RENDICQNTI DELtA SOCIETA ITAU ... N... 01 MINERALOG(Ir. E PETROLOGI.... 1988. 'obL 4}.2. pp. 49';1·'08

Accessory alteration in peraluminous at the hydro~hermal stage: a review

MICHEL C ... THELINEAU CREGU me! G.S. CNRS.cREGU, B.P. 23, '4501, Vandoeuv~-les·Nancy, France

ABSTRACT. - U. Th and REE distribution in (notamment ['uraninite et la monazite) et de leur peraluminous granites is essentially cOntro!1ed by remp[acement par des mineraux accessoires neoformcs accessory such as monazite. uraninite, apatite (so[utions solides complexes. carbonates, phosphates). and. to a lesser degree, . Although the nature and La cristalliution de mineraux neoformes, pn!sentant des distribution of such minerals are comroUed by magma solubwtes plus impO'lantes que: les mineraux acc;essoires fe1ltute$, they Jruly be significantly affected by $ubsolidus d'origine magmatique. est tres importante pour le alteration. Thus. different examples of hydrothermal lessivage u1tcrieur des eiCmenlS traces par des fluides aJteration have shown that trace e1emmlS may exhibit hydrothermaux. De telles altcrations ou neoformations conlrlsted behlviour. due to differential stability of dc minenux accenoires depend: 1) des facteurs primlry accessory minerals (especially uraninite and controllant la pm;:olltion des fluides a travcrs les roches monnite) and their replacement by authigenic phases (rapport eaufrochc:, degri de microfracruration .... ); 2) la (complex solid solutions, C1IrbonatC$ and phosphates). nature des minerlux accessoires, et en particulier la Crystallization of authigenic minerals having higher solubwtc des minmaux accessoires d'originc: magmatique so[ubilities than the magmatic accessory minerals is en condition hyd ro therm ale (stOOe de dissolution­ extremely important for further leaching of trace alteration); 3) la composition des fluides et les elements by hydrothermal fluids. Such alteration of changements intervenant dans les conditions physico­ magmatic accessory mineTals in granites and dissolution· chimiqucs lors de sradel uitetieurs de depot. recrystallization processes depeoo on: 1) fanou controllina fluid percolation through the roc:k (/roc:k Man db: MincrlUX acccssoires. U Th, Terres rares, ratio, degree of microfracturing. etc). 2) nature of the alteration hydrothc:rmale. leucogranite peralumineux . accessory minerals and especially the solubility of the minerals of magmatic origin under hydrothermal conditions (dissolution-alteration stage), 3) fluid composition and changes occurring in the physical­ Introduction chemical conditions during the later deposition stage, Key words: Accessory minerals, U, Th. REE, The distribution of U, Th and REE in Hydrothermal alteration, Peraluminous . peraluminous granites is firsdy controlled by the magmatic stage. These trace elements, as well as Zr, P, etc., are not incorporated in the main rock· forming minerals because of the RESUME. - La distribution et les teneurs de U, Th ct low partition coefficients between the magma des tCITes rares dans les granites peralumineux est and minerals such as , or essentiellement oontroll~ par les mi~raux accessoires. phyllosilicates, but in accessory minerals such tels que la monazite, J·uraninite. l'lpatite et. a un moindre dcgre, le zircon. Bien que la nature et la as uraninite, monazite, zircon or apatite. distribution de tels mincraux accessoires soit d'abord Consequently, their content in the whole rock contron~ par les call1Ctcristiquc:s du magma, dies is firstly dependant on the factors which peuvent ctre affc:ct~s de maniere significative par les control the distribution and nature of the attentions subsolidus. Ainsi, differents exemples d'a1teration hydrothc:rmaie ont montre que les ciCments accessory minerals. Thus, knowledge of the en traces peuvent avoir un comportemc:nt tlis COntrastc. mineralogy and thermodynamical properties en fonction de la stabilite differentieUe de lcurs portcurs of accessory minerals, which may bear more 500 CATIIEUNEAU M

than 80% of the above mentioned trace distribution of accessory minerals crystallizing elements, is the key to understand the from the melt depend on four group of geochemical features of granites. parameters (PAGEL, 1981, 1982a, b; CUNEY For many years, most of the accessory et al. , 1979; CUNEY and FRlEDRlcH, 1987; minerals, except uraninite, have been CATIiEUNEA U, 1987c): the trace element considered as fairly unsoluble and metastable contents (1) and chemical features (2) of the under hydrothermal and supergene magma, (3) the degree of magma evolution, conditions. This assumption led to consider (4) the physical-chemical conditions of magma first the whole rock contents in U-Th-REE crystallization. Figure 1 represents the factors as relatively good tracers of the magmatic controlling parageneses at the magma stage, processes, and second Th and REE as and a possible sequence of crystallization. relatively immobile in granites, except in The distribution of V, Tb, and REE does severe hydrothermal alterations. Thus, not depend only on the nature and abundance uraninite abundance has been mainly of each accessory mineral acquired at this investigated as a tool for the recognition of stage, but also on the trace element potential source rocks for uranium. distribution among each mineral. The V­ Consequently , peraluminous granites which content in monazite or thorite and the Th­ may be rich in uraninite, were considered as content in uraninite, for instance, may be favourable environments for hydrothermal highly variable according to magma chemistry leaching and deposition of uranium (RANCHlN, or magma evolution. Thus, as a given trace 197 1; MOREAU, 1977; FRlEDRlOt et al., 1987, element is heated by several minerals, detailed among others). mineralogical studies are required to establish In recent years, new data have been the complete distribution of its content in the obtained on the stability of monazite and rock. Figure 2 gives a schematic distribution zircon during metasomatic, hydrothermal of La and V among the different rock forming (CATHELlNEAU, 1987a, b) and ductile minerals in V-rich peraluminous granite. It structuring processes (GUlNEBERTEAU, 1986). shows that uraninite and monazite are major Such works have demonstrated that under constraints for V and La contents respectively specific conditions, accessory minerals may be in the rock, but that the V content in altered and U, Tb, REE leached. Thus, the monazite and zircon, or the La content in purpose of this paper is to investigate the role phylIosilicates and apatite cannot be ignored of hydrothermal fluids as factors controlling in the mass balance. the alteration of accessory minerals, and the consequent changes on the trace element geochemistry of granites. 11. Changes in accessory mineralogy at the hydrothermal Sklge The alteration of accessory minerals in l. Distribution of V, Th, REE among minerals granites during subsolidus fluid-rock At the stage of granite crystallization, interactions depends on (CATHEUNEAU, accessory minerals have two origins: 1987c): «1) the nature of the: mineral, and crystallization from the melt, and mechanical especially the solubility of the: mineral (Sds) transport by the magma of accessory minerals under the dissolution conditions, 2) the of external origin, as those inherited in solubility (Sf) of this mineral in the fluid relatively large amount from the partial which is a function of the initial concentration melting of metamorphic rocks. Thus, the of the elements such as V, Tb, REE and inheritance of zircon (POLDERVAART and ligands in the percolating fluid, 3) the ECKERMANN, 1958; HoPPE, 1965) and water/rock ratio and the fl ow regime in the monazite (MU-LER and MiTI1.EFELD, 1982; granite, 4) the exchange and interaction SAWKA et al., 1986) is relatively common since surface between the fluid and the minerals, the solubility of such minerals in magmas is which depends on the degree of relatively low. The nature, abundance and microfracturing and amount of microcracks ACCESSORY MINERAL All"ERATlON IN PERAWMINOUS GRANITES ElC.

!MAGMATIC STAGE I

l'

Fig. 1. - M.in w:essory minerals aystallizing .t the magm.tic; $!age in pertiuminous granites (following d.l. from liter.ture .nd especially PAGEL (1981,1982.) .nd CUNEY and FII.IEDRlCH (1987)). in minerals. The higher the solubility differemial in-situ alteration of minerals, 2) difference (SrSds)' the larger the amoum of crystallization of authigenic minerals in other mineral which can be dissolved. Therefore, sites (microcracks, vugs, etc.) after moderate the most favourable conditions for the to important transport of demons in solution. dissolution of a given accessory phase may be predicted if the parameters constraining the 1) In-situ alteration of accessory minerals highest (SrSds) values are known. The two last factors (4 and 5) have an Accessory minerals of magmatic origin may extreme influence on the rate of alteration of be partially to entirely altered and replaced minerals. As the accessory minerals are small­ by authigenic minerals. Each accessory sized, scattered in granite minerals (, mineral has a specific behaviour under given biotite, quartz, etc.), and represem a very physical and chemical conditions, and will small volume of the rock, a high degree of transform into specific alteration products, as microfaulting is required to allow fluids to shown by Figures 3 and 4. In this case, interact with them. This condition is changes in the trace element content of the frequently obtained in peraluminous granites rock is described by the mass balance of the from the Variscan range, which are spatially chemical reactions of solubilization or associated with major shear zones. Thus, alteration of the early minerals. The most demonstrative examples of monazite or zircon representative reactions for carbonates and dissolution have been described in granites phosphates are given in Table 1. affected strongly by ductile to brittle deformation (northern border of the u 0.' Kf'PI Mortagne batholith, Vendee, France, ~-r-"""M.·.. 8i CATIlEU NEAU, 1982; GUlNEBERTEAU, 1986), or in granites affected by subsolidus alteration " such as the quartz dissolution process (CATHEUNEAU, 1986) which generally occurs in granites affected by strong microfracturing (PECHER et al., 1985). Two different cases may be distinguished among the disturbances occurring in accessory Fig. 2. _ Repartition of U and La among main rock minerals of magmatic origin: 1) partial and forming minerals of pertiuminous granites. CATHEUNEAU M.

1Hydrothennal stage] Uranlnlte Monadte Apatite Zircon (Thonte) (XenoUme) I I \ f \ ID.-.ltu alte':',tlon ofm.patle aceeuory mlneralt: /, Coffinlte LREE PhOSPhal e5 ~ \Metamlct /' / REEcarbonatC5 I mlncrals , J. (hydration and .' P-alteration) Supply In Y. H E- rich carbonates '~/ HREE.Y or phospates '-.l.. -"""" , LEACHING ' , '\... \.7 >JU IREE HREE,Y Zr, Tb P f I C!y!talllu.tlon of authl(erue acceuorz mlnenls : I • \ U.P.REE rich thonte. Zr rich slllcates. apatite. ltenoUme , \ Y.REE nch carbonates and phosphates 11 / / " Abnormal, reconcentratJon Hydrothermal leaching (DePOSits) (Dispersion) - ~

Low·T.. al t eration p..rocesses I surildal.. and supergene alteration by dlagenetic, meteoric fluids)

Fig. 3. ~ Schematic represcntltion of main stages of alteration and crystallization of accessory minerals, and stages of U, n, REE, P, Zr mobility It the hydrothermal stage.

Uraninite is frequently lacking in surface 1973; RtMSAITE, 1982a, b ... ) typical of the samples due to supergene alteration, thus oxidizing zone. yielding significant U losses (BARBlER and Monazite may be partially (corrosions) to RANCHlN, 1969; FRIEDRlCH et al., 1987). entirely dissolved, or affected by dissolution Uraninite is obsttved either as a fresh mineral - recrystallization processes. In the case or as a boxwork, giving evidence of complete of the Pierres Plantees alteration pipe alteration of the mineral and replacement by (CATHELlNEAU, 1986, 1987a; RE SPAUT, phyllosiHcates and (hydr-) oxides. It is 1984; RESPAUT et ai., 1988), monazite difficult to interpret whether such an recrystaIlization caused complete resetting of alteration results from a hydrothermal or a the U-Pb system, at around 30 Ma after supergene process on the basis of microscopic granite crystallization, and a partial LREE loss observations. This explains why uraninite in the whole rock. Monazite alteration and behaviour under hydrothermal conditions is replacement by REE-carbonates is also a relatively badly documented and subject to rather common process in granites (RlMSAITE, discussion. In rdatively infrequent cases, some 1982a, b; MARUEJOL and CUNEY, 1985) alteration products have been identified, such submitted to strong alteration processes such as coffinite or hydrous oxides which could be as quartz dissolution and albitization, or interpreted as hydrothermal phases. However intensive biotite chloritization. REE­ most of them are UCV!) secondary minerals carbonates are parisite or HREE-rich parisite such as phosphates or (LE and STUSSI, and occur either as microcrystalline or needle

Fig. 4. ~ Micropbotographs of acxnsory minertls from peraluminous granites (+ , 01" If refer to I microphotograph taken wi lh crossed or uncrossed polan respcctivdyJ: 1 . uraninite with lureole filled with phyliosilicltes ( + ). 2· uraninite oo:x:wa-k filled with phyUa;ilicates and iron oxides (+).3 - monazite 1If). 4 - parisite replacing a monuite (+). , - apltite crystals within a biOlite ( ... ). 6 . hydrothermal apatite crystau in I clvity rcosulting from quanz dissolution Uf). 7 - zirconium rich silicates(zr$iI) surrounding mlgmltic zircon cores (+ J. 8 . hvdrothermal (P, U, REE. Y) rich thorile (+). ACC ESSO RY MINERAL ALTERATION IN PERAWMINOUS GRANITES ETC.

"> ,.:,. ',. \ CATHEUNEAU M.

TABLE 1 Possible dissolution and alteration reactions of apatite, monazite and xenotime (choice of species in solution was made from consideration of most probable conditions during studied processes)

MONAZITE)(EN01lME (REE,y)P04...... + H2O = HP042- + (REE,Y}3+ + OH­ or lteDotime

2 (REE."r')P(4+ ea2+ +2 F-+3 HOO:r • ea(REE.Y)z(C03I3f'2 + 2Hl"042-+H+ parlalte or Y-parlalte

1REE,"J'IRl4 + 6H20+3AfJ+ +HF'042-", tR£E.~+ 7 H+ floreaclte

APATITE

CasCP04J3IOHl + 3 H2O .. 5 ea2+ + 31iP042- + 4 OH­

easlP04I3IOHl + H2O + 4 OH- + (REE,Y)3+ + 3 AJ3+" {REE,YlAI3(P()4J2;(0H)6 + HP042- + 5 ea2+ - .....d ..

masses or small prismatic crystals within (hydrothermal, or supergene, BANFIELD, microcracks or around monazite crystals. 1985), is questionable. Zircon, such as monazite, may be corroded Anatase is the most frequent Ti-bearing up to complete dissolution (CATI-fEUNEA U, phase even in apparently fresh granites, 1987b), or affected by metamict disintegration probably due to the instability of ilmenite and (RANKAMA and SAHAMA, 1950; ANDERSON, ti tanomagnetite, and to the lack of titanite 1941; CARUBA et al. , 1975) consisting in crystallization in Ca-poor peraluminous progressive hydration and destruction of the granites. Ti is also expelled from biotite during crystalline network, probably due to the chloritization, and is mobilized in some cases effects of self-radioactive damage. In some such as albitization- quartz dissolution cases, a fringe of zirconium rich silicates, processes, during which new anatase considered as resulting of hydrothermal crystallizes in ab.mdance in the vugs of quartz­ overgrowth, surrounds a previoos zircon core. depleted granites. Zirconium rich silicates were observed in albitized and quartz-clepleted granites and are 2) Authigenic minerals (discrete to significant especially enriched in Th, P, REE, AI and U, mineralizations) Ca (CATHEUNEAU , 1987b). Apatite may be completely dissolved and Numerous descriptions in the literature then redeposited in albitization processes mention the presence of accessory minerals accompanied by quartz dissolution. in sites which undoubtedly attest to the Authigeruc apathes may be very abundant in subsolidus crystallization of such minerals. such altered rocks as disseminated prisms or Most of these authigenic phases are the same sphaerulites made of apatite needles, this minerals than those replacing accessory producing P enrichments up to 1 or 2%, minerals of magmatic origin, but most cannot which are abnormal values for peraluminous be identified positively as products of the in­ granites. In other cases, apatite may be situ alteration of a previous phase. Such data replaced by f10rencite (SAWKA et al., 1986) mean that significant transfer of U, n, REE or rhabdophane (VLASOV, 1966) during or P may occur through the partial to complete alteration process the origin of which dissolution of one to several accessory ACCESSORY MINERAL AU'ERATION IN PERAUJMINOUS GRANITES ETC. 505

minerals, transport of elements by a solution and redistributed within a gramtiC pluton and precipitation of authigenic minerals in a under rates which are essentially dependent site which may be relatively far from the on the physical-<:hemical conditions prevailing dissolution zone. In this case, the approach in the rocks. to the problem is similar to that of any study of hydrothermal or metallogenic processes. Therefore, the amount of authigenic accessory Discussion and conclusions mineral, which can be precipitated from a Peraluminous granites, as well as most of fluid as a result of a change in the physical· granites, are affected by long. lived fluid chemical conditions, depends on the circulation, which are for the most part later concentration of trace elements under the than the magmatic stage and independent of transport condition, and the solubility granite cooling (CATHELlNEAU , 1987a; difference (SI-Sd): Stt·Sdp. being the CATHELINEAU et aI. , 1988). It is clear that, difference betweeri the solul::iilities of the throughout the hydrothermal history of a authigenic mineral under transport and granitic body, a significant contribution of deposition conditions respectively. hydrothermal process to the present·day Authigenic minerals are mostly complex geochemical features must be considered not solid solutions, which may be either silicates only as a possibility but as a reality. (zirconium rich silicates, U·REE·Ca-Y rich Considering the U, Th, RE£ content of thorite, .. .)., phosphate (V·Th rich xenotime, granites, the rate of changes in the crandallite group, ete.) or carbonates (LREE geochemical features acquired at the magmatic to HREE-Y rich parisite). The stage is a function of: microphotograhs of Figure 4 give some aspects 1) the degree of transformation of of these minerals in thin section. magmatic accessory minerals in the case of Major differences characterize the in·situ pervasive alteration (such as albitization, or alteration and new crystallization of accessory chloritization), and the nature of the al teration minerals: 1) the water/rock ratio and 2) the products. In this case, the system may be amount of authigenic mineral which may considered as semi-closed, and changes in the precipitate, which are much higher in the mineralogy do n€lt necessarily imply significant second case, 3) the time necessary for the U, Th or REE transfer, the mass transfer achievement of the process which is higher being controlled by the mass balance relative in the case of pervasive in·situ alteration than to each alteration reaction. However, the in typical channelized hydrothermal crystallization of carbonates or phosphates circulation, 4) the degree of disturbance of such as parisite or crandallites in place of magmatic paragenesis, which remains monazite or apatite is extremely important for relatively low in the second case, due to low further late processes, since such minerals reactivity of accessory phases in the host rocks have significantly higher solubilities than the during the deposition of hydrothermal accessory minerals from which they derived. minerals in veins or microcracks. As a consequence, REE may be largely Abnormal enrichment in U, Th and REE mobilized during stages of low- to medium­ have been observed for instance in albitized range temperature, during which authigeruc and quartz-depleted, granites from the Mt minerals may be easily leached whilst early Lozere area (Bouges peraluminous granite, accessory minerals remain stable; southern part of French Central Massif, 2) the nature and amount of authigenic CATHEUNEAU, 1987b). In such altered rocks, minerals which may crystallize in the granite the abundance of apatite, phosphothorite, and from the fluid phase. In this case, the supply xenotime is such that element transfer must in trace elements from the fluid disturbs the have occurred along important distances, and early geochemical features by a that large volumes of the source rock have superimposition of the different element been altered. This suggests that significant contents relative to the crystallization of each amounts of U, Th of REE may be transported newly-formed mineral. ,06 CATBELlNEAU M.

Alteration of a specific accessory mineral CARUBA R .• BAU10tER A., MAl'O J., TURCO G. (19n) . whauver i[S ongln, magmatic or Eiuik tomfJtlraJi~ dn propri&h InPtCtives tit zircom IryJroxylis JY1Ithitiqun tt tk zitrollS m&mit::tc natu~lJ: hydrothermal, probably controls the trace bypothm- tk gmist dts malatol/S. Petrologie, 1(1), element of the fluid percolating in the 57·70. granites, independently of the effects of CATItEUNEAU M. (1982)· Lts giStmt1/ts d'uranium Sud fractionation process which may occur during Amroritaim lih spatiJIkmmt aux ltutogmnill!1 tt" kur mineral dissolution. Therefore, the REE tl/tai$Sllnt mttamorphiqu~; ~latiOnJ ~t intmutionJ ml1r In minlralisatiol/S ~t divm tont~tc glologiqutJ tt pattern of the common hydrothermal mineral structuraux. Sci. de la Terre, M~m. 42, 3n p. (fluorite, carbonates) which reflects the fluid CATltEUNIiAU M. (1986) . Tht hydrothermal alkali pattern may also be strongly influenced by the mttasotnatirm tfftcts on grrmilic rockJ: quam dissobltion nature of the accessory minerals which were and rtlami subso/iduJ thanIP. Journal of Petrology, 27, Part 4, 945·965. leached in the source rocks. Thus, the CATIlELlNEAU M. (1987a) . Lts intmlttionJ m~ {luirks instability of monazite and LREE.rich et roches: thermometrit tt moJilisation. Exl!1l/pk d'un carbonates or phosphates may explain the sys~m~ glothtrmiqut actif (Los k.u/rts, Mtxiqut) tt LREE enrichment of pitchblende, or d'altm/ fossiln tUnJ la dXlint VarUqut. Doet. Thesis, INPL Nancy, ~03 p. fluorite observed in deposits located in CATltELINIiAU M. (1987b)· U·Tb·REE mobility during peralurninous granites (CATHEUNEAU, 1987c), albitizalion and quam. dissolution in graniloim; ftJidtnct Similar conclusions have been proposed by from $Qulh-etlJt F~nth Massif Ctnltal . Bull. Mineral., PAGEL et al. (1987) from the study or uranium 110, 249·259. CATHEUNEAU M. (l987t) . U· Tb-KEE mobility in f/Jfnilic oxides of different geologic environments. tJlvironmtJIfJ III tM bydrolht7mal sf4g~. Proc. of the It is worth noting that fluorine, phosphate Intern. Workshop on .MclIllogencsis of uranium and. to a lesser degree carbonate acdvities deposits., IAEA·Vienna, March 1987, in press. exert considerable control over all the CATttELINEAU M. , MARIGNAC C., DUBESSY J., POTY B., WEISBROD A. , RM1BOZ LEROV j. (1988) · Fluids I), c., alteration reactions involving REE (Table in granitic tnvironmtJIlJ. Rend. S.I.M.P., vol. 43 (2), and that REE speciation at high temperature 263·274. remains one of the (relatively badly known) CUNEV M., LEROY J., PAGEL M. (1979)· Comporttmtnt key for a correct understanding of the tk {'uranium t t du thorium uns ks granius uranifbts processes. /ranfllis. Sci. de I1 Terre, SCrie clnformatique Geologique.. 13, ,,·63. In the light of such data, careful CUNEY M. , FRlEDRICIt M. (1987)· Pbysico-thtmica/and mineralogical observations appear to be a crystol-themical tonrrolJ on acCtssory mineral paragentsls necessary prerequisite to any interpretation in granitoitis; implications for uranium mttollagtntJiJ. of trace element geochemistry. Such study Bull. Mineral., 110, 235·259. FallmRlc u M., CUNF.Y M., POTY B. (1987) . Uranium could ensure that the present-day geochemical gtOtkmisJry in ~/uminous Nogrrll/ill!1. Uranium 3, features of granites were acquired at the 353·385. magmatic, hydrothermal or supergene stages GUINE6ERTEAU B. (1986) . u massif granitiqut tk and may especially justify the use of purely Mortagnt Jur Sivrt (Vmdk). Strutturt, gravimltrit, mi~ m plau: distribution tk U, Th, K. G«ll. Urlnium, magmatic models before any attempt at Mem. Nancy, 11 , 218 p. chemical modelling. HoppF. G. (1%5) . Morpholagiscbt UntcJllebungm als Beitrage ~u Zirkon Alter~timmungtl/ , 2, Mitttilung. N . Jahrb. Mineral. Ab., 103, 273·285. LE V.T., SrussIJ.M. (1973)· Lts minmux d'uranium tt dt thorium rksvanill!1 tk la Montagnt &urbonnai~ (Massif Ctntnzl/mrrfllis). Asstxiatiom tt paragenim. Sci. REFERENCE S de I1 Terre, XVlII, 4, 353·379. MAR UE,jOL P., CUNEY M. (1985) · Xihuashan tllngsttn· ArroERSON B.W. (1941) · TM thr«zi7rons. Gemmologist, !>taring granius aangfi, China); mineralogical controls London, 10,56·57. on KEE, Y, Th, U mobility during magmatU; tIIOlution and IryJrotbmnal altnution. Abstract K 54, EUG Ill, BA.'1FIEW j.F. (1985)· Minnulogy and tkmistry off}Tlnit~ weathmng. M. Se. Thesis, AU5[n.lian National Strasbourg. University, Canberra. MOREAU M. (1977) · L'uranium tt ks granitoidt1; tlsai BAlUlIEIl J., RANCfiIN G. (1969) . Influenu dd'altlration d'interpritation. In .. Geology, minin8 and extrac tive processing of uranium •. Symp. t.M.M. Londres, m&loriqu~ sur I'UNnium" Utili k ITatt dims k f}Tlni~ 83·102. a dna mitas at SI Sy/vn~. Geochim Cosmochim. Actl, 33, 39-47. MtLLEJ. C.F., Ml'rn..Ef'ELD O.W. (1982)· Depktion of ACCESSORY MINERAL ALTERATION IN PERAWMINOUS GRANITES ETC. 507

light rtlrt~rih tkmClts in /tlsic mDgtnlIs. Gcology, 10, RANKAMA K., SAIIAMA T.G. (1950) . Gnxhnnistr'j. 129· 1)). Chicago Univ., ChiC1lgo Press. PAGEL M. (1981) - FltCteun tk distribution tt dt RF,sPAIJT j.P. (1984) - Giochronologit ~t gnxhimit concClfrtltion tk rUl'Ilnium tt du thorium dam qudquts iwtopiqw U·Pbtk la miniralisation uranir~tks Pinm fPlnittJ tk fp chaint htrcynimntd'Europt. Doel. 1besis, PIPntm (Lo:irt) tt tk son mcaissant: k massif granitiqw Nancy Univ. de fp Margmde. Thesis, USTL, Monlpellier, 122 p. PAGItl. M. (1982a) - SucctsSion P'2rDgbthiquN tlUt/tun REsPAIJT j .P., CATHEt.lNI!AU M., LANCEt.OT J .R. (1988) tn urDnium Jts minbaux acctssoim Jam IN rrxhts . 5ucctssi~ mobilization.rttkposition 0/ uranium at tht gronitiquN: gpik pour fp rtCkrcht fk gmnit(S /w()rtlbkf Pierrts Plant«s deposits (Margtride, Franu): EviJenu afp prisnlCttk gisemClts d'urtlnium. Comple'Tendu du from mintraU:JV tlnd U-Pb isolopts, Chem. Geo!. Symp. _Metho:les de prospect de ['uranium.., Paris, (submitted). aCDE edil., 445-456. PAGE!.. M. (1982b) - Tht mintrDU:Jgyand gnxlxmisfry 0/ R.:iMSAITE J. (1982i) . The kaching 0/ ftldionur;/irks and urtlnium, thorium tmd nl~rth tlnntmts minnrJ/ofy tmd othn iom during allcrltion and 1rP/acm7tnl 0/ IJ«tsSory gnxhnnistr'j in two fadioactivt gTJIfIim 0/ tIN VOJgti. mintrals in radi()(JCti~ rodts. In .current Research .. , Franu. Min. Mag., 46, ))9, 149·16l. Part B, GcoI. Surv. of Canada, paper 81·1 B, 25)-266. PAGEL M., PrNTE, G., ROTACII·TouuJOAT N. (1987)· RIMSAITE J. (l982b) . MintraU:Jgica/ Dnd petrochnnical Tht rart tDrth tkmenl in natural ufDnium oxidn. propertin 0/ INterogCln>us gmnitoids rocks from Monograph Series on Mineral deposits, 27, 81·85. radioactivt OCCUfTCIUS in tht Grenvilk struClUrtS PECI!!!R A., LESPINASSE M., LE-ROY j. (1985)· Rtfptiom p1QJ!inu, o,llariO and QIIth«. In: Uranium in granites, btlwetn fluid ine/usions lrails DnJ rt&ional strtsS /Md: ed. V.T. Maurice, Gco!. Surv. of Canada, Paper a tool/Of fluid chlOnoWgy. An txampko/ an infnlgranitic 81·23, 19-}0. uranium Ort dtpOSit (northwtJl Massi/Ctntral, Franu), SAWJ(A W.N., BANPIELD j,F., CHAPPEll B.W. (1986) Lithos, 18 ,229-237. . A wtalhntd·rtfpl~d origin 0/ wi~ad monazitt in PoWERVAART A" EcK£Rl\.L\NN F.D. (1958) . Growth 5·typt granitn. Gc:ochim. Cosmochim. Acta, 50, phn/omCla in :i1'('on 0/ aulochto11Ous granitn. Gcol. 171·175. Soc. Am. Bull., 66, 947-948. Vusov K.A. (1966) - GnxhnnisJry QlJd mintraU:Jgy 0/ RANCIIlN G. (1971) - lA giochimit tk I'uranium tl la Tart tinnClts and vn~tic t'jpes 0/ thtif rkposits. In di//k&lcwlion granitiqut dons la provinu ul'Ilni/m du .. MiMralogy of rare elements., 2, isr:atJ program for Non/·Limousin. Sci. de la Terre, Mem., 19, 394 p. scientific translations Ltd, Jerusalem, 293-297.