American Mineralogist, Volume 76, pages205-210, 1991

Experimentalstudy of -richgranitic : Part I. + + quartzequilibrium

Axsovr SrnlsrraN, MlntrNn La.clcrm Laboratoire de G6ologie,Ecole Normale Sup6rieure,URA 1316, 24, rue Lhomond,7523l Paris, France

Ansrnncr Petalite is one of the major lithium aluminosilicate minerals occurring in Li-rich granitic pegmatites.Experiments have been carried out at a confining pressureof 1.5 kbar, and at 450 "C and 600 "C to study the equilibrium between petalite, albite, , and the coexisting chloride solution. Very little Na or Li enter the structure of petalite or albite respectively.When petalite coexistswith albite and quartz, the alkali composition of the fluid is buffered. The value of the Na/(Na + Li) ratio of the fluid has been determined to be 0.520 + 0.020 at 450 "C and 0.545 + 0.015 at 600 "C in the bufferedmedium. This indicates that temperature has only a very slight influence on the composition of the buffered solution under the given experimental conditions.

Ir.rrnooucrroN London, 1986) whereas eucryptite would be a replace- mineral of secondary origin (Norton et al., 1962; Li is one of the characteristicelements of granitic peg- ment Burt, 1982b, 1982c). Natural occurrences matites, where it is concentratedto varying degrees.Dur- London and provide important qualitative information on the pres- ing magmatic fractionation, Li does not behave as a typ- stability field of petalite: thus petalite ical alkali element (Heier and Billings, 1970). It is sure-temperature stable at high temperatureand low pressure. incorporated only in negligible amounts into the octahe- seemsto be At localities, petalite has been replacedisochem- dral sitesof ferromagnesianminerals owing to its suitable several intergrowths of and quartz (e.9., ionic size (0.68 A) but low charge.As the crystallochem- ically by 1972; Rossovskii and Matrosov, ical misfit prevents Li from entering the structure of felsic Cernf and Ferguson, and quartz (e.g.,Hurlbut, 1962).These rock-forming minerals, its concentration in melt increas- 1974)or eucryptite frequently are pseudomorphic after petalite es with crystallization, leading first to the maximum pos- replacements presumably form with decreasingtemperatures. sible contents of Li in rock-forming phases (feldspars, and units are considered micas), before it reachesthe level sufficient to trigger the Many of the albite-rich primary in origin. The formation of secondaryal- crystallization of Li minerals. to be replacement(albitization) of pre-existingminerals The most common independentLi minerals in lithium bite by pegmatitesis a well documentedand an important pegmatitesare the major lithium aluminosilicates petal- of also phenomenon hydrothermal stage.All three lithium ite, LiAlSi4O,o, a-spodumene, LiAlSirOu, a-eucryptite, in the may be converted to albite in quartz- LiAlSiO4, a variety of lithian micas including , aluminosilicates Na-rich environments (Burt et al., 1977; Lon- the phosphates -montebrasite, LiAl- saturated, Burt, 1982c). So, albite is generally present in PO.(F,OH), and triphylite, Li(MnFe)POo.As don and pegmatitic system as an associatedmineral, both in a group, the lithium aluminosilicates,spodumene, petal- the primary secondarylithium pegmatite bodies. ite, and eucryptite are the most abundant and most fre- and light data, we have carried out experi- quently encountered Li minerals in pegmatites. These In the ofthese two systems, petalite-albite-quartz and three phasesare valuable indicators ofthe conditions of ments on the spodumene-albite-quartz,in equilibrium with a (Na,LD crystallization in lithium pegmatites(Stewart, 1978;Lon- solution, in order to investigate the field of Li- don and Burt, 1982a,1982b, 1982c).Information on their chloride granitic pegmatites.The results of theseexperiments stability relations is therefore important to the under- rich presented in parts I and II (Lagache and Sebastian, standing of the petrogenesisof lithium pegmatites. are l99l) ofthis study. Ranked by Heinrich (1975) as the third most abundant Li mineral, petalite occurs principally as giant crystalsin the inner parts of zoned pegmatites.It is most commonly Pnnvrous ExPERTMENTATwoRK associatedwith quartz and feldspars (Cernj' and Fergu- Stability relations among the lithium aluminosilicates, son, 1972;Stewart, 1978;London and Burt, 1982a).Fresh with or without qtJartz, have been thoroughly investigat- crystalsare vitreous, transparentto transluscent,and col- ed by ceramistsbecause ofthe fluxing properties and low orless,white or grey. Spodumeneand petalite crystallize thermal expansionof lithium aluminosilicate glassesand directly from silicate magmas(l,ondon and Burt, 1982d1' glass-ceramics(e.g., Hatch, 1943; Roy et al., 1950; Os- 0003-004x/91/0 1 024205$02.00 205 206 SEBASTIAN AND LAGACHE: Li-RICH PEGMATITES

Until recently, lithium pegmatiteswere considered to crystallize from a granitic silicate melt coexisting with a concentrated saline fluid (Jahns and Burnham, 1969; Stewart, 1978; Cernf et al., 1985).Norton et al. (1962) and Jahns (1982) attributed the origin of latest assem- n J blagesto the role ofa supercritical fluid exsolved during the crystallization of the core of the pegmatite. Recent a\ studiesby London et al. (1988, 1989) on vapor under- N I saturated experiments with Macusani glass + HrO sug- L gest that the formation of pegmatite fabrics stems pri- marily from fractional crystallization in a volatile rich melt. A vapor phasedoes not appear to be necessaryfor the development of the primary features of pegmatites (fabrics and zonation). While an aqueousfluid is clearly presentduring solidus or subsoliduscrystallization, there is ...* T,oC little information on the chemical composition of this phase. London (1987) characterizesthe late magmatic Fig. 1. Experimentalpressure-temperature phasediagtam for fluids by their high concentration of B, P, and F; Cl is the systemLiAlSiO4-SiO,-EO after London(1984). The dia- relatively low. Until now, most of the experiments on mondsshow the pressure-temperatureconditions ofthis study. rare-alkali elements systemshave been performed with The squaresshow the pressure-temperatureconditions of the studyon the spodumene+ albite + quartzassemblage (Lagache Cl-bearing fluids (Lagacheand Sabatier, 1973;Lagache, andSebastian, l99l). Ec: eucryptile;ps : petalite;Q : quartz; 1984;Webster et al., 1989;Manier-Glavinaz et al., 1989; Sp : spodumene. Sebastianand Lagache,1990). In order to compare these results to this experimental study of Li-rich pegmatites, we have also carried out oru experiments with a chloride tertag et al., 1968). Most of theseexperiments explained solution. some important aspectsof their stability relations, but Following Stewart (1978), lithium pegmatitesoccur at were not related to the context oftheir occrurencein peg- temperaturesof >500 "C at any pressureor greater than matites. Hydrothermal phase equilibria experiments by 625 "C at 2 kbar. Burnham and Nekvasil (1986) have Stewart (1963) provided the first geologicallymeaningful shown that the lowest temperature of the liquidus of the quantitative data on the stability field of petalite. Stew- HrO-saturated natural pegmatite melt is at about 660 "C art's work confirmed that petalite is the high temperature, and 2 kbar, which is in good agreement with the diagram low pressureequivalent of the assemblage(spodumene * from London et al. (1989). According to the above stud- quaftz) and that the isochemical replacement of petalite ies and to fluid inclusions and isotope studies (Bazarov by (spodumene* quartz) is triggeredby cooling at mod- and Motorina, 1969; Taylor et al., 1979; London, 1986) erate pressures.The studiesby Burt et aI. (1977), London crystallization under quartz-saturated conditions is and Burt (1982b) and London (1984) in the system thought to occur at temperaturesbelow 660'C and pres- LiAlSiO4-SiOr-HrO have furnished the pressure-temper- suresbelow 4 or 5 kbar. In the caseofthis study on the ature diagrams that are directly applicable to the petro- petalite + albite + qvartz assemblage, all the experi- genesisof lithium pegmatites.The qualitative phase di- ments have been performed at 1.5 kbar and at two dif- agramsoflondon and Burt (1982c, Figs. 4 and 5), based ferent temperatures:450 "C and 600 "C. The same tem- on experimental phase equilibrium studies at moderate peraturesand a pressureof4 kbar have been chosen for pressure and temperature explain the formation condi- the experimental study on the a-spodumene + albite + tions of eucryptite or the metasomatic replacement of quartz assemblage,and 750 "C and 1.5 kbar for the spodumeneand petalite in the course of pegmatitic evo- p-spodumene + albite + qtrartz assemblage(Fig. l). lution. The experimental studies by London (1984) in- The fluid is a Li-Na chloride solution (1,11).Informa- dicate that the stability field of petalite is bounded by tion is not available on the phasedomains in the system B-spodumeneat high temperature(>685 'C), by a-spodu- LiCl-NaCl-HrO, but under our experimental conditions, mene + quartz at moderate to high pressures and lower the system NaCl-HrO is situated in the supercritical do- temperatures,and by eucryptite + quartz at low pressures main (Sourirajan and Kennedy, 1962). Weisbrod (per- and temperatures (Cernj.and London, 1983), as shown sonal communication) estimates that the LiCl-HrO do- in Figure l. main of immiscibility is at still lower temperature.

TABLE1, Chemicalcomposition of the petaliteused

sio, Alro3 Liro Naro KrO Fe"O. Mgo Rbro 78.96 16.12 0.13 0.08 0_07 0.01 0.007 0.004 0.00 100.331 SEBASTIAN AND LAGACHE: Li-RICH PEGMATITES 207

Tlau 2. Resultsof the experimentsat 450 "C, 1.5 kbar

Final bulk solid composition Solution comDosition Reactants pmol/100 mg pmol/100pL Number Days mg mol pL Na Li Na Li Nacl 13 60 Pe 100 T Pe 323 0.003 26 74 0.26 Licl 38 Nacl 25 2 60 Pe 100 + Pe 1 321 0.003 25 73 0.26 ucl 75 3 60 Pe 100 Nacl 50 Pe+Q+Ab 22 310 0.07 50 46 0.52 4 60 Pe 100 NaCl 100 Pe+Q+Ab 45 282 0.14 53 47 0.53 c 60 Pe 50 Nacl 100 Pe+Q+Ab 89 235 0.28 53 47 0.52 o 60 Pe+O+Ab 50 Licl 50 Pe+Q+Ab 104 205 0.34 54 50 0.52 7 60 Pe 50 Nacl 200 Pe+O+Ab 166 153 o.52 54 47 0.53 I 60 Pe+O+Ab 100 NaCl 50 Pe+Q+Ab 180 135 0.57 52 48 0.52 q 179 134 0.57 50 46 0.52 60 Pe+O+Ab' 100 Nacl 50 Pe+Q+Ab '175 10 60 Ab+Q 1(X) Licl 100 Pe+Q+Ab 45 0.80 50 51 0.50 11 60 Ab+Q 50 Licl 100 Pe+Q+Ab 210 95 0.69 49 50 0.50 Licl 100 12 60 Ab+Q 100 + Pe+Q+Ab 312 0.98 54 47 0.53 Naol 100 ucl 50 13 60 Ab+Q 100 + Ab+Q 303 4 0.99 57 45 0.56 Naol 50 '14 60 Pe+Q+Ab 50 Naol 200 Ab+Q 303 4 0.99 61 40 0.60 Note.' See text for explanationsof results. Reactants: Pe : natural petalite; Q : quartz; Ab : albite gel, Ab' : natural low albite. Final bulk solid composition: Pe : petalite,Q : quartz; Ab : high albite.

The equilibrium studied here is of Na+ and Li* in solution is a function of the tempera- ture, pressure,and composition of the solid phase. LiAlSioO,o + Na+ + NaAlSirOs + SiO, + Li*. (l) ExpnnrurNTAL PRoCEDURE, Quartz is always present in the assemblage,and we as- sume that it is pure SiOr. Applying the laws of mass ac- The starting materials for mineral synthesiswere nat- tion at equilibrium, one finds that the ratio of activities ural colorlesspetalite (chemical composition is in Table

TABLE3. Resultsof the experimentsat 600€, 1.5 kbar

Final bulk solid composition Solution composition Reactants pmol/100mg pmol/l00 pL Number Days mg pL Na u x Na Li

NaCl 13 15 18 Pe 100 + Pe 324 0.003 26 72 0.27 Licl 38 Naol 13 't 16 18 Pe 50 + Pe 322 0.003 6 72 o.27 ucl 38 17 30 Pe 100 NaCl 25 Pe+Q+Ab 11 303 0.04 56 44 0.56 18 18 Pe 100 Naol 50 Pe+O+Ab 28 287 0.09 52 42 0.56 19 18 Pe 100 Naol 100 Pe+Q+Ab 50 275 0.15 55 47 0.54 20 18 Pe 50 NaCl 1 100 Pe+Q+Ab 83 243 0.26 57 46 0.55 2'l 18 Pe+Q+Ab 50 Licl 1 50 Pe+O+Ab 102 217 0.32 54 44 0.55 22 30 Pe 50 Nacl 1 150 Pe+Q+Ab 120 185 0.39 53 44 0.55 23 18 Pe 50 Nacl 1 200 Pe+O+Ab 186 157 0.54 55 46 0.54 24 18 Pe+Q+Ab 100 NaCl 1 50 Pe+O+Ab 176 13i! 0.s7 56 46 0.55 25 18 Pe+Q+Ab- 100 Naol 50 Pe+Q+Ab 184 135 0.58 56 48 0.54 26 18 Ab+Q 50 Licl 100 Pe+Q+Ab 202 110 0.65 56 48 0.54 27 18 Ab+O 100 Licl 100 Pe+Q+Ab 202 54 0.79 52 46 0.53 28 18 Pe+Q+Ab 50 Naol 100 Pe+Q+Ab 255 64 0.80 56 46 0.55 29 30 Pe+Q+Ab 50 Nacl 150 Pe+O+Ab 274 20 0.93 s3 M 0.55 Nacl 100 30 18 Ab+Q 100 + Pe+Q+Ab 326 0.98 52 47 0.53 Licl 100 NaCl 50 31 18 Ab+Q 100 + Ab+Q 321 4 0.99 57 43 0.57 Licl 50 32 18 Pe+O+Ab 50 Nacl 200 Ab+o 328 5 0.99 61 38 0.61 Note: See text for explanationsof results. Reactants: Pe : natural petalite; O : quartz; Ab : albite gel; Ab" : natural low albite' Final bulk solid composition: Pe : petalite; O : quartz; Ab: high albite. 208 SEBASTIAN AND LAGACHE: Li-RICH PEGMATITES

45OoC, 1.5kbor after the experiment. The tubes were welded at both ends and subjectedto the required pressureand temperature in a Bridgman type pressurevessel. The vessel was en- tirely immersed in the furnace, preventing a temperature

J '... gradient over the capsules.Temperature was monitored \ I and measured @ \ by external chromel-alumel thermocouples situated closeby the charge.The thermocoupleswere J cal- + B ibrated against the melting point of Pb. The cumulative z uncertainty due to regulation and measurementwas es- timated to be within + lo/s+) 'C. The filling of the vessel with HrO was calculated using PVT from z data Kennedy (1950) and Burnham et al. (1969) in order to reach the

I required pressure.The pressurewas not measuredduring o o5 to the experiment. Its uncertainty is directly proportional to Pe + No/(No+Li) solid Ab the uncertainty of the temperature. o The duration of the experimentswas 18 or 30 d at 600 'C and 60 d at 450 "C. At the end of the experiment the 600"C l.5kbor t.0 , pressurevessel was cooled in a compressedair blast. The tubes were opened and solid and aqueous phases were c extracted using deionized HrO and separatedin a centri- fuge. The solid phasewas then dried and the solution was o a made up to a definite volume. Li was determined in both solid and solution by atomic absorption and Na by flame J emission spectrophotometry.The precision obtained for N;+-x both is better than 2o/oof tbe amount present. The chlo- z ride concentration was checkedto verifi that most of the solution had been recovered.The crystalline solid phases z were identified by X-ray diffraction.

I A Rrsur,rs 05 t0 The results are presentedin Tables 2 and 3. X is the Pe + \q/(No+Li) solid Ab Na mole fraction of the total Li plus Na in the solid D assemblageartd Y is the Na mole fraction in solution. Calculations are made for solids in micromoles fumol) Fig.2. Isotherm-isobar qC of distributioncurves at 450 (a), per 100 mg and for solutions in micromoles per 100 pL. and 600 "C (b). Slantinglines connect the startingassemblage Graphical representation is shown by the classical iso- and final assemblagefor an individual experiment.The solid therm-isobar distribution diagrams (Figs. 2a and 2b) in circles representpetalite @e) or albite (Ab) + quartz (e) and which the bulk composition empty circlesrepresent (Pe + Q + Ab). of the solid assemblageis plotted against that ofthe solution and expressedby the Na/(Na + Li) ratio, which varies from 0 to l. The two l) from Minas Gerais, Brazil and albite gel prepared by sets of experiments conducted at 600 "C with different the classical gelling method (Hamilton and Henderson, durations, led to similar compositions of solids and so- 1968). The chemical composition of the gel was verified lutions, indicating that a steady state has been attained. by wet chemical analysis.Petalite was finely powdered in Lines connectingthe starting nonequilibrium assemblage arragatemortar. Varying amounts (50-100 mg) of petal- and the final bulk assemblageshow that equilibrium could ite or a mechanical mixture of albite gel and natural quartz be attained in the forward and reversedirections. in stoichiometric proportions were weighed in Au tubes In Figures 2a and 2b the system is bivariant along AB of 2.5 to 4 cm length and 4.4 mm diameter, to which and CD. Along AB, petalite is enriched in Na until point varying volumes (25-200 pL) of alkali chloride solutions B where albite starts to crystallize. Point B is not strictly were added. Some experiments were conducted with a determined by the experiments. The composition X of mixture of I mol of petalite, I mol of quartz, and I mol petalite saturated in Na is situated between 0.003 and of albite. For the experiments near the petalite compo- 0.07 at 450 "C and between0.003 and 0.04 ar 600 qC.In sition, a mixture of LiCl and NaCl in the ratio 3:l was any casethe value of the ratio Na/(Na + Li) in petalite added and for those near the albite composition, a l:l is very low. This result agreeswith the chemical analysis mixture of LiCl and NaCl was added. This permits the of natural petalite (Cernf and London, 1983).Along DC, amount of Na in petalite or Li in albite to be fixed, there- albite is enriched in Li until point C where petalite starts by retaining a measurableamount of Na or Li in solution to crystallize. At both temperaturesthe maximum of the SEBASTIAN AND LAGACHE: Li-RICH PEGMATITES 209 ratio Na/(Na + Li) in albite is 0.015 + 0.005.Very little Cernf, P., and Ferguson,R.B. (1972) Petalite and spodumenerelations. I l, 660-678. as by Heier Canadian Mineralogist, Li enters the structure of albite already shown Cern!, P., and London, D. (1983) Crystal chemistry and stability ofpetal- and Adams (1964)for natural samples. ite. Tschermaks Mineralogische und Petrographische Mitteilungen, 3 l, The horizontal section BC representsa univariant sys- 8 I -96. tem along which petalite saturatedwith N4 albite satu- Cemi, P., Meintzer, R.E., and Anderson, A.J. (1985) Extreme fraction- granitic pegnatites: examples of data rated with Li, and quartz coexist in equilibrium with the ation in rare-element Selected and mechanisms.Canadian Mineralogist, 23, 38 l-421. fluid. Along BC the three-phaseassemblage buffers the Hamilton. D.L.. and Henderson,C.M.B. (t 968) The preparation of sili- solution composition (I') which remains constant at Y : cate compositions by a gelling method. Mineralogical Magazine, 36, 0.545+ 0.015at 600"C and Y: 0.520+ 0.020at 450 832-838. "C. These results show that in a buffered medium, the Hatch, R.A. (1943) Phase equilibrium in the system Liro-Al,O.-Sior. Na/Li ratio of the solution is only slightly larger at ele- American Mineralogist, 28, 47 l-496. Heier, K.S. and Adams, J.A.S. (1964) The geochemistry of the alkali vated temperature than at lower temperature. metals. In L.H. Ahrens, Frank Press,and S.K. Runcorn, Eds., Physics Two experimentswere conducted with natural low al- and chemistry ofthe earth, p. 253-382. Pergamon Press,Oxford, Unit- bite instead of albite gel as the reactant, and the results ed Kingdom. show that this doesnot changeeither the solid assemblage Heier, K.S., and Billings, G.K. (1970) Lithium. In K.H. Wedephohl,Ed., geochemistryII. Springer-Verlag,Berlin. We must recall that in all Handbook of or the solution compositions. Heinrich, E.W. (1975) Economic geologyand mineralogy of petalite and the experiments starting with the albite gel, in hydro- spodumenepegmatites. Indian Journal of Earth Sciences,2' 18-29. thermal conditions, albite always crystallizes with the high Hurlbut, C.S., Jr. (1962) Data on eucryptite from Bikita, southem Rho- temperaturestructure (Wyart and Sabatier,1956). A sim- desia.American Mineralogist, 47, 557. pegmatitesbodies. In P. Grn!, ilar observation was reported previously in Sebastianand Jahns, R.H. (1982) Intemal evolution of Ed., Granitic pegmatitesin scienceand industry, p. 29!-327. Minet' Lagache(1990). alogical Association of Canada Short Course Handbook, Winnipeg' Canada. CoNcr,usroN Jahns, R.H., and Burnham, C.W. (1969) Experimental studies of peg- This study has permitted us to determine preciselythe matite genesis: I. A model for the derivation and crystallization of pegmatites.Economic Geology, 64, 843-864. alkali composition of Na and Li in the Li-rich pegmatite Kennedy, G.C. (1950) Pressure-volume-temperaturerelations in water- medium. When petalite saturatedwith Na and albite sat- American Journal of Science,248, 54U564. urated with Li are simultaneously present, together with Iagache, M. (1984) The exchangeequilibriurn distribution ofalkali and qtrartz, the ratio Na/(Na + Li) of the coexisting chloride alkaline earth elements between feldspars and hydrothermal solutions- solution is buffered at a value which is very near 0.50, In W. Brown, Ed., Feldsparsand feldspathoids,p. 247-279. Reidel' almost independent of the temperature. Dordrecht, Holland. Lagache,M., and Sabatier,G. (1973) Distribution des 6l6mentsNa, K, The extremely restricted solid solution formation of Rb, et Cs a l'614t de traces entre feldspaths alcalins et solution hydro- sodium petalite and lithium albite agreeswith the ana- thermale e 650 qC, I kbar: Donn6es exp6rimentales et interpretation lytical results of natural petalite and albite samples. thermodynamique. Geochimica et Cosmochimica Acta, 37, 2617-2640. In a following paper (Dujon et al., in preparation) we lagache, M., and Sebastian,A. (1991) Experimental study of Li-rich gra- pegmatites: Part II. Spodumene * albite + quartz equilibrium. discuss the thermodynamic implication of these results nitic American Mineralogist, 76. in press. together with those obtained on the two assemblages I-ondon, D. (19E4)Experimental phase equilibria in the systemLiAlSiOn- spodumene + albite + quartz and + albite + SiOr-H,O: A petrogenetic grid for lithium-rich pegmatites- Amencan quarlz. Mineralogist,69. 995-1005. -(1986) Magmatic-hydrothemal transition in the Tanco rare-ele- AcxNowr-nocMENTs ment pegmatite: Evidence from fluid inclusions and phase-equilibrium experiments.American Mineralogist, 7 l, 376-395. This work is part of the doctoral thesis of the first author to whom a -(1987) Internal differentiation of rare-elementpegmatites: Effect scholarship has been granted by the French govemment. It was financed of boron, phosphorus and fluorine. Geochimica et Cosrnochimica Acta, by the Institut National desSciences de I'Univers, Grant Number 883851, 5t,403-420. Dynamique et Bilan de la Terre, the Centre National de la Recherche London, D., and Burt, D.M. (1982a) Alteration of spodumene,monte- Scientifique, and the Universit6 de Paris VL We wish to thank D. Irndon brasite and lithiophilite in pegmatites of the rvVhite Picaho District, and P. Cern! who's works inspired the very beginning of this research; Arizona. American Mineralogist, 67, 97-113. their critical and fruitful comments irnproved the manuscript. -(1982b) Lithium-aluminosilicate occurrencesin pegmatites and the lithium-aluminosilicate phasediagnm. American Mineralogist' 67, 483- Rrrnnrxcns crrnn 493. -(1982c)Chemicalmodelsforlithiurn-aluminosilicatestabilitiesin Bazarov, L.S., and Molorina, I.V. (1969) Physico-chemicalconditions 67 494-509 ' during the formation of rare-metal pegmatite of the sodium-rich typ€. pegmautes and ganites. American Mineralogist, ' -(l9s2d)Lithiummineralsinpegmatites. InP'cerni'Ed.'Granitic DokladyAkademiiNauksssR, lgg, 124-126. p. Mineralogical Associa- Bumham, C.W., and Nekvasil, H. (1986) Equilibrium properties of gra- pegimatitesin scienceand industry, 99-133' nitic magmas. American Mineralogist, 71,239-263. tion of Canada Short Course Handbook, Winnipeg, Canada' Burnham, C.W., Holloway, J.R., and Davis, N.F. (1969) The specific London, D., Hervig, R.L-, and Morgan, VI' G.B. (198E)Melt-vapor sol- qC. volume of water in the range 1000 to g900 bars, 20 C to 900 ubilities and elemental partitioning in peraluminous granite-pegmatite American Journal of Science, 267A, gO-gO. systems: Experimental results with Macusani glass at 200 MPa. Con- Burt, D.M., London, D., and Smith, M.R. (1977)Eucryptite from Arizona tributions to Mineralogy and Petrology, 99' 360-373. and the lithium alumino-silicate phasediagram. Geological Societyof London, D., Morgan, VI, G.B., and Hervig, R.L. (1989) Vapor-undersat- America Abstracts with Programs, 9, 917. urated experiments u/ith Macusani glass * H'O at 200 MPa' and the 2to SEBASTIAN AND LAGACHE: Li-RICH PEGMATITES

internal differentiation of granitic pegrnatites. Contributions to Min- vated temperaturesand pressures.American Journal ofScience,2l0, eralogy and Petrology, 102, l-17. I I 5- l4l. Manier-Glavinaz, V., D'Arco, Ph., and lagache, M. (1989) Alkali parti- Stewart, D.B. (1963) Petrogenesisand mineral assemblagesof lithium- tioning between beryl and hydrothermal fluids: An experimental study rich pegmatites (abs). Geological Society ofAmerica Special Paper 76, at 600 lC and 1.5 kbar. EuropeanJournal ofMineralogy, 1,645-655. I 59. Norton, J.J., Page,L.R., and Brobsr, D.A. (1962) Geology of the Hugo -(1978) Petrogenesisof lithium-rich pegmatites.American Miner- pegmatite, Keystone, South Dakota. U.S. Geological Survey profes- alogist, 63, 970-980. sionaf Paper 2978, 49-127. Taylor, B.E., Foord, E.E., and Friedrichsen,H. (1979) Stableisotope and Ostertag,W., Fischer,G.R., and Williams, J.P. (1968)Thermal expansion fluid inclusion studies of gem-bearing granitic pegmatite-aplite dikes, ofsynthetic B-spodumeneand B-spodumenesolid solution. Journal of San Diego County, California. Contributions to Mineralogy and Pe- the American Ceramic Society, 51, 651-654. trology,68, 187-205. Rossovskii, L.N., and Matrosov, I.I. (1974) pseudomorphsof quartz and Webster, J.D., Holloway, J.R., and Hervig, R.L. (1989) Partitioning of spodumene after petalite and their importance to the pegmatite-form- lithophile elements between H,O and HrO + CO, fluids and topaz ing process Doklady Akademii Nauk SSSR,216,164-166. rhyolite melt. Economic Geology, 84, 116-134. Roy, R., Roy, D.M., and Osbom, E.F. (1950)Compositional and stability Wyart, J., and Sabatier,G. (1956) Transformations mutuelles des feld- relationships among the lithium alumino-silicates:Eucryptite, spodu- spar}lsalcalins. Reproduction du microcline et de I'albite. Bulletin de mene,petalite. Joumal of the American Ceramic Society,33, 152-159. la Soci6t6 Frangaisede Min6ralogie et de Cristallographie,79, 574- Sebastian,A., and Iagache, M. (1990) Experimental study of the equilib- 581. rium between pollucite, albite and hydrothermal fluid in pegmatitic systems.Mineralogical Magazine, S4, 447-4 54. MaNuscrrm REcETvEDFesnueR.v l, 1990 Sourirajan, S., and Kennedy, G.C. (1962) The system HrO-NaCl at ele- Mauuscnryr AccEprEDNovsussn 7. 1990