Canadion Mineralogist Yol.22, pp. 499-502(1984)

MINERALSOF THE BRAVOITE_ VILLAMANINITESERIES AND CUPRIAN SIEGENITEFROM KARNIOWICE,POLAND

MAREK A. ZAKRZEWSKI Institute of Earth Sciencs, Free University, De Boelelaan 1085, 1081HV Ansterdam, The Netherlands

AssrRAc"r ample of polymetallic mineralization in Paleozoic rocks in close spatial proximity to the Triassic Zn- Copper-bearing Ni-Co-Fe disulfides with a -type Pb deposits of "Mississippi Valley type" of structureand cuprian siegenitehave beenrecognized in gale- southeastern Silesia. The mineralization occrus as na from 4 min61 occurrence'bf Pb-Cu mineralization in two assemblages:one rich in , with mar- Permian travertine from Karniowice, Poland. The pyrite- casite, pyrite and products of their oxidation, and phases 6Te occur as minute, optically and compositional- another rich in with rare , pyrite ly zonedoystals. The composition of individual zones , varies and the cuprian Ni-Co-Fe describedin this from cuprian pyrite with 2.9 wt,tlo Qn thr'engh cuprian bravoite to villamaninite CuojArh.46Co0.1aFeq.0a$2.Cupri- paper. Galena forms crystals and inegular grains up an siegeniteCusjlNi1.a5Col.1sFe0.0sSa probably formed by to 5 mm in diameter in porous, soft calcareous transformation of the disulfides. travertine. All the grains are coveredwith a layer of cerussiteup to 300 pm thick. Anglesite occurs but Keywords: villamaninite, cupriau pyrite, cuprian bra- is rare. Small flakes of covellite commonly occur at voite, cuprian siegenite, electron-microprobe analysis, the contact between galena and cerussite. Cerussite Poland. also occurs with covellite around the cuprian Ni- Co-Fe minerals. The original polished investigatedby Lipi- SoMMarns section arski & Zakrzewski (l9l) contains only a few grains of galena. A second sestion was prepared from a On a d6couvert des disulfues cuprifbres de Ni-Co-Fe a structue du type pyrite et de la siegenitedans ta galbne crushed sample preconcentrated by hand picking. provenant d'un indice de min6ralisation en Pb-Cu dans du Electron-microprobe analyseswere performed with travertin permien de Karniowice (Pologne). Les disulfures a Cambridge Instruments Microscan MK-9. Natur- seprdsentent en grains minusculesqui montrent une zona- al and synthetic compounds were used as standards. tion en propri&6s optiques et en composition. D'une zone Apparent concentrationswere correctedby ZAFwith i une autre, la pynte cuprifbre (2.990 Cu en poids) passe the MK-9 on-line program. d la bravoite cuprifdre et c€lle-ci i la villamaninite Cue3l.{i6.a5Co6.uFfo.oc&. La siegenite,cupriftre elle aussi CUPRIANBRAVoITE - YILIAMANI.ITE (Cu931Ni1.a5Col.lBFfo.05S4), serait le produit d'une trans- formation des disulfures. The cuprian disulfides having the pyrite structure Clraduit par la Rddaction) and compositions in the bravoite-villamaninite gs1- Mots-clds: villamaninite, pyrite cuprifbre, bravoite cupri- ies occur exclusivelyas a idiomorphic zoned crystals fbre, siegenite cuprifOre, analyse par microsonde included in galena. In places, the concentration 6lectronique, Pologne. reaches a few hundred crystals per urm2; isolated crystals were found in almost every grain of galena. IxtnooucnoN The averagesize of the individual crystals is about 10 pm, rarely up to 30 rdn. During ttre course of investigations of trace Pb- The individual zones in the crystals of disulfide Cu mineralization in the Permian travertine of Kar- reach up to 10 pm across,but in most casesthey vary niowice, 20 km west of Krak6w, Poland, anomalous betweenI and 3 pm. Becauseof the small size,differ- Co and Ni contents(0.1-1 wt.9o) were found as a ences in hardness and reflectivity could only be result of the spectrogxaphicanalysis of galena (Lipi characterized qualitatively. Observations on tle arski & Zakzewski l97l). Observations in reflected pyrite - cuprian bravoite - villamaninite solid- Iight showed very small grains of a tenta- solution seriesfrom Karniowice support the conclu- tively identified as linnaeite. Electron-microprobe sions ofVaughan (1969)with regard to the relation- analysis revealedthe mineral to be a member of the ship betweenthe physical properties and the chemi- siegenite-fletcherite isomorphous series.Numerous cal composition in tle pyrite-bravoite series. In small zoned cryst4ls with compositions in the reflected light, the pyrite end-memberis yellow and bravoite-villamaninite series were also observed. hard; increasingNi and Cu contentsr6ult in a lower- The investigated occurrence of sulfides is an ex- ing of hardness,a pinkish grey color and a lowering 499

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of reflsctance. The crystals are relatively resistant to member of the CuS2-NiS2series, with a composi- oxidation and generally remain unaltered in cerus- tional range betweenC\Ni2S6 and C\rNiSa,and thus site, but in placesthey are limonitized; their primary between 33 and 50 mol. 9o CuS2.According to this compositional zonality is then reflected by the inten- the "villamaninite" of Ypma et al. (1968)as well as sity of brown internal reflections in individual zones. the copper-rich disulfide from Lubin, Poland (Moh The presenceof copper in pyrite-group minerals & Kucha 1980) should be classified as fukuchilite. is rare and has only been described from a few lo- It is interesting to note that compositions similar to calities, the most imFortant being the Providencia the fukuchilite from Villamanin were not found by mine near Villamanin (L6on, Spain), the type local- Maaskant (1968), who performed 29 analysesand ity of villamaninite. Villamaninite has beeirredefined obtained tle range of compositions indicated by the as a Cu-Ni-Co-Fe mineral having the pyrite struc- dotted field in Figure l. The villamaninite in- ture and sonfaining CbS2 in the range between 25 vestigated by La lelesia et al. (1974) from the same and 75 mol. 9o (Ypma et sl. 1968). Shimazaki & locality also plots within this field. Clark (1970)proposed the name for compositions 1athis paper the Ni-rish disulfide phase with more close to the join CuS2-NiS2,whereas for composi- thaa 25 mol. 9o CuS2 are designated as vil- tions close to the join CuS2-FeS2,the name lamaninite Clable 1, #1,2), those with CuS2 in the fukuchilite was proposed. Moh & Kullerud (1982) range between 25 and 5 9o (arbitrary) as cuprian also designated villamaninite as an intermediate bravoite (#3-11) or cuprian pyrite (#12), and those with lessthan 5 9o as bravoite (#13). The composi- tion of the iron-rich bravoite (#4) is very close to Me 52-type fukuchilite. Considering the results of the electron- microprobe analysesas glven in Table I' it should O lGrniowice be borne in mind that they only approximatethe real ,* composition, as the 3-4 pm diameter of the X-ray ,lf Villomonin spot often exceedsthe thicknessofindividual zones. oo O Lubin The results obtained are projected onto the FeS2-NiS2-CoS2plane, and the CuS2 content is proportions Me, So-type shown by numbers and contours. The of Ni, Fe and Co in the cuprian disulfides from Kar- tr lGrniowice niowice resemblethose from Villamanin; their Cu content, however, reashes only 36 mol. 9o CuS2. DVillomqnin The shape of tle CuS2contours can be interpreted as a result of two trends: firstly, the Cu content is related to the Ni/Fe ratio @ig. l, points 3, 12, L7, 22,?5 and9, 15, 18,30; secondly,for a givenNi/Fe ratio, Cu showsan antipathetic relation to Co (points 3, 11, 18).The sympatheticrelationship between Ni and Cu and tle antipathetic one betweenNi and Fe

TABLE 1. RESULTS OF ELECII$-NICR()PR@E A|TALISES OF VILLIIIAIIII{M, CUPRIAII BMVOIN I'{D CUPRIAI{SIEGOITTE FRONUMllIilICE' I'PPERSILESIA

Ualght t At@ic PrcPodloc illreral cu fe Co llt S Total Cu F. Co lll S

l Vlll@nlnle 18.1 2.0 6.5 21.6 51.4 99.6 0.36 0.04 0.14 0.46 2.01 2 13.4 1.3 15.1 18.5 5t.l 99.4 0.26 0.03 0.32 0.39 1.98 3 Brdvol& 11.t 14.6 18.0 50.7 97.7 0,n 0.0a 0.31 0.39 2.00 4 11.1 n.2 0.7 6.5 52.2 98.7 0.22 0.65 0.01 0.12 2.02 5 9.4 11.9 7.5 19.7 50.5 99.0 0.18 0.26 0.15 0.41 1.91 6 8.9 15.2 17.8 51.5 99.7 0.17 0.14 0.32 0.37 L.97 NiSz 17.9 5.7 14.8 51.4 97.5 0.r5 0.14 0.12 0.32 2.03 Co 52 '/o So 7 7.7 mol Cur I 6.6 4.9 13.6 22.r 49.4 96.6 0.13 0.11 0.29 0.47 1.93 9 6.4 7.9 16.8 tg.o 49.0 98.1 0.12 0.17 0.34 0.37 1.4 Frc. l. Compositions of tle Cu-Ni-Fe-Co disulfides. 10 5.6 12.9 l8.O 52.6 101.0 0.11 0.26 0.26 0.37 1.98 95.8. 0.09 0.69 0.12 0.10 ?.m CuS2content calculat- l1 4.3 5.8 4.6 50.6 Numbers and contours indicate 12 Pyt.le 2.9 42.6 o.t - 53.2 98.8 0.06 0.94 2.05 ed on the basesof Cu + Ni + Fe + Co = I and Ni 13 Brrvolb 1.6 18.6 14.9 52.3 t01.0 0.03 0.29 0.38 0.30 1.94 + Fe + Co : l. Sources:Karniowice: tlis study, Lu- l4 Slegenlte 6.4 1.4 2r.5 25.2 40.9 95.5 0.33 0.08 1.19 1.40 4.15 bin: Moh & Kucha (1980), Villamanin: (dotted field) 0.6 21.9 27.0 O.8 96.4 0.30 0.04 1.19 1.47 4.08 Maaskant (1968), (Y) lpma et al. (1968), (L) La lgle- 0.4 21.4 21.4 8.4 95.5 0.30 0.02 1.17 1.5t 4.08 sia et al. (1974). r lncludes 3.4 f,t. t Pb frcd adJacent galona

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"i "-,-i;"-:---- .F'<-""'-'--"""-'Cu"'-':-.J9-.- '\. (*,:l' \,

5 10 ]5 20 25r.m Ftc.2. Concentrationprofile across zoned crystals of disulfidefrom Karniowice.

can also be observed on a concentration profile minerals and siegenite,iron and copper are preferen- through a zoned crystal (Fig. 2). The behavior of Co tially concentratedin pyrite-type phases. is more complex; in the central zonesa maximum There is general agreementthat copper-bearing of Co is related to a minimum of Fe, whereason the minerals with the pyrite-type structure are meta$ta- edges,high Co is correlatedwith a high Fe content. ble (Shimazaki & Clark 1970, Vaughan & Craig 1978).The occurrenceof cuprian siegenitein Kar- niowicesuggests that it was formed from the pyrite- CUPRIAN SIEGENITE type disulfides.This is indicated by l) the shapeof The only grain of cuprian siegenitefound in Kar- the siegenitegrain which is reminiscentof a row of niowice is enclosedin galena. It is an elongate severalcrystals ofdisulfide,2) its porous nature, 3) (150x 30 pm), somewhatporous grain. The cuprian the presenceof covelliteand 4) its chemicalcompo- siegeniteis optically isotropic, with a white color and sition. The projection of the composition of siegenite a reflectancehigher than that of galena.The pores in the FeS2-NiSr-CoS,diagram (Fig. l), recalculat- : are filled with cerussiteand, in a single case,with ed on the basesof Ni + Co + Cu + Fe I and : covellite. Cerussitealso occurswith flakes of covel- Ni +Co *Fe 1, showslow Fe and Cu values, lite around the gain at the contact with galena.There whereasthe Ni/Coratio resemblesthat of the disul- are no intergrowthswith disulfide minerals, but at fides. The analysisof the cuprian siegenitefrom Vil- a distanceof l0 pm, a conc€ntration of severalzoned lamanin plots within the iron-poor part of the vil- crystals occurs, also surrounded by'cerussitewith lamaninite field (Fig. l). minor covellite. It is interestingto note the presenceof composi- Resultsof electron-microprobeanalyses frsm three tions of the pyrite-typephases in which all four ca- points on the grain are given in Table l. The low to- tions (Ni,Co,Cu,Fe) are presentin major quantities tal of about 96 wt.olois probably due to'the porous (Iable l, #5-10).The compositionof siegeniteis rypi- nature of this mineral. The composition cotresponds fied by the presenceof only three cations, which is to an intermediatemember between Ni-rich siegenite, in agreementwith the observation of Riley (1980) CoNirSa, and fletcherite, Cu(Ni,Co)rSa, and is that no member of this group has beenreported with designatedas cuprian siegenite.Minerals of this series four cations in major quantities. are only known from the Viburnum Trend, U.S.A. (Craig& Carpenterl%7),thetypelocality of fletch- AcrNowI-SocEMENTS erite, and from the Shinkolobwe and Kambowe My colleagueDr. E.A.J. Burke and two anony- depositsinZatre (Riley 1980).The "unusual white mous refereesare acknowledgedfor critical review linnaeite" from Villamanin has a composition of the manuscript. Microprobe work was carried out Nit.rrCoo.r2Fee.1sCue.13Sa(Ypma et al. 1968), arrd by Dr. C. Kieft and Mr. W.J. Lustenhouwer.Fa- should be classifiedas cuprian Ni-rich siegenite. cilities for theseanalyses were provided by the Free University and the WACOM, a working group for analytical geochemistry subsidized by the Nether- DISCUSSIoN lands Organization for the Advancement of Pure The cuprian Ni-Co-Fe minerals from Karniowice Research(Z.W.O.). occur only as isolatedinclusions in galena,suggest- ing that galenaformed a microenvironment in which REFERENCES the Ni-Cu-Co-Fe-S systemcould remain poor in Cnarc, J.R. & Cenrurrnn, A.B. (1977):Fletcherite, iron. An iron-rich environment contributed to the Cu(Ni,Co)2Sa,a new thiospinelfrom the Viburnum formation of the chalcopyrite assemblagewith mar- Trend (NewLead Belt), .Econ. Geol.72, casite and pyrite. Considering the pyrite-group 480486.

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Le IclBsu, A., Cenar,r.sno,M.A. & MSNENDEZort- Rrr.ev, J.F. (1980): Ferroan carrollites, cobaltian Verlr, F. (1974):Estudio mineralogico de la vil- violarites,and other membersof ttre linnaeitegroup: lamaninita (Cu,Ni,Co,Fe)(Se,S)r.Bol. Geol, (Co,Ni,Fe,Cu)35a.Mineral. Mag. 43' 733'739, Mineral, 85, 436-441. Suruazarc, H. & Cr.anx, L.A. (1970): Synthetic Ltrrensrr, l. &ZexpeBwsxt,M. (1971):Ore minerali- FeS2-CuS2solid solution and fukuchilite-like zation in the Karniowice sinter. Kwartalnik Geol. minerals.Can. Mineral. 10, A8-664. 75, 317-324(Polish, Engl. abstr.). Veucnan, D.J. (1969):Zonal variation in bravoite. Meesrevr, P. (1968):Electron-Microprobe Analyses Amer. Mineral. 54, 1075-1083. of Villamaninile. Unpubl. report, Free University, Amsterdam. & Cnerc, J.R. (1978):Mineral Chemistryof Metaltl SuVides.Sulfides. CambridgeCam University Press,Cam- Mon, G.H. & Kucre, H. (1980):Villamaninite. /n Ore bridge, England. Syntheses,Phase Equilibria Studiesand Applica- tions. Report 1978/79(G.H. Moh, ed.). Neues Yprua,P.J.M., EvERs,H.J. & Woelsonncr,C.F. Jahrb. Mineral. Abh. 139. 113-154. (1968):Mineralogy and geology ofthe Providencia mine (Le6n, Spain), typeJocality of villamaninite. & Kur,r.rnuo,G. (1982):The Cu-Ni-S system NeuesJahrb, Mineral. Monatsh., 174'191, and low temperaturemineral assemblages.Soc. Ge- ology Applied to Mineral Deposits,Spec. Publ,2, ReceivedAugwt 9, 1983,revised manwcript accepted 677-688. Springer-Verlag, Berlin. October26, 1983.

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