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Home , Augelite, Barringer Hill, Beraunite, Hureaulite, Lithiophilite, Messelite

American Mineralogist, Volume 67, pages 180-1E9, 1982

The of

EorrBo sy GonooN E. BnowN. Jn. Department of Staffird Univ e rsity, Stanford, California 94305

The Mineralogical Society of Anerica, in conjunction with che Friends of Mineralogyy held a eynpoeiuu on February 15-16r l98l in Tucson, Arizona, on the Mineralogy of Pegnatites. Gordon E. Brown, Jr. of Stanford Univereity served ae organizer and technical chairnan and Richard A. Bideaux of Bideaux Minerale, Tucaon, Arizone, gerved as local general chairmen.

Ihe tt'o day progran, attended by over 150 nineralogiste, coneisted of 17 invit,ed or contributed PePersr which deecribed a variety of pegnatite localities in the U.S., Canada, South A.merica, Africa, and Ehe USSR, and aix papers on nore general subjecte ranging from Ehe origin of color in pegfiatite ninerale Eo iaotopic and experioental etudieg bearing on the paragenesia of pegnacites. In addition, Clifford Fondel of llarvard Univereicy preoented an infornative plenary lecture on the nineralogy and nining of early Anerican pegnetites.

Of the lrrenly-three papere presenled, five were of a review nature and are listed by citle only. Abslrects of lhe other eighteen ere reprinted beLow. G.E. Brown, Jr.

HINERILOGT OF THE BADU PECUATITE, LLANO COUNTY, TEXAS ElberE A. King, Department of Geology, Univeraity of Houaton, Houaton, Texas 77004

since the diecovery of lhe Badu pegnatite in 1935 by ilre. Tillie Badu uoss, the pegnacire hae been worked-interEittently 1" 9 eource of feidepar and, in r"-".r,t y".r", for decorative quertz. The nine is located aPProxiEately 4 nilee southueat of Buchanan Dan and 0.6 niles south of the ilano-Burnet highrray. Thia -location ia only 4.5 nilee s 35q{ fron the famoue pegmacite, shich is now flooded and setl below lhe eurface elevation of Lake Buchanan. The eurface exposure of the Badu is approxi- )roximately 35b feet wide. Ttre pegiatite ctriefiy con- hit.ic pink nicrocline, eone of which are rnore than 30 rtale. Minor ninerale in the Badu pegmatiEe include E€, sphene, anaEaae, , , linonite, ats in the rnaeeee have produced aEtracEive which are deeply etched and contain fluid inclueione routheast ua11 of the present oine pit conEaine a )etailed exaninaEion of this area revealed ephene peeudouorpha, now moetly altered Eo anatase. The alteration of the ephene apparently was cauaed by a late stage fluorine-rich fluid which ceueed the production of the fluoriie-anatase-te.aiite aesembrage. Thig reaction can be degcribed by a ainple chenical equacion if che sphene ie assuned to contain ninor anounEs of irqr and hydroxyl. The najor poition of thig reaction hae been reproduced in the laboracory.

PEGMATITES OF TnE ttAUsAU PLUTON, WISCONSTN AI FaIster, Al Falater Mioerals, Wauasu, I{ieconsin 5440I

fire l{ausau Pluton, a largel eubvolcanic body of Precaobrian age, ie expoeed over an area of approxi- metely 360 equare km in_Marathorr County, wiscongin. It conaistg oi Liotite-tearing eyenite-and is cut by nuueroue dikeg of pegnatite that are nost abundant in an outcrop area of auout b oquare km. some of theoe dikes are aa much ae 80 n long and E thick, but correeponding average dimensione for a1l the dikea probably are lees than 20 n and I n. About one-tiird of the pegnaiite boiiee contain irregular po"t"i", ranging in uexiuurn dimenaion fron lese than I cm co at least 4 or- that have yielded an unusual .rrii.ty oi uinerala. Nearly 50 epeciee have been identified Ehue far.

The Eost abundant and wideepread pockec constituents are quartz, , nicrocline, muacovite, and clay uinerale. Surprisingly co@on to nany of the pockets are'aLmaniin", rn"t""., , brooiite, chloriEe, -tanleliter goethiter groeeular, henatite, , lepidocrocite, opal, , pcilolelane, rutiler eiderite and xenocime. Leea comron nineiale, a few of then found in'only - one pockei to date, include anhydrite, , barite, bavenite, , , boulangerite,-pariei-te-aynchesite; calavlrite, cookeiEe, fluorice, , gold, janeaonite, . nanganocalcite, nicrolite, , 9anidi19r aphaleriter. e'''biconiter etilpnonelanef , and eeveral other species not yet identified. Thie rernarkable aeeemblage, which evidently representa a sy6tem wich unuaual concentrationa of Ber Nb-Ta, Sb, and Ti, hae provided excellent epecirnene and aone auperb nicro-naterial. The pegnatite occurrencea are not widely knownr but chey have yielded nany notevorthy crystale deepite ragher diificult collec ting conditione.

0003-004x/82/0102-0 l 80$02.00 180 BROWN: PEGMATITES lEl

SOUEFAMOUS PEGI..IATITE LOCALITIES IN TTE U.S.S.R. Borie H. Shnakin, United Nations, New York, New York 10017

There are nunerous nineralogically diverse pegnaEiEe depoeite in the U.S.S'R.r aone of wtrich are of econooic importance. The localitiee reviewed Lelow are paet and present producere of nany of Ehe exceptionally fine nineral epecinena that appear in European and American nineralogical mueeuns.

Trro iocereBting pegnatite regione are located within the Fenno-Scandinavian ehield srea Thoee locaEed on Ehe xeivy niage, Kola Penineula contain abundant amazonites of Ewo Predoninant colors: -griae-gtJ"n. greeniah-blue and Pegnatites located in northern Karelia are characterized by abundant ir"corrit., t'cergmic- mineialer" and red nicrocline and have a variety of acceea-ory,uinerale including uraninite. The Volynek pegoatitee, located wichin Ehe ltkrainian ehield, are asaociated with the Korosten (enoky granicic pluton. fn.y cotrtain niarolitic cavities filled nith large cryetale of norion quartz)r green beryll and rosy .

Two famoue pegnatite localigiee occur in the Ural6t (l) niarolitic pegnatites of the Mursinka-Aduy belt near Sverdlovgk containing beautiful cryetale of blue toPaz and heliodor beryl occurring on the ttcomb" Miaek wtrich aurface of a peculiar at-bite; and (2) iranitic pegrnatitee in the Ilnensk mounEaine near 6""onite and nuneroua REB-Nb-contairiog .""c""eory ninerals. The latter Pegoatites are located contain tthelvine", near nephelioe pegnatitee vtrich con.Eain abunlant cancrinite, eodalite, etc. Interes!ing touroaline-, beryl-, columbite-, caesicerite-bearing pegrnatites are located in the Turkestan Ridge area, Uziekian"poJ,5"rr"-, nepublic, ientral Aeia. In the Baikal region near Sludyanka and.in the 0lkhon region (Taiheran'St"pp" o., th; Nlf ehore of Baikal) there are pegmatitea containing and numerous REE in the accesssory ninerafs. Miarolite pegnatites occur at tranelaikalia (in the Adun-Chelon nountaine and Borgchovo'chny Ridge area along tie Snifta River) and conEain excellent crystalo of quartz, berylr topazt and varioua varietiee of tourmaline. The ilama peguaEite beltr located in the North Baikal Highland io rich (India) in muecovite and conprieee various genetic types Including analogues to the Bihar pegoatitee which bariuu contain t'ruby nica veing". Finally, th. iig-"otcaining pegoatites of the Aldan Shield contain orthoclaoe and nany accesaory minerale.

ALPINE TYPE DERYL-EMERALDDEPOSITS NEAR IIIDDENITE, NORTITCAROLINA John Sinkankas, 5372 Van Nuye Courtr San Diegor California 92109

Occurrences of beryl and its chromium-bearing variety enerald in the vicinity of Hiddenite, Alexander County, North Carolina have been known gince I8]5. Several previoue atcenpts to e:(Ploit the dePositd for ninerii epecinene and gematones have net rrith only linited aucceos. Moet descriptione of Ehe dePosits c16ss them as pegnatites enclosed in the local biotite-gneies but field examinacions in 1969 thoeed that they are hydrotherual veine depoeited along a seriee of croes-cutEing fractured in the gneiea. In non:aaprolitized portione, wa11 alteration extenda to 6everal cn wiEh Ehe production of replacement roe"o.ri.te and albite with sone . Within the veine, many of which are only parcly filled, quartz (nilky, amoky, late anethyatine), nuecovite, albite, goethite (ieeudonorphouo efter Fe-bearing carbonate), beryl- (aquanirine, late enerald) and rutile are comon epeciee. The morphology of the veins aa well aa the !'FundorEgruppe mineralization bear strong reseublancea Eo the Alpins klefts claseed as l0frt by If.A. Stalder, and others, in Die Mineralfunder der Schweiz (f973). Deepite the preeence of snall Pegnatile bodieeinterca1atedinttre@aPpearscobeconfinedtotheveingnentioned.For theae reasona, the veins are claesed ae Alpine in type and poasibly repreaent a unique node of emerald occurrence. Alchough no epodumene-bearing body was examined during the authorra vieit in 1969r it is algo likely chae the chroniurnj bearing epodumene (hiddenite) frorn thie diEtrict ie unique in ita oode of occurrence.

BISXUTHIAN STIBIOCOLIN,TBITE-TANTA],ITEAND OTI1ERUINERALS FROU THE LITTLE THREE I{INE, RAMONA' CAIIFORNIA Eugene E. Foord, U.S. Geological Survey, Scop 905, Box 25046, Denver Federal Centerr Denverr Colorado EO225

Bienuthian etibiocolunbite- and other rare apeciee occur in Ehe Pocket zone of Ehe niEh nain Little Three -pegnatite-aplire . The biauuthian 6tibiocolumbite-tantaliEe ie ageociated topaz, Iepidolile, tournaline (), cleavelandite, quartzr , orthoclaser uicroliEe- rrannicrolite, and several aecondary mineral phasea: montmorilloniEe, pucheriter bisnutite, and cookeite. CryBtald of bianuthian stibiocolunbite-tantalite are euhedral, often doubly EerEinaEedr 0.01 m to 20 @ in parallel to b (vith or r.iirrr dimeneion, black, elongated along 111 eometioes flattened on ar and striated without, polysynEhetic twinning). Electron- microprobe analyeee of four cryetals shos existence of etrong coupoeitional- zoning, ranging from (sbg.97Big.14)1.g1(Ta6.+sgo.zlTio.fawg,tt)l.ooo4-ih; --roeiinun - \9 Bi/Bi+Sb reEio ie 0.33 (sb;.928i0.10)1.62(Nrg.B3rag.ggTi'.65wO.02)0.9904.-S-pEtrdiapttiJ ana-ltr-e tiininu"i-le 0.b6. iniiydie of bulk cryscals confirne the presence of significant aEounrs of Ti (0.71), l{ (0.72), and Sn (O.O7Z). LeaaE oquares refileoent of powder daEa (40 reflectione) yielda: g- 4.952(7), b = 11.803(17), c - 5.596(8), V - 327.11(6)Ar. Meagureddeneitiee range fron 6.60 to 6.78. r82 BROWN: PEGMATITES

Urannicrolite conEeine major amounta of Bi and minor amount.s of lfu, Ce, La, Pb, Sb, ancl Sn. Spectro- graphic analysee of several aeeociated rninerale alEo show trace to major amounts of'abnornal elenenie (As, Sn, Ge, REE).

Moet of the pale- to nediun-blue topaz shows gronth zoning (yellow fluorescence) under SW ultraviolet liEht. The fluorescence Eay be related to the ce .nd Fe of th. too"". "orrt"ni

The unueual compoeitiona and chenical zoning of several of the coexisting ninerals were controlled by the individual geocheoicbl environmenEs within the Little T"tlree pegnaEite: dike eystem. These ProPerties are consiaEent with a genetic nodel Ehat involvee fractionation of a cloeed sysBen silicage melt coexieting sith an aqueoua vapor phaae. Final cryetallization of pocket takea place fron the reaidual aqueous phase. Phyaical dieruption and fracturing of pocket contents, as nell a6 additional (including growth that on broken eurfacea), favore a rechanisn such as pocket. rupture. Losg of the equeous fluid aleo pernitted preaervation of the pocket conEenta.

FOOTBI{INE UINERILOGY John Sanpeon l,lhite, DepartEent of Mineral Sciencee, U.S. National Mueeum, Waahington, D.C. 20560

The conplex mineralogy of the Fooce Mineral Conpany epodunene mine near Kinge Mountain, North Garolina, can be divided into four dietinct stages. A11 of the nearly 100 different speciea found there nay be readily aeeigned to one of Ehese stages, and all of the conponentg which compriee these phaoes were in the prinary pegnatite or the sallrock. Excepcional feat,ures are che lack of zoning, the renaikably high (about 201) epodumenecontentr and the almosE Eotal abeence of in the prinary pegnatite.

Stage I required that an already cryatallized, dry, epodunene-rich pegoatite wae squeezed, toothpaste- liker into aophibolite and schiat along and acrose the fol-iation Eo forn- conplex swarma in a belt 25 nilee long. The prinary minerals include microcline, quartz, epodumene, Mn-, caasiterite and beryl.

Stage II involved fracturing of the prioary pegnatite sith eome brecciation, providing conduits for hydrothernal solutions which diesolved ouch of the prinary pegnatite and reacted wiEh che wallrock to eeal it. Li-, Ce-, Rb-bearing phaaee formed by replaceEen! at the conract, while albite and Li, Be, Sn high te'perature phaeea forned in vuggy leached-out areao and aolution conduite.

SEsge III produced oainly anhydroue phoephates of t1n, Ga, Fe, Li; precipitated at temperataures lower than Ehoae of Stage II minerale, but by eirnilar processes.

Stage IV miueralg are Ehe product of hypogene alteration of che Stage III suite, and are confined to the uPper levels of the quarry. Theee are noetly hydrated, low-teaperature phosphatee. Thie locality has produced 6even nec apeciee.

TIIE f,ARDING PEG}IATITE: A SuuMARy OF RECENTRESEARCL Bryan C. Chakoumakoa, DeparEment of Geological Sciencee, Virginia Polytechnic Institute and SCate Univeraity, Black€bur3i, Virginia 24061; Marcia E. Regialer, BDl4 Corporation, Albuquerque, New Mexico 87106; Dougala G. Brookins and Rodney C. Ewing, Departnent of Geology, Univereicy of Nev Mexico, Albuerquerque, New ilexico 87131; Gary P. Landie, U.S. Geological Survey, Denver Federal CJnter, Denver, Colorado 8022j.

Ihe Harding . Pegnetiter located in the Picurie Range 30 krn SW of Taoe, New llexico, has yielded comrer- cial beryl, niobiuro- minerale, lepidoliEe and epoduoene over a period of half a century. The PegnaEite is being donated by Arthur Montgonery Eo the Univeraity of New Mexico to be preserved for educalional purposea.

The Ilardiog pegoaticee crop out in a belt 800 m long and 50-150 n wide. The main dike, exposed for a length of 300 n vith a naxintrn thickneee of 24 n, dieplayi remarkable inrernal zonation. Zonee of conEras- 'ingr'61ogy ting parallel the contacEB of che dike. nijttt ficrrofogic units are distinguished: (l) border zone of quartz + albite + muecovite + perthite; (2) nagsive quartz + albite + nuecovitel (3) quartz + lath apodumene; (4) quartz + sgsTy albiti + perthite; (5) blocty perrhi-te * qrrrit" + albite; (6) nicrocline + epodumene+ Iepidolice + albite + + quartz (,,epotted rockr,)1 (J) cleaveTandiee + rose nuecovite + quartz; and (8) cleavelandiEe + quarEz + muacoviEe. Tte latcer three are partially or wtrolly due !o subso- lidue replacenent.

Agee for 42 shole rock and mineral aeparatea fron the individual zones were detlrnined using Rb/Sr. The linear fic of the Rb/Sr data for cleavelanditeg from the cleavelandite-quarti zone yielda an- age of 1r396 + I72 n.y.b.p.; for wtrole rocke of therrepotted rock" unit, 1,336 + 73 n.y.b.p. The average of theee tuo ages, 11366 n.y.b.p., may be taken as the age of the pegnatite. BROWN: PEGMATITES lE3

Fluid inclueions in 52 beryl and quartz eaoplea from aLl Che lithologic unirs were examined. llomo- genization teuperatures (uncorrected for preseure) for primary inclusions from the wall, maeaive quartz and fluid inclueion luartz-lath spodunene zonea are in the range of 27sol to 325oC. The eatinated aalinity, baged on freezing point depreBsion, ahowe Ehac prinary inclueions have a consistent ealinity of t4-I6 wt.z NaCl. Ttre e8ti[lated fluid preasure, baeed on ieotope data and the NaCl and- CO2 content of the fluids io the inclueione, pressureo in the range 2.0-2.5 kbar (6.0-7.5 km). Pressure correcEed honogenizat.ion tenperaturea",tgg""t" are coneistent with the previously deEemined liquidue and aolidue for a composiEe Harding aanple conEaining 8 wt.Z waEer.

Tf,E TANCo PEGMATITE, SoUI1IEASTERNMANIToBA P. Ceriy, Departnent of Earch Sciencee, Univereity of llanitoba, l{innipeg, It{aniEobar R3T 2N2r Canada

Rare-elenent granitic pegnatiEee are wideepread in the Canadian Shieldr particulsrly in the Archean Superior and Slave Provincea. In the Superior Province, their occurrencea are concentrated in greenetone belts, especially so in the English River and Quetico Subprovincee in the aouthltesc parc of the Shield. It is in the foruer eubprovince wtrere the giant Tanco deposit ie located, known for ite leading role in the world Ta production and for iEa regervee of Li, Rb, Ce, Be, Ga and of indugtrial ninerale. It belonga to the t{innipeg River pegmatite district, in utrich eight geochenically and nineralogically dietinct pegnaEite groupa rJere recently defined, and roosE of their parenEal graniEee identified. Ilowever, the source of Tanco and its Bernic Lake group ie not exposed on the surface.

The Tanco pepatite is a eubhorizontal lenticular body, I00 x 500 x'l t io conaieting of "ir", seven zonea of largely prinary cryacallization and Ehroreplaceuent units. So far, 73 nineral epeciee have been ideutified in this pegnatite. The most remarkable of ghese are 9 minerale of Sn, Nb-Ta, and Ti; 28 nat,ive eleBenta, sulfides and eulfoealte; petelite and eucrypEite; Gs-rich beryl; hafnian zirconl two menberg of the analcioe- eeries, and tno nev speciee, tancoite and cer6yite. Coopoeitional characteri8t.ice of nost minerala indicate exErene levele of frectionation atlained by the pegnatite: K/Rb is ae loll aa 4.0 in K-feldspar and 2.1 in lebidotite, and Rb/C6 decreaaes to 8.0 and 4.5 in these apeciee, respeclively; Nb/Ta ie 0.05 in and 0.01 in uicrolice; Al/Ga reachea lt00 in feldapare and 260 in aome micae; ZtlH'f il ia close to 5.0, and Zn/Cd rangee fron 42 to 0.7.

KINDREDS AND DISTRICTS OF MRE-MINERAL PECI.IATITESIN COLORADO E. lfillian Eeinrich, Deparcrenc of Geological Sciencee, The Univereity of Michigan, Ann Arborr Michigan 48 r09

Rare-nineral pegnaEiEes in Colorado are widely distributed, but Precenbrian ones are concentrated in: (l) ttre Front Range fron the l{yoning line to Pikee Peak, (Z) ttre Arkansag River area from Canon Cicy to Selida and Troup Creek Paas and, (3) ctre Quartz Creek dieErict of Gunnieon County. Tertiary rare-Dineral pegFatiEes occur in the Collegiate Range on Uount Antero. Precanbrian pegnacitea fall ingo four uain groups: (l) thoee related co Boulder Creek granitoid,plutons (^,1700 t0.y.) (Eight Hile Park diatrictt Fremont Co.); (2) those related to Silver Plune granitoid plutone ('u1400 n.y.) (Cryatal Mtn. diatrict, Larioer Co.); (3) those related to Ehe Pikee Peak betholith (n,t040 n.y.) (South Platte diatrictr Jeffereon Co., amazoniEe pe$oatitee of the Pikee Peak area); and (4) thoae related to the Mt. Rosa alkalic (t1000 u.y.) (cryolice peglnatites of the Cheyenne Mtn. area).

'oe[e The rare-eleuent mineralogy of the pegnatiEee depende ou concentraciona of lhe rare-eleoents in their parent granitoide. Although the three main generatione of granitoide each have their oitn charac- teriatic aeaenblage and concenErations of rare eleuenc8, lhere ig coneiderable variation froo one Plugon to another or even in zoned plutone. The genetically related pegnatitee reflect both lheir kindred descent and thie district variation in their rare-mineral aeaemblagee. Thua, for e:cauple, Li sinerals occur in gome to.ldEi-tiEEi pegmat.ite dieEricts (Quartz creek; Eight Mile Park); in Silver Plune dietricts (Crystel Mtn.); end in one Pikes Peak district (Crystel Park). Siailarly RE ninerals are found in pegnatitea deecended fron Boulder Creek plutone (Lookout Utn., Fremont Co.) fron Silver Plume Plutons (Janeatown) and fron t.he Pikee Peak (South Plette). rE4 BROWN: PEGMATITES

TEE BTACK CLOUDPECMATITE, TELLER COUNTY,COLORADO william B. simone, Department of Earth sciencea, Univereity of New Orleane, New orleane, Louisiana 70122 E. I{i1lian Heinrich, Deparbenc of Geological Sciencea, University of Michigan, Ann Arbor, Michigan 48109

The Black Cloud pegnatite r"'hich occura near Divide, Te1ler County, CoIorado, ia one of the nost unuaual rare-earth eleEent nineral pegnatitea of North America. The pegoatite, which wae worked for feldepar in the 1950'e and again for quartz in the 1960te ie expoeed in iwo open cuts. The depoeit ie ellipeoidal in ehape with a bulboua nose that tapers sourheastvard. It ie roughly 350 feet in length and is as ouch as 230 feet wide. contacts with ihe aurrounding Boulder Creek granite are eharp no exonorphic effecte. The body exhibite a well-defined internal ional stucture coieieting of: l) Wall"ith Zone of graphic granite;2) 0uter Core of irregular massee of nicrocline perthite and quaitz with rare beryl cryetale; 3) Inner Core- of rnaaeive white quartz. Large booka of biotice eeveral feet acroos and up to five inches thick are localized along the contact between the inner and outer core. Fluorite- and alLice-rich unice replace earlier formed uinerale of the prinary zonal eequence. Theae replacement units are the aource of an exteneive euite of rare-earth minerals. Fluocerite is the no8t notable of theee. Thie exceedingly rare mineral, which is found at only one other U.S. locality, ie preeent in naseee up to eight inchee long ueighing over one pound. Aseociated rare-earth Einerala i.r"ira. the following groups:

a) Fluoridee: fluorite, fluocerice b) CarbonaEe: baetnaesite c) : monazite, d) Oxidee: samarsksite, yttroEantaliEe, ferguaonite e) silicaEee: zircon' th6rite' and geveral :l**l:it::1i;::::'

Other replaceoent phaeee include bertrandite, kaolinite, eericiLe, chloritee, opal, and iron and Bangane8e oxidea. The preeence of this dietinctive aeeenblage and the of such characteristi" r""fr"o.y "Lr"rr"" PeguraEite minerala ae toumaliner , and apatite, and the rarity of rorlecovite and zircon nake the Black Cloud unique anong pegnatitea of the United States.

RECENT PROGRESSIN EXPERIMENTALSTUDIES OF PEGUATITE GENESIS Philip H. Fenn, Department of Geology, University of California, Davie, California 95616

The experimenlal studies on the geneaia of granitic peglraEites pioneered by R.H. Jlhns and c.w. Burnhan in the late l950re have been continued and extended. using the rm" sanplee of the Spruce Pine, Norch Carolina and Harding, New Mexico pegnatitee, the detailed phaee"orpo.ite equilibria aL functions of teEPerature and water content have been detemined at confining presnured of Zr 5r- and 8 kilobara. The nucleation deneities and crystal growEh rates of Ehe feldspare ani quartz have'been measured at several igotherme at 5 kilobars ae functione of Ehe waEer content of the initial nelt. The growth norphologiea and 6Pstial dietribution of the varioue cryeEalline phaaee, both as ieolated cryatale .-na it interaccion with other phaaee, have alao been tabulated. Theee parameters are ueeful in .developing Eodels to explain nany of the Eexlural features wtrich are diecinctive of pegoatitee.

one of the nost exciting reeults of the pre8ent research hae been the direct eynthesi8 of graphic inEergrowlhe of quarEz. in albite or oligoclaae. A nodel hae been developed to explain the origin of trrit texture based on the sinultaneous of quartz and feldspar iroo the roelt under condiliona of local suPersaturetion. The preeence of Ehie texture tends to indicate certain relationehipe betseen various kinecic factors euch aa the nucleaEion end grorrth rate of feldepar and the diffuaive redistribution of components aE the.oelt-eryetal interfece rather than any stste of bulk chenical equilibriun.

It ie hoped that in studying theae pegmatites, an extreoe case in the developnenE of granitic texturesr inaighta inEo the more normal paths of crystallizaEion nill be gained. BROWN: PEGMATITES 185

LIGHT STAIII.E ISOTOPE GEOCHEI'{ISTRYOF GMNITIC GEM- AND NON-GEM-BEARINGPEGMATITES Bruce E. Taylor, Department of Geology, Univeraity of California, Davie, California 95615

The study of oxygen, carbon, and iaotope sysEenatice of whole-rocke, mineral separatesr and inclueion fluidg from granitic pegnatitee had elucidaced many detaile regarding the magmaEic cryelallization hietory of certain pegmatitee. FurEher, auggeetion of the brigine of many of the coireticuente of pegnatitea (including gen roinerale)1 comparison of isotopic variations in pegrnatifee of Precanbrian to Late CreEaceoua ager comparison of both deep- and ehallow-eeaEed environnenta, and distinction between magnaEic and hydrothermal featurea in pegnatites and asaociaEed wall rocke are aleo poaaible. Isot.opic conpoeiBione are generally sinilar for all granitic pegoatiteB examined, but differencea in nineral fractionaEione for siaple and complex pegnatiles are found. Examples froo nore than ten oajor pegrnatite discricte in North America and Scandinavia are diecuesed.

The whole-rock oxygen ieotope compoaiCion of pegnaEites appears in moeC cases to reflecC pre- crystallization iaotopic exchange eith wall rocke, wtrile "closed-systen" cryetallizaEion is indicated for the greater pert of a pegnatiters cryatallization history. oxygen isotope fractionations indicate EemPer- aturia of iorqation (540-8OOoC) coopatible with experinental data. Lower solidue temPeratureB of Li-bearing pegpaCites are reflecEed by larger isotopic fractionatione, and eubeolidua cryatallization of nany uinerels ia indicated by both textural and ieotopic evidence.

The hydrogen ieotope variaBione of mriscoviEe, biotite, and water released fron fluid inclueiona indicate that inEeraction rrith aeteoric nater iB not typical of pegnacite enplacenent and crystallization. -80 o/oo). Ttre iaotopic coopoeition of falls within the range ofrrrnagnaticttwaEer (6D = -40 to The neaeured hydrogen ieotope fractionaEiona between inclueion fluid and hydrous minerale indicate tenPeratures of cry8tallization of uaguatic to hydrothernal etagea to be n'700 to 500oC.

The carbon iaotope^ coropoeitions of CO2 releaaed from fluid inclueione are typically in the range of -6.0 to -8.0 o/oo (Ol3C). Some variation- beyond this range (-2.2 to -15.6 o/oo) nay be due to late- slate coutaaination from wall rocks, loes of CO2 fron pegwtEites during cryeEallization, or to analytical difficultiee due Eo the very emall eample eize involved.

CEM-BEARINC PECMATITES AT KLEIN SPITZKOPPE, NN{IBIA (SOUTII-WEST AI'RICA) Richard A Bideaux, Bideaux l'linerale, Tucsonr Arizona 85702

Ttrere pegnetitee have produced fine epecinena peaking in the lare 1930'4. Klein sPiEzkoppe ie intruaive into the Dauera schiste (+ 500 n.y.). granite, nith occaeional larger oiarolytic cavitiee. wallrock nay be altered to touEoaliner I 'DosEthe edjacen! c;@on eccessory oinerala throughout the Spitzk lege Ehan 300 oecers of cover.

Microcline, oflen blue, is abundant in the r lamellae p8rtially digeolved. The toPaz is uou yater-clear cryatal8r uaually colorleae but rarely I alwaye elongaEed on c. They uoat comonly are pale The localicy i6 noted for fine yellow beryl crysta: oinerals sre green to yellow octahedrel fluorite, phe

There are uarked ainilaritiee begireen these pegmat.iEea and thoee occurring at UE. AnEeror Colorado' 186 BROWN: PEGMATITES

TIIE GEOLOGYOF LITHII'M PEGMATITES IN TITE DISTRICT, MARICOPAAND YAVAPAI COUNTTES, ARTZONA David London and Donald M. Burt, Departnent of Geology, Arizona state Univereity, Tempe, Arizona 852gI

The cryatallizaLion oequence and alteration history of prinary-zoned-pegmatitee , Bontebrasiter and have been studied in nine of the Htrice picacho dietrict (WPD), tr.iro,... A general (and einplified) crygtallization e.qr..r"L lor these pegoatitea appears to be:

plag ioc la se-quar !z-mi c ro" I ir.-lborder

-p ---l-wa ni c roc I i ne-q uar tz I agi oc I a ee- ( mue cov i te ) I I

rni croc I i ne-quar tz- ( apodunene )----l quar Ez- opoduEene -intermediate zoneB quartz-EonEebragite-

quartz-( I irhiophili r" )T-"o""

Lithiophilite also occurs with columbite-tanEelite, Mn-apatite, end Mn-cournaline (verdelite) in relatively coaree-grained cleavelandiEe conplexe6 that. appear to have replaced pre-exiscing pegnatite. X-ray powder PaElernsr refined ce11_ paraneEere, nicroprobe analysee, and eome opEical p.op"r-til"- have been deEeroined for moet of the following tJpD phaeee:

Prinary Li-ninerals I0. Ca-hureauliEe 21. augelite l. epodunene 11. robertsit.e 22. ecorzalite 2. montebragice (4-6 rrtzF) 12. fillowiue 23. kulanite 3. lithiophilire 13. dickinsonite 24. carbonate-apatit,e Secondary Minerale 14. fairfieldite phases Other prinary- 4. eucryptice 15. Mn-chloro-apatite 25. micae 5. albite 16. rhodochroeite 26. Mn-tourrnaline 6. nicag 17. nontebrasite (2-3 wtZF) 27. zi-tcon 7. lE. crandallite 28. beryl 8. triploidire 19. hydroxy-apatite 29. nanganocolunbite 9. eoaphorite 20. brazillianite 30. colunbite

TEE OCCURRENCE OF PHOSPHATEI.TINERALS IN GRANITIC PEGHATITES: Alt EXAMPLEOF LITLIOPHILITE FROM THE STEHART MINE NEAR PAIA Jameg E. Shigley, Gorden E. Brown, Jr. and Richard H. Jahne, Deparcment of Geo1ogy, Stanford Univereiry, Stanford, California 94305

A conparieon of thirteen sell-etudied, Li-rich granitic pegnatitee ntrich contain prinary phoephete niuerala has showrr eooe eignificenE sinilaritiee and diff""enc." in their feetures. Localitiee'aurveyed include Branchville, Connecticut; Palermo, New Hanpehire; Varutrask, Svedenl Bernic Lake, uanitobei Hagendorf, Genaanyl Newry, Maine; whiEe Picacho, Arizona; Key6tone, south Dakota; Viitanieni, Finland; Sapucaiar Brazil; Biki^ta_,-z,inbabwe; Harding, New Mexico; and iala, California. These pegmatitee vary in geologic (2.6 age to 0.15 b.y.), in hoet rock type, in apparent depch of enplacenent, an4 in size and ehape. They each exhibit an internal zoning etruecure, wii-h the prinary phoeihatea uaually occurring in the iutermediate zonee cloeely aeaociated wiih ttre core zone. rn aaaition'to q,r".tr, ferdspare and nicae which conprise the bulk. of-.these pegmatiEee, phosphaEes are aleo aesociated nith a variety of Li-gilicates such a€ epodumene, , pecalite and .- The nuober of prinary phoephites in granitic PegEatiteB is linit.edt with the Eost abundant phasea being lirhiophilire-iripttyrir" r.itr.rnlreipoi, anbrygonite-uonlebraeiEe (Li,,Na)Al(po4)(FroH), " and apaciie ca5(io4)3(r,ou).-These-p"irary currenr evidence suggesta theee minerale cryetallized directly from a pegnatitic nelt. phoephatea can occur either aa crude crystale or massive nodulei which range from eeveral centimetere to Beveral EeEerB in elze. pegnatitea .The aurveyed shcnr a divereity of eecoidary phoephatea wtrich forned by a conbination of hydration, oxidation, alkali-leaching, and metaeonatiem or lrre prirrty phosphatee undei both hydrothernal and eupergene condition6. Theee secondary phaees often contair, aaditionai elemenrs such as Na, Mg, Zn, Sr, Bar Be and . - K. Hydrothernar alteration ie thought Eo be a reeult of late-Btage reaction beEween the regidual PegnatiEe fluid or other hydrothernal aolutiona and the earlier-forroed iinerare. The variable extent of hydrothernal alteracion observed in different pegnatites appearli to be a function of the p"iioa of time tha-t the pegnatite wae subjected to high teuperaturJ and pressure Da$tretic-of conditiong. The Stewart pegEatite in the Pala of _Dietrict San Diego--County i8 e typic;I exanple a conplex, internally-zoned granitic pegnacite which contains both Li-gilicate ana ti-phosphare Ein;rals. Anblyioniie, 'aite.wtrich eitribire no evidence of hydrothermal alteration, occura in naesive bodiee in Ehe core oi ttre Euhedral cryotals of lithiophiliEe up to 30 cn in eize are found in the quartz-microcline interrediate zone aseocieted with a emall nuober, of eecondary phoaphatee wtrich appear to be nainly of aupergene origin. The aPParent-ahall4 depth of enplacemenE ( < 3 kn) of the stevarC pegnatite .,rgg""t" chac there wag little opporEunity for the formation of secondary phosphatee by hydroEheroal alteiacion, in contrast to Ehe extenaive alteration found in peguatites enpiaced at greate; aeptrre. BROWN: PEGMATITES lE7

TUE PIIOSPUATE I,IINERALOGY OF TflE PALER}.{OPEGUATITB Anthony R. Karnpf, Natural tliotory Huseuraof Los Angeles Councy, Loa Angelee, California 90047

Ttre Paleruo No. I pegoatice near North GroEon, New Hanpehire hae yielded a Sreater variety of phoaphate uineral epeciee lhen eny other pegoatite in lhe world. A toEal of 56 distinct epecies (excluding uranylphoephaEee) have been verified including l1 which were firet diacovered here.

The phoephaEeg are concentraCed near the boundary between the internediate zone and core of Ehe pegnatite wtrere prirnary phoaphate phaeee cryat,allized during che sequential cryetallization of the pegpetite. Four Fe-l,ln bearing prinary phoephatee: , wolfeite, earcopaide, and grafconiter and Iro nf bearing prinery phoJphatee: a,lgeiite and nontebraaite, have been recognized. Triphylite ie voluoetrically noet inportant.

Attack on lhe prinary phosphateE, principly triphylite, by late-stege, core-derived solutione was pronounced and resulted in a varieEy of replacernents depending upon the chenigEry of the eoluEione. Sinple eoluBione produced ludlanite and replacenentsl CO2-rich eolutions yield.ed ; "q*o,r"calciuo-rich eolutione produc,ed carbonate-apatite; whielockite, eodium and calciun-rich eolutione produced arrojadite and alluaudite; and einple oxidation yielded ferrieicklerite and heterosite. Ueually eoroe coubination of these replacenenEo ie obeerved. Table l. The prinary pegnalit.e phoaphate minerala*

Number End-member Narle Formr:Ia Specie e

Glaeerite-derived Btruc turea

*BeuEite-graf ca(ltn, Fe) ( Po4) 2 tonite 2 2 o *t{y 1I i eite- f errowyl 1i eite (Na,Ca)r(iln,Fe rMg)rA1(PoO), F i1 I onite- j ohnaooervi 1I ei te tlarca(unr Fe), (ro4), 2 *Apatite group ca5(F,otr, c1) (Po4)3 4 **Dickinaonite-arro j adire KNa,(Mnr Fe) 2 rOAlF(PO4)l2 Griphite (Mn,Na)rCaFeAl2F2(Po4)6 2 *-zsieee lite (ltn, Fe)2F(Po4) z *Trip loidite-wo1f eite (Mn,re)2 (oH) (Po4) 2

Whitlodkite Ca9(Mg,Fe)H(Po4) 7 2

Hexaqonal cloee-packed structuree

*Lithiophili te- triphy lite (Li,Na)(un,Fe)(Po4) 3 Sarcopeide (re,un,Mg)r(PoO), I Lithiophoephate Li3(Po4) I

Other structures

Ber linite Ar(PO4) I Hurlbu tite ceBe2(Po4)2 I Beryllonice NaBe(POO) I trolleite A14(on) (Po4)3 I 3 *Anb lygon i te-uon teb ra ai Ee (Li, N8)Al(F,oH)(Po4) 3 t Auge Ii te A12(oH)3(Po4)

*The ninerala in each calegory are arranged in approxinate decreasi.ng te8peracure of cryatallization.

rr*MoaE comon epecies. lE8 BROWN: PEGMATITES

Wichin - the replacement unite, and in hydrothernal veins shich have traversed Ehem, are found the u}riad of well crysEallized eecondary phoephatea. The eecondary phosphatee are obaerved to occur in eeveral basic aesenblagee wtrich are most readily related to certain proninent cationE. Principle aeeenblagea noted are as follows:

l. Calciun: carbonate-epatite, rrhitlockite. 2. Iron-rnanganeae: a. reduced (Fe+2;t arrojadite, alluaudite, phosphoferrite, ludlanice, vivianite, oetavivianite, meeaelite, anapa^ite, fair-fieldite, hureaulite. b. incermedi6te (Fez+ and FeJ+): rockbridgeite, dufrenite, barboealite, atrunzite, whitrooreite, berauni te. c. oxidized (Fe3+)s laueite, peeudolaueite, stenartiEe, xanthoxenite, nitridatite, jahneite, ecrengite, phoephoaiderite, kryehanovekiEe, leucophoaphite, tavorite, bernanite, f errisicklerice, heterosite. 3. Aluminuto: ecorzalite, aamueleonite, bjarebyite, palermoite, goedkenite, goyazice, , foggi.te, paravauxiEe, gordonite, montebraeiteq , wardite. 4. Berylliun: moraeeite, roecherite, hydroxyl- 5. Zinc: phoaphophyllite, hopeite, schoonerite

No order of cryatallization ie inplied by thie liet.. However, Ewo general trenda in the cryE!allization aequencee are obaerved: laEer phasea ueually exhibit greater degreea of hydration and, when poeeible, greater degreee of oxidation.

THE PRII,IARY PEGMATITE PITOSPHATEMINERALS Paul B. Moore, Department of the Geophyeical Sciencee, The University of Chicago, Chicago, Illinois 60637

Over 180 nineral speciea are known fron granitic pegnatitea. Of these, at le6st 40 are prinary phases; that ie they crystallized early, directly fron rhe pegnatitic &agtoa or liquid. The eerliest formed nineralg are anhydroua and eome (euch ae triphylice) ar" itrt starting nateriale for a whole chain of secondary hydrothernally revorked products.

prinary _ The. PhoepaEe8 have been divided into three caEegories baeed on their crystal structures (Table I). Their atrucEure8 are often exceedingly cooplex and two of then--dickinsonite and fillowite--are aEong the ooet complex in the entire mineral kingdon. Ttre dickinsonite-arrojadite geries ia literally t'garbage a baeketrrr nith over tlrenty components occurring in the structure.

- Giant cryetala are known for the prinary phoaphatee. Exanplea include over one m in dimeneion for graftoniter apatite, arrojadite and triphyliEe. Such phaeee nay be inportant nodels for nuclear waste containere eince the phaees are refractory, densely-packed and their Eetanict examplee ehon no sign of leakage or exchange of ione. The most frequently occurring priuary phoephates are: Eriphylite, apatite, , arrojadice and anblygonite.

THE GEOLOGYOF PEGMATITESIN THE WITITEPICACHO DISTRICT, MARICOPAAND YAVAPAI COUNTIES, ARIZONA David London and Donald M. Bur!, Departnen! of Geology, Arizona State Univereity, Tempe, Arizona 8528I

The cryecallization sequence and alEeration hietory of primary spodumene, montebrasite, and lithiophilite have been studied in nine zoned pegnatites of che White Picacho district (wPD)r 6ai"ot". A general (and simplified) cryetallization sequencl tor these pegmatites appears to be:

p 1a g i oc I a se-q ua r t z -mi c ro t i r.__---Jb or de r " nic roc line-q uarrz-p Iagioc lise- (muecovi te)-l-wall

rnicroc 1i ne-quar tz- ( epodumene quar tz- Bpodunene -inEermediate zoneg quartz-montebrasit

quar tz-( li th ioph il i t. )T-"o."

Lithiophilite aleo occurs with colunbire-tantelite, Mn-apatite, and Mn-tourmaline (verdelite) in relatively coarse-grained cleavelandite conplexeo that appear to have replaced pre:existing pegmatiee. X-ray powder Patternsr refined cell parameEers, nicroprobe analyses, and eome optical properties have been deternined for most of the following WPDphasea: BROWN: PEGMATITES 189

Prinary Li-ninerals 10. Ca-hureaulite 21. augelite I. epodumene ll. 22. ecorzalite 2. Bont.ebrasite (4-6 wtZF) 12. fillowite 23. kulanice 3. litt iophilite 13. dickineonite 24. carbonate-aPatite Secondary Minerals 14. fairfieldite ocher Prinary phasee 4. eucryptite 15. Mn-chloro-apatite 25. nicas 5. albite 16. 26. I*ln-tourmaline 6. nicae 17. nontebrasite (2-3 httZF) 27. zitcon 7. hureaulite 18. crandallite 28. berYr 8. triploidice 19. hydroxy-apatite 29. nanganocolunbite 9. eoeohoriEe 20. brazillianite 30. columbite nd Most. secondary minerale occur as fine-grained replacement aseemblagee in spodumener Bontebrasite' and lithiophilite.- -controlled pseudonorphic aiteracion of Ehe prioary Li-ninerale- is widespread pegmalitest the apparently resulted fron subeolidus ieactione with residual pegnatiti- fluids' rn the WPD eoifori"g- general aequencea of aecondary mineral parageneses have been recognized:

L+4+5+5+6+6 2+ 77 + 18 + 19' 6 + 19 + 20 + 2l + 22 + 23 + 6+ 24 + 3 + 7 + 8 +9 + 16 + 12 + 13 ll + 14+ 15 + 16 Li speciee (or primary crystallization of the t{PD pegnatites reflecte lhe usual increase in activites of an increase in the increa'sing-tendency for Li Eo replace Na and K in alkali aluninosilicates), as well as the stable primary activities of the acidic volatilee P and F (as montebrasite succeeds epodumeneas as gubsolidue Na- Li-phase). Late-8tage developmenC of cleavelandiEe complexee may have conlinued . probably-began meEaso.atia6 (albitization of epoduroene). ca-netasomatisn of montebraeite and lithiophilite acidic concurrently r{ith albitization. Na- and ca-meta6onatism were followed by relatively, -(K+H)- in the !{?D neiaaoratisil (weak greisenization) Ehat produced much secondary nica. Late-stage -fluids of oH- peg6agites were flot i'-rich, as evidenced Uy fow F contents of secondary nonEebrasite, by fornation ana Ctapatitee, and by the virCual abeence of lepidolite, EoPaz, fluorite, and triplite.

ORIGIN OF COLOR IN PEGI,IATITEI,TI,NERALS Technology, George R. Roeemau, Division of Geological and Planetary Sciencee, California InsEitute of Paeadena, California 91I25 of The colore of nany aEEractive minerals in gen pegoatitee ajpear Eo be due, in part, to a hiscory pipk from l'tnz+, and much deeper red to ionizing radiation. Tourualine ie- gt"e. fron ^FeZ+, the possibility that "*Oo".r""il;--M"3.:- irliJi'." iq rhe laborarory can tr-aneforn Mn2+ to Mn3+ suggesting the coloration of the sane process happena in nature. Manqaneae and radiation are algo involved in crystal green. kunzice. Lavender trtt"ite arieee frou Mnl+. Exposurg to intense radialion turns the but which Thie change ie believed to involve Ehe fornatior, of uo4*. KunziEee wtrich are blue when nined in che fade upon exposure to light deuonstrate the occurrence of radiation induced oxidation Pegmatite ve ins .

of Fe3+' Beryl is blue frou-ilrtr Fe2+- but Eurn^e golden ye11ow with radiation due Eo the fornation directly froro Greeo bervl containa f"2* end Fe3+. Ir is not knorrn ehether yellow beryl foros Fe3+ or fi-ret incorporates Fe2+ which is aubsequently oxidized by radiarion.

a Blue and browo gopaz are produced by radiation. No chenical cause of the colore ie known, although wiEh the correletion rrith hydr;gen ion concenErition and color zones hae been obaerved. A correlation AmechyeE color concentretion and etru;Eural eite of hydrogen ion haa aleo been obeerved with anethyst. quartz, having radiation iovolvee bolh iron and railiation. It is yet to be deterEined whecher 6moky feldepar induced color involviit aluninura ione, alao Jhowe color correlaEions with hydrogen ion. Amazonite juaE lead color is generaEed [y irradiation of feldepar containing 1ead, but factora other than conceotration are involved.

They ere in the pyrope-aluandine-apeeeartite seriee oue cheir color co Un2* and Fe2+ aaong t,he fev pegaatite-uinerala for shictr radiation has not been aeeociated with color.

REVIEWPAPERS (LISTED BY TITLE ONLY)3

1. Gordon E. Brown' Jr': On the Nature of Pegmatltlc Fluids

2. Rlchard V. Grrlnesl The Braslllan Pegnat1Ee Provlnce

3. Rlchard H. Jahns: Roles of Aqueous Vapor Ln Pegnatlte Genesis

4. vandall T. Klng: Crystallization Hlstory of a Newry, Malne Pegrnatlte

5. Wlllard I.. R6berts: Secondary Phosphate Mlnerals fron Pegrnatltes of the Black Hllls' South Dakota