt:: dayi>. The O105t import­

am areas of ceramic c1ay production in Spain are localed in th Guadalquivir basin (Bailen area) dl1d the Madrid baslr, (La Sagra Alcalá de Henares).

Thecontinental Neogene basin ofthe Heilinarea supplies90\:/{, o: Spanish diatomite production.

26

Metallic ores

The rnost ¡mporta!1t ore are tcc Z!l"Ph~Ag

volcanogenic stockwork::; (nctwork orc~bod¡cs) mi.,d i?l Neogenc

volcanic rocks in south-CU51crn Sp~llf 1). The ami interpretation ofthes.e ore depos.its. are controvcrsü:.!, but in aH case:, thc Ncogcnc vu\canism playec an cssential role ir; the ore genesis (Manteca & Ovejero, 199.:n Slivl!f h,lS becn míned :;incc RUlll2.f,

times in La Unil)n-Cartagcna dlstrÍCc Supcrgcnc cnrichcd C¡)fbnr,~

ates and sulphídes in gossans wen: mincd in thc ninctccnth ccnturj.

T!lC main deposits mincd in this district ~ire Icad, silvcr, zinc. and mino;' barytc anO ¡ron ores. After the Spanish ci\'il waL the croduct1on 01' the district fose to 90 Mt. producíllg lcad (1.2 MU.

z:l:1C (L6 Mt) and sil ver O.S kl), Tw() Pb··Zn,··Ag stoekworks ha\c

beco described re::.:ently in the Mazarrón dn;trict one or thc:;..:; depositscontains 2,9';!f1 zinc. 1 %l Icad. 2í:S g·'t ~i¡\'cr and () Mt ore. and thc 8tner contains 2.3%) zinc, 0.7%1 lead. 20 gil silvcr in a 5 Mt ore (Rodríguez, 1992),

, ¡

1

I j (

G6 Mineral resources

TERT1ARY METAlLlC ORES ¡SPAiN¡

• Sedimefltary oves

.... Volcl'lroge01c "",,$

Fig. 1, S,Jh:IDatíc locatiOQ map uf Tertiary metallic ores (~text),

The Roc31quilnr gold-alunüe fleld lS re1ated to calderas in the Cabo de Gal3 xeogcnc volcanic an~a (Hg. 1). Arribas Rosado (1992) described ore grades up to 10 giL Mined since 1970s, ltS

produclion rea.:hcd ~5 kg ln 1989. Thc N~! Ibenan Penmsula, NW of the Duero Basin and thc El

Bierzo B<13In. \Vas mined for gotd in Rontan times (pérez Garda & Sanchez Palencia. 1985, 1992). More than 7 x 105 m:> of gold­beari!lg scdíments have becn removed in ayer 600 mines. The total amOLr,t of exploited by the Romans in the alluviai dcposits W~15 about200 t (Porter & AJvarez Moran, 1992,. Gold grades up to

300 mg Au'm J have boco deS\:ribed in thealluviat fandeposits ofthe Las \t1édulas Fonnatiorl 111 the Bierzo Basin (see Chapter '\'9). Channel tiH dcposits contain gold flakes Qver 70 microns aCrOSS

(Pércz G2.rcia & Sánchez Palencia, 1985). Therc are repons of gold grades up 10 50 mg Au/m J in rile Omañas Formation in the northern Duero Basin.

Some í'Opper occurrences have been described in the Ohgt. __ x:ene

c0r:gjomcratcs of the norln Ebro basin. The mam ore mincrals are cupntc. calcosine, galena and nativc copper, aH them rc1ated tü

granular cemenlation of congjomcrates. Ore depQsítion is though1 lo be induccd by the oxidising action oí infiltralIonal water on the formation walers of the Oligoccne sediments. The thickness of individual conglomerate layers rcaches g m. The major occurrence 15 lhe Biel :vhne (Zaragoza), with estimated reserves about 500 kt

ano copper contents awuod 1.7-2~'ó. SmaH oxide-hydroxide rnanganesé ores have been mined in the

Campos de Calatrava (Bolaños district) Slnce the ulneteenth ccmury. (Crcspo Zamorano, 1988 a and b). The ore deposits are rclated to Pliocene aUuvial~fan sedjments of the Guadiana aasin. Manganese ores occur as granular ccment ln conglomerates and aIsú as manganiferous crusts. Both types may be rclated to low­temperature tbermal waters derived from the Campos de Calatrava

Fig. 2. Sebematic tocaDOn map ofbrowncoalliglÚtesand sulphur deposíts, an oil shales amI urnnium occurrences (see te~"t).

vukanism. Grade in these ores reaches 3.59';/1) manganese. ano 0.051 % cobalt, with inferred resources of 15.6 Mt (Crespo Zamo!

ano, 1988aand b). Occurrencesofmanganeseoxíd~hydroxidesa

granular cerncnt ores have bren dted in the westem pan ofthe Ebp and Ca!atayud basins.

Lignitcs. brown coal, oH shales and related sulphur 2nd

uranium

AL present the Tcrnary basins of the lberian Peninsul produce up to 17 Mt per year of brown coal, and sorne importan

quantities ofHgnite (Fig, 2). Spain was the second largest sulphuI producíng country in Europe during {he first part of the presen century and thc Tertiary basins were the main suppliers uf thi úroductlOIl. In the 19705 native sulphur mining stopped as ;:onsequence of sulphur recovery as a bi-product of oH and ga

desulphuration.

The sulphur brimstone was obtained f(om bíoepígenetic su1phu deposi ts. The 1912 Spanish $ulphur prod llction was i 4 kt, and at th

sarne time italy, the Ellropean leader, reacheda productionof60 kl The most important sulphur mines since Roman times are locatCJ in Coto Menor (Hellin basin). Up to eight sulphur seams, less tha: 1 m thíck, have been exploited, with a 16% sulphurcontent. At th height of its activity this mine produced more lhan 50 kt per yeal

The rock age al the Hellin sulphur deposits is Late Miocene ti

Pliocene. Other bioepigenetic sulphur deposits and occurrence have been described in the Baza, Fortuna, Lorc.a and Almerí. basins (Reyes el al .. 1992), the Libros basín (Anadón el al., 1989: and Alcoy (Reyes, pers. cQrnmun.).

The Íncrease of erude oil prices since 1971 has resulted in th ¡ocrease of oü shale and coal exploratiún in the Tertiary basin (Reyes & Feíxas, 1984; Reyes & Crespo, 1984). Laminated oil shale in the Neogene basins of SE Spaín (Almería, Fortuna, Lorc<l

28 M .A, Garcia del Cura el al,

Table 1, Properties 01 oil shale deposits in the Cerdanya, Campms,

Ribielos a1'ld Libros basins ofeaslern Spain (see Fig" 210r the

location of these basins)

Thickness TOC Yield BasÍn Age (m) ('lo) (I/t)

Cerdanya Middle to Lite Miocene 250 >5 Campins U pper Oligocene 150 IU 50 Ribesalbes Lower Miocene 100 1-15 87 Rubielos Lower Miocene 250 30 Libros Upper Miocene !O 1-2.6 20--70

Note: TOC=total organic carbon,

Tabie 2. Uranium reserves iJ-¡ lignite seams of the Calaf, Sta. A1ariú áe Queral! /village ro {he SSJY oI Calaf;, and Afequincn;:a areas

(see Fig. 2 for Jocations)

baslils (littnra] basins) and the Xinzo ca Limia basin (SE Galicia)

{sec Chapter W9), The age orthe Tert13ry coal-bearing sediments IS

flOI c1car, because there 15 a controversial dlsparity jn thc dates interpreteé from mamma1 vertebrate biolonation and from palyno­logícal biozonation (Chapter W9).

As Pontes de Garda Rodrigue::: basin This busin is locatcd in (he NW-SE-striking stroctural corrídor that extends for 55 km., vía Pedroso As Pontes - Moinonoro (Sanlanach el al"

1988). It is an elongate basio with 7km maximallcngth and a \vídth varying [rom 1.5 lO 2,5 km (Bacelar el al., 1991). As mentioned

earlier, the As Pontes basin is a compressional basin partly controHcd by a dextral $trik~slip fault. The sedimentary filI was alternarely overthrust hy. and onlapping, the Hercynian hasemcnt during the successive defonnation phascs. ThecoaJ seams appear 10

llave formed as a consequence of relative rcstrlction and expansiún between the lirnnic and alluvlal systcms in response te lhe varying subsidence ofthe defonnation phases. Two depocentres developed in the basin: one Iocated in thc ;-";\\1. the \\'est Field, and another

located in the SE, the East Field. The fiil of tl1e As Pontes basi;¡ ha;;

Area Reserves l Resourcesi been divid~d into fom sedimentary units represented in both coal fie:ds. The thickness of individuai seams varie:. from 0.5 lO 15 m.

Calar Sta Maria de Querah. l\.kquillenza - Fraga ~ Almaret

Note: 'Reserves US $15-30ílb lI,O,

15.3 13.6 51.9

26J 26.3 93.4

Hellín), located in a marine pre~evaporitjc environment of

Tortonian~Messianian age, have been described (Reyes et al..

1984). O" .heother hand. A""dón el al. (1989) have described seme oil shale occurrences in the Cerdanya, Campill&, Ribesaibes, Rubie­los and Libros basins (see Fig. 2). Sorne technical propertie:; ~ TOe (total organíe carbon), oil yield (lí!) aud geologlCal data (age, oil bearing shales unjt thickness) --- have been induded in lable L

Radioactivhy anomaHes in the tign1te seams of the Calaf and Mequinenza areas (Ebro basln) (Ramirez Ortega. 1966¡ loo lO the investigation of the uranium contents and distribution 1n thest: Tertiary basins. As a result of this explo;'"ailon, tile uraniurn

resources ofthe lignite seams ofboth basins have been estimatec as

up to 80.8 k. ofU (which sells at l..lS$15-30 per pound ofU,O~1 (:\rIartín Delgado, 1975) {Tahle 2). At present severe difficulties in extracting uranium froID tignites, in addition to the availability of

important Spanish high-quality uranium in proven quantity, make these Terüary deposlts uneoonornÍc.

Fossilfuels (vil and gas excluded;

Brown coa/s of the Galida hasins

Several Tertiary basíns occur along two cextrai slip fau!1 lones in NW Spain. Brown coa]s were formed Ín the tcrrigenous deposits of these basins, as a result of the evolution of the alluvial

and limnic systems. The largest coal deposits recordeó so far in tr.c

zone occur in the As Pontes de García Rodríguez anó MeÍrama

a:-¡G dis:vhys contlDuity alor:.g the basír;. although thcrc are lateral

changes to terrigenous sedimer.ts in the marginal facies. In thc basin. 19 coal seams have been ¡dentified. Tnree main lignite typcs nave been djstinguished: browncoaL xiloide and pyrOpiS¡:1C ligmte. the last rnam]y formed by resin::;. The vi¡rinÍtc reflcctancc varies

[rom 0.1 to OA, the average being 0.3 (Martín Calvo. 197Jt Thc average calorific value varies trarn 1600 to 2200 kcalfkg. TOe waste" lignite ratio average in tiJe open pit tr.incs is up 10 threc. Thc 1979

reserves of the As Ponte s basin were 318 i'\"ll. and thc 19R9 lignite production in the bastn was 12.6 Mt.

Aleirama basin This basin is located in tne NW~SE­striking strucmral coffidor via Lendo~\1eirama-,.aaimil (Sanla~ nacn et aL 1988). The 3urface area ofthe basin ís aboUL !.5 km}; il

has an elongate shape. wÍth a long axis le:lglh l)!' ~i.h(1Gt 2.6 km. parallcJ lo the mall1 dextral strikc-s1ip Jaul:. Tbe th;c::Za~>s of lh¡;;

basin fill 1" up tú 250 m and it 15 lOr:giludinaily fojdcd. Thc

production in 1989 was t!sHmated as up lO 5 Mt, and tbe p;oved reSOl:.rCes. are nearly 80 MI.

Xinzo da Limia basin Thí~ ba)ín l:; Jocated in the Vi¡­

lalba~Maceda~Xjnzo da Limia struCltlral lln:::aliol1. which trenes NNE-SSW. The sediment fill of the ba$i:l is up lo ?5(J m thick. aoe.

up 10 i30 m ofthis may be lignitc scams, Thc quahcY ofchc js browr: coa!. and the proven reserve;; may attain 4.',] Me Thc

economic potential of the dcposit W¡'.S in\'cstigatc-d rcccntly by ENDESA (Baltuille, pers. com"'"n.;.

Lif(niu:s of {he Ebro Basin $evcraJ coal sequences deveiopcd in Ohg('CenC ümes in

the Tertiary Ebro bastn. Despítc tile faet thut thc individual scams oí coal are thín ana subeconomic, mimng has laken place sincc the

nineteenth century in the CaÍ2.f and Mequinenza areas, In both

G6 M:neral resources 29

;.¡,rea:., the nrgaoic bjomarkcrs identlfied by Gorch el al. (~992) ::.how

tha~ the ongmai org:anic matlcf derived maínly from

and hactc:-ia

p:üms

{'afa! :HUI T;¡:.; coal-bearing stratigraphic scction

(clfIr:ed in tbe Scgar:-'-l iacusrrinc system and consÍsts 01' Umestone~"

mads, tcrrigenous une cvcn eV<ipOri¡:JC sedimeots of Early OUgo­cene agc(Gúrch da!., ] 992). Th~ palud:ne-lacustrine. coa!-bcaring

mtcrvuls cüosis.t maínly 01" lin:estone and grey :r:udSiOne beds that intcrtlnger \\'Hh knticubr chunncl-nH <;and.stones showing éf(js~­beddi:¡g and ripplc iaminations. The grey massive :r:uds:ones are Imerbeddcc \\.'ilb coal é.cams ranging [mm a few ccntimctrcs ~o

0.8 m in thicknes:-:., ();gano-sulphur compounds(Gorch el al., 1(92)

are r:m:r.ly ;..;spor:s:h!e for thc high ~ulphur content ortbe lignites. The coals (0r.:-.;:;1 n:unly of jignite tú sub-bituminous ('oal \\.¡th (;~)lorift(; \,-dtJ<2:S ~na¡ '.-ary rr¡JIU 6,400 to 7.042 (Cabrera &

Saez, 19x7:, J <.;ulchlir cOnlent ~hat v2.ries fmm 2.98 to 8.36% and ash contc-nt L\nging !'rnm 16,46(;!(¡ to 24.\8%. The rescrv..;s j;¡ tile Calar arca arr: IIp lO.'-1- Mt (fG:\'1E, 1985). From lhe petrologlcÚ:

poim of \'ICW. thc clJals are vitrinite~nch wíth minor an:ounts 01

exinite :lnÓ incrtlle. The vitriníte reftectancc ranges from 0.4 to 0,7

{!vÍttrtil1 Ca!\ ll. I 'Ji}.). This author pointed out the relations.hip hetwcen the 'J:ai1lU!n content ;md thc organic matter contcnL ,md

~hat ~;:aniun: is prclücntia¡Jy associated with humines and humic

POT ASS!C ANO SOD!C SAL TS AND CELESTINE '

:' ~a:1 "¿'~lalOI11(l ()\$It1C\

Ka.2 Navarra dlstrict

, "i(H Viile.rrJbia m,M "1&-2 VI'laoono;os milla' 'Ja<) C<I'l:ltO n"no ~¡¡¡'" 8elOw.do 'Il'1'6 Na-6 AIoa~adre "-Jna Na~ Ca¿\al'¡,dbaSl~

oOGCoJIT&1'\OOS NnCl q~roo mIne

,:v 1 \A(lf\tir,¡<II!<S ""In!

Sr,2 E;;;é:Í;¡or ----~--- .. _--~ .. _~ ~

Fig.3. Schematic locati<m map of PQtassíc salts. sodic salts aod cclcstínemines (se<> text).

acid [meaons. Local \'aiues of up te 0.180(/(1 U 308 content haye Recently. Ramos-Guerrero el al. (1989) have described the Binisa­bt.""en recordcd, ,¡;ü:oJgh ';,vcnge values are oearer tu 0.020% ¡cm member, which consists mainly ofan alternation onimestone

LJO:;< (biodastic wackestone) and lignites. The eoais consisr mainiy ofa

.\lcquinen:a art'u The coal-be~uing straugr:¡phic inle!:"­

n:d fonned in lhe Lu-; ?víonegros iacustnne system and consists of

limestones. marls. anJ evaporític and terngcnous sedllnents úf the Late OligoC";llC, The ímmcdiatc coal-hearing strata of the Los

Moncgros lacuslrinc :\ystem conslst main!)' of paje brov .. 'n to grey

mier:i::c lioc::,tones. grey mucstones and mjnor sandsl0ne leuses

Jad sheet:>. Thn: kr:tj(:u~cr c~'al seams il1lerfinger with the lower and

m;dd!e p(~rt 0[' i!~e '.J:1i~, Incij'viduai ~eal"!1S are ge:neraily thln wíth sharp and \;;ell-dcf.r:c:c bou:1danes. Tt:c average :hicknc5s ¡:; less

than 0,3 m, ú.nd vuries fro:l', 2. few cer.rimctrcs 10 0,9 m. The :;::oal

deposits consist mainly of an <lsh-rich ~¡gnite. witt: 3(~53\V(\ ilVtt'age

ash content, a high 5111phur contcnt. nu:ging from L5:! to 11.83%,

and calorific values rang¡ng from 3.500 to 5.500 kcal,'kg (Cabrera &

Sácz. 1987). The pro ven reserves are 260 Mt (laME, 1985}, TabJe 2 p:Tsents O:lta on the uraoium resources io both the Calar

and the Mequiner.za coai areas.

O¡ha Terrian coat basins The onl)' mines active at present and not a!ready discussed

are 10 Balearte Basíns. These mines produce up 10 14 kUyear of

ligníte. The identified reserves of]ignite in lhese busins are up tú 71.4-

M10 and the proven reserves are 29 Mt (Fig. 2). In the Balearíc lslands. Jacustrine dcposils huye been describcd,

úfEarly Oligocenc, Ludian-Sannoisian agc (Colom. 1983) and of Middlc Eocene age I Ramos-Guerrero el al., 1989). Only the deepcst

Jacustrinc facies of the central part of Manorca contams lignite searr:s (Sta \1aría. Binisalem. Alaró, Inca, Lloseta and Selva).

humic matrix that contains exinic macerals, such as rcsinite and cuüníte (Ramos Guerrero el al., 1989) v.,.:ith calorific values up to 4.6 kcaL'kg_ L 7% sulphur content and J 8.5% ash content (Cafom,

i983í. Lignite occurrenccs in Tertiary basins have becn cited in the

Cerdanya. Alcoy, Guadix-Baza and Granada basins (Arenas del

Rey). In the Prats-Alp afea of the l'\eogene Cerdanya basin sorne

lignite beds have been ídentified in unit e 01' Anadón el al. (1989) (Fig. 2), The lignite-bearing sediments ofthe A1coy, Guadix-Baza and Granada basins have been reported as Late Mi,?cene - Plio­cene. Lignites from these basins are maínly soft brown eoaIs.

In the Neogene Madrid and Duero baslns, tn the iower evaporitic uníts. aná also in the limnie shaHow marly sedlments, minor organic

¡cater occurrences (lignites and/or oH shaJes, have becn cited.

Potassic and sodic salts~ and celestine

SpanisÍl T ertiary hasins. both continental and marine,

L':ontain thick evaporitic deposits from mús! ages of lhe Teniary.

Potassium salts. sodium salts (sulphate and minor chlotlde), celes~ tine and gypsum are obtained from th~ Tertiary basins. In this

sectlon we focus on potassic and sodic salts and celestine. (Fig. 3).

POlassic salts

The Spanish production of potassic salts has decreased

from 860 kt ofK,O in 191\1 to 585 kt in 1991. Al! the production is

concentrated in t\\'o mineFcl.l distrlcls: Cata10nia and Navarra.

30 M.A. García dd Cura el al.

Table 3. Ettimáléd mineral reserves OlpOlGSsic salts in lhe

Cata.[onia and Navarra distrÍCts

District

Catalonia Navarra

Proyen

10470 2000

Source.' From ¡TGE (19921,

Amount of resource (kt)

Probable

9185 8000

Possible

l6645 12000

Estimated mineral resources and reserves in these areas are pre~ sented ín Table 3,

Salinity increased dramatícally 1.1 the Sub~Pyrenean basÍn during the Late Eoceoe···Early Oligocene (Ludian); most probabiy íl was this salinity tritÜS tnat was responsible fol' the deposüion of potassic

saIts in the basin. Deep dril! noles reach potassic salts in the central part of the Ebro basin below a thick cover of 01¡gocene~Neogenc sediments, Pueyo (1975) and Rosell (l983J inte,preted the depo­sitian of salt as related tu marine brine with a lo\\" I.~on:ent of magnesíurn sulphate. The basln underwent active nappe {ovcr­thrust) tectonics after the deposition ofthe salls and, according:;o Rosell (1983). tbe Catalonia district remaÍned in the a utochthonous

zone, whereas the Navarrese district was lransponed by thrusting.

CATALAN POTASSIC BASIN

350 m

300

can-:al:iT0 a'1d top $alt

2SC

B ¡ayer A layer

--- "",,--,

g!SS~i CAANALUTE

lf!.iItI SYLViNITE

ráicT8~ hAUTE

:';,. ':. TI ANMYORITE(:)R GYPS~~J.)

ená!!1 MUDSTONE

NAVARRESE POTASS1C BASI~~

IOp .f,'~if¿;" maristone

too sal:

bottor'"'. sa:t basa: anhydr<te

!guaiada fI.~a'1SlOne Pamplona Marls:ore

As a result, erosion removed the seams of potassic salts in the eores Fig. 4. Strntigraphíc secoon ("Qrrelation betwcen Catalonian sud Navarrese

of the anticlmes of the Navarrese rlistriCL whilc tbe anticlinaJ eores potassíc basins. Arter RoseU (1983).

were preserved ¡n the Catalonü: district under a thick eover or Oligocene scdiments.

Catafonia disuict The structure of the Catalan cIslr'ict is an E~W·trending syncHne, with salt thicknesses ranging from 150 to 500 ro (Pueyo, 1975) as a consequence oflocal tcctonÍcs" in thc

Cardona diapir the tbic-kncss of potassic salts reaches 2000 m. Thc

main, and best~known mines (Cardona. Balsareny and Sur;Cij are located in this distrie!.

Tbe stratigraphic sectlon indudes. from bouom lo top tFig. 4J:

L Marine roarls (Igualada maris). 2. 4 tú 5 m, lamÍnated anhydritc. 3. 130 to 200 m. massive halite (sa! de n;.uro). 4. 5 to 20 ro, lower pot.assic unlt. consisting of decimetrc

sequences of terrigenous clay_ carbonates, sulphates,

harlte and silvitc. Th15 unit 15 ciivided jmo two by a thick ¡ayer of massive halite.

S. 4ü to 80 m. upperpotasslc unÍt (carnallitic unit) inc1udjnt: severaJ seams (threeor fourm the Suria mine. and more in other localities). It IS interesting to note that the contenl oí" haiüe (low-grade potassíc salt) in lhis unlt increase;; when the seams are thinner and less numerou~.

6. 85 to 120 m, grey mudstones, or transítion unit. Sorne intercalations of halite have been described in thc lower part of thIS uni~.

7. 500 m (or more). lacustrine reddish deposíts (top).

NavarreSr? distriu As in the forrner case. the potasslc salts are associated \'vith

m2TÍnc marls (Pamplona marlsi. Thc only mme (Subiza shafO lS

located in a synclinal basin (the so'called Pamplona potassic basir: o; Sierra del Perd6n potassic basln). hut a rescarcb programme has

only rccemJy been initiated A general stratigraph1c succcsslon mcludcs~

L Deep marine rnarls (Dottom,. ..., 0.6 to J ~n, laminated anhydnte uniL

.'. Almosl 10 ffi. 10\\'cr bandea. massiw htllite enit (sal dt.' muro)_

4. J m, lmver !30tassic uniL formcd hy 18 silvinitc~ha¡¡tc couplcts: SQme al' Ihem are uscd as markers.

5. 12 m. carnailític untt. made IIp nI' e;ght halitc·-carnallilC

couplets" 6. Tol' halite uniL made up 01' sequenccs of decimcfre· w

mctrc-thici:. red mudstoncs a:1d centlmetn>thlck haliu ... ' :ayers"

7. Up to 50 m. I.op marls. r:iUostoncs with sorne anhydrit.:

[t should be noted that tui s stralígraphic scction ¡s very similar to the one in the. Ca¡alonia dlstrict (Fig:. 4). The onl)l diffcrcncc is the

total thickncss.

G6 Mineral resources 31

Tabie 4. Reserves (~I .,'¡)(li;~m saíls in Spanish mining ¡{istrie!'?

Company

Crimide~a

Foret M ¡nera S. l\·1arta Sulquisa

Raw tr.ateria! Plant lacatioo

Glaubcrite Cerezo l.ie Río 1'lrO:1 Thenardite Vi;¡arrubia Glaubente Belorado Glauberite VillaconcJos

====~===

,Vo/es.'

(a) Open~pít solUlJon: (b) underground mine, Sourcr,' From ITGE (1991)

Sodiwn WlirS

Für m2.ny year5, Spain has been .. he European leader :r:: natural s0dium sulphatc production. and al1 01' it comes from

Tertia¡y continental basins. Thc 1990 Spanish natural 5.odiUlU

'5ulph2.te production.ll1 tc:ms ofNa]SOi content. amountcd to 714 ::L ::40 kt fraln thenardite only in thc Madrid basin. and the rcrr:aindcr from glauberiíe in both the :\1adríd and Ebro basIn>. particularly lhe T atia.ry Trench or Bureba Corridor in lh>': wcster:1

pan ofthc Ebro basin (ITOE, 1992). Table 4 presents somedata 0:\

the reserves 01' thc mining districts. Thcre are l\VO active mines in the Madrid basin {Fig, :5). one

located near Villaconejos~Colmenar de Oreja, a.nd another located ne3r ,he eightecnth~century rnu:e;n V1I1arrubia de Santiago.There

are many no~longer-active mines b the M2.crid basin. but. in (!le pas!. the most common mcthod of recove,ing salts was 10 use saEne springs and wells (c,g. Espartina!ó. Carabaña, Carcabzdlana.

Loechesl. and sorr;e uf these werc cven being expJoited ia Roman tImes,

The mine locatcd ntar Vil1aconejos~Colmenar de Oreja (the Ffltima mine}, 1:3 ¡in open-pitdíssoJution mine. Thcminera i glal~bcr~

¡te is prefercntlally dissolved In poois locared over a bOO of glauberit~anhydrite lhat is 27 m thíck. The brine is recovered by pumping ¡rom wells ana scnt to an evaponuion plant where top­~ualir: sodium sulphate precípitates. Thc 50urc-e brines of the evaporation plant are ¡ntroduCéC into pools and then recirculated (Ordóñcz ét aL 1982).

The mine 10cated near VilJarrub13 de Santiago {'El Castellar'} is o. pillar and room undcrground mine Ihat works a )-8 m thick thcnardite hed \vith minor glauberitc. ll1e minenll cxtracted ¡s

processed in an cvaporatÍon plant to obta.in thc cornmercial SOdlUffi

sulpbate (Ordónez el aL, 1982).

The Neogenc stratigraphic record ol' the :Madrid basin is sum­marised by Megias el al. (1983) and by Calvo el aL ¡Chapter e:). The sodium su!phate :r-Ínes are locatcd in the Lower Unit, Tbe sedirnentological intérpretation of the LO\ver Unit or Saline Cr.it has been discussed by Ordófiez el al. (1992) aud by Ordófiez & Gard~l. del Cura (1995), The mineralogical2.nd petrological fcatures 01' the e:::onomic saline deposits have been described Garcia ce¡ CJfa (1979'1. García del Cura el aL {l979) and Orti erol. (1979). The

ExtraclIvc Ba::;in ",ethod

Ebro Trcnch a ~adrld basin b Ebro Trench a Madrid basin a

Proved reserve (Mt)

19 15.5 63 57

'=-=w.~' ;_~..>'XBil"

:_.'f"f:HW' : EiI Mlt)"AfOWf ~OQ'HI' . == LóW'.;l '"'

!;:=~~iKUlE : L ~'t~~lc.\lWltl=~ !m~Tl\'CJ.FOOHAT['. :~::t=iq~,~_,,,,1!O:»W: : 00 C_M~¡J.lltllil!lJ.\¡jj ! ~ ..v,vf~tww.,,_

Hg. 5. Locatioll map of main active mines in Madrid basin: l. Vicálvaro scpioiite mine; 2. Almodóvar sepioUtt mine; 3--6, Yepes-Cabañas de La Sagra mines (bentonítes :l:nd sep¡olite); 1. La Sagra cernmic raw ciay mines; 8 ami 9. Esquil'tasspt;ciai day mines: 10 Alcali ceramic raw clay mines; 11. VilIacol\é-o jCtS ('fátima míne'}sodium sulphatemine(glauberite); aOO 12, ViUarrubia ('El Castellar') sodium sulpbate mioo {glanberite and thenardire).

only paJeontological data obtained from the Saline Unit are lhe flora found in an exploration drill hole near the Víllaconejos mine.

This flora indica tes a Late Ollgocene - Early :Miocene age for the

S¿línc Unit (Alvarcz Rami~ i!l al" 19891. The 'El Castellar'mine is pJaccd ín the IJpperSalincSubuIliL The

sedimentology and facies ci:istributiDn ofthis Upper Saline Subunit

are poorly understood, and are, at presenL under review by the

3uthors of this chapter. However. it is possible to point out sorne distinctlve [catmes 01' tbs Upper Satine Subumt,one being the presence 01' thenarditc as the rnain minera!, and an'other being the local and restrictcd character ofthis Subunit.ln thís Upper Subunit

it h; possible to identify at least SIX repeiitions oC the fúllowing sedimentary dm to m sequence: 1. reddish mudstone containing interstitlal haUte; '1 muddy tcrrigenous sediment±

halite ± glauberite: 3. massfve thenardite ± glauberite. The thenar­dite± glauberitc bed ffiined in Vil1arrubiais up to 8 m thick (Fíg. 6),

The massive thenardite mined there displays a typical bIue colour ana 15 thought to be 3 secondary mineral from rnirabilire. ThlS soft

32 M.A. García de! Cura el al.

® UPPER uNIr

M100LE UNIT

LQWER UNI'"

" ;~~:. :.:. '.' ;;;;;; ~ 15 --"~::~-,

'" ~lliJ···~··L.~. : ...• ,,\.-" ~'-_ '~-" C'v ~ --:=-=-~--

~ G"r- ',.- v v'

G_AUlli-'iiH. -L.A'.lINAJW'.U:::S-U-l'- --MAl'TL -rOt."rALi~c

ANffYORI~;:

s""c, t,AR O'oSiJ'~

G~';>SlI'¡

::Cru;ftlOY"SWt :-.z::-z:z,

S"filA1 J:clAPblC O\..'V;O<> ,1\,Un­"'>.0'0" '{ARSTIECATC'.

YIFA?UTE

T>-t.:: ... ..,;:m;;¿

RiOD M:JDSTONE ,.,n,.., HAL,';[

L"'C":S7;:¡NE·PAllTlA~ U"ES-;CNE

;oLN,ATIL¿ OEPOSIT~

DOLOS7ONi'

Flg.6. Location of VillarrlJbla tbenardite±giauberite mine. Stratigrapbíc sectiotl of central part of Madrid basin aud a det2iled secriofl of thenardite seam mined tbere.

ane \vet crystaHine mirabilite precursor of lhenardite formerl} contaíned sorne precjpitaled idiomorphic crystals of glauocritc that are now enclosed in massive thenardlte,

The g'auberite mine of VlUaconejos exploits the iowcr Salíne Snbunü (Fig. 7). This Subunit i5 thought to have fonned ¡n a perennjal sahne lake surrounded by a wide mudtbL As pointed ou: by Ordófiez el al. (1983) and U trina el al. (1992). brÍJ;cs of th¡s salinc

lakc werc derived mainly frorn the weathenng of Upper Crel,l­

ceous--Paleocene marine evaporites. Saline mineral associations ir; this stratigraphic mterval are reported in Fig. 7. Glauberite úCCUE

as a rnassive bcd of idiomorphic glallber:le crysta[s, with minor

magnesite maris interbedded with anhydnt::: anc mic:itic magnc­siüt Glauberite cements and nodu:ar anhydr;tc hal'c rccently bce~ intcrpreted to rcsult [rom the eady diagene::c g!auhemisation of

primary anhydrite in I.he muddy tacusuinc beh dwring episodes of lo\\' lake water leve!s (OrdÓÜI?Z & Garda del CUf;J. 199.3).

The Cerezo de Río Tirón, Santa Marta and Bclorado glauberitc

rnlnesarclocatcd in thc Tertiary Tre¡;ch" 'La Buret'K! Corridor'. tnal COnnects the Ebro and Duero basins. GJ~ubente r:nine:¡ are locatcd in tnc Cerezo Evaporite FonnailQn ofuncertain Late Miocenc agc. and are restricted to the central part of a sma]1 basin. The Evaporilc Formullon displays sharp latera! facies changes JO non-economic

de1ntal sediments through salme mudslones \ .. "ith nodul:.tr anhyd­rite, A perenníai saliD e model has heen proposed 10 cxplain the general fealures of the Evaporite Formauon (Mcnduiña el (11 ..

1984), The detrital sediments la{erally assocÍined with the salm.c deposits have been interpreteu as the distal pal"t 01' a progradíng lacllstrine deltaic system, and thi:; modcl has been used in th.,;

ex!>loration of the Santa Marta mine. which started production in 1989.

Tbe recovery method used in Cerezo de Río TiróYl ane Bdorado

is similar to that described in the Villaconcjos rr.ine. that:::-; to :$a)'. \{1:

:JJ Z O N CJ Z OC W I

~ W S

150

, 100"

50

, O m 1

G

A+D H

A+D P+H A+D P+H

G+H P+H A+H

ill GLAUBERITE (G) >,~.~.! ANHYDRITE (A)

, o o , HAUTE (H)

, •• ~ POLYHAUTE (PI

~ DETRITAL ~ MINERALS íD)

M: MAGNESITE

C: CALCITE

GYGYPSUM

f"ig. 7. Schematic: mineralogícai section of an exploration dril! bole I.ocatro clase to the VlUaconejos glaube-rite minl'.

G6 Minerui resourccs 33

AV .. U1P\LSYSTEM ~'Mil' ;N"el

-'-SHALLOW SAU\t LACUSTPiUE $YSTF~'

--.'.~~Q1~~ .

Vigo 8. Paleoem-ironmeuial :inri sedimcnto!ogical modcl of Alcanadre non­acth'c mine. Adaptéd from Salvsny & OrH (1992),

apeo 1m solutio:1 H:ine n:t dowtl to a glaubeiitc seam; the ¡;;::mlting brine is tlle mw material for top-qLnúty commerc2.1 sodium

suiphate. The Cerezo [yapOrilc Forrnauon stratigraphic interval contains

dltcrnatíom 'Jf metré-thlck seams oí' rr.icrocrystaíline glauberite and non-economic muddy anhydritc. The numbcr of glauberitc

seams is up to eíghI. but i.hc recovcry methods, aad the commercíal productivity oí' Lhe seams. are conditioned by the ?rcsent~day topography ¡~nd by the impoverish:nent of the upper seams by infiltration 01' meleonc wate:;s.

Somc no-Ionger-active underground mines with glauberit~ have becn dcscribcd from the wcstern Eoro basir.. Thcsc gJaubcrite deposits are ~ocatcd in :hc Lerin Formatíon of Late O!igoce:-Jt:­Early Miocene agc !Salvany, 1984: Salvan y & Orti. 19Y2. 1994). These authors have rCéently proposed a paleogeographic2J ana scdimem.ological model lO explain the rnain fcawres o[ the Alca­nadrc mine zone (Fig. 8). The thicimess ofthe ovcrburden and the tlunness orthe glauberite beds result in hígh values ofthe stripping ratio ano the submarginal cconomlC cllaracter of these occurrences.

Sorne glauberite occurreuces in toe central part of the Eb¡o basin ;lod below the halite beds of La Real rr:ine (Remolinos-Zaragoza) have been described lFcrnández Níeto & Galán, 1979: García Veigas (Ir al" 1991). Some outcrops of giauberitc beds havc <11';0

::,cen reported in the Caiatayud basin (iGME. 1980; Sánchez \1oral el a!.. 1993).

HaJite rocK salt is present in both continental and marine T ertiary baslns ofthe Iberían Península, The 1990 Spanish produc­tiouofsodiumch1oridewas3.3 Mt, 19.8°/" o[which wasobtainedas a byproduct of TcrtIary porassic sait recovery. and 3.2% was obtained from the Tertiary Ebro basin. A high proportion oí' toe remaindcr was obtained [rom the natur¿:l evaporation 01' marine brines, and a smaller proportion fror.1 Triassic rock sal! deposits. The rock salt deposits of Remolinos anó Torres de BerreHen in lhe Zaragoza Formation (Lower Mlocene) o[ the centra! pan oí the

Ebro basio have been mined for a long time. Proved reserves amount to more than 16 :\1t ~aCL Thc halite deposit is up to 100 m thick. and oonSlsts of decimetre laytrs of halite with miflor uodular

anyhdrtte (Oni & Pucyo. 1977), The lateral contínuity of the deposlt i$ over 30 km slong thc E;:;ro nvcr valley (Ortí, (990).

Cdestine

Spanish ce1estinc production has risen from about 19 kt in 19XO :0 more ihan 80 kt in 1990. Spain is the thírd country in lhe

\\-orld ranking of production ofthís mineraL Celestine is produced from thc \:1ontcvíves mine, about 12 km soutnwest of Granada (Granada Province). Thc Montevivcs ore grade is 80{¡!il SrS04 , with

proven rese-;vcs 01' 3 Mt. Thc regulari:y o[ the ore body in lois case cnabies the deposit lo be competitívely concentrated by the fto­tation method.

The Montevives mine ís ¡ocated in a sr.1a~l hiil in the central part

01" the T c:-tiary Granada basln. The host sedimentar)' materials are oi' Miridle to Late Mioccnc age. Reccntly, Rub-io 1"'avas (l990) has pointed om rhe :íC¡JX domic struct'Jre of the Ore DOciy and thc

tcctonic character ol' the cdestine ore bod: oUlcrap. Thc celestine ore is strata baund, up to 40 m thick, and itdips 20"

tJ 50° towards the northwest. The cciestir.e minerahsation displays Ci. mm~sca¡e. clcu~dark banded Iexture similar to the- primary

::ctromatolite texturcs ofthe hOSl lin:estone and marls. The rich ore display;; a massive structure and earthy aud/or microcrystalline textures wiLh ob¡iteration of primary structures, The ore body 15

\vdl stratified ln layers rallging from 20 to 50 cm thick. In addition 10 celestine, the mineral pamgenesís ofthe Montevives ore deposits ¡neludes calcite, dolomite, quartz. gypsum. strocianite, Fe-Mn oxides and hydroxides, phyllosI1icates. efC.

The EsC".izar viHage celest1:te occurrence is an E-W-striking outcrop with more than 10 km tateral contmuity - the Escúzar

Ceiestine Belt ofMartin el aL (1984). The host. rock ofthe celestine me is aIso a stromatolitic lünestone. and the thickness ofrhe deposit is rough!y 20 m. The average cdestine content is lower than al Montevive5, and rarely rises 10 55%. A significant feature of this occurrencc is the presence of a karstic surface at the LOp of the deposit, with dalines and other katstic depres-sions filled by low­grade brc-cciated ore and stramaw1itc carbonates. Escúzar has cstimated reserves of about 1 Mt,

Both the Montevives und Escu.zar celestinc deposits have beeo interpreted a...'i [he resullS of cady diagenetic c--ementation of stroma~ tolític carbonates woen cessicaüon processes followed the faH in sea·level (Martln e! al.. 1984). In this modeJ. the s-trontlum is dctived from marine connate wsters.

Othercelestíneoccurrences have becn ctted in the Duero Tertiary b3s1n (Ordóñez el al.. 19t:O), ana Ebro basln (Rubio Navas, 1990).

Speeial clays (sepiolite, attapuI~te and bcntonites), ceramíc clays and diatomites

Sepiolite, attapulgite and bentonite deposits are com~ monl)' associated in the Tertiary dayey formations, and in conse­quence these minerals are mined together or in the same areas. The, offidal statistical data of these special clays show sorne contradic­tory interpretations beca use the uses ofthe special clays are similar

34 M.A. García del Cura et al.

SPECIAL CLAYS {SEPIOllTE, ATIAPULGITE AND BENTONITE), CERAMIC CLAYS ANO DlATOMITES

~=---......... _----

• Se:lX},::¿

• 3.1CkWC~

* N'3.¡YJ'';''''

.. &:l4~W\(¡f>

Fig. 9. Sclrematíc location map of special clays (sepíolite, aJtapuJgíte and bentonite). ceramic clays ami diatomites (see tex!).

and geúerally connected with tbe physicaJ propcrtic.s of ab::;orption.

exchange capacity, ele. As a consequence. we a150 melude In this

CERA,.,K W" , Cf",r;NT RAW W,1!-hl"',

Fig. 10. Schtmatic cross~sc('tion of the Neogene Madrid hasin (adapted from :\1egia;; el al., 1983) showing stratigt'ílphié 10catiol1 of maio mined mineral deposits: glauberite, tÍlenardite, sepiOUfC. benOOlllte. ceramic clays, Portland cement raw materials, dimettsion stone (Colmenar iimestone) aggregates (crushed 1intestones), lime raw materials aud uranium occurrences.

daSS1C mammal site (Cerro A:móCZ)v3:- $¡1e) of Middle to Lf!tC' Aragonian age islocatcd in :he muddy :mirls at the lOp of ¡he lower

sectlon the diatomite deposits because these physical properues are sepiolite layer. The seplOlitc vanes Octv,'ccn 65%) and moré also their most characterlstic [eature.

Sepiolile

The 515 kt produccd in Spain jn 1990 were o3tained entirely from the Tertiary basins: 453 kt fram tne Madrid basm, 61 kt from the Calatayud basin and 1 kt from the Duero basie, The sepiolite resources in the Madrid basin reach 100 ?'vil. anc thc estimated production capacity is more than 1 Mt¡ycar, Sepio¡itc is also present in the attapulgite deposit of Lebrija (El Cuervo nur.c Guadalquivir basin), with a sepiolile grade ofup to 5~(1) (Fíg, 9).

In the Madrid basin. sepioJite is quarried at Vicálvaro. V'lllcl,:-'j<;. Parla and San BIas, to the somh ofthe ciry on\:1adrid (fig. 5). and Yunclillos (prov. Toledo) (Galán & Castillo. 1984; Ord6ñcz el al,.

1992), The sepiolíte seams occur at the top of fming-upward sequenccs of arkosic sandstones. The economic sepíoli te :;eCl ms oceur at an intennediateposition between the lacustnne deposils ol' the Middle Unit ofthe Madrid basin and c.rkúsic scdimems dcrived [rom granitoid and high-grade metamorphic souree arcas tha! outcrop in the northwestern part ofthe Madrid basln (Fig. 1 ()).

Tbe dassic sepiolite dcposits of Vallecas-Vicalvaro were exploited three centuries agn lo oblain Ihe lilrht rough stonc oi" Madrid buildings. and specíaJ refractory c\ays. The area! extent of these deposlts tS almost 6.6 km2-, ane they consisl of ~wo exploitablt:

layas of sepiolite with sharp lateral changes of facies tI,) the nejghbounng abundant arkosic sandstoncs. Thc tbickncss 01' ttle upper layer. the richest in seplolite. is up to JO m, and ít is ~cparatl:J from the Jower sepio]ite Jaycr by more than 15 !TI 01' non-teOnoml;.' muddy sandstones. The Jower seplolílC layer ís 1 to 5 m lhitk, A

than 95 % , being accompaníed by smectItes. Q'J3.!'tz. íIli:c, fcldspars

&nd carbonatcs:, This is the wúdd's !TIOS~ importal:t knO\vn c.eposi:

ofs:epiolilc (Galán & Castillo, 1984L The Yunciillos ::.epiolite deposig ex:end over 3 k!'r;: and th<:iC a:-~

t\\'o sepiolitc~conta¡ning The lower sepiolite ¡ayer is richer

than the upper ¡ayer and its thlCkness Ís up to 3 m_ Thc uppcr laye-r

conrajns sruectitc and nodular cherL Th.z IOCallOrl 1:::' dose lo Vallccas and Vicalvaro. In ParacueHos del Jarama íe:üst of tbe city of \-1adrici¡ therc are :mportam reserves 01' sepiolite. probably subeconorr:ic bccausc ofttJe thkk é(lver anO it:, localion in:in urban arC<.L Thc searns Ol the Paracucllos scpiolitc dcposits are intcrbcd­

Jca with bu:,rowcd murid;: arkosíc sdndstones and. in plaees. with

:'eworked sepioljtc and pak:o~ob (A lonso C'! aL 1986). Thc genesis of the Paracuello5 sepiúlite deposils has been reponed as edaphjc to paJ\1dal lil a distal aHuvial nm enVlronmC:H (Calvo el oC J9g6). Sorne uranium vanaJates (yuyamuni:.el have beco forrr:ed in the cdaphic enV\ronmen~. aS50cÍatcci wit;¡ dolocrctcs ane with ver­

tebrate remains in tbe m[lr1s. (A:Tibas., 1963). In O'Jr opinion, it:s possible te define a S('"iotile br:/r along thc Me.crid arkoslc trcnc~, eJongatcd from N\V to SE Írorn YuncliHos. to Paracuellos del Jarama. with many sepioiitc OCcurcnccs 2.» a~ r;orth L~ Sagra, north Esquivias. Parla. North Getafe, etc:.

In the Calatayud basin, sepiolite mads wereexploited J few years

ago in thc fsabel mine (Orera). The annual p:-oduction ofthis mil1c. a¡; we have pointed out bcrorc. ,vas up to 61 kt in 1990 CfTGE. 1992).

Thc scpiolítc depo!;its 01' the Cahuayud basio are interpreted as lucustrine depo:jits in l:l brackish shallO\v lacustrinc cfl\,-ironrncnt.

Arauzo el af, (19R9) describe thc mineraJogical paragcnesis: doJo­mite, iIlílC. smectite and quartz. 'with minar amounts of calcitc.

G6 ¡'vlineral resources 35

,~ij¡!i\~1 AUochtonou$ materials

-- Cross se<:tion

El Cuervo-Arcos SW road

¡:: > 1 Quatemary

¡:-:-::¡ Continental Pliocen"

II!I Marine Plioceno

Los Tolles i..ake

1

f !'lE

Pe Palygorskite

Sp Sepíolite

Illlíle

Sm Smectile

~soil

~ nadular limeSlone

~ palygorskite clay

palygorskíte man n!~ clayey sand

¡J::Il sandy limestone

m marly limestone with lossils

!i53 limastone _ sepiel •• ciay

Ilmestone with chert ...... chef!, soil. diatomite ...... sapiome-patygorsl<ite ':v: JI i quartzose sand

IAQm --5c"'o-m-~

Fig. 11, Geolo~icallocation uf El Cueno attapulgjte mine, cro~ction and detailed stratigraphic secrion. After Galán & Ferrero (1982).

feldspars, chloritc and káolinite ir: the Mara anea. and sepioiítc alternating wíth smectites in the Orera area. Early diagenetk vaciose to edaphic processes of carbonate-sihceous (due to dlatoms and,'or detrÍlal clays) sediments may explain the genesls of the sepiolíte marls. Other occurrences of seplOlite mar;::; south o: Guadalajara(Madrid basinj and Cuestas Facies (Duero basin) may be lnterpreted in a similar way.

AllilpulJ!.ite

The 1990 Spanish attapulgite productlon was 54 ky. The mest important production comes from the El Cuervo 2.ttapulgite mine (Sevilla and Cádiz provinces,l and onl::; 4 kt was from thc Torrejón el Rubio attapu!gite deposit (Flg. 9).

The El Cuervo mine is located in a Pliocene to (?)Quatcrnary Jacustrine deposit (Galán & Ferrero. 1982) (Fig. 11). Two main units are distinguished: a lower mady ¡ayer and an upper palygors­kirie (attapulgitic) layer. The thickness. of the attapulgite iayer varies from 3 to 30 m with an attapulgite grade ofbetwccn 35 and 75%1 and with minor sepiolite (O~30f%) and calcite. lt includes sorne fossiliferous limestonc beds interbedded in the attapuighe scam. Tne estimated rcsources are up to 30 Mt.

The Torrejón el RublO deposit lS located in the smail Tertiary fault basin of Torrejón ei Rubio (Galán & Castillo, (984). The SQurce area and the basement of lhe basin are deeply weathered slates:. The lowest basin tm is. composed of weathered slate material

and this Jayer is overlain by a terrigenous--rnuddy bed Wilh a thicknes.s that varíes from 6 to 50 m. On top ofthis bed (0,5---4 m) an attapulgite grade úf up to 70 11/0 can be measured. Paragenesis ofthe at:apulgite deposit is. in addition :0 attapulgite. palygorskitci ¡¡lite ± sn:ectitc(saponites) ±_ chlorítes:.:::- sepiolite ± quartz::!:: feld-

5pars an¿ dolomite. The genesis ofthe attapulgite deposits appears to be a resuh of a magnesium-rich wcatheringprocess thar affccted clayey, probably iHite-rich. sediments (Fig. 11),

$ome attapulgite occurrences have been described in the lacus­trine scquences of the Tertiary Duero basio: Gurda del Cura &

Lópcz Aguayo (1974); Pozo & Leguey (1985); in Sacramenia: Martin Pozas el al. (1983): aud in Bercimuel: Suárez el al. (l989) and Suarez el al. (1991). Other le$s~important attapulgitc occur­renees have been described in whkh the mineral forros: a cemenl of the proximal cetrital facies of the Madrid and Duero baslfls (Ordóñez el ai., 1977; Megías el al.. 1982~ Leguey el al., 1984a and b). The paragenesis ofthese attapulgite occ~rrem.-"Cs indudes paIy­

gorskite± cristobaltte ± dOlomite, interpreted as late diagenetic: Cernent uf the arkosíc sandSlOnes.

Bentonires

The 1990 Spanish produclion ofCa-bentonite was 151 kt, and this carne froIn two districts: Cabo de Gata (Almena province) and ViIlaluenga (Toledo provincc).

The Cabo de Gata district deposits are associated with the

36 M,A. Garda del Cura el al.

1

N s

2

N

3

N

4 N

N 5

WATER SURfACE

,*'S ! RAÑA

§ ILLITiC ClAY

E'ílH SANDAND PALYQCJRS"IITE

f!IIll] ALTERATION ZQNE

• SLATE

s

s

s

s

Itig. 12. Scbematic ínterpretation of Torrejón el Rubio attaplllgitc deposit from the l. ucathering (If substrate; 2, clayey sand sedimentaoon and early diagenetic {vadose) magnesium~rich attapulgite. probably related to lo\\' sed1mentation; 3, siltíng up sedimentation; 4, aUúviaI fan ('raña') depoo¡¡its; S, flunal network trencbing. After Galán & Castillo (1984).

Neogene cak~alkaHne vokanism of SE Spain, with an age of thc vúlcanism varying between 8 and 17 Ma.

The maln bentonite mine t5 In fue La Serrata,-Los Tranco~ deposit, al1d the production of this mine il;; up tú 100 kt/year. The proven reserves are estimated as 3.5 Mt (1. Teodoro, pers. com~ mun,). According to Doval {1992) the average purity oí' Ü1C

smectites is up to 98°/Q. The genesis ofthese bentonitedeposits 1& IOW

temperature (about 40-70 ~C) hydrothermal altcration ofvo!carüc

rocks (Leone el aL 1983): about 70 oC in the Sierra dI'::: Galá and

about 40 ~C in the Sertéta de 1\ijac The mineralogical paragenesis

oftbe Serreta de Níjar deposits-has been descrjbed by Caballero cE

(JI (1983) as formed mainly of smectitcs, the only phyllosilica:c

prestnt in the fine fmetions belonging to the montmorlllonite­beideUite--nontronite series, along with jarosite, py:olusite and alpha-trydimitc (probably neoformed) and quartz, plagiodase ane.

potassium feldspars; inhentcd minerals from the paren~ rocks; the

parent l"ocks are rhyolites, dacites and trachytes. Thc exchange cation capacity is Na + > Mg2 -... > Ca:: + > K +, ánd the chemical compositiún of the bentoníte displays wide variations even wilhin

the same deposiC The most important bentonite deposits al Scr::eta

de Nijar are dosely related [O N50E strikingfis:;ures and commonl) display vein~fill featmes.

The bentonites of the South Cabo de Gata 2ane consist or smectite,jarosite. zeolite and trydimitc, as neofonned minerals, and

of plagioclase. potássium feidspar, amphiboles and micas as mi¡:­

erais inherited from the parent materíals (CabaUero el aL 1985).

Inaddition to this vokanogenic interpretatíon ofthese bentonite deposlts, F. Ferrero (1984) has pointed out the pmbable inftuence ol' halmyrolytic processes in the genesis of sorne o;:' the blankc:

bentollite deposits, The geochemlca] data seem 10 exclude a manne­

origj!J for the alteration salutíon, 2.nd favour tbe idea tha~ thc solutiom resulted froIT! a syslem of meteofÍc watCT$ hcaled by a geothermal cyc1e (Gaballero el al., 1985).

The Villalueng.a district (Toledo provincc) ís ¡ocated in the Midd!c Unit ofthe Ncogene Madrid basin (T\ilíddle Aragonian). lt occurs i:1 a transítional z{)ne between the Olller marginal facies and inner chemical facies of the lacustrine sequenccs. These bentonite

deposíts usualiy occur in laterally continuous leve];;, 0.4<! rr. thick. Common;y. the bentonites are inte!"";:;a~atcd 10 tite lacustriGe sequcnces with distal deltaic IT!icaceous sands an¿ dolomit:c carbD~

nates. sorne chert nodules and olher mudstones, The mineralogy of the bentonÍtes 1S essentiaUy Mg-rich smectítes. rnústly stevensite

ano saponite (Galán el al" 1986; Pozo ei al.. 1991). and thcÍr

potemial as backfilling aud seahng matenal in high-level radíoa2-

tive waste disposal is very iuteresting (Cl.:el,'as. 1992; Cueva.." et aL

1993), The reserves of the Madrid basin are probahly up to 10 Mt. ¡ocatee in a closed srratigraphi::: position from Cerro del Aguila (Vil131uenga) to the southern par! of lhe city of Madrid. markedl:, parallel to the sepiolite belL The reserves oC the: rnmcJ d~~posits al

CerfCl del Aguila (Vi1!aiucnga) are up lo 0.7 ¡Vlt

Sorne ·pink clays' forroed by lnterstratified kcrolhc. f'.l. .... si prob­

ably stevenslle whh interlayercd kcrolüe rclatcd to tillo': bentonitc deposits. are found (Martín de Vid",le::; el al., 1999. 1991). Thése

'pink clays' have been used as an oil discolouranL Pink c!ay layer~

are associated wtth dcssication levels devclopcd OYer bcn~onitic day

bcds (greeo colour). The pO\isiblc rcsourc~s of pmk clays in the

Madrid basin are up to 2 Mi.

Ceramic e/ays

Almost a1l tne marginal and basal formations ol' thc

continental Tertiary oasíns of 1he lberían Peninsula conlain da)'

sedíments that are being used as cerarr.ic raw matcrials. In this facles the::.;; are largc volumes of n:aterial 1hm a::c poten ti al sourees ol"

ceramícclays. They have 11 variabje mmeralogical comp0sítior:. bu:

¡Hite is generally thc- rnost 2-bundant phyl¡o$i~icale mineral. Com­merciai interest in tnese day-rich scdíments depcnd:s o:) lhe physical properties of the erude material s: plasticüy. drymg: capácity Wilh·,

out shrinkagc, extnt5ionability. fixing: lempcrat'-lfC, and, after fir­ing, degree ofeffiorescencc. permeabllity and cornprcsslvc strength,

G6 :Yfineral resources 37

etc Howe\-er. ::1e distancc from the lot:ation tlf the daJ>rich

sediment deposits:o ¡he pOlentiai cop.sump1ior. centres rnay be lhe most irnportam economic factQr, hecausc haLlage CO$13 may

quickly make the pricc prohibitÍve.

Rl:cently, GonZ<ilcz Diaz (1992) has reviewed Spanis!: ceram:c day:;, The most irr.portant ceramic-clay production a,cas are

:úca:ed b thc Glladalquivi:- basio {Bailén} and in Madrid basin (La ;,agr:h,\¡:;aiade Henare3) (Fig. 9).

Tht: cera;nic raw mate:-ials :T:l0ed ir; lhe Ba'1én afea _ue 01' Mío.;cne age, and have af: averagl! mmcraiogical composüion of 20% quanz, J2% fcldspars. 25% calcite a:1d 54°jo phyllúsilicate.

mainly il;itc and smectitc íGonzález el aL 1986t The ce:-amic íaW materiais exploited in La ¡Toledo pro-

dnce) :tnd A:ea~á c.~ Henares Uv1adrid are !ocated in ¡he

Lowcr L'nÍl oftne Neog:cne rv1adrid casin tLower Aragonlan). The <lVcrage content of i1litic days is up to 50%) l'\r1endujña. 1988:

Garcia et at .. 1')\)0). Rcsources amount 10 500 Mt. These clay-nch ;;eoin;cots are used to add a top~quality silicate component ro

Po:t:<md ceme:H íGaréÍa Cdlej<! el al., 1991). Thc potteries produc­

lioD al La Sagra :-e¿chcs 1· 5 \<lt per year. Clays from the basal Lnit (Tierra de C2.mpos i úi' the Duero basin

in the area ncar Valladolid are aIso C'xploited :oruse as cerat:1ic raw

marcrlais.

Dia!O!nlles

Spanish dií![Om;te rroduction dur:ng 1990 was ;U: kt.

lower than thc J 986 production. Spa;-ush diatonue de!1osjts occur in ]'\cogene formatíons in lhe southcrn pün of Spain ir. tbe Guadalquivir B~tsir. {Porcuna and Martos), the Prebetic intramon'

Table 5. Reserves and revources Id diatomite deposits in [he Hellin (h'.fric[

C.najo CJrnariHas Calderones Elche Hijar

r 1 7.5 r II lB.7 29 rm 5 Rl 152 Rll ! 33 12 337 RIlT ~ 8 34

Vores. Reserves (r) ana idenrifíed resou:ces iR) in :\1t for the different basÍns. 1 Sí01 < 3W'j,¡: I{ 30% < SiO~ < 70':>"0; 111 Sj02 > 70~'0. 50urce: Adapted fmm Rcguciro ei a( (1993).

spans :he intcrv¡:u fmm Late To:-tonlan to Eorly Mcssfnian (Reyes el al., 1984),

Diatomaccous scdiment occurrences, sometimes mines, have been cited in the GuadalquivÍf Ba~in. for example at Sanlúcar de

Barrarr.eda, Porcuna, and Martas. Earlier in this chapter we nave ::ired :he diatomaceúus sedíments in ¡he El Cuervo attapulgite

dcposit. Other occurrer::ces have been cited in the Madrid basin {CJ.lvQ el aL. 1988), <loe. in the Cercanya basin, In this last occur­

re-nce. daled as Middle-Late :\rriocene_ Anadón et al_ (1989) have

de':lcribed a diatomaceous mudstone facies Wi1h fine lamination,

Dimension {building} stone

~¡,me b2.sins 2n¿ lhe Internal B~lics mtramontane Late Mioccnc Spaln pbys a ver;.: ioponant role in the world SlOne busins (Sorbas, V~ra, ar..d ~¡ja, in Almcría a:ld :'v1urcia provin.ces) índustry. The natural ~tone production of Spain accounts for ¡('ah',), ¡9g4~ Rcg.utlíC el al.. 1993).

The Prcbetic arca supplies more th,m 9C"jn o:' ~:1e :o-:.a! Spanish

diatOlTIlte produnion. The HelEo dialomite dijtrict éxter.ds o\'-er !llOr(' tban íOO km'::. and the dlutomite occurs here in seve!""dl bas:n:5 that \Verc ci::hcr separa[cd or epísodically interconnected: thc

Bl1sin. C:1marillas Basio, Calderones Basin. Elche de la Sícrra Basin and Hijar B2.s1n (see T2.ble 5), Tbese nvc t:nramontane

hasins outcrop along thc i'\'1undo <lud r¡ver val;eys. A schematic stratigraphic column fm thesc basin~ has been proposcd recently by ElíZJ.ga & Calvo (1988) (Fig. 13). Sedimcnto!ügical a~ld

¿¿ta hav~ becn reviewed reccntly by Bellaoca el al. (1989).

The dialO:naccous sediment5 are c~ose tu Facies E just aboye a 30-

50 m thick megaslump. These :1-:egaslumps are associatcd witb volcamsm llnd,or a probably tectonic :-cactivation Ol the basim.

The KiAr age orthe volcanism mcasured in the Monegrillo i5 up to

5 ':\1a IBeilón t'! a/ .. 1981}. The mCl!-llslump-!evel offers the besl markcr in prospecting for dintomÍte ín tile district {Regueiro el al..

19931. Ten per cent of Spanish d;ato;r,üe production is from tne Níjar

Basin (Almena); these diatomaceOl~S sediments ¿re lotátee. in rnm­

thkk laminated shales formed by couplets of dark organic-::-ich oil

-¡hale and c1car diátornitc·rich laminac. The age of the depo5;t5

13.2% of the worid toral (Lombardero & Regueiro. 1992), Sorne T ertiary limestones of the I nner Prebetic 15níts have great

pur:ty ano souncness. are easily polished and may be considered as \:0mmerclal f)jurbles' ormarDies oftype e, according tú lhe Marble lr:::;tlt:.lte of America (\HA). The quarries are grouped :rr.ainly in lhrcr arcas. C;)to Pinoso and Peiia de Zafra j!l Alicante province

and Sierra de ia Puena in :\1urcia province. Thc most famous qLuries are located in Coto Pínoso, where the 'Crema Marfil' marbie lS obtaincd: lhe 1989 production ofblocks \Vas up to lOs m3 •

nnd the proven reserves are 7 x J03 011 . From a petrographic point

of\'iew the Coto Pina so h:-nestone may be dassified as a biosparite­biomicríte (Llopis & López J~meno, : 991).

The 'Colmenar de Oreja Limestonc' has becn obtained froID the Upper Unir ofthe Madnd basio (Fig. lO), and it has been used since the eighteenth centur~y in the constructioh of buildings and monu·

m.:nts in :!.:htdrid (Dapen~i e{ aL 1988), According lo the ASTM ¡American Sút:iety for T~s\.ing 01' \t1aterials) Standard C-568-79. Colmenar limcstone lS arnong the most suitable for use for the outside ofbuildings {Dapena el aL 1988), Colmenar limestonesa-re paludlUe-lacustrine biosparitcs with less than 2.45 % porosii:y. At

present, Colmenar Hmestones and other similar limestones úf the llpper Unit of Madrid ¿;re intensivclY used as crushed

38 M.A. Garda del Cl~ra el al,

~ DISCONTINUrrY

~

~

~

w

~

o -

~

OISCONTlNíJlT"

M S G

FACies e

FAClESB

FACIES A.

sulf~r

chBrt OOCJies

klyers o! lammar aM seCOm.l11')' gy;:lsur¡;

Hg. 13. SehematiC' stratigraphic secriQn of Cenajo basin: A, conglorru.'ratic basal betls; B, sandy layers in laminated nil shales; C. tbis subunít consísts of altemations of laminated detritaI carbonate aOO gypsum; D, megaslump subunit probabJy matea tu cmptivc yo[earusm (5.7 ± 0.3 Ma. after BeJUm el

al., 1981), E, diatomaceous sedirnents. Aft.er Elizaga & Calvo (1988). '1'51."' refcrs to TC<'to sedimentary nnit (chapter Gl).

aggregate raw materials, cement raw materials, and lime fa'>\" matenals (> 98%, CaCO:d and fillers fGarcía CaHeja. 199J; Garctd Calleja el al., 1991: Garcia del Cura el aL, 1993).

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