Revista Brasileira de Geociências 12(1-3): 426-436, Mar.cgei., 1982 - São Paulo
ARCHEAN ANO EARLY PROTEROZOIC MINERAL OEPOSITS lN BRAZIL
EDUARDO CAMILHER DAMASCENO·
ABSTRACT \ ln this papel' is prcscnted a rough rcvicw anel au up-to-date compilation on thc Archean and Early Proterozcic mineral deposits in Brazil and their mctallogeny. Thc large Precambrian shields which cover about 2/3 of lhe Braziliun territory cnclosc a greal nurnber of ore mineralizations. Among thcsc the most important and well investigated are thosc ofiron , manganese. galei, base melais (Cu, Pb, ZI1), nickcl , asbestos, chromitc. pcgmatitc ruincrals (tin , colurnbite-tantalitc and gemstoncs}, uranium. tale, magncsitc and limcstones. Their host rocks are rcprcscnted by four main geologic cnvircnmcnts : volcanic-sedimcntary (iron 1'01' mations and greenstone belt type structures), mafic and ultrumaflc complcxes. granulitic zoncs and granitic-gneissic bclts. ln severa! cases only thc protore is Archean and 01' Early Proterozoic in age anel the ore enrichment is rclatcd to Cenozoic process as observedfor some iron. mangancsc, nickcl and placer mineral deposits. II is vcry difficult to establish lhe correct ages for many mineral dcposus duc to the complcx geologic history, rcacuvauon and supcrfmposed geological process in the Prccambrian terrain. For the prcsentation 01' this papel' the following age subdivision is considcrcd: Early Proterozoic - up to 1,800 Ma (Transamazónicc Cyde) Late Archean - J,OOO~2,600 Ma (Jequié Cydc) Early Archean - more than J,OOO Ma (prc Jequié-Guriensc Cyclc} The munes, location , geologic environmcnts. economic figures and other data on the mineral deposits mentioncd herc corrcspond lo the 1:2,500.000 Gcological and Mineral Deposits Mal' ar Brazil lo be publishcd by Departamento Nacional da Produção Mineral (DPNM).
INTRODUCTION Arehean and Early Proterozoic min be published by Departamento Nacional da Produção Mi erai deposits are very important to mining in Brazil and nerai (DNPM l. Some general information from Almeida alsc show a spccial scientific intcrcst. This paper is con ct ai. (1981) and Bcurlen and Cassedannc (1981) was also cerned with an up-to-date review and a brief description uscd. 01' lhe main Archean and Early Proterozoic Brazilian The main mineral deposits attributed to the Archean and mineral deposits. ln spite ofthe scarce information available Early Proterozoic, are indicated on Table I classified in some metallogenic data will be given. ln severaI cases the accordance with the following geological environments: scd lack 01' detailed maps and basic data ma de the intcrpre imentary-volcanic mctamorphosed sequences, rnafic and tation 01' the geological cnvironmcnts involved and the ultramafic cornplexes, granulitic zones and granitic-gneissic proccss of the ore emplacement difTicult. The ages for many belts, classification suggested also by Wernick (1981) for mineral deposits and related host rocks should be considered the Brazilian Archean sequences. with care because in this study they are preliminaries. The ln many cases only the protore is Archean and Early following age subdivision was considered: Proterozoic and the ore enrichment was devclopcd later, during the Cenozoic. ln this case there are gold and tin Early Proterozoic·· up lo 1,800 Ma (Transamazônico Cycle) placers, lateritic manganesc, nickel and some iron ores. Late Archean ··3,000-2,600 Ma (Jequié Cycle) ln Table I and in lhe following descriptions of mineral Early Archean - more than 3,000 Ma (pre Jequié-Gurien- deposits, the sarne names referred lo in the above rnentioned se Cycle). DNPM map will be used : • For northern Brazil: Another difficulty, was that ii was impossible to mention Early Proterozoic: Vila Nova Group, Grão-Pará Group, ali lhe authors who published many papers deseribing Rio Fresco Formation specific Archean and/or Early Proterozoic mineral deposits Archean: Xingu Complex and related geology. ln this review, speeially prepared for • For the northeast lhe ISAP-Inlernalional Symposium on Archean and Early Middle lo Early Proterozoic: Gurupi Group, Caicó Group Proterozoic ir was our intention to show the most up-to-date Archean: "Complexo Cristalino" inforrnation recently published and to bring new data to • For the central and eastern lbe knowledge of lhe mineralization processes developed Middle Proterozoic to Archean: Barbaeena Complex, Rio in the primeval history of the Earth. das Velhas Supergroup, Lafaiete Formation, Minas Su Many data On mineral deposits referred lo in this papel' pergroup (Cauê Habirite), Boquira Formation, Conten carne from lhe new version 01' the geologic and mineral de das-Mirante Complex, Colomi Group, Brumado Com posits map ofBrazil, I :2,500,000 scale, prepared by Compa plex, Andrelândia Group, Paraíba do Sul Complex, Acid nhia de Pesquisa de Recursos Minerais (CPRM) with the intrusives, Goiás mafic-ultrarnafíc (Cana Brava, Barro Al collaboration of many geologists (including P.c. Branco, to, Niquelândia and other small bodies), Campo Formoso R. Mignon and E.C. Damasceno for mineral deposits) lo ultramafics.
* Departamento de Engenharia de Minas, Escola Politéclúca da USP, Caixa Postal 8174.05508 -.- São Paulo, sr, Brazil Revista Brasileira de Geoctênctas, Volume 12 (1·3), 1982 427
Table 1 - Main Archean and Proterozoic Brazilian mineral deposíts
VoloMnlc·selUmanuy MoO","ullrMmoOc Cllmpl.x.. G... lssJc.grultk~pIex" Gnnl>lltl. bell1 NnI.-dloetup ElemelU or Greenslnnc bell lron ,onnal! Rulna. dn Pilar. Serro do PHarde Goi,I•. Nova Uma, Pau...Pique (?I. Tapai'" (1). SIlo Sopé. Chapada dos Cavaleanle. Jaeobina. Ao (MorlO Velho Mioe). Cri,,,., Turiacu-Gurupi (?l. Ublilra (As Au) GuimarAes,llaiIUb ••Mauér;. No,'a Roma Araci - Scrrinha São Gonculo-Campunha (?l TapajÓ., Sorr. d(lSGr8daú. Gllajarlt- Mirim (Au Ag) MElraRo-"IChllpadul,.Silo Juliilo. Palmeirópoli'. Amori... no do Ilr.,il (Ni CuCol Jaguaruri·Curaci,.Cora1bli Iliúbli (?) c, Camji" (501000. Buhi.). Jaguarari.Cu,açi,.Caraibli (?l (Maflc.Ullramuflc Oranulil.') F.,'lnalm SiloJoão do Piau;, Calingueiro Ipanema. Liberdade. BalTo N' AI(o. NiquelfiudiEl. !'ru(I,poli' (proIO"'J (Morro do Niquei). Silo Féli. do Xingu. All)cri..no do Brasil (Ni Cu CoI Senhor do UonOm.Usui<(?) Pedra Bllln,,". PiOm·l. Sórr<>. Almmda. Queimudu'. Campo C, Formo.o. Cao Luf";elc (Morro da Minal. M" Quadriliucro fcrrifero Mina. Gerai,. Serra do Na"io Scrra do. Cnraj:',s Umodi - Lidnio de Almeida (prnlOle) Se". dm C"rujú, (A,,,II, Maraú, Slo, Anlónio de Je.u. AraÇOiaba, hnberal (1) (Duri("ama, Sereno) Urandi-J.cn",d (?) PbZn lInqllira Mine I?I Rio Claro. Marlinópolls. Silo Félix do Xingu Cana n",,", Pon!ali"". Pilar de Go"". PoçÓCs. Unlulh" A,be'10' l("bemba, Mo.u"da'. Balalh" (?l n"",> AlIO llapad. Cri,i,.', Pilar de Cuull!,éi", ('.rand"Í, lIrumado. AruealU rale Goi,,, hnberubu. S,lo Raimundo No"ulo.lguul'" n Con(endu, do Sincorl, (Cu Pb) W No,," Treoln (?) Igualu-Judo<. (',,"el •. Magn..ilc IIrumado""ArnC"IU Brulnudo. Aracah' AI Serr" do. Carujú•. 101010"'1 Nnv. Li",,, Morrn do lIaú, CuparoÓ.. Nb. 'n.ae. s». ilomhé, Mimo'" do Sul. Muqui, Kaolin lluberai. !'i«nó""li'. Anu~,'. ('"rm,iha. Sanl" Rubelilu. MaTj[ae. Ilanhóm. Gem'looes Resplendor, reemo Olllni (?I Fcld,par Terelinha (Emcraldl Oovernador Valadures (~l Arnçual. Mar de Espanhu se Silo Jooo Dei R.i. Monte Mapue," (?) (ore and prOlore) Alegre dc Goi'" (?I.Novo Airilo. P.", M"lnquinha rn M. II"" Vista,Serra do Mel. Ouuriba (?) Kyanile Male". Leme. hamaralldiba (prn(orol Capelinha. Serro da. Arara' Apalile ll"mhé. S"o,,; Ipir',·Pedra, Aha. PiqueI Carneiro. Silo Jo~ do Oraphile Egilo. hapecerica, Formiga. Maleu. Leme, Rui Barbosa, - !'edra Azul Arapi'""", Flo,esIEl. Campo Alegre de Ulurdcs. Ti(V. Fel Independência laço.ll"mari Lagoa Real. S.J. E.pinhara. (?) U Jacohino Unlaia o-u. pl Vcrmiculile Pauli,(ana.D.lIusilio timeOlonc. llalva, Euclidelândia. M..hles Palmai, Piqueri, aalo"i. P. Machado. Qui~aba, C. do Ilapcmirim. Rib. do Ouro Coai RioFrcsco OUanl Quam. vem. Wi 56', OU~UPI'. Au Silo Luís c • q ~ > ,'i>~ Fortaleza ? Territôrio de • 'A AC01A8A-l,!n r·-~ ~ ."'~";,;~::'. ! Ir/l.TAIAI~'T'.IJ )o Fernando de ...... ' ~ Noronho 6'- 'Q TA'TUBA u <> Ter••i no <>c' ... ~~~~OS~Au • ''r'Ni ~ll~ ;,(A,LVOIlAo:-f' ~TON(polm',"IO 18°_ , l' ')t "&AL1LÉIA-POOlTMll'IO Q" NOVA LIMA-l,lOIlIlO , ANTONINA·fo DIJAPE-Ialo ·C ritibo JOINVILLE -fo' NOVA TIlENTo-W' FtorionóPolis SÃOSEPi-AU:/.í0. / toAleQre ""~V'"" O ~oo 400 km , '0' Figure J - Location map, Main Archean anel Ear/)' Proterazoíc mineral deposits • For .southern Brazil: lron Iron formations and high-grade iron orebodies are a Early Proterozoic: Porongos Group (Cerro Mantiqueiras common and very important economic event in the Brazilian formation), acid plutonics precambrian terrain. Archean iron (magnetite), iron-tita Archean: Porongos Group (Cambai Supergroup), Tabu nium and iron-titanium-vanadium deposits are present in leiro Group, "Complexo Cristalino". the highly metamorphosed and granulitic units, The most known oecurrences are those at Antonina, Joinville, Sento BRAZILlAN ARCHEAN ANO EARLY PROTERO ,Sé, Campo Alegre de Lourdes, among others, The Antonina ZOIC MINERAL OEPOSITS The very large Precam magnetite ore bodies - recently redescribed by Arioli (1980) brian shields enelose many interesting ore deposits. With - are included in iron bearing quartzites, gneisses, amphi some exceptions, the most important Brazilian ore deposits, bolites and chlorite schists, However, the most voluminous mines and mineral resources are related with Archean and iron formations are those ofthe Early Proterozoic and Tran Early Proterozoic terranes. Among these. the most impor sarnazônico Cyelethat occur in Minas Gerais - Quadrilá tant are those of iron, gold, manganese, copper, zinc, lead, tero Ferrífero - and Pará states - Serra dos Carajás, nickel, asbestos, tin- chrornite, pegmatite minerais, uranium The Carajás iron forrnation is composed of a unit of tale, magnesite and others, which will be brief1y described hard itabirites (oxide facies) interbedded with two metaba (Fig. I). sic volcanic sequences. Hematite ar.d martite are the maio Revista Brasileira de Oeocténctas, Volume 12 (1-3), 1982 429 with very simple tools) are a common scenario in the main drainage systems. Despite the number of deposits, only a small group of primary gold mineralizations has been well investigated. And it was based on these scarce data that a preliminary ciassilication for the Brazi1ian gold deposits was effected, as follows: • Stratabound deposits enciosed in metasedirnentary-meta volcanic host rocks, represented by Morro Velho mine CANGA and other mineralizations near Nova Lima, Minas Gerais and the Weber zone in the Araci-Serrinha Complex, SIL TSTONES, SANOSTONES Bahia (Teixeira and Kishida, 1980). CONGLOMERATES For some of these metasedimentary-metavolcanic Arche z an sequences, rnany authors recently proposed a greenstone • 1""1 belt structure type (Araci-Serrinha and Pilar-Itapaci-Crixàs, Montalvão and Bezerra, 1981). GRANITE • Gold-bearingquartz veins widelydistributed in the shields, METAVOLCANIC related with granitic rocks (Goiás, Mato Grosso and Pará states) and metasedimentary metavolcanic environments. IRON ORE • Paleoplacerdeposits in metaconglomerates as at Jacobina (White, 1957; Lemos, 1974) and Serra da Moeda, Minas Gerais. • Pb-Zn-Cu-Ag-Au sulphide deposits. at Boquira mine, METAVOLCANIC Caraiba and Serra dos Carajás deposits. The Nova Lima region gold deposits are enciosed in the GRANITES. AMPHIBOLITES, SCH1STS, Rio das Velhas Supergroup and, among others, Morro Velho' QUARTZITES and Raposos mines are the most important economic dep osits. Morro Velho has produeed more than 250 tons of gold during its history. The orebodies are typically strata Figure 2 - Serra dos Corakís. Generallzed cross secüon tmodijied bound shaped and are ciosely related with carbonate-iron from Beisiegel ct al., 1(73) formation. The host rocksarechiorite schísts, sericiteschists, phyllites and quartz-carbonate rocks. Vial (1980a)described in the Raposos mine, four mineralized facies: oxide (magne tite), carbonute [siderite. ankeríte, iron-dolomite), silicate iron minerais in the high-grade ores, but magnetite and (biotite, cummingtcnite-gruncrite) and sulphide (pyrite, pyr· goethite also occur (Santos, 1980, 1981 I. The wcathering rhontc. arsenopyrite and chaicopyrite), ali related with gold. is considercd as the main iron ore enrichment factor, but The Nova Lima distriet was investigated by many au there are both supergenc and metasomatic ores, as also thors as Tolbert (1964), Moreschi (1977), Fleischer and occurs in thc Quadrilátero Ferrífero (Fig. 2). Routhier (1973), Vial (I 980a, 1980b) and Ladeira (1981). Another iron formation covers a large arca in Minas Ge Tolbert (1964) considered the Raposos mine as a hydrother rais from nearBelo Horizonte to habira andncrthward (Por mal deposit, with the gold preferentially replacing siderite teirinha zone) into Bahia State. The Cauê Itabirite (oxide -rich bands in the iron formation. Fleischer and Routhier facies) is the main unit in the iron formation which may (1973), based on boron anomalies in the ore-bearing hori have an average thickness of about 250 m and can be traced zoos, suggesteda "consanguineous" origin to the tourmaline over an area of about 400 km. Ali the large high-grade iron bearing gold deposit of Passagem de Mariana. They also orebodies are enclosed in these oxide fades. According to obscrved the lack ofevidence between submarine vo1canism Dorr II (1973) "the Cauê Itabirite was deposited as a blanket and lhe gold mineralizations at Passagem de Mariana Iormation in a stable shell' ar miogcosynclinc cnvironmcnt mine. Furthcr studies conduced by Vial (1980a, b) in and it interfingcrs with thick and widesprcad dolomite beds. Raposos rcfcrred to a possible vulcano-sedimentary origino A direct contribution of volcanism to the depositonal basin The sarne origin was proposed by Moreschi (1977) for the duringlhe deposition ofthose ironforrnations isnot known", 'Faria gold zonc, also relatcd with iron formation. But thereare different opinions on the origin of the primary Recently, Ladeira (1981) reported basaltie vugs pillow iron ores. Suszczynski (1972a) suggested a voicanic origin lavas outcropping in Morro Velho mine adits. These vol to thcCarajàs primary ores. On the other hand, Barbosa canic fcatures areclearly related with the chemicalsediments (1976) considered the Serra dos Carajás and Quadrilátero ofthe Lapa Seca and the Iron Banded Raposos Formations, Ferrífero iron formations as mainly chemical deposits. Por which are the gold host rocks. Teixeira and Kishida (1980) teirinha (Rio Pardo de Minas) is almost a detrital iron described the Weber Zone stratabound gold deposit , Araci deposit. -Serrinha, Bahia, and have proposed a syngenetic exhalative origin for the mineralizations related with rnctavolcanic Gold Many primary gold mineralizations are present in -rnctasedimentary rocks, thc Brazilian Precambrian shiclds. Placcr dcposits. small ln Central Brazil, mainly in Goiás, gold mineralizations mines and "garimpos" (a man and/or a small group of are known at Pilar, Crixás, Cavalcante and Nova Roma, workers who exploit a surface 01' a near surface deposit among others, Berbert et a/o (1980) described the Iithological 430 Revista Brasileira de Geociências, Volume 12 (l-3), 1982 and structural controls for the gold mineralizations in the • Volcanic-sedimentary deposits, as those 01' Palmeirópolis following types : (Zn-Cu-Pb) and possibly Chapada (Mara Rosa, Early • Gold deposits related with granitic-gneissic environrnent, Proterozoic?) in Goiás and Salobo and Bahia orebodies in general quartz-sulphide veins enclosed in granodiorite, in Serra dos Carajás, tonalite and milonite host rocks. • Mafic-ultramafic complexes as Americano do Brasil (Ni • Gold deposits related withvolcano-sedimentary sequences -Cu-Co) and Mangabal in Goiás, (greenstone belt structure type), as quartz veins (Cha • Mafic-ultramafic highly rnetamorphosed rocks as copper péu de Sol mine, Berbert and Mello, 1973) and disseminat mineralizations in Vale do Curaçá , Bahia State. ed bodies enclosed in tourrnaline quartzites, itabirites, There are some discussíons on the correlations and ages chlorite-quartz schists and graphite schists, for Chapada and Palmeirópolis mineralizations. However, The Serra das Andorinhas gold deposits (South 01' Pará) it is possible to consider Palmeirópolis as Early Proterozoic, are associated with quartz and metachert interbedded in Danni and Teixeira (1981) c1assified the Palmeirópolis com chlorite schists. Hirata et ar (1982) suggested the relation plex as sills and dikes related lo folded zones, Companhia 01' the gold mineralization with a greenstone belt structure. de Pesquisa de Recursos Minerais (CPRM) is exploring two Serra Pelada gold orebodies - at present, the most famous main Zn-Cu-Pb bodies near Palmeirópolis village. Figuei "garimpo" in Brazil- are enclosed in low metamorphic redo et ar (1981) published a description 01' these deposits, grade chlorite schists, carbonaceous sandstones and silts considered as stratabound due to the presence of rnassive tones 01' the Rio Fresco Forrnation. Meireles et ar (1982) Zn sulphide minerais in the rnafic and acid volcanic rocks considered the manganese bearing breccia and siltstones as (amphibolites, metatuffs and schists) contact zone (Fig, 3), the lithological controls for the gold mineralization, Pd, Ag There are also Cu rninerals disseminated orebodies, and Cu are related with native gold. The Serra dos Carajás copper rnineralizations are rela The Tapajós region gold placer deposits are considered ted with three main geological environments (Santos, 1981): as originated from primary quartz veins, but Silva (1982) volcanic-sedimentary, volcanogenic and sedimentary, The suggested a possible association with a greenstone belt, volcanic-sedirnentary Salobo type orebodies are associated Cumaru is another important "garimpo", There, lhe gold with amphibole schists bearing magnetite and garnet. Boro occurs in the amphibolite fracture zones and in acid volcan ite and chalcocite are the most common sulphides which ic rocks (Vale, et al., 1982), occur as dissemination, fracture filling and massive bodies Gold occurrences are also known in the western Brazilian always with magnetite, Farias and Saueressig (1982) consi border (Rondônia and Mato Grosso States). Berbert et ai, dered the Salobo 3A body as a stratabound type. (1980) related the quartz-bearing veins 01' Aguapeiand Ju Yet referring to Santos (1981) opinion, lhe MMI copper ruena to granites. Granulitic zones at Ubaira, Bahia enclose body is a volcanogenic type enclosed in amphibolites and As-Au mineralizations. amphíbole schists. ln this case, chalcopyrite is the main copper sulphide, occurring as disseminations or stringers. Copper Archean and Early Proterozoic copper minerali And lhe third type, the Bahia copper body is related with zations in Brazil can be classified in three main groups: low grade metamorphosed sediments - sandstones, grey- MORRO SOLTO NW SERRA DOURADA MORRO DO FERRO MORRO. PRETO eoov C-2 o 5 10 15 20l\.m ~ CANABRAVA MAFIC ARAXÁ GROUP .J ~ GRANITE -c ~ ULTRAMAFIC COMPLEX li:... Z ur r::-~ WEST UNIT IRON U ~ FORMATlON LENS o SCHISTS .. .'. a , EAST UNIT ~ AMPHIBOLlTES ~G o o o Figure 3·- Palmeírópolis, Generaíized Cl'OSS section(modijied from Figueiredo et al., 1981) Revista Brasileira de Geociências, Volume 12 (1-3),1982 431 wackes, siltstones and pelitic rocks - from the Rio Fresco • Siliceous-carbonate protore - Lafaiete and Morro da Formation, Chalcopyrite is the main copper mineral. Mina The Americano do Brasil Ni-Cu-Co deposit is enclosed • Carbonate-itabirite protore - Quadrilátero Ferrífero de in a mafic-ultramafic sequence, With the mafic unit - mainly posits gabbros - there is an irregular shaped mineralization (SI • Clastic protore - Caraça deposits, body), possibly originated by a magmatic segregration pro Serra do Navio, at present the most important high-grade cess. The ultramafic rocks - dunites and peridotites - en oxide ore Brazilian mine, is also formed by Cenozoic weath close a vein-Iike rnassive ore body, Pyrrhotite, pyrite and cring supcrgene process from Archean-Early Proterozoic chalcopyrite are the most common sulphide minerais, The rocks bearing manganesé minerais. These. mainly carbonate Cu-Ni-Co rnineralizations of Mangabal I and II are also and silicate bearing schists are closely related with graphitic related with mafic-ultramafic rocks and are located about lenses of the regíonal quartz-biotite-garnet schists (Vila No 40 km west of Americano do Brasil. The Mangabal mineral va Group, Transamazônico Cycle). izations were recentlydescribed by Pfrimer et ai, (1981) Serra dos Carajás has also manganese deposits, briefly as disseminations and fracture filling bodies in gabbroic described by Santos (1981): rocks, Some important copper deposits are situated in the Vale • Azul - related to pelitic sediments of the Azul Member, do Curaçá, Bahia, and among those, Caraíba is' the most Rio Fresco Formation, bearing manganese carbonates. famous. The mineralization is associated with lens ofrnafic • Buritirama and Sereno - both related with Grão-Par" -ultramafic rocks enclosed in a high metamorphic granulitic Group (quartzites, quartz and biotite schists). The pro belt. Hypersthenites. norites, gabbros and anorthosites are tore is composed of silicates and carbonate manganese the common rock types present. Pyroxenites and hypersthe minerais. nites are the most importam copper mineralization host Manganese protore enclosed in granulitic rocks at Maraú rocks (Lindenmayer, 1980), The orebodies are in general and Santo Antônio de Jesus (Toniati and Barbosa, 1973), disseminated but there are veinlets too, Chalcopyrite and Bahia, also produced high-grade oxide ores by weathering, bornite are the maio copper ore minerals, frequently accom The Urandi-Jacaraci-Licinio de Almeida manganese pro panying magnetite, ilmenite and graphite, Lindenmayer (op, tores were attributed to a volcanic-sedimentary sequence eit,), proposed for the Upper Curaçá Valley copper deposits (Archean?) by Mascarenhas (1979), a magmatic segregation origin process with some contrib utionofsulphur from the host rocks, But there are other ideas Nickel Archean and Early Proterozoic mafic and ultra to explain these deposits, as a sedimentary-metamorphic mafic complexes are a common feature in some regions of origin proposed by Suszczynski (1972b), the Brazilian Precarnbrian shields. Many of these cornplexes are host rocks or the rock favourable to nickel, asbestos, chromite and tale deposits. Manganese Manganese-bearing minerals and protores The most important mafic-ultramafic Ni mineralized are distributed in some Archean and Early Proterozoic units, and well investigated as well, are those of Barro Alto sequences, but the high-grade oxide ores constitute a and Serra da Mantiqueira (Niquelândia), Goiás State (Ber supergene weathering product, in general Cenozoic. Con bert, 1970; Figueiredo ct ai" 1975) (Fig, 4), Sulphide nickel sidering main interests of ISAP, only the manganese protore orebodies are also present in Americano do Brasil and Man will be dealt with in this paper. gabai, already described. Some discussions ao ages, corre The most "important mangancse protore bearing units in lation and the geological process of rejuvenation affecting the Archean and Early Proterozoic are those of Minas Ge these complexes still happen. But some of these rocks are rais (Lafaiete and Quadrilátero Ferrífero regions), Serra do very old and could be representative of the primitive Earth Navio, in Amapá Territory and Serra dos Carajás. ln Bahia crust (Cordani and Hasui, 1975). Recently, Danni and Tei small manganesiferous units also occur. xeira (1981) redescribed the Precambrian mafic-ultramafic ln Minas Gerais, the Nova Lima Group (Rio das Velhas complexes ofGoiás and proposed a new cJassification. Barro Supergroup already mentioned in the descriptíon of gold Alto and Serra da Mantiqueíra (Fig, 4) were included as deposíts) encloses zones of rnanganesiferous silicates (gar related with granulitic sequences and as layered types of net, rhodonite) and' carbonates (rhodochrosite) "that have metamorphosed peridotites, pyroxenítes and norites. The been traced discontinuously for nearly ISO km" (Dorr II, authors c1assified also Americano do Brasil and Mangabal 1973). With this unit , high-grade manganese ore mines, now as tholeiitic differentiates, sills and stocks also related with exhausted, are connected. Special mention must be made granulític zones. for the Lafaiete District, where the Morro da Mina mine Concerning lhe Brazilian nickcl deposits, the Archean (ar Merid mine) is the most important manganese ore mine and Early Proterozoic ages are importam for the emplace in Minas Gerais. During its history, Morro da Mina mine ment, metasomatism (serpentinization) and metamorphism has produced large tons of rich oxide ores, but now it is of the mafic-ultramafic Ni bearing rocks. The enrich being exploited the primary manganese protore (due to the ment and ore formation are rclated with the Cenozoic exhaustion of the high-grade oxide reserves and the develop laterization process on supergene conditions, The lateritic ing of a process to use the low grade manganese primary Brazilian nickel deposits are considered as formed from protore). olivine alteration, and Ni silicates (garníerite) are accumu ln Quadrilátero Ferrífero there are iron-manganese de lated in special physiographic conditions (with 'lhe exception posits related with dolomite-bearing itabírites of the Iron of Americano do Brasil and Mangabal whích are primary Formation. These deposits were mentioned by Gonçalves Ni-Cu sulphide ore bodies). and Serfaty (1976), Gonçalves, E. (per. comm.) have propo The Serra da Mantiqueira lateritic Ni deposits are relat sed a c1assification for the Minas Gerais manganese deposits ed with pyroxenites interbedded with peridotite, anorthosi based on the nature of the protores, as follows: te and gabbro zones. Barro Alto has a similar sequence, 432 Revista Brasileira de Geociências, Volume 12 (1-3), 1982 EX PLANA TION MIOOLE PROTEROZOIC ~ ARAI , SERRA DOURADA ANO SERRA DA MESA MARANHÃO EAAlY PAOTEROZOlC r::v::vl VOLCANIC - S[OlMENTARY PAI.MEIRÓPOLIS SEQUENCE BA 51 N ~ ARCHEAN r::'.':-.-.,:;':j CRIXAS - OREENsrDNE 8ELTS MAFIC ULTRAMAF1C COMPLEI(E5 CANA .R...V.... SERRA MANTlOVEIR" ANO IIARRO ALTO. rr-r-a GRANIT1C - ONE1SSlC CQMPl.[XES l.-'--'.J PARANA o 50 100 11m BA51 N CATALÃO ___-L ~'_ -'18"00' 18"00' - FiKIII"<' 4 - Arc/1(,{1II III/{! jlm/í'/'o:oic g('o/lIgic units iII Goiás {m(}(lijie{/ FOIl1 Morini, 0..1., FUe/-". KA., Doni, 1.( .. Dardcnc, M.A, (jt}!'\/l. ln: Nuscíninnu, 1.5;.. '''('/oso. F.D.LM. (' 5(1I)()1((. L.A. (/9!'\2l] containing an eastcrn gabbroic zone. a central ultramafic Pontalina (Beurlen and Casscdanne. 1981, Girodo. 197:11 ~ zonc (pcridot itcs and pyroxcnitcs í and a wcstern anorthositic are asbestos occurrenccs in Goiás. Also in Bahia liabe zonc. Rcccnily. Trcscascs and Oliveira (1981) rcdcscribcd raba and Poções - and in Minas Gerais - Mostardas. Nova rhc Barro Alto nickcl dcposits. Lima - othcr chrysolitc oceurrcnccs are known. At Pratápolis. Minas Gerais. thcre is another latcritic Ni Anthophyllite mincralizations associated with a metamor mincralizauon - the Morro do Níquel mine - also rclarcd phic volcanic-sedimentary unit (amphibolites, marbles. with 'ln ultramafic scrpentinized intrusion (Trescases and quartzires. schists and migmatitcs. Farina. 1966, 1974) Oliveira. 1978). Liberdade and Ipanema are smaller Ni oeeur at Batalha (Campestre mine. Alagoas State). occurrcnccs ln Minas Gerais. Some Ni deposits are presem ln the northcast of Brazil. Tungsten The most importam tungsten (scheelite ldeposits as in Catinqueira and São Raimundo Nonato (Santos, 1974) in Brazi1 are associaicd with the Precambrian final stagcs also formed by a wcathering laterization process over rnafic (Brasiliano Cycle) and nol wit h Arehean and Early Pro te -ultrarnafic complexes. ln Araguaia-Xingu and Serra dos rozoic periods, despire some discussions on the Caicó Group Carajús rcgions. Santos (19811 eited Onça (Carapanã I. Puma tungsten-bearing tactites. Some wolframite-quartz veins (Ca tctél. Jacaré anel Serra do Quuupuru Ni deposits. Ber associated to granodioritcs in Nova Trento, Santa Catarina nardelli (1981al described lhe Vermelho lateritic Ni body may be auributed to Early Proierozoic (Tabuleiro Groupj, associatcd with scrpentinized rnafic-ultrarnafic rocks in the despire lhe Suszczynski (1975)opinion for a Brasiliano Cycle Serra dos Carajas. association. Asbestos Archean and Early Proterozoic asbestos deposits Tin Many tin mincralizaticns are presem in the Brazifian in Brazil are associaicd with serpentinized mafic-ultramafic Precarnbrian granitic rocks: (Bettencourt et al.. 1981 l. A cornplcxcs and with highly mctamorphosed scdimcntary large arnount 01' the tio rock matrix is Middle Protcrozoic, rocks. The most important deposit is the SAMA mine at but in many cases the granito ages are not well cstublished. M inacu, Goiás. enclosed in the Cana Brava mufic-ultramafic However. there are some tin deposits cuclosed in Archcan complcx. very similar to that rcportcd for nickel mineral and Early Proterozoic granitos and pcgmatites. possibly re izarions, juvcnated during Iurthcr rccionic cvents. Thc São João dei Milewski. fi at. (1970) dcscribed lhe Cana Brava ehryso Rei tin-bearing pegrnarites are elearly rclatcd with a gra tile asbestos mineralization as a siockwork 01' cross-fiber niiic-gncissic cornplcx (Barbaccna Cornplcx ?). Possibly some fracture filling typc. Slip-Iibcr also occurs in Iault and frac tin-bearing pegmatítes 01' Monte Alegre de Goiús may ture zoncs. Iron oxide and serpenlinc are the main asbestos be Early Protcrozoic (duc to field relations and cmplacemcnt associated- minerais. ln basement roeks). Mapuera, Maloquinha, Paru, Novo Santo Antônio da Laguna, in the Barro Alto mafic~ultra Airão and other tin bearing granitoids in the Amazonian ma fie complex. (Fig. 4) ,and Morro dos Dois Irmãos at region and Amapú may be Early Proterozoic too. Revista Brasileira de Oeocuncios, Volume 12 (1-3), 1982 433 The columbite-tantalite, cassiterite and rnicrolite minera Pegmatites ln addition to the tin-bearing pegrnatites, al Iized pegmatites at Nazareno-Volta Grande-São João dei ready mentioned. there are a lot ofthese rocks in the Precarn Rei were described by Francesconi (1972). These pegmatites brian. bearing columbire-tantalite, mica, gemstones, beryl, are complex in shape, there are sim pie and zoned types, spodurnene, RE minerais (as samarskite), feldspar. quartz presenting clear features ofboth magrnatic and hydrothermal and kaolin. The most importam pegmatite provinces are stages, Uppcr Precambrian (Brasiliano Cyclc) as thosc in south 01' Bahia (Itambé. Itapctinga j, Espirito Santo (Mimoso do Baryte Some baryte-bearing Pb, Cu and Zn veins are re Sul), Minas Gerais (Araçuai. Galileia. Governador Vala lated with Archean sequences mainly in Bahia. Silva and dares, Teófilo Otoni. Divino de Sào Lourenço. Serra do Lago (1974) described baryte mineralizations in the greens Caparaó j and Borborema. Thcse pegmatitcs wcrc described tone type Contendas-Mirante Complex composed by meta by some authors and among othcrs can be mentioned basic. rnctarnorphosed dolomircs and bandcd iron for Fanion. Arioli and Moura (1978). Angeli (1978) and mations. Orcioli. Galeá. Espindola and Cunha (1978). Early Pre cambrian pegmatites were not yet defined. but possíbly Apatite Granulitic belts enclosing some apatite deposits they are present in Brazil (as in Amapá, p. eg). are known in Bahia. Veiga and Couto (1981) described the nature and the distribution of apatite in the Ipirá-Pedras Aluminium Large bauxite deposits were formed by late Altas arca. The apatite deposits are enclosed in pyroxene rization process on Cenozoic sedirnentary sequences and on and diopside-bearing rocks and in syenitic pcgrnatites, Ver Mcsozoic alkaline rocks. But some small mines in Nova rniculite, caleedony and scapolite are the apatite accessory Lima-Ouro Preto region, Minas Gerais, and the bauxite minerais. Apatitc mincralization is auributcd to pelitic scd deposits recently rcported at Serra dos Carajús (Assad and irncnts. later mctamorphoscd to diopsidic rocks, Rcmobi Beisiegcl. 1982) werc produced by laterization 01' Archean lizing and metasomatic process were also- involved, and Early Proterozoic rocks, The Carajús region deposit N5 Plateau - is a blanket bauxite body formed by lateriza Lead (zinc, silver) , Some lead-bearing zinc and silver Lower tion of ma fie rocks attributed 'lO the Grão-Parú Group. Precambrian occurrences were reported by Cassedanne (19711. Among these, the most important is the Boquira Magnesite and tale Ali the Brazilian magnesite deposits mine. in Bahia. Thc vein type Boquiru ore bodies arc cncloscd are associatcd with volcanic-sedirncntary metamorphic Ar in a mctavolcanic-mctascdimcntary gcological scqucnce cheun and Early Proterozoic geologic units, Only small mag representcd by lhe Bcquira Formauon (amphibolites. itabi ncsitc occurrcnccs are cncloscd in maflc-ultramaflc rocks. rires. marblcs. quartzites and schists), Arnphibolites bearing The most importam magncsite orebodies are situated at magnetite are the lithologic control of lhe ore bodics. Ga Serra das Éguas (Brumado, Bahia). Castela (ncar Sento Sé. lena, sphalerite and pyrite are the main ore minerais and Pilão Arcado. Bahia also )and Iguat u-Orós (Ceara I. At Serra chalcopyritc, pyrrhorite and molybdenite are acccssories. das Éguas stcatitc tale is an associated mineral and consti Espourteille and Fleiseher (1980/ considered the Boquira tutes a by product in magnesite mining. These magnesite lead deposit as syngenetic and as stratabound in shape. -steatitc deposits are cnclosed in the Brurnado complcx Mascarenhas (1979) considered the Boguira Formation as a greenstone belt according to Mascarenhas (1979) - dolo a greenstone belt (Archean "), Pb, Pb ages determinations mires and quartzites.. indicare 2.600 Ma for the Boguira lead (Cassedanne, 1981). The Igualu-Orós magnesite bodies oceur as lenses in carbonate mctamorphic rocks. Chromite Manychromite dcposits are known.in the Ar Tale is also relatcd \Vilh malic-ultramafic rocks, a~; at chean and Early Proterozoic Brazilian terranes (Table I). Irapaci, Pilar (Goiús), Igllape. Cananéia. Sào Raimundo The presence of chromite was noticed at Pedra Branca Nonato and Carandai. The Igllapc deposits wcrc dcscribed (Cearú State). Senhor do Bontim. Uauú, Cansanção, Quei by Carvalho (197.1). who eonsidcrcd the tale as formed by madas. Campo Formoso (Bah;a State), Igarapé do Breu serpentinization of uitramafic dikes. (Amapá), Pium-i. Alvorada, Serro (Minas Gerais State) and in Goiús. Titanium, vanadium (and iron) Many·titanium-vana The most important chromite deposits are {hose ofCampo dium-iron occurrenees are associated with highly metamor Formoso (Cascabulhos and Campinhos mines), Andorinha phosed granulitic beits. The best known mineralizations are (Medrado mine). in Bahia. and in Goiús (exhausted deposits). those of Floresta (paradella cr ai.. 1979), Campo 'Alegre de Figueiredo (1977) mentioned about twenty chramite Lourdes, Ubaira. Iaçu and Itamari (Lago er ai.. 1978). occurrences in Goiús. a!l related with smal! serpentinized Campo Alegre de Lourdes ar Pedra Comprida is an ilmc mafic~ultramafíe bodies. Arnong these Morro Feio and Hi~ nite~hematite deposit enclosed in gneiss ofthe Colomi Group drolina deposits are the most voluminolls (cluvial and pod (Casscdannc, er ai. 1976). Titanium anel iron minerais are concentrations, in the serpentinites). Santos (1981) made considercd as formed by magmatic processo references to chromite deposits at Araguacema and Quali~ puru. The Campo Formoso chromite dcposits oc<;ur as pcr Limestones and marbles Some Iimestones. doi omites feetly layered orebodies, cumulus and pod disseminated and marbles are rclated with metasedimentary Archcan and zones in serpentinites (ehlorite-serpentine-talc schists), due Early Proterozoic scquences. ln general calc-silicale minerais to a magmatic segregation processo The Campo Formoso were developed in these carbonate roeks duc to mclamorphic chromite-bearing serpentinites cover a large area about cvcnls. Hov,'ever, lhcrc are some hi.gh-grade and pure limcs 50 km in a north-south direction and 1 km wide (Beurlen tone deposits cncloscd in granulitic rocks as Ihosc ai Italva and Cassedanne, 1981). There are also other chromite (Angeli. 1978). Euclidelúlldia (Rio de Janeira Statc) and occurrences in Bahia enclosed in granulitic rocks (Uauú). Serra do Mar (dolomiles. Sào Paulo Slale). Szuben and Mascarenhas (1979) related the maflc-ultramalic rocks of Presotlo (1974) dcscribed mctamorphic limcstones 01' Po Campo Formoso to the Jacobina grcenstolle bel!. rongos Group (Encantadas Formation). 434 Revista Brasileira de Geociéncias, Volume 12 (1-3), 1982 Archean and Early Proterozoic marblcs occur at Ca The Complex Archean and Early Proterozoic geology choeiro do Itapemirim and Quixaba (Barros Filho and high-grade metamorphism, folding, faulting, metasomatism Moço, 1978). - makes it very difftcult to understand the ore genesis proc ess. And this complexity contrasts with the very simple Uranium Brazilian Lower Precambrian uranium mineral chemical and mineralogical composition of the primary ore izations are related to metaconglomerates, as thosé of Serra minerais, mainly oxides and sulphides. da Moeda (Minas Gerais) and Jacobina (White, 1957; Le ln this paper an attempt was made to establish some corre mos, 1974) both gold-bearing. There are also uranium de lations between lhe ore deposits, lhe associate lithology and posits in albitized granites (some of them possibly rejuve the tectonic-orogenic Guriense-Jequié and Transamazônico nated in Upper Precambrian) as those of Itataia, São José cycles. With the Guricnse-Jequié Cycle lhe following mine de Espinharas and Lagoa Real. ralized units may be connected: • Sequences of mafic-ultramaflc rocks, some of them pre Gemstones Pegmatites and pegmatites cutting mafic senting layered structure, bearing nickel (serpentinized rocks are the main gemstones-bearíng host roeks ín the Bra olivine protore and sulphide primary orebodies), copper, zilian Lower Precarnbrian. Franco (1981) made an interes chromite, asbestos and tale as the mineralizations known ting review ofthe gemstone deposits in Brazil, which are rela at Americano do Brasil, Mangabal, Serra da Mantiqueira, ted with granitic gneissic eomplex - pegmatites bearing be Cana Brava, Barro Alto, Morro do Niquei, Campo For ryl, chrysoberyl, citrine quartz, tourmaline, aquamarine moso and São Raimundo Nonalo (São João do Piaui). and ma fie roeks sueh as those ofCarnaiba, Gavião, Pirenó• Vermiculite and emeralds are still associated with mafie polis, Itaberai, Santa Terezinha and the Itabira emerald rocks. bearing deposits, • Granulitic rocks bearing Fe-Ti-V (Antonina. Campo Ale gre de Lourdes, Itamari, Floresta, Iaçu), apatite (Ipirá). Vermiculite Vermiculite deposits are associated both with manganese protore (Maraú) and lhe Curaçà copper de Arehean and Early Proterozoie mafie rocks. At present, posits, among others. the Massapé mine, at Paulistana (Piaui State], is the most • Grecnstonc belt structure typê bearing stratabound gold important vermiculite producer in .Qrazil. This deposit was dcposits at Nova Lima and Araci-Serrinha. magnesite described by Hennies and Stellin Júnior (1978) as associated -steatitc (Serra das Éguas) and manganese protores (Uran with metabasic rocks enclosed in migmatites. Other small di and Lafaietc-Morro da Mina). vermiculitc occurrences are known at Brumado, Dom Ba sílio and Aracatu. With the Transamazênico Cyclc may be associatcd the following units: Grephite and semianthracite Many graphite occurrences • Sedimcntary-volcanic iron formations in the Quadriláte are present in Precambrian rocks, mainly in schists and Irac 1'0 Ferrífero. Porteirinha and Serra dos Carajás and man tured gneisses. The most importam graphite mineral deposits ganese deposits in lhe Serra do Navio, Buritirama and in Brazil are those of Itapecerica, Mateus Leme, Pedra Azul, Sereno. Rui Barbosa and Piquet Carneiro. • Volcanic rnafic rocks contributing for lateritic bauxite and Only a small coai occurrence is known in the Brazilian nickel prolores ai N5 Plateau and Vermelho and MM I Precarnbrian. This coa 1. which occurs as thin beds in the copper orebodies, Serra dos Carajás. Rio Fresco Formation. was c1assified as semianthracite • Sedimentary environments bearing manganese deposits (Santos, 1981). But it is possible to consider this carbona (Azul. Rio Fresco Formauon). gold (Serra Pelada) and ceous material as a shungite type, in general associated with gold-uraniurn (Jacobina). Precambrian schists. • Granitic rocks, as Maloquinha and Mapuera suites and possibly other granitoids bearing tin, molybdenum (Ro· Molybrjenum A small number of Precambrian granitic raíma, Serra dos Carajás), gold (related quartz veins) and bodies in tbe Amazonian region present molybdenite, as the pegmatite minerais. occurrences in Roraima Territory (Serra do Mel and Gua • Greenstone bclts, as the gold orebodies in lhe Serra das riba). Also in lhe Serra dos Carajús granite and in the Salobo Andorinhas. and MM I copper bodies there are molybdenite disseminai ions (Santos, 1981). During the Lowcr Prccambrían, the deposition 01' large iron formations was undoubtcd the most spectacular evcnt Kyanite Kyanite-bearing schists are common rocks in thc conccrncd with ore genesis and mctallogeny occurred in rnetamorphic Precarnbrian zones. The weathering promotes Brazil. Our rnost important mineral rcsources - lhe high the kyanite residual enrichment forming deposits as those -grade iron ores - are connected with those formations. of Capelinha, Itamarandiba and Serra das Araras. Mafic-ultramafic activity had a greal effect also in tbe metallogcnesis. bringing a lot 01' mineral dcposits, CONCLUSIONS The Brazilian mineral deposits auri buted to the Archean and Early Proterozoic are connected Addendum This paper was prepared for lhe ISAP·lnler· to the Guriense-Jequié and Transarnazônico CycJes. Larer national Symposium on Arehean and Early Proterozoic remobilization evidence is present in many mineralizations -Geologic Evolution and Metallogcnesis and it is a preli and has probably influenced the ore genesis. ln some cases minary contribution to the IAGOD Cornrnission on Tecto rejuvenation process related lo lhe Brasiliano Cycle (Upper nics of lhe Ore Deposites (CTOD), Working Group 2 Precambrian) is clear. . programm, Revista Brasileira de Oeocténcías, Volume 12 (1·3), 1982 435 REFERENCES ALMEIDA, F.F.M., HASUI. Y.. BRITO NEVES, B.B. and FUq<.. R.A. FARINA, 'M, - 1974~ Panorâmica da tipologia dos depósitos minerais ~ 1981 - Brazíttun structural provinccs: an introduction. Earth Sei. ReI'. do Nordeste do Brasil, SOe, Bras. Geol.. Anais do XXVIII Congr, Bras. 17:1-29. Geol. 6:79-94, Porto Alegre. ANGELI. N. - 1978·- Pesquisa de calcário e cauüm no Norte do Estudo FERRAN, A. - 1974 - Panorama do níquel no Brasil. Centro Moraes do Rio de Janeiro. 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