Quick Search:    advanced search

GSW Home   GeoRef Home   My GSW Alerts   Contact GSW   About GSW   Journals List   Help

This Article Abstract Figures Only Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in ISI Web of Science Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Tallarico, F. H. B. Articles by Rego, J. L. Search for Related Content GeoRef GeoRef Citation

Geology and SHRIMP U-Pb Geochronology of the Igarapé Bahia Deposit, Carajás Copper-Gold Belt, Brazil: An Archean (2.57 Ga) Example of Iron-Oxide Cu-Au-(U-REE) Mineralization

Fernando H. B. Tallarico

Instituto de Geociências, Universidade Estadual de Campinas, Caixa Postal 6152, 13.083-970, Campinas, SP, Brazil, and Centre for Global Metallogeny, School of Earth and Geographical Sciences, University of Western Australia, 35 Stirling Highway, Crawley, Western Australia 6009, Australia

Bernardino R. Figueiredo

Instituto de Geociências, Universidade Estadual de Campinas, Caixa Postal 6152, 13.083-970, Campinas, SP, Brazil

David I. Groves, Natalie Kositcin, Neal J. McNaughton and Ian R. Fletcher

Centre for Global Metallogeny, School of Earth and Geographical Sciences, University of Western Australia, 35 Stirling Highway, Crawley, Western Australia 6009, Australia

José L. Rego

Companhia Vale do Rio Doce, Caixa Postal 51, Serra dos Carajás, 68.516-000, Parauapebas, PA, Brazil

Corresponding author: e-mail, dgroves{at}segs.uwa.edu.au

	Abstract

Top Abstract Introduction Regional Geology and Metallogeny Geology of the Igarape... Geochemistry Sampling and Analytical... SHRIMP U-Pb Results Strontium Isotope Composition of... Model for the Igarape... Discussion References

 
A striking feature of the Carajás region, Brazil, is the clustering of a variety of different types of Cu-Au deposits. The most abundant in the belt are the >200 million metric tons (Mt) of Fe oxide Cu-Au-(U-REE) deposits, which, despite the variety of host rocks and different orebody morphologies, share a number of diagnostic features, including (1) intense Fe metasomatism leading to the formation of grunerite, fayalite, and/or Fe oxides (magnetite and/or hematite); (2) intense carbonate alteration (mainly siderite); (3) sulfur-poor ore mineralogy (chalcopyrite and bornite); (4) quartz-deficient gangue; (5) extreme low REE enrichment, and (6) enrichment in U and Co. The Igarapé Bahia deposit is perhaps the best documented Fe oxide Cu-Au-(U-REE) deposit of the belt, containing about 219 Mt at 1.4 percent Cu and 0.86 g/t Au. The Cu-Au ore consists of steeply dipping breccia bodies that are hosted by hydrothermally altered metavolcano-sedimentary rocks.

SHRIMP II zircon dating of the host metavolcanic rocks gives a ²⁰⁷Pb/²⁰⁶Pb age of 2748 ± 34 Ma. This suggests a correlation between the Igarapé Bahia volcano-sedimentary sequence and the Grão Pará volcanic rocks, which have published ages of ca. 2.75 Ga. SHRIMP dating of monazite from the matrix of ore-bearing magnetite breccias gives a ²⁰⁷Pb/²⁰⁶Pb age of 2575 ± 12 Ma, confirming the epigenetic nature of the mineralization and placing it ~175 m.y. after accumulation of the host volcano-sedimentary sequence. The 2575 ± 12 Ma SHRIMP age of hydrothermal monazite from the Igarapé Bahia mineralization is indistinguishable from published conventional ²⁰⁷Pb/²⁰⁶Pb ages for zircons from the Archean A-type granites of the Carajás belt, indicating that mineralization processes at Igarapé Bahia were temporally related to these A-type Archean granites. The wide range of highly radiogenic ⁸⁷Sr/⁸⁶Sr ratios (0.714–0.755) of carbonates from the Igarapé Bahia deposit suggests multiple crustal sources, consistent with a magmatic-hydrothermal origin. SHRIMP dating of zircon xenocrysts recovered from crosscutting diabase dikes indicates a maximum ²⁰⁷Pb/²⁰⁶Pb age of ~2670 Ma, consistent with field evidence and the age of host rocks, but does not unequivocably constrain the age of the ores.

The styles of hydrothermal alteration, mineralogy, and geochemistry of the Igarapé Bahia ore, as well as published fluid inclusion and stable isotope data, support its classification as a member of the world-class Olympic Dam-type Fe oxide Cu-Au-(U-REE) group of deposits, as previously argued by several authors. The SHRIMP age of 2575 ± 12 Ma for hydrothermal monazite indicates that Igarapé Bahia is an Archean example of this deposit group.

	Introduction

Top Abstract Introduction Regional Geology and Metallogeny Geology of the Igarape... Geochemistry Sampling and Analytical... SHRIMP U-Pb Results Strontium Isotope Composition of... Model for the Igarape... Discussion References

 
THE CARAJÁS bELT is a highly mineralized province, with world-class iron and manganese deposits (Tolbert et al., 1971; Valarelli et al., 1978; Gibbs and Wirth, 1990) and also a large number of Cu-Au deposits, known collectively as the Carajás Copper-Gold belt (Fig. 1). There appears to be two distinct types of Cu-Au deposits in the Carajás region. The first group includes Cu-Au-(W-Bi-Sn) deposits (e.g., Breves and Águas Claras), which contain quartz veins and may or may not have associated Fe oxides and are genetically related to the cooling of Paleoproterozoic (ca. 1.88 Ga) A-type granites, as discussed below. The second group includes several world-class (>200 Mt) Fe oxide Cu-Au-(U-REE) deposits (e.g., Salobo, Sossego, Cristalino, Cento e Dezoito, and Igarapé Bahia), which, despite the variety of host rocks and different orebody morphologies, share a number of diagnostic features.

View larger version (72K): [in this window] [in a new window]   FIG. 1. Geologic map of the Carajás Copper-Gold belt, showing the major iron, manganese, Fe oxide Cu-Au-(U-REE) deposits and the Breves Cu-Au-(W-Bi-Sn) deposit. Modified from Tallarico et al. (2004). The Itacaiúnus shear zone is a broad zone centered on the Carajás fault and bounded by the two major faults (bold lines) shown to the north and south.

Previous genetic interpretations of the Igarapé Bahia deposit included syngenetic volcanic-hosted massive sulfide deposit (VHMS; Besshi-type) models (e.g., Ferreira Filho, 1985; Almada, 1998; Villas and Santos, 2001), epigenetic hydrothermal-magmatic models with ore related to Paleoproterozoic (ca. 1.88 Ga) granites (e.g., Lindenmayer et al., 1998), and multistage models that invoke an interplay of Archean and Proterozoic processes (e.g., Ribeiro, 1989; Mougeot et al., 1996). However, similarities with the Australian Olympic Dam deposit (Roberts and Hudson, 1983; Oreskes and Einaudi, 1990; Reeve et al., 1990) have encouraged several authors to propose an epigenetic hydrothermal model related to an alkaline magmatic component of unknown age (Oliveira et al., 1998; Tallarico et al., 1998; Soares et al., 1999; Tazava, 1999). Uncertainties in interpretation relate partly to poor exposure of fresh rocks but are mainly due to the absence of robust geochronologic data on the ore and host rocks.

The aim of this paper is to provide an overview of the geology and geochemistry of the Igarapé Bahia deposit and to constrain the age of the mineralization using SHRIMP geochronology. These data are used to test whether the deposit is contemporaneous with the Archean volcanic sequence or with alkaline granitoids of either Late Archean or Paleoproterozoic age.

	Regional Geology and Metallogeny

Top Abstract Introduction Regional Geology and Metallogeny Geology of the Igarape... Geochemistry Sampling and Analytical... SHRIMP U-Pb Results Strontium Isotope Composition of... Model for the Igarape... Discussion References

 
The Carajás region (Fig. 1) lies on the eastern portion of the Archean Amazon craton, being truncated to the east by the Neoproterozoic Araguaia belt and to the west by Proterozoic sequences (Docegeo, 1988; Tassinari and Macambira, 1999). To the north, it is concealed by Proterozoic and Cenozoic sedimentary rocks of the Amazon basin (Pinheiro and Holdsworth, 1997). To the south, it is in contact with the Rio Maria block (Docegeo, 1988; Huhn et al., 1988), a relatively older, typical granitoid-greenstone terrane that hosts lode gold deposits, such as the Sapucaia and Cumaru deposits (Villas and Santos, 2001, and references therein).

Basement rocks consist of gneiss and migmatite of the Xingu Complex and orthogranulites of the Pium Complex that were metamorphosed at ca. 2.8 Ga (Machado et al., 1991; Rodrigues et al., 1992; Pidgeon et al., 2000). According to Araújo et al. (1988), the Pium Complex represents slabs of infracrustal rocks uplifted through deep shear zones and could possibly represent the suture zone between the Rio Maria block and the Carajás belt. In the Carajás belt, the basement assemblage defines a broad, steeply dipping, east-west–trending ductile shear zone (Itacaiúnas shear zone), which experienced multiple episodes of reactivation during the Archean and Paleoproterozoic (Pinheiro and Holdsworth, 1997; Holdsworth and Pinheiro, 2000).

The Carajás region includes one of the best preserved Archean volcano-sedimentary successions in the world. These rocks, assembled under the Itacaiúnas Supergroup, record different metamorphic grades, ranging from virtually unmetamorphosed and undeformed, to lower greenschist facies (Grão Pará Group) in the innermost portions of the belt, and intensely sheared amphibolite and/or granulite facies (Salobo Group) at the northern edge of the Itacaiúnas shear zone (Docegeo, 1988; Olszewski et al., 1989). Volcanism occurred at ca. 2.75 Ga (e.g., Machado et al., 1991; Trendall et al., 1998). The Grão Pará Group is the dominant volcano-sedimentary sequence in the Carajás basin and includes low-grade metavolcanic rocks that host significant banded iron formation (BIF). These contain the giant iron deposits, such as Serra Norte, Serra Sul, Serra Leste, and Serra de São Felix, that contain total resources of 17.3 Bt at 66 percent Fe (Tolbert et al., 1971; Gibbs and Wirth, 1990).

Sandstone and siltstone deposited in a shallow marine to fluvial environment (Águas Claras Formation, Nogueira et al., 1994, 2000) overlie the volcanic rocks of the Grão Pará Group. A minimum age of 2645 ± 12 Ma for the Águas Claras Formation was determined by Dias et al. (1996) by conventional U-Pb analysis of zircons from crosscutting gabbro dikes. A SHRIMP U-Pb age of 2681 ± 5 Ma was determined by Trendall et al. (1998) from a sandstone sample containing zircons apparently derived from syndepositional volcanic rocks. Based on this age, Trendall et al. (1998) inferred that the Águas Claras Formation could represent the uppermost unit of a continuous accumulation in the Grão Pará basin that lasted less than 100 m.y.

The Carajás region has been intruded by granitic magmas of distinct ages and compositions. Paleoproterozoic intrusions (ca. 1.88 Ga; Machado et al., 1991) include several anorogenic granitic plutons, such as the Central Carajás and Cigano granitoids. The latter belong to the most extensive A-type Proterozoic province of the world (e.g., Santos et al., 2001) that covers thousands of square kilometers of the Amazon craton. Archean intrusions include granitoids and diorites of the Plaquê Suite (ca. 2.74 Ga; Huhn et al., 1999b) and younger alkaline granitoids (ca. 2.57 Ga), such as the Estrela Complex (Barros et al., 1992, 1997, 2001; Barros and Barbey, 1998), the Old Salobo Granite (2573 ± 2 Ma; Machado et al., 1991), and the Itacaiúnas Granite (Souza et al., 1996). The Estrela Complex is the best documented example of the Archean alkaline granitoids in the Carajás belt. According to Barros et al. (1997), it consists of an east-west–trending, heterogeneously sheared monzogranitic batholith that has a characteristic A-type geochemical signature defined by high K₂O + Na₂O, extremely high FeO_total/FeO_total + MgO ratios, and elevated Zr, Y, and Nb. Fabric analysis of the Estrela Complex indicates that magmatic activity was syntectonic and coincident with the closure of the Carajás basin (Barros and Barbey, 1998; Barros et al., 2001).

A striking feature of the Carajás region is the clustering of a variety of different types of Cu-Au deposits. The most abundant in the belt are Fe oxide Cu-Au-(U-REE) deposits that are hosted by a variety of rocks and have different orebody morphologies, although most are near-vertical (>75°) breccia bodies. The most significant examples of this deposit type are Salobo, with resources of 994 Mt at 0.94 percent Cu and 0.52 g/t Au (Farias and Saueressig, 1982; Vieira et al., 1988; Lindenmayer, 1990), Igarapé Bahia, with resources of 219 Mt at 1.4 percent Cu and 0.86 g/t Au (Ferreira Filho, 1985; Almada, 1998; Tazava, 1999; Tallarico et al., 2000), Sossego, with resources of 355 Mt at 1.1 percent Cu and 0.28 g/t Au (Cordeiro, 1999; Lancaster et al., 2000), Cristalino, with resources of 500 Mt at 1.0 percent Cu and 0.3 g/t Au (Huhn et al., 1999a), and Cento e Dezoito with resources of 170 Mt at 1.0 percent Cu and 0.3 g/t Au (Rigon et al., 2000).

A second style of Cu-Au deposit, characterized by a Cu-Au-(W-Bi-Sn) association, includes a number of small- to medium-sized deposits that appear to be genetically related to Proterozoic A-type magmatism. Representative examples are the Águas Claras Cu-Au-(W-Sn) deposit, with resources of 9.5 Mt of oxidized ore at 2.43 g/t Au (Soares et al., 1994; Silva and Villas, 1998) and the Breves Cu-Au-(W-Bi-Sn) deposit, with resources of 50 Mt of primary ore at 1.22 percent Cu, 0.75 g/t Au, 2.4 g/t Ag, 1,200 g/t W, 70 g/t Sn, 175 g/t Mo, and 75 g/t Bi (Tallarico et al., 2004).

A major question to be resolved in the Carajás copper-gold belt is the relationship between the relatively small (<50 Mt) Paleoproterozoic (ca. 1.88 Ga) Cu-Au-(W-Bi-Sn) deposits (Tallarico et al., 2004) and the much larger (>200 Mt) Fe oxide Cu-Au-(U-REE) deposits. One possibility is that they are both related to the ca. 1.88 Ga A-type granites, but a number of important differences between the deposits make this unlikely. In particular, the Fe oxide Cu-Au-(U-REE) deposits are characterized by (1) intense Fe metasomatism leading to the formation of fayalite (e.g., Salobo; Lindenmayer, 1990), grunerite, and/or Fe oxides (magnetite and/or hematite); (2) extensive carbonate alteration (mainly siderite), at least in the lower temperature deposits; (3) S-deficient nature of the ore sulfides (chalcopyrite, bornite, and primary chalcocite); (4) quartz-deficient nature of the gangue, (5) extreme low REE enrichment (approximately 10⁴ x chondritic values), and (6) enrichment in U and Co. Given the common alkaline association of Fe oxide Cu-Au-(U-REE) deposits elsewhere in the world (e.g., Hitzman et al., 1992; Oreskes and Hitzman, 1993; Campbell et al., 1998; Groves and Vielreicher, 2001), it is possible that these deposits of the Carajás belt are related to more alkaline rocks than the 1.88 Ga A-type (e.g., Kerrich et al., 2000) granites, including the ca. 2.57 Ga alkaline complexes of the Carajás belt (e.g., Estrela Complex, Old Salobo Granite). In this case, the deposits of the Carajás belt would represent one of the oldest known members of the iron-oxide Cu-Au-(U-REE) group worldwide. A genetic link between copper-gold mineralization and Archean magmatism has been established recently for the Salobo iron-oxide copper-gold deposit. Requia et al. (2003) determined Re-Os ages from molybdenite and a Pb-Pb age from bornite-chalcopyrite-magnetite of 2576 ± 8 Ma, which overlaps the previously published age of 2573 ± 2 Ma for the Old Salobo Granite (Machado et al., 1991). These data confirm that main-stage mineralization at Salobo was contemporaneous with Archean granitoid magmatism of alkaline affinity in the region (Requia et al., 2003).

	Geology of the Igarapé Bahia Fe Oxide Cu-Au-(U-REE) Deposit

Top Abstract Introduction Regional Geology and Metallogeny Geology of the Igarape... Geochemistry Sampling and Analytical... SHRIMP U-Pb Results Strontium Isotope Composition of... Model for the Igarape... Discussion References

 
The Igarapé Bahia deposit is hosted by a hydrothermally altered metavolcano-sedimentary sequence, the Igarapé Bahia Group. The host sequence, together with the Furo Trinta, Acampamento Norte, and Acampamento Sul orebodies, crop out in a small structural window within the overlying sandstone of the Águas Claras Formation (Fig. 2A). The orebodies define a circular structure at surface, with a shape similar to that of an alkaline ring complex (Fig. 2B). The Alemão orebody is covered by a 250-m-thick discordant layer of sandstone and is a faulted part of the Acampamento Norte orebody (Soares et al., 1999).

View larger version (70K): [in this window] [in a new window]   FIG. 2. A. Geologic map of the Igarapé Bahia Cu-Au deposit and geologic cross section A-A’ through the Acampamento Sul orebody (modified from Companhia Vale do Rio Doce/Docegeo, 1996, unpub.). Cpy = chalcopyrite; mgt = magnetite; sid = siderite. B. Structural map of the Igarapé Bahia copper-gold deposit. Coordinates and depth in hole for drill holes from which dated samples were taken are given in Table 2.

View larger version (165K): [in this window] [in a new window]   FIG. 3. A. Photomicrograph of the primary sedimentary bedding that has been bent around a chalcopyrite (cpy) nodule and is continuous with discordant veins containing chalcopyrite (plane-polarized light, 384/141.50 m). B. Photomicrograph of a set of discordant and concordant chlorite + chalcopyrite veins crosscutting the sedimentary bedding (plane-polarized light, 384/141.20 m). C. Photomicrograph of a mineralized Fe chlorite breccia with a fragment of laminated sedimentary rock from the hanging wall in a chlorite ± magnetite ± chalcopyrite matrix (plane-polarized light, 353/168.70 m). D. Magnetite breccia with abundant chalcopyrite (cpy), crosscut by carbonate veins (BHMAG-003/407.25 m). E. Photomicrograph of the matrix of a magnetite breccia with abundant biotite (bi) showing pleochroic halos due to uraninite inclusions (plane-polarized light, BHMAG-003/407.25 m). F. Photomicrograph of the matrix of a magnetite breccia showing the textural relationship between chalcopyrite (cpy), bornite (bn), and magnetite (mgt; reflected light, BHMAG-001/476.00 m). All drill core is stored by Companhia Vale do Rio Doce at Igarapé Bahia.

Supergene alteration and ore types
At Igarapé Bahia, weathering was responsible for the development of a 200-m-thick supergene profile (Zang and Fyfe, 1993; Angélica, 1996) in which gold and copper were dissolved, separated, and reprecipitated in different ore types. The upper part of the profile includes a gold-bearing gossan that extends to a depth of approximately 150 m. The gossan is composed mainly of goethite, hematite, gibbsite, and kaolinite and has traces of secondary copper minerals and REE-rich phosphates (florencite, crandalite, and rhabdophane). From 150 to 200 m, there is a transitional zone where supergene copper was precipitated. This copper-gold ore is composed of goethite and hematite, together with abundant secondary copper minerals, including native copper, chalcocite, digenite, cuprite, malachite, azurite, and pseudomalachite.

The primary copper-gold mineralization occurs below 200 m and consists mainly of Fe chlorite, siderite, and magnetite-rich breccias.

Hypogene hydrothermal alteration and breccia types
The ore-bearing breccias of Igarapé Bahia are essentially polymictic. They are classified according to matrix mineralogy as Fe chlorite breccias, siderite breccias, and magnetite breccias. The rock fragments have angular to subrounded shapes and diameters that range from a few millimeters up to 20 cm. The fragment to matrix ratio is highly variable, possibly reflecting different fluid/rock ratios or different mechanical processes accompanying brecciation.

Iron chlorite breccias and siderite breccias possess virtually the same matrix mineralogy, which is typically fine grained and includes Fe chlorite, siderite, magnetite, chalcopyrite, and minor tourmaline. Siderite breccias contain a much higher percentage of siderite, clearly distinguishing them from the iron chlorite breccias (dominated by Fe chlorite) in thin section.

At the Acampamento Sul and Furo Trinta orebodies, mineralization is hosted preferentially by siderite breccias, whereas at the Acampamento Norte and Alemão orebodies, mineralization is associated with magnetite breccias. Mineralized iron chlorite breccias occur at the margins of all orebodies (Fig. 4).

View larger version (32K): [in this window] [in a new window]   FIG. 4. Schematic distribution of the hydrothermal alteration zones of the Igarapé Bahia Cu-Au-(U-REE) deposit (not to scale).

Scanning electron microscopy (SEM) investigation of the breccias has revealed the presence of trace amounts of molybdenite, galena, cobaltite, hessite, altaite, cassiterite, ferberite, scheelite, uraninite, parisite, bastnäsite, allanite, monazite, apatite, and fluorite. The breccia matrix also is reported to include chloride-rich minerals such as ferropyrosmalite (Tazava, 1999) and scapolite (Althoff et al., 1994).

Several vein types crosscut the mineralized breccias and the host metavolcanic sequence. Veins are discordant to bedding and rarely display comb structures. The most common types are calcite + chalcopyrite ± fluorite ± stilpnomelane veins, ankerite ± chalcopyrite ± gold veins, siderite ± calcite ± chlorite ± chalcopyrite veins, and chalcopyrite ± biotite ± K-feldspar ± tourmaline ± REE mineral veins. The chronology of the veins is unclear due to poor exposure and equivocal relationships in drill core.

Primary copper-gold mineralization
Primary copper mineralization at Igarapé Bahia comprises xenomorphic and poikiloblastic chalcopyrite in the matrix of breccias. Rarely, chalcopyrite is rimmed by chalcocite, digenite, and covellite due to oxidation reactions along grain boundaries. In magnetite breccias, unlike siderite and Fe chlorite breccias, the chalcopyrite is intergrown with bornite. Rare pyrite occurs as inclusions in chalcopyrite in the more sulphur rich assemblages.

The major copper-rich ores contain gold in all breccia bodies. Additional subeconomic copper is disseminated or occurs in veins or nodules in distal, altered host rocks with negligible gold content.

Chalcopyrite nodules occur in the laminated upper unit of sedimentary rocks (Fig. 3A), where the primary bedding is deformed around the nodules. The nodules are mineralogically zoned, with rims enriched in inclusions of euhedral Fe chlorite in association with minor albite and quartz and cores consisting of massive chalcopyrite, with inclusions of K-feldspar, cobaltite, thorite, monazite, and apatite. The chalcopyrite nodules are interpreted to be epigenetic because they are linked to veins with the same mineralogy and zoning pattern, which are both discordant and concordant to the sedimentary bedding (Fig. 3A-B). Rarely, these sedimentary rocks also have strata-bound replacement textures with infilling of the more porous and permeable layers of the laminated rocks with chalcopyrite.

Native gold occurs in the matrix of the breccias as fine-grained (5–20-µm) inclusions in gangue minerals (quartz, siderite, and chlorite), chalcopyrite, and rarely magnetite. The gold grains contain up to 12 wt percent Ag, but the bulk Ag grades of the ore are subeconomic. Gold may also contain inclusions of tellurides (hessite, Ag₂Te) and sulfides (argentite and/or acanthite, Ag₂S).

	Geochemistry

Top Abstract Introduction Regional Geology and Metallogeny Geology of the Igarape... Geochemistry Sampling and Analytical... SHRIMP U-Pb Results Strontium Isotope Composition of... Model for the Igarape... Discussion References

 
Major, trace, and rare earth element (REE) geochemical analyses of host volcanic rocks, BIF, and ore-bearing breccias of the Acampamento Sul orebody (DDH 340) are presented in Table 1. All samples from DDH 340 were analyzed for major elements, using X-ray fluorescence spectrometry (XRF). High-precision trace and REE analyses, using laser ablation inductively coupled plasma-mass spectrometry (ICP-MS), were also performed on all samples. Gold, Pt, and Pd (30-g samples) were analyzed, using fire assay with an atomic absorption spectrometry (AAS) finish. Fluorine was determined using an ion-specific electrode, As by hydride generation with AAS finish, Hg by the cold vapor method with an AAS finish, and CO₂ and S by LECO analysis. All geochemical analyses were conducted at the Lakefield-Geosol laboratory in Brazil.

Iron chlorite, siderite, and magnetite breccias have similar REE patterns (Fig. 5) characterized by strong low REE enrichment (~10⁴ chondritic values). Although the absolute concentrations of REE vary the patterns for altered metavolcanic rocks, quartz diorite dikes, and mineralized breccias show similar low REE enrichment. The REE pattern of BIF differs significantly from that of the ore-bearing breccias, arguing against a syngenetic sea-floor volcanic origin for the Igarapé Bahia mineralization, as previously suggested by Villas and Santos (2001). The contrasting La/Lu ratios of the host metavolcanic rocks (70–250) and the ore-bearing breccias (1,000–2,500) indicate that low REE were selectively concentrated during hydrothermal alteration and mineralization. The positive correlation between La, Ce, P, Cu, and Au (Fig. 6) supports the suggestion that the low REE minerals (e.g., monazite) are part of the ore paragenesis and, therefore, are suitable for dating mineralization.

View larger version (45K): [in this window] [in a new window]   FIG. 5. Representative rare earth element (REE) distribution patterns for host rocks and mineralized breccias from the Igarapé Bahia Fe oxide Cu-Au-(U-REE) deposit, showing the extreme low REE enrichment of the breccia ores and surrounding volcanic rocks. Chondrite values are from Evensen et al. (1978).

View larger version (18K): [in this window] [in a new window]   FIG. 6. Geochemical plots showing the relationship between Au and Cu enrichment and enrichment in Ce and La in the host volcanic rocks and the mineralized breccias. A. Log-log plots: A. Ce (ppm) vs. Au (ppm). B. La (ppm) vs. Cu (wt %). Plots illustrate the strong correlation of REE with Au and Cu and hence the likelihood that monazite is related to Cu-Au mineralization.

	Sampling and Analytical Procedures for SHRIMP Analysis

Top Abstract Introduction Regional Geology and Metallogeny Geology of the Igarape... Geochemistry Sampling and Analytical... SHRIMP U-Pb Results Strontium Isotope Composition of... Model for the Igarape... Discussion References

The host metavolcanic rock samples from the lower unit display an isotropic fabric defined by abundant fine-grained chlorite associated with minor albite and quartz. The primary mineralogy has been obliterated by intense chlorite alteration. The abundance of chlorite and the limited amount of quartz indicate a mafic composition, which is confirmed by previous geochemical investigations of the Igarapé Bahia metavolcanic rocks (e.g., Ferreira Filho, 1985).

The diabase dikes crop out as extremely weathered saprolite. Fresh samples are only obtained by drilling some 200 m below the surface. Field relationships indicate that the dikes crosscut both the host volcanic rocks and the ore (mineralized breccias). The samples collected for geochronology show no evidence of hydrothermal alteration or overprinting, display an ophitic texture, and are characterized by abundant plagioclase and clinopyroxene with accessory magnetite.

Magnetite-rich breccias crop out as extremely altered gossans. Fresh material was only reached through drilling below a 200-m-vertical depth. The breccia samples may include fragments of host metavolcanic rock and BIF that occur in the matrix of euhedral magnetite with minor chlorite, siderite, fluorite, grunerite, biotite, microcline, and sericite. Copper sulfides (mostly chalcopyrite with lesser bornite) are paragenetically late and surround other phases in the matrix. Gold is present as inclusions within copper sulfides.

The separation of zircons was carried out at the Universidade Federal de Ouro Preto, Brazil, with final handpicking at the University of Western Australia. The samples were crushed, and a <60-mesh fraction was collected and cleaned. The final selection of zircons was handpicked and mounted in epoxy resin disks together with chips of the 564 Ma CZ3 zircon standard (Pidgeon et al., 1994; Nelson, 1997). The disks were polished to expose the zircon grains in section. After detailed photography and SEM imaging, the disks were cleaned and coated with high-purity gold.

Uranium-Th-Pb isotope analyses of sectioned single zircons were carried out on the sensitive high-resolution ion microprobe (SHRIMP II) at the Curtin University of Technology, following the procedures documented by Compston et al. (1986), Williams and Claesson (1987), and Smith et al. (1998). Data were processed using the software package SQUID 1.00 (Ludwig, 2001a).

Monazite analyses were performed in situ on fragments of samples that were split or drilled from polished thin sections and mounted in epoxy disks. The monazite Pb/U standard VK1 (488 Ma) was cast in a separate mount. Analytical and data reduction methods for monazite are described by Foster et al. (2000) and Rasmussen et al. (2001).

The uncertainties in the radiogenic Pb isotope ratios are governed principally by ion-counting precision in the isotopes of direct interest and also in ²⁰⁴Pb, which provides a measure of common Pb. Because the ²⁰⁴Pb content indicated by the analyses of most of the sample zircons is similar to that obtained from the standard zircon analyses, it is assumed that all the Pb came from the gold coat of the sample surface. The data used for age determinations all required very low common Pb corrections and are therefore insensitive to the choice of common Pb composition. All analyses with higher levels of common Pb have other indications of isotopic disturbance, and the common Pb cannot be assumed to be original, so the choice of composition is necessarily an estimate. The total Pb in each analysis was corrected from common Pb by stripping initial ²⁰⁶Pb, ²⁰⁷Pb, and ²⁰⁸Pb from the measured amounts, using the observed ²⁰⁴Pb and Pb with the composition of Broken Hill galena.

Ages were calculated using U decay constants from Jaffey et al. (1971). Analytical uncertainties given in the tables and shown in plots are 1. The ages from pooled data are weighted means, with uncertainties given as 95 percent confidence limits. Plots were prepared using ISOPLOT 2.49 (Ludwig, 2001b).

	SHRIMP U-Pb Results

Top Abstract Introduction Regional Geology and Metallogeny Geology of the Igarape... Geochemistry Sampling and Analytical... SHRIMP U-Pb Results Strontium Isotope Composition of... Model for the Igarape... Discussion References

 
Representative cathodoluminescence (CL)-SEM images of zircon types from the host metavolcanic rocks (samples B18C and B18D) and the diabase dikes (samples B21D and B36A) are presented in Figure 7. Zircon morphologies vary from euhedral grains with distinct crystal faces to well-rounded grains and grain fragments. Cathodoluminescence imaging reveals that most zircon grains have intense oscillatory zoning (e.g., Fig. 7A, D, G, H), whereas relatively few have limited to no visible internal structure (e.g., Fig. 7B, I). Zircon grains with distinctively older cores and younger overgrowths are common (Fig. 7E, F, H), and analyses reveal that there is some correlation between morphology and/or internal features (e.g., compositional zoning) and age. This is evident where placement of the SHRIMP spot resulted in the analysis of older cores (e.g., Fig. 7E), where SHRIMP spots overlapped older cores and younger rims resulting in mixed ages (Fig. 7A), and where two analyses on one grain gave ages not within error of each other (Fig. 7A).

View larger version (53K): [in this window] [in a new window]   FIG. 7. Representative cathodoluminescence (CL)-SEM images of analyzed zircon grains from host metavolcanic rock samples B18C and B18D and diabase dike samples B36A and B21D. The locations of SHRIMP analyses for dated grains are shown as circles. All ages are 207Pb/206Pb ages. Discordant data are marked with a (d). A. B18C.1-1 and B18.C1-2. B. B18C.3-1. C. B18C.6-1. D. B18D.2-1 and B18D.2-2. E. B36A.6-1. F. B36A.3-1. G. B36A.5-1. H. B21D. 6-1. I. B21D.7-1. J. B21D.2-1 and B21D.2-2.

Zircons analyzed from the host metavolcanic rock (Fig. 7A-D) comprise euhedral whole grains with relatively well defined crystal faces and terminations (Fig. 7A), subhedral to rounded grains (Fig. 7C-D), and rounded zircon fragments with no clear internal structure (Fig. 7B). Cathodoluminescence is moderate to strong, and almost all grains within these samples display relatively clear, concentric, euhedral, oscillatory zoning patterns.

A total of 13 spots were analyzed in nine zircon grains (Table 3). Only three concordant analyses from two grains (C.1-1, C.1-2, C.6-1) possibly define the rock age (2748 ± 34 Ma, MSWD = 2.7; Fig. 8), with two discordant analyses from another grain (D.2-1, D.2-2) giving similar ²⁰⁷Pb/²⁰⁶Pb ages. Among the other data, two are unquestionably inherited, ²⁰⁷Pb/²⁰⁶Pb ages of ~2865 Ma (C.2-1, D.1-1), consistent with previously reported ages for the Xingu Complex (e.g., Machado et al., 1991). The remaining data are all >25 percent discordant, except for C3.1, which has an anomalously young ²⁰⁷Pb/²⁰⁶Pb age of 2003 ± 9 Ma (Fig. 7B) and may be a reset age.

View larger version (20K): [in this window] [in a new window]   FIG. 8. Concordia plot of SHRIMP data from zircons from the host metavolcanic rocks of the Igarapé Bahia Fe oxide Cu-Au-(U-REE) deposit. The weighted mean 207Pb/206Pb age from the concordant analyses (shown as unshaded) is 2748 ± 34 Ma (MSWD = 2.7). Samples UWA-B18C and UWA-B18D.

Zircons analyzed from mounts B36A and B21D comprise euhedral whole grains and fragments with well-defined crystal faces and terminations (Fig. 7F-H). Moderately to well-rounded grains are noted (Fig. 7E, I), with one grain displaying an irregular, fragmented morphology (Fig. 7J). Cathodoluminescence is strong, and almost all grains display clear concentric euhedral zoning patterns. A few grains have extremely bright CL, especially along rims and within cores. Several grains have more complex and irregular zoning patterns, particularly in the central regions. There are clear structural discontinuities between core regions and rim zones in several grains (e.g., Fig. 7E, F, H), indicating xenocrystic cores (e.g., structurally discordant patterns in their central regions, overgrown by more systematic and concentric, zoned zircon rims; Fig. 7E). This was confirmed by the SHRIMP analyses.

A total of 39 spots were analyzed from 32 grains, but no consistent date emerged from the data set. Approximately half of the analyses, mostly from grains with higher U or high ²⁰⁴Pb, are >5 percent discordant (Table 4). The remaining 20 concordant analyses from 19 grains yielded ²⁰⁷Pb/²⁰⁶Pb ages that range between 3050 ± 9 and 2653 ± 48 Ma. It is evident from CL imaging (Fig. 7E) that the SHRIMP analysis that gave an age of 3050 ± 9 Ma was partially placed on an older core. All analyzed grains display corrosion textures, indicating that zircons were not in equilibrium with the host magma, and are likely inherited. Analyses B21D.2-1 and B21D.2-2 gave ages of 2691 ± 52 and 2653 ± 48 Ma, respectively, and correspond to the irregular grain depicted in Figure 7J. This grain is the youngest concordant zircon analyzed. Therefore, the maximum age of host dike intrusion is ~2670 Ma.

View larger version (115K): [in this window] [in a new window]   FIG. 9. Representative backscattered electron images of sample UWA-B34, showing analyzed monazite grains (white) in apparent textural equilibrium with chalcopyrite (cpy) and magnetite (mgt) in the matrix of ore-bearing breccias of the Igarapé Bahia Fe oxide Cu-Au-(U-REE) deposit. Other associated minerals are siderite (sid), apatite (ap), and chlorite (chl). The locations of SHRIMP analyses for dated grains are shown as circles. All ages are 207Pb/206Pb ages. Discordant data are marked with a (d). A. B34.5.3-1. B. B34.5.2-1. C. B34.4.2-1. D. B34.7.3-1. E. B34.4.1-1. F. B34.6.2-1.

View larger version (18K): [in this window] [in a new window]   FIG. 10. Concordia plot of SHRIMP data for monazite from the matrix of mineralized magnetite breccias (sample UWA-B34) of the Igarapé Bahia Fe oxide Cu-Au-(U-REE) deposit. The weighted mean 207Pb/206Pb age of the main concordant cluster (unshaded), shown in the inset, is 2575 ± 12 Ma (MSWD = 1.19).

	Strontium Isotope Composition of Carbonate Minerals

Top Abstract Introduction Regional Geology and Metallogeny Geology of the Igarape... Geochemistry Sampling and Analytical... SHRIMP U-Pb Results Strontium Isotope Composition of... Model for the Igarape... Discussion References

 
Eight carbonate samples from the Igarapé Bahia deposit were concentrated from the matrix of ore-bearing siderite breccias and crosscutting veins to investigate their strontium isotope composition (Table 6) as a means of constraining fluid source. Preparation of carbonate samples and subsequent isotopic analyses were carried out at the University of São Paulo, Brazil. Prior to isotopic analysis, X-ray powder diffraction analyses were performed at Companhia Vale do Rio Doce to determine the carbonate specie(s) in each sample.

The ⁸⁷Sr/⁸⁶Sr ratios of the Igarapé Bahia carbonates are highly radiogenic and indicate crustal derivation (Table 6). These values are inconsistent with the isotopic composition of seawater at ~2.575 Ga (Veizer and Compston, 1976) and with the initial ⁸⁷Sr/⁸⁶Sr ratios of the Grão Pará metavolcanic rocks (0.7057 ± 0.0010) determined by Gibbs et al. (1986). This evidence clearly precludes seawater as a major component of the hydrothermal system, as would be expected if the deposits were syngenetic (e.g., VHMS model of Ferreira Filho, 1985; Almada, 1998). The wide range of highly radiogenic ⁸⁷Sr/⁸⁶Sr ratios (0.714–0.755) of the Igarapé Bahia carbonate minerals suggests multiple crustal sources, consistent with an epigenetic magmatic-hydrothermal origin (Fig. 11). Hydrothermal calcite and tourmaline from the Salobo deposit have similar ⁸⁷Sr/⁸⁶Sr ratios (Mellito, 1998), suggesting that highly radiogenic strontium signatures are common to Fe oxide Cu-Au deposits of the Carajás belt.

View larger version (21K): [in this window] [in a new window]   FIG. 11. 87Sr/86Sr vs. time diagram showing the isotopic evolution of seawater (Veizer and Compston, 1976), continental crust and mantle (Faure and Powell, 1972) relative to the carbonate minerals from the matrix of mineralized breccias and crosscutting veins of the Igarapé Bahia Fe oxide Cu-Au-(U-REE) deposit. The Igarapé Bahia samples clearly indicate a crustal derivation. ACPS = Acampamento Sul orebody.

	Model for the Igarapé Bahia Fe Oxide Cu-Au-(U-REE) Mineralization

Top Abstract Introduction Regional Geology and Metallogeny Geology of the Igarape... Geochemistry Sampling and Analytical... SHRIMP U-Pb Results Strontium Isotope Composition of... Model for the Igarape... Discussion References

The positive correlation between REE, P, Au, and Cu, and textural evidence of chalcopyrite in equilibrium with REE minerals in the mineralized breccias (Fig. 9), supports the suggestion that monazite is genetically related to the precipitation of copper and gold in the Igarapé Bahia deposit. Thus, the in situ dating of monazite, from the matrix of ore-bearing magnetite breccias, constrains the age of ore formation. The SHRIMP ²⁰⁷Pb/²⁰⁶Pb age of 2575 ± 12 Ma of hydrothermal monazite indicates that the mineralization occurred ~175 m.y. after accumulation of the host volcano-sedimentary sequence. The data obtained from zircon xenocrysts recovered from the diabase indicate a maximum ²⁰⁷Pb/²⁰⁶Pb age of ~2670 Ma for dike emplacement, consistent with field evidence and the SHRIMP ages of the ore and host rocks (Fig. 12).

View larger version (36K): [in this window] [in a new window]   FIG. 12. Summary of the SHRIMP ages obtained in this study compared to conventional U-Pb zircon ages and Rb-Sr bulk-rock ages of the Estrela Granitic Complex, the Old Salobo Granite, the Itacaiúnas Granite, Re-Os ages of molybdenite, and Pb-Pb model ages of bornite-chalcopyrite-magnetite mineralization at Salobo, and the host metavolcanic rocks of the Igarapé Bahia deposit.

The epigenetic nature of the Igarapé Bahia Cu-Au mineralization is supported by field evidence that includes the presence of fragments of rocks from both the lower and upper unit in the mineralized breccias (Fig. 3C) and the presence of chalcopyrite-rich veins and nodules in the upper unit (Fig. 3A-B). The circular shape of the cluster of breccia bodies (Fig. 2B) is similar to that of ring complexes associated with the intrusion of alkaline magmas.

Chlorite thermometry of the mineralized breccia, determined by Tallarico et al. (2000), indicates relatively high temperatures (313°–375°C), consistent with the fluid inclusion data of Ribeiro (1989) and Lindenmayer et al. (1998), which indicate the presence of a high-temperature (150°–430°C) group of high-salinity (up to 40% NaCl equiv) inclusions. Assuming that the fluids depositing magnetite and gold were similar to those postulated for other magnetite-rich Cu-Au systems (e.g., Davidson and Large, 1994; Skirrow and Walshe, 2002), copper and gold transport was most likely by chloride complexing, which could also explain the high REE concentrations (e.g., Gieré, 1996).

The stable isotope data of Oliveira et al. (1998) and Tazava (1999), from calcite and siderite in the matrix of mineralized breccias and crosscutting veins from the Igarapé Bahia deposit, yield a narrow range of negative ¹³C values (–9.3 to –5.8) and a relatively wide range of ¹⁸O values (0.7–9.4; Fig. 13). The negative ¹³C values are consistent with a homogeneous deep-seated carbon source from which carbonate minerals were precipitated within a limited pH range. The wider range of ¹⁸O values may be the result of mixing or overprinting of deep-seated solutions (high ¹⁸O) with meteoric fluids (low ¹⁸O). Additional evidence for the latter is provided by a second, low-temperature (100°–150°C) group of low-salinity (~10% NaCl equiv) inclusions identified in the studies of Ribeiro (1989) and Lindenmayer et al. (1998).

View larger version (14K): [in this window] [in a new window]   FIG. 13. 18O vs. 13C diagram showing the field for carbonates from the Igarapé Bahia Fe oxide Cu-Au-(U-REE) deposit (Oliveira et al., 1998; Tazava, 1999) compared to carbonates from carbonatites, freshwater limestone, marine limestone, and the Olympic Dam deposit. The data are consistent with an association with alkaline rocks. Modified after Oreskes and Einaudi (1992).

	Discussion

Top Abstract Introduction Regional Geology and Metallogeny Geology of the Igarape... Geochemistry Sampling and Analytical... SHRIMP U-Pb Results Strontium Isotope Composition of... Model for the Igarape... Discussion References

 
The previously proposed VHMS models for Igarapé Bahia (e.g., Ferreira Filho, 1985; Almada, 1998; Villas and Santos, 2001) are negated by the new geochronologic data. Additionally, the grade-tonnage data of the Igarapé Bahia deposit (219 Mt of primary ore at 1.4% Cu and 0.86 g/t Au) contrasts markedly with that of most VHMS deposits, which contain <100 Mt ore (Large, 1992; Slack, 1993; Barrie and Hannington, 1999). The ore paragenesis of the Igarapé Bahia deposit, characterized by magnetite + chalcopyrite ± bornite with significant amounts of U (28–380 ppm), F (390–31,000 ppm), P (900–6,200 ppm), La (260–2,300 ppm), and Ce (450–4,400 ppm), contrasts dramatically with that of VHMS deposits, which normally lack significant concentrations of Fe oxides, typically contain pyrite and pyrrhotite, and do not have anomalous concentrations of U, F, P, or REE (Large, 1992; Slack, 1993; Barrie and Hannington, 1999). The SHRIMP monazite ages, together with the mineralogical, geochemical, and radiogenic and stable isotope data from the Igarapé Bahia ore, indicate an epigenetic hydrothermal-magmatic origin, temporally related to the emplacement of Archean (~2.57 Ga) A-type granites of the Carajás belt.

Iron-oxide Cu-Au-(U-REE) deposits have been recognized as a distinctive ore deposit type during the last decade (Hitzman et al., 1992; Oreskes and Hitzman, 1993). Representative examples of this group include the Olympic Dam deposit with resources of 2,000 Mt at 1.6 percent Cu and 0.6 g/t Au (Roberts and Hudson, 1983; Reeve et al., 1990; Hitzman et al., 1992; Cross et al., 1993; Oreskes and Hitzman, 1993) and the Ernest Henry deposit with resources of 167 Mt at 1.1 percent Cu and 0.5 g/t Au (Williams, 1998). These structurally controlled epigenetic deposits share a number of common features such as (1) high tonnage (>100 Mt) and low copper (<2.0 %) and gold (<0.8 g/t) grades, (2) abundance of magnetite and/or hematite, (3) oxidized and S-poor ore paragenesis (chalcopyrite, bornite, and/or chalcocite), (4) low SiO₂ content of the ore, and (5) a metal association of Fe-Cu-Au with anomalous low REE, U, P, and F (Hitzman et al., 1992; Oreskes and Hitzman, 1993; Williams, 1998; Groves and Vielreicher, 2001). Mineralization at all deposits involved high-temperature (200°–600°C) ore fluids that were extremely saline (as much as 50 wt % NaCl equiv), acid, and oxidizing, and carried metals as Cl complexes (Hitzman et al., 1992; Oreskes and Hitzman, 1993; Davidson and Large, 1994), with involvement also of relatively low temperature and less saline fluids (Oreskes and Einaudi, 1992; Oreskes and Hitzman, 1993; Gow et al., 1994; Haynes et al., 1995; Barton and Johnson, 1996). The styles of hydrothermal alteration, the ore mineralogy and geochemistry, and the strontium isotope data presented here, together with previous stable isotope and fluid inclusion data, strongly support the classification of Igarapé Bahia as a member of the world-class Olympic Dam-type Fe oxide Cu-Au-(U-REE) deposit group, as previously argued by several authors (Oliveira et al., 1998; Tallarico et al., 1998; Soares et al., 1999; Tazava, 1999). The SHRIMP ²⁰⁷Pb/²⁰⁶Pb age of 2575 ± 12 Ma for hydrothermal monazite from the matrix of mineralized breccia clearly defines Igarapé Bahia as an Archean example of the deposit group.

Several other Cu-Au deposits of the Carajás belt, such as Salobo (2576 ± 9 Ma; Requia et al., 2003), Sossego, and Cristalino, share a number of characteristics with the Igarapé Bahia, such as (1) intense Fe metasomatism resulting in the formation of grunerite, fayalite, and/or Fe oxides (magnetite and/or hematite); (2) intense carbonate alteration; (3) sulfur-poor ore paragenesis (chalcopyrite and bornite); (4) absence of quartz due to silica dissolution; (5) extreme low REE enrichment; and (6) enrichment in U and Co. The similarities between these deposits and Igarapé Bahia indicate that they might also be genetically related to the intrusion of Archean (ca. 2.57 Ga) Estrela-type alkaline granites or deeper, associated, but unexposed, alkaline intrusions in the Carajás belt.

	Acknowledgments

 
The authors wish to thank the Companhia Vale do Rio Doce (CVRD) for access to the area, support during fieldwork, and for access to their electron microprobe laboratory. Marion Marshall, from the School of Earth and Geographical Sciences of the University of Western Australia (UWA), is thanked for technical assistance and SHRIMP II sample preparation. The authors thank Brendan J. Griffin and Sharon Platten, from the Centre for Microscopy and Microanalysis of the UWA, for SEM assistance. We acknowledge Maurício Carneiro, from the Geology Department of the Universidade Federal de Ouro Preto, for assistance during sample preparation. Colombo Gaeta Tassinari is thanked for his assistance during preparation of carbonate samples and Sr analyses at the Centro de Pesquisas Geocronológicas of the Universidade de São Paulo, and Romulo Simoes from the Universidade Federal do Para is thanked for support with the reference compilation. We are indebted to Richard Vielreicher for assistance with improving the quality of the paper. Zircon and monazite analyses were performed on the Western Australian SHRIMP II operated by a WA university-government consortium with Australian Research Council support. We are indebted to the Fundação de Amparo a Pesquisa do Estado de São Paulo (FAPESP) for research grants 98/14401-5 and 99/03058-0. We are also grateful to the Society of Economic Geologists Foundation for financial support through the Hugh E. McKinstry grant for the year 2000. Journal reviews by Nick Oliver and Daniela Rubato, and incisive and helpful comments of Mark Hannington are appreciated and his careful editing significantly improved the manuscript.

May 1, 2002; October 20, 2004

May 1, 2002; October 20, 2004

	References

Top Abstract Introduction Regional Geology and Metallogeny Geology of the Igarape... Geochemistry Sampling and Analytical... SHRIMP U-Pb Results Strontium Isotope Composition of... Model for the Igarape... Discussion References

 

Almada, M.C.O., 1998, O Corpo Acampamento Sul do depósito Bahia, Carajás: Características geológicas e fluidos hidrotermais: Unpublished M.Sc. thesis, Belém, Brazil, Universidade Federal do Pará, 99 p.

Althoff, A.M.R., Villas, R.N., and Giuliani, G., 1994, A mineralização cuprífera da Área Bahia, Serra dos Carajás (PA): Evolução dos fluidos hidrotermais e modelo metalogenético: Geochemica Brasiliense, v. 8, p. 135–155.

Angélica, R.S., 1996, Mineralogia e geoquímica dos gossans e lateritos auríferos na Região de Carajás, Estado do Pará: Os depósitos de Igarapé Bahia e Águas Claras: Unpublished Ph.D. thesis, Belém, Brazil, Universidade Federal do Pará, 115 p.

Araújo, O.J.B., Maia, R.G.N., Xafi, J.J.S., and Costa, J.B.S, 1988, A megaestruturação arqueana da folha Serra dos Carajás: Congresso Latino-Americano de Geologia, VII, Belém, Sociedade Brasileira de Geologia, Anais, p. 324–333.

Barreira, C.F., Soares, A.D.V., and Ronzê, P.C., 1999, Descoberta do Depósito Cu-Au Alemão-Província Mineral de Carajás (PA) [ext. abs.]: Simpósio de Geologia da Amazônia, VI, Manaus, Sociedade Brasilaira de Geologia, Extended Abstract Bulletin, p. 136–139.

Barrie, C.T., and Hannington, M.D., 1999, Classification of volcanic-associated massive sulfide deposits based on host-rock composition: Reviews in Economic Geology, v. 8, p. 1–11.[GeoRef]

Barros, C.E.M., and Barbey, P., 1998, A importância da granitogênese tardi-arqueana (2.5 Ga) na evolução tectono-metamórfica da Província Mineral de Carajás-O Complexo Granítico Estrela e sua auréola de contato: Revista Brasileira de Geociências, v. 28, p. 513–522.[GeoRef]

Barros, C.E.M., Dall’Agnoll, R., Lafon, J.M., Teixeira, N.P., and Ribeiro, J.W., 1992, Geologia e geocronologia Rb-Sr do Gnaisse Estrela, Curionópolis, PA: Boletin do Museu Paraense Emílio Goeldi, Ciências da Terra, v. 4, p. 83–104.

Barros, C.E.M., Dall’Agnoll, R., Barbey, P, and Boullier, A.M., 1997, Geochemistry of the Estrela Complex, Carajás region, Brazil: An example of an Archean A-type granite: Journal of South American Earth Sciences, v. 10, p. 321–330.[CrossRef][Web of Science]

Barros, C.E.M., Barbey, P., and Boullier, A.M., 2001, Role of magma pressure, tectonic stress and crystallization progress in the emplacement of syntectonic granites. The A-type Estrela Granite Complex (Carajás mineral province, Brazil): Tectonophysics, v. 343, p. 93–109.[CrossRef][Web of Science][GeoRef]

Barton, M.D., and Johnson, D.A., 1996, Evaporitic-source model for igneous-related Fe oxide-(REE-Cu-Au-U) mineralization: Geology, v. 24, p. 259–262.[Abstract/Free Full Text][CrossRef][Web of Science][GeoRef]

Campbell, I.H., Compston, D.M., Richards, J.P., Johnson, J.P., and Kent, A.J.R., 1998, Review of the application of isotopic studies to the genesis of Cu-Au mineralization at Olympic Dam and Au mineralization at Porgera, Tennant Creek district and Yilgarn craton: Australian Journal of Earth Sciences, v. 45, p. 201–218.[Web of Science][GeoRef]

Compston, W., Williams, I.S., Campbell, I.H., and Gresham, J.J., 1986, Zircon xenocrysts from the Kambalda volcanics: Age constraints and direct evidence for the older continental crust below the Kambalda-Norseman greenstones: Earth and Planetary Science Letters, v. 76, p. 299–311.[CrossRef][Web of Science][GeoRef]

Cordeiro, A.A.C., 1999, Pesquisa mineral: panorama atual da CVRD na Amazônia [ext. abs.]: Simpósio de Geologia da Amazônia, VI, Manaus, Sociedade Brasilaira de Geologia, Extended Abstract Bulletin, p. 80–83.

Cross, K.C., Daly, S.J., and Flint, R.B., 1993, Mineralization associated with the GRV and Hiltaba Suite granitoids: Geological Survey of Southern Australia Bulletin 54, 242 p.

Davidson, G.J., and Large, R.R., 1994, Gold metallogeny and the copper-gold association of Australian Proterozoic: Mineralium Deposita, v. 29, p. 208–223.[Web of Science][GeoRef]

Dias, G.S., Macambira, M.J.B., Dall’Agnol, R., Soares, A.D.V., and Barros, C.E.M., 1996, Datação de zircões de Sill de metagabro: Comprovação da idade arqueana da Formação Águas Claras, Carajás, Pará [ext. abs.]: Simpósio de Geologia da Amazônia, V, Belém, Sociedade Brasileira de Geologia, Extended Abstracts Bulletin, p. 376–379.

Docegeo (Rio Doce Geologia e Mineração S.A.), 1988, Província Mineral de Carajás. Litoestratigrafia e principais depósitos minerais: Congresso Brasileiro de Geologia, XXXV, Belém, Companhia Vale do Rio Doce and Sociedade Brasileiro de Geologia, Anexo aos Anais, 165 p.

Evensen, N.M., Hamilton, P.J., and O’Nions, R.K., 1978, Rare-earth abundances in chondritic meteorites: Geochimica et Cosmochimica Acta, v. 42, p. 1199–1212.[CrossRef][Web of Science][GeoRef]

Farias, N.R., and Saueressig, R., 1982, Jazida de cobre Salobo 3A: Simpósio de Geologia da Amazônia, I, Salvador, Bahia, Secretaria de Minas e Energia, p. 61–73.

Faure, G., and Powell, J.L., 1972, Strontium isotope geology. Mineral, rocks and inorganic materials: Monograph Series of Theoretical and Experimental Studies 5, New York, Springer-Verlag, 188 p.

Ferreira Filho, C.F., 1985, Geologia e mineralizações sulfetadas do Prospecto Bahia, Província Mineral de Carajás: Unpublished M.Sc. thesis, Brasília, Brazil, Universidade de Brasília, 112 p.

Foster, G., Kinny, P., Vance, D., Prince, C., and Harris, N., 2000, The significance of monazite U-Th-Pb age data in metamorphic assemblages: A combined study of monazite and garnet chronometry: Earth and Planetary Science Letters, v. 181, p. 327–340.[CrossRef][Web of Science][GeoRef]

Gibbs, A.K., and Wirth, K.R., 1990, Geologic setting of the Serra dos Carajás iron deposits, Brazil, in Chauvel, J.J., Yuqi, C., and El Shazly, E.M., eds., Ancient banded iron formations (regional presentations): Athens, Theophrastus, p. 83–102.

Gibbs, A.K., Wirthe, K.R., Hirata, W.K., and Olszewski Jr., W.J., 1986, Age and composition of the Grão Pará Group volcanics, Serra dos Carajás: Revista Brasileira de Geociências, v. 16, p. 201–211.[GeoRef]

Gieré, R., 1996, Formation of rare earth minerals in hydrothermal systems, in Jones, A.P., Wall, F., and Williams, C.T., eds., Rare earth minerals: London, Chapman and Hall, p. 105–150.

Gow, P.A, Wall, V.J., Oliver, N.H.S, and Valenta, R.K., 1994, Proterozoic iron oxide (Cu-U-Au-REE) deposits: Further evidence of hydrothermal origins: Geology, v. 22, p. 633–636.[Abstract/Free Full Text][CrossRef][Web of Science][GeoRef]

Groves, D.I., and Vielreicher, N.M., 2001, The Phalabowra (Palabora) carbonatite-hosted magnetite-copper sulfide deposit, South Africa: An end-member of the iron-oxide copper-gold-rare earth element deposit group?: Mineralium Deposita, v. 36, p. 189–194.[CrossRef][Web of Science][GeoRef]

Haynes, D.W., Cross, K.C., Bills, R.T., and Reed, M.H., 1995, Olympic Dam ore genesis: A fluid-mixing model: Economic Geology, v. 90, p. 281–307.[Abstract/Free Full Text][CrossRef][Web of Science][GeoRef]

Hitzman, M.W., Oreskes, N., and Einaudi, M.T., 1992, Geological characteristics and tectonic setting of Proterozoic iron oxide (Cu-U-Au-REE) deposits: Precambrian Research, v. 58, p. 241–287.[CrossRef][Web of Science][GeoRef]

Holdsworth, R.E., and Pinheiro, R.V.L., 2000, The anatomy of shallow-crustal transpressional structures: Insights from the Archean Carajás fault zone, Amazon, Brazil: Journal of Structural Geology, v. 22, p. 1105–1123.[CrossRef][Web of Science][GeoRef]

Huhn, S.R.B., Santos, A.B.S., Amaral, A.F., Ledsham, E.J., Gougêa, J.L., Martins, L.P., Montalvão, R.G.M., and Costa, V.G., 1988, O terreno "granito greenstone" da região de Rio Maria-Sul do Pará [ext. abs.]: Congresso Brasileiro de Geologia, XXXV, Belém, Sociedade Brasileira de Geologia, Anais, p. 1438–1452.

Huhn, S.R.B., Souza, C.I.J., Albuquerque, M.C., Leal, E.D., and Brustolin, V., 1999a, Descoberta do depósito Cu(Au) Cristalino: Geologia e mineralização associada-Região da Serra do Rabo-Carajás-PA: Simpósio de Geologia da Amazônia, VI, Manaus, Boletim, p. 140–143.

Huhn, S.R.B, Macambira, M.J.B., and Dall’Agnol, R., 1999b, Geologia e geocronologia Pb/Pb do granito alcalino Arqueano Planalto, Região da Serra do Rabo, Carajás-PA: Simpósio de Geologia da Amazônia, VI, Manaus, Sociedade Brasilaira de Geologia, Extended Abstract Bulletin, p. 463–466.

Jaffey, A.H., Flynn, K.F., Glendenin, L.E., Bentley, W.C., and Essling, A.M., 1971, Precision measurement of half lives and specific activities of ²³⁵U and ²³⁸U: Physics Reviews, v. C4, p. 1889–1906.[CrossRef]

Kerrich, R., Goldfarb, R., Groves, D.I., and Garwin, S., 2000, The geodynamics of world-class gold deposits: Characteristics, space-time distribution, and origins: Reviews in Economic Geology, v. 13, p. 501–551.[GeoRef]

Lancaster Oliveira, J., Fanton, J., Almeida, A.J., Leveille, R.A., and Vieira, S., 2000, Discovery and geology of the Sossego copper-gold deposit, Carajás district, Pará State, Brazil [abs.]: International Geological Congress, 31^st, Rio de Janeiro, Sociedade Brasileira de Geologia, Abstract volume (CD-ROM).

Large, R.R., 1992, Australian volcanic-hosted massive sulfide deposits: Features, styles, and genetic model: Economic Geology, v. 87, p. 471–510.[Abstract/Free Full Text][CrossRef][Web of Science][GeoRef]

Lindenmayer, Z.G., 1990, Salobo sequence, Carajás, Brazil: Geology, geochemistry and metamorphism: Unpublished Ph.D. thesis, London, ON, University of Western Ontario, 407 p.

Lindenmayer, Z.G., Ronchi, L.H., and Laux, J.H., 1998, Geologia e geoquímica da mineralização de Cu-Au primária da mina de Au do Igarapé Bahia, Serra dos Carajás: Revista Brasileira de Geociências, v. 28, p. 257–268.

Ludwig, K.R., 2001a, SQUID 1.00—a User’s manual: Berkeley Geochronology Centre Special Publication 2, 17 p.

——2001b, User manual for Isoplot/Ex rev. 2.49—a geochronological toolkit for Microsoft Excel: Berkeley Geochronology Centre Special Publication 1a, 56 p.

Machado, N., Lindenmayer, Z, Krogh, T.E., and Lindenmayer, D., 1991, U-Pb geochronology of Archean magmatism and basement reactivation in the Carajás area, Amazon Shield, Brazil: Precambrian Research, v. 49, p. 329–354.[CrossRef][Web of Science][GeoRef]

Mellito, K.M., 1998, Aplicações dos sistemas Rb-Sr, Pb-Pb e Sm-Nd no depósito polimetálico do Salobo 3A, Província Mineral de Carajás, Pará: Unpublished M.Sc. thesis, São Paulo, Brazil, Universidade de São Paulo, 90 p.

Montalvão, R.G.M, Tassinari, C.C.G., and Bezerra, P.E.L., 1984, Geocronologia dos granitóides e gnaisses das regiões do Rio Maria, Fazenda Mata Geral e Rio Itacaiunas, Sul do Pará (Distrito Carajás-Cumaru) [abs.]: Congresso Brasileiro de Geologia, XXXIII, Rio de Janeiro, Sociedade Brasileira de Geologia, Resumos, p. 153.

Muogeot, R., Respaut, J.P., Briqueu, L., Ledru, P., Milesi, P., Lerouge, C., Marcoux, E., Huhn, S.R.B., and Macambira, M.J.B., 1996, Isotope geochemistry constraints for Cu, Au mineralizations and evolution of the Carajás province (Pará, Brazil) [ext. abs.]: Congresso Brasileiro de Geologia, XXXIX, Salvador, Sociedade Brasileira de Geologia, Extended Abstracts Bulletin, v. 7, p. 321–324.

Nelson, D.R., 1997, Compilation of SHRIMP U-Pb zircon geochronology data, 1996: Geological Survey of Western Australia Record 1997/2, 189 p.

Nogueira, A.C.R., Truckenbrod, W., Costa, J.B.S., and Pinheiro, R.V.L., 1994, Análise faciológica e estrutural da Formação Águas Claras, Pré-Cambriano da Serra dos Carajás [ext. abs.]: Simpósio de Geologia da Amazônia, IV, Belém, Sociedade Brasileira de Geologia, Resumos Expandidos, p. 363–364.

Nogueira, A.C.R., Truckenbrod, W., and Pinheiro, R.V.L., 2000, Storm and tide-dominated siliciclastic deposits of the Archean Águas Claras Formation, Serra dos Carajás, Brazil [abs.]: International Geological Congress, 31^st, Rio de Janeiro, Sociedade Brasileira de Geologia, Abstract volume (CD-ROM).

Oliveira, C.G., Tazava, E., Tallarico, F.H.B., Santos, R.V., and Gomes, C., 1998, Gênese do depósito de Au-Cu-(U-ETR) de Igarapé Bahia, Província Mineral de Carajás [abs.]: Congresso Brasileiro de Geologia, XL, Belo Horizonte, Sociedade Brasileira de Geologia, Proceedings, p. 137.

Olszewski, W.J., Wirth, K.R., Gibbs, A.K., and Gaudette, H.E., 1989, The age, origin, and tectonics of the Grão Pará Group and associated rocks, Serra dos Carajás, Brazil: Archean continental vulcanism and rifting: Precambrian Research, v. 42, p. 229–254.[GeoRef]

Oreskes, N., and Einaudi, M.T., 1990, Origin of rare earth element-enriched hematite breccias at the Olympic Dam Cu-U-Au-Ag deposit, Roxby Downs, South Australia: Economic Geology, v. 85, p. 1–28.[Abstract/Free Full Text][CrossRef][Web of Science][GeoRef]

Oreskes, N., and Hitzman, M.W., 1993, A model for the origin of Olympic Dam-type deposits: Geological Association of Canada Special Paper 40, p. 615–633.

Pidgeon, R.T., Furfaro, D., Kennedy, A.K., and Nemchin, A.A., 1994, Calibration of zircon standards for the Curtin SHRIMP II [abs]: U.S. Geological Survey Circular 1107, p. 251.

Pidgeon, R.T., Macambira, M.J.B., and Lafon, J.M., 2000, Th-U-Pb isotopic systems and internal structures of complex zircons from enderbite from the Pium Complex, Carajás province, Brazil: Evidence for ages of granulite facies metamorphism and protolith of the enderbite: Chemical Geology, v. 166, p. 157–171.

Pinheiro, R.V.L., and Holdsworth, R.E., 1997, Reactivation of Archean strike-slip fault systems, Amazon region, Brazil: Journal of the Geological Society [London], v. 154, p. 99–103.[Abstract/Free Full Text][CrossRef][Web of Science][GeoRef]

Rasmussen, B., Fletcher, I.R., and McNaughton, N.J., 2001, Dating low-grade metamorphism by SHRIMP U-Pb analysis of monazite in shales: Geology, v. 29, p. 963–966.[Abstract/Free Full Text][CrossRef][Web of Science][GeoRef]

Reeve, J.S., Cross, K.C., Smith, R.N., and Oreskes, N., 1990, Olympic Dam copper-uranium-gold-silver deposit, in Hughes, F.E., ed., Geology of the mineral deposits of Australia and Papua New Guinea: Melbourne, Australian Institute of Mining and Metallurgy, p. 1009–1035.

Requia, K., Stein, H., Fontboté, L., and Chiaradia, M., 2003, Re-Os and Pb-Pb geochronology of the Archean Salobo iron oxide copper-gold deposit, Carajás mineral province, northern Brazil: Mineralium Deposita, v. 38, p. 727–738.[CrossRef][Web of Science][GeoRef]

Ribeiro, A.M.R., 1989, Estudo geoquímico do sistema hidrotermal relacionado à mineralização cuprífera da Área Bahia, Serra dos Carajás, Pará: Unpublished M.Sc. thesis, Belém, Brazil, Universidade Federal do Pará, 134 p.

Rigon, J.C., Munaro, P., Santos, L.A., Nascimento, J.A.S., and Barreira, C.F., 2000, The Alvo 118 copper-gold deposit: Geology and mineralization, Serra dos Carajás, Pará [abs.]: International Geological Congress, 31st, Rio de Janeiro, Sociedade Brasileira de Geologia, Abstract volume (CD-ROM).

Roberts, D.E., and Hudson, G.R.T., 1983, The Olympic Dam copper-uranium-gold deposit, Roxby Downs, South Australia: Economic Geology, v. 78, p. 799–822.[Abstract/Free Full Text][CrossRef][Web of Science][GeoRef]

Rodrigues, E., Lafon, J.M., and Scheller, T., 1992, Geocronologia Pb-Pb da Província Mineral de Carajás [ab.]: Congresso Brasileiro de Geologia, XXXVII, Sao Paulo, Sociedade Brasilaira de Geologia, Primeiros Resultados, p. 183–184.

Santos, J.O.S., Groves, D.I., Hartmann, L.A., Moura, M.A., and McNaughton, N.J., 2001, Gold deposits of the Tapajós and Alta Floresta domains, Tapajós-Parima orogenic belt, Amazon craton, Brazil: Mineralium Deposita, v. 36, p. 278–299.[CrossRef][Web of Science][GeoRef]

Silva, C.M.G., and Villas, R.N., 1998, The Águas Claras Cu-sulfide ± Au deposit, Carajás region, Pará, Brazil: Geological setting, wall-rock alteration and mineralizing fluids: Revista Brasileira de Geociências, v. 28, p. 315–326.[GeoRef]

Skirrow, R.G., ands Walshe, J.L., 2002, Reduced and oxidized Au-Cu-Bi iron oxide deposits of the Tennant Creek inlier, Australia: An integrated geologic and chemical model: Economic Geology, v. 97, p. 1167–1202.[Abstract/Free Full Text][CrossRef][Web of Science][GeoRef]

Smith, J.B., Barley, M.E., Groves, D.I., Krapez, B., McNaughton, N.J., Bickle, M.J., and Chapman, H.J., 1998, The Scholl shear zone, West Pilbara: Evidence for a domain boundary structure from integrated tectonostratigraphic analyses, SHRIMP U-Pb dating and isotopic and geochemical data of granitoids: Precambrian Research, v. 88, p. 143–171.[CrossRef][Web of Science][GeoRef]

Soares A.D.V., Santos, A.B., Vieira, E.A., Bella, V.M., and Martins, L.P.B., 1994, Área Águas Claras: Contexto geológico e mineralizações: Simpósio de Geologia da Amazônia, IV, Belém, Sociedade Brasileiro de Geologia, Bulletin, p. 379–382.

Soares, A.D.V., Ronzê, P.C., Santos, M.G.S., Leal, E.D., and Barreira, C.F., 1999, Geologia e mineralizações do depósito de Cu-Au Alemão-Província Mineral de Carajás (PA): Simpósio de Geologia da Amazônia: Manaus, VI, Sociedade Brasileira de Geologia, Proceedings, p. 144–147.

Souza, S.R.B., Macambira, M.J.B., and Scheller, J., 1996, Novos dados geocronológicos para os granitos deformados do Rio Itacaiunas (Serra dos Carajás, PA): implicações estratigráfica [ext. abs.]: Simpósio de Geologia da Amazônia, V, Belém, Sociedade Brasileira de Geologia, Extended Abstracts Bulletin, p. 380–383.

Slack, J.F., 1993, Descriptive and grade-tonnage models for Besshi-type massive sulphide deposits: Geological Association of Canada Special Paper 40, p. 343–371.

Tallarico, F.H.B., Rego, J.L., and Oliveira, C.G., 1998, A mineralização de Au-Cu de Igarapé Bahia-Carajás: Um depósito da classe óxido de Fe (Cu-U-Au-ETR) [abs.]: Congresso Brasileiro de Geologia, XL, Belo Horizonte, Sociedade Brasileira de Geologia, Proceedings, p. 116.

Tallarico, F.H.B., Oliveira, C.G., and Figueiredo, B.R., 2000, The Igarapé Bahia Cu-Au mineralization, Carajás province: Revista Brasileira de Geociências, v. 30, p. 230–233.

Tallarico, F.H.B., McNaughton, N.J., Groves, D.I., Fletcher, I.R., Figueiredo, B.R., Carvalho, J.B., Rego, J.L., and Nunes, A.R., 2004, Geological and SHRIMP II U-Pb constraints on the age and origin of the Breves Cu-Au-(W-Bi-Sn) deposit, Carajás, Brazil: Mineralium Deposita, v. 39, p.68–86.[CrossRef][Web of Science][GeoRef]

Tassinari, C.C.G., and Macambira, M.J.B., 1999, Geochronological provinces of the Amazonian craton: Episodes, v. 22, p. 174–182.[Web of Science][GeoRef]

Tazava, E., 1999, Mineralização de Au-Cu-(±ETR-U) associada às brechas hidrotermais do depósito de Igarapé; Bahia, Província Mineral de Carajás, PA: Unpublished M.Sc. thesis, Ouro Preto, Brazil, Universidade Federal de Ouro Preto, 81 p.

Tolbert, G.E., Tremaine, J.W., Melcher, G.C., and Gomes, C.B., 1971, The recently discovered Serra dos Carajás iron deposit, northern Brazil: Economic Geology, v. 66, p. 985–994.[Abstract/Free Full Text][CrossRef][GeoRef]

Trendall, A.F., Basei, M.A.S., De Laeter, J.R., and Nelson, D.R., 1998, SHRIMP zircon U-Pb constraints on the age of the Carajás Formation, Grão Pará Group, Amazon Craton: Journal of South American Earth Sciences, v. 11, p. 265–277.[CrossRef][Web of Science][GeoRef]

Valarelli, J.V., Bernardeli, A., and Beisiegel, W.R., 1978, Aspectos genéticos do minério de manganês do Azul: Congresso Brasileiro de Geologia, XXX, Sao Paulo, Sociedade Brasileira de Geologia, Proceedings, p. 1670–1679.

Vieira, E.A.P., Saueressig, R., Siqueira, J.B., Silva, E.R.P., Rego, J.L., and Castro, F.D.C., 1988, Caracterização geológica da jazida polimetálica do Salobo 3A – reavaliação: Congresso Brasileiro de Geologia, XXXV, Belém, Sociedade Brasileira de Geologia, Anexo aos Anais, p. 97–114.

Villas, R.N., and Santos, M.D., 2001, Gold deposits of the Carajás mineral province: Deposit types and metallogenesis: Mineralium Deposita, v. 36, p. 300–331.[CrossRef][Web of Science][GeoRef]

Veizer, J., and Compston, W., 1976, ⁸⁷Sr/⁸⁶Sr in Precambrian carbonates as an index of crustal evolution: Geochimica et Cosmochimica Acta, v. 40, p. 905–914.[CrossRef][Web of Science][GeoRef]

Williams, I.S., and Claesson, S., 1987, Isotopic evidence for the Precambrian provenance and Caledonian metamorphism of high grade paragneisses from the Steve Nappes, Scandanavian Caledonides, II. Ion microprobe zircon U-Th-Pb: Contributions to Mineralogy and Petrology, v. 97, p. 205–217.[CrossRef][Web of Science][GeoRef]

Williams, P.J., 1998, An introduction to the metallogeny of the McArthur River-Mount Isa-Cloncurry mineral provinces: Economic Geology, v. 93, p. 1120–1131.[Abstract/Free Full Text][CrossRef][Web of Science][GeoRef]

Wirth, K.R., Gibbs, A.K., and Olszewski, W.J., 1986, U-Pb ages of zircons from the Grão-Pará Group and Serra do Carajás Granite, Pará, Brazil: Revista Brasileira de Geociências, v. 16, p. 195–200.[GeoRef]

Zang, W., and Fyfe, W.S., 1993, A three-stage genetic model for the Igarapé Bahia lateritic gold deposit, Carajás, Brazil: Economic Geology, v. 88, p. 1768–1779.[Abstract/Free Full Text][CrossRef][GeoRef]

This article has been cited by other articles:

				R. P. Xavier, M. Wiedenbeck, R. B. Trumbull, A. M. Dreher, L. V.S. Monteiro, D. Rhede, C. E.G. de Araujo, and I. Torresi Tourmaline B-isotopes fingerprint marine evaporites as the source of high-salinity ore fluids in iron oxide copper-gold deposits, Carajas Mineral Province (Brazil) Geology, September 1, 2008; 36(9): 743 - 746. [Abstract] [Full Text] [PDF]

				M. Hitzman, M. W. Hitzman, and R. K. Valenta URANIUM IN IRON OXIDE-COPPER-GOLD (IOCG) SYSTEMS Economic Geology, December 1, 2005; 100(8): 1657 - 1661. [Abstract] [Full Text] [PDF]

				D. I. Groves, R. M. Vielreicher, R. J. Goldfarb, and K. C. Condie Controls on the heterogeneous distribution of mineral deposits through time Geological Society, London, Special Publications, January 1, 2005; 248(1): 71 - 101. [Abstract] [PDF]

This Article Abstract Figures Only Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in ISI Web of Science Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Tallarico, F. H. B. Articles by Rego, J. L. Search for Related Content GeoRef GeoRef Citation