The Sediment-Hosted Stratiform Copper Ore System

Hitzman, Murray W.; Kirkham, R V; Broughton, David; Thorson, Jon P.; Selley, D

doi:10.5382/av100.19

Cited by 95 publications

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“…The mineralization is also observed in brecciated and faulted lithotypes occurring mainly in the lower part of the Kundelungu Group (Figure 1). The primary stratiform Cu-Co sulfide mineralization is early syn-diagenetic (Dewaele et al, 2006;El Desouky et al, 2010;Muchez et al, 2008) and occurred around 820 Ma (Selley et al, 2005) and/or after ~750 Ma (Hitzman et al, 2005). Later mineralization events took place before or during the pan-African Lufilian folding (Cailteux et al, 2005;Decrée et al, 2011;Decrée et al, 2014;Dewaele et al, 2006;El Desouky et al, 2009;Haest and Muchez, 2011;Haest et al, 2007;Haest et al, 2009;Kampunzu et al, 2009).…”

Section: Geological Settingmentioning

confidence: 99%

Rare earth element fractionation in heterogenite (CoOOH): implication for cobalt oxidized ore in the Katanga Copperbelt (Democratic Republic of Congo)

Decrée

Pourret

Baele

2015

Journal of Geochemical Exploration

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Heterogenite (CoOOH) is the most abundant cobalt oxide mineral in the Katanga Copperbelt, which hosts around half of the world's known reserves of mineable cobalt. Heterogenite formed by the oxidation of Co-sulfides and accumulated as residual deposits during a Pliocene weathering event. Bulk analysis samples of oxidized cobalt ore samples containing with variable heterogenite concentration display two rare earth element (REE) patterns: (i) Type 1 is enriched in middle REE, with a negative cerium anomaly and a relatively low REE content; (ii) Type 2 is variably enriched in light REE (LREE), without a cerium anomaly and *Revised Manuscript with No Changes Marked Click here to view linked References with higher REE content. However, in situ LA-ICP-MS reveals that the Type patterns are due to the mixing of heterogenite with a LREE-rich mineral. Weathering processes leading to heterogenite formation mainly consist of water-rock interactions at high Co activity, in the near-surface environment. These result in the formation of a lateritic deposit. Heterogenite precipitates at near-neutral pH conditions together with manganese oxides. REE are mainly fractionated between these Co-and Mn-oxide minerals. In the deeper part of the oxidized profile, cobalt activity decreases and the heterogenite stability field shifts to alkaline pH conditions due to the dissolution of dolostone in the bedrock. In such an alkaline environment, REE speciation is mainly driven by carbonate complexation/precipitation. This environment would be favorable for the formation of REErich carbonate which is intimately associated with heterogenite (LREE-rich Type 2 patterns). The combined whole-rock and in situ geochemical analyses presented here clearly help (1) to distinguish the REE signature of the Co oxidized ore (mineral paragenesis comprizing heterogenite) and of heterogenite itself, and subsequently (2) to highlight two different chemical environments for the formation of heterogenite in supergene ores. This study therefore improves the understanding of REE behaviour and metal mobility in nearsurface environments, and more particularly in environments where the supergene ores form. In the future, the approach developped here can be applied to other Co-Ni-Mn lateritic deposits such as those in New-Caledonia and Cameroon.

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Section: Geological Settingmentioning

confidence: 99%

Rare earth element fractionation in heterogenite (CoOOH): implication for cobalt oxidized ore in the Katanga Copperbelt (Democratic Republic of Congo)

Decrée

Pourret

Baele

2015

Journal of Geochemical Exploration

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“…Los resultados microtermométricos que se presentan en este trabajo, junto con datos reportados en por González-Sánchez et al (2009), García-Alonso et al (2011), Chadouli et al (2014) y De la O Burrola et al (2014), denotan una actividad termobárica que abarca desde la diagénesis al metamorfismo para las rocas siliciclásticas de las cuencas de Chihuahua y Sabinas. Así, en el caso del yacimiento de Las Vigas, las características de los fluidos de inclusiones son compatibles con salmueras de cuenca, habiéndose generado durante la transformación diagenética a metamórfica de los sedimentos donde están involucrados fenómenos de termorreducción, y disolución de sales y sulfatos (Rose, 1976(Rose, , 1989Galloway, 1982;Livnat et al, 1983;Sverjensky, 1986;Brown, 1992;Hitzman et al, 2005;Chadouli et al, 2014).…”

Section: Origen De Los Fluidos Mineralizantes Del Azufre Y De Los Meunclassified

“…Es un hecho conocido que en las cuencas hidrológicas cerradas puede producirse una circulación convectiva de salmueras sedimentarias, con la consiguiente lixiviación de metales. En particular, en presencia de acuitardos sobre lechos rojos, se favorece el desarrollo de diferencias en densidad debido a las variaciones de temperatura y salinidad (Hitzman et al, 2005), de lo que resulta una convección por las diferencias de densidad así generadas. De este modo, puede generarse la lixiviación de metales en series clásticas y la concentración de éstas en las salmueras sedimentarias, mientras que la precipitación de los sulfuros puede producirse en múltiples etapas con presencia de agentes reductores (Lovering, 1963).…”

Section: Origen De Los Fluidos Mineralizantes Del Azufre Y De Los Meunclassified

“…Además, son importantes debido a que pueden contener concentraciones significativas de otros metales como Ag y Co y, en menor grado, de Zn, Pb y U (Brown, 1992(Brown, , 1997(Brown, , 2003. Ocasionalmente también pueden presentar concentraciones importantes de Au, V y elementos del grupo del platino (EGP) (Hitzman, 2000;Hitzman et al, 2005). En general, los depósitos de tipo Kupferschiefer tienden a ser de mayores dimensiones y presentar un mayor interés económico que los depósitos asociados a lechos rojos.…”

Section: Introductionunclassified

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Modelo de formación de los yacimientos estratoligados de Cu en lechos rojos de Las Vigas (Chihuahua, México)

Gonzáléz-Partida

Camprubí

Pironon

et al. 2017

BSGM

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In the tract of the Chihuahua and Sabina intracratonic basins, stratabound copper deposits are systematically hosted by siliciclastic rocks of the Las Vigas, San Marcos and Huizachal formations. The deposits in the Las Vigas area, Chihuahua, occur in the upper part of the Valanginian-Hauterivian Las Vigas Formation, which is conformably overlain by gypsum and limestones of the Barremian La Virgen Formation. Other local evaporites are those found in the Jurassic La Casita Formation. The Las Vigas stratabound copper deposit was mined with grades between 2 and 4 % Cu and occasional grades of 1 g/t Au and 80 to 100 g/t Ag in four 1 to 4 m-thick mantos. The hypogene metallic minerals in this deposit are chalcopyrite, bornite, pyrite, sphalerite and galena, along with quartz and calcite, mostly as disseminations. Notably, part of these ores occurs as replacements of fossil tree logs (m-sized) that contain the same minerals as mantos. The close examination of fossil tree logs emphasizes the epigenetic and stratabound character of copper ores. Representative fluid inclusion associations were studied in calcite and quartz from mantos, lenses and fossil logs. Fluid inclusions contain halite, calcite and chalcopyrite daughter crystals, as determined by means of Raman microspectroscopy. The calculated salinity of mineralizing fluids ranges between 16.6 and 32.0 wt. % NaCl equiv., temperatures of homogenization range between 104º and 205 ºC, and relevant N 2 , CO, CO 2 and CH 4 contents were determined. δ 34 S VCDT values in chalcopyrite range between-12.0 and 13.7 ‰. These values are compatible with sedimentary or metasedimentary sources for sulfur, significant amounts of sulfates that were leached from evaporites, besides the occurrence of bacteriogenic sulfate reduction processes orthe interaction of mineralizing fluids with organic matter. δ 13 C VPDB and δ 18 O VSMOW values in hydrothermal calcite range between-7.96 and-0.71 ‰ and between 22.38 and 26.39 ‰, respectively; these are compatible with a trend in diagenesis due to burial of marine sediments, much alike MVT deposits in Coahuila and Texas. The above data indicate that mineralizing fluids in Las Vigas are basinal brines with minor meteoric inputs, which underwent convection within the siliciclastic series by means of differences in density as they dissolved evaporites of the overlying La Virgen Formation. Abundant organic matter in the Las Vigas Formation would have enabled mineral precipitation by means of sulfate reduction-such interpretation is supported by the occurrence of Cu ores along with silicification in fossil tree logs. As a consequence, the Las Vigas deposit is generically ascribed to the group of epigenetic copper deposits hosted by red-bed series that rim marine basins, or deposits of the Kupferschiefer type.

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“…Structurally controlled vein-type Cu deposits and sedimenthosted stratiform Cu (SSC) deposits commonly occur in the same district, such as in Kupferschiefer in Europe (R€ uckentype), the Zambian Cu belt in central Africa, and the Paradox Basin in North America (Hitzman et al 2005). These two types of mineralization are thought to be either cogenetic, that is, a basinal fluid origin (Morrison & Parry 1986;Breit & Meunier 1990) or to have different fluid origins (Vaughan et al 1989;Torrealday et al 2000).…”

Section: Introductionmentioning

confidence: 99%

Fluid inclusion and isotopic constraints on the origin of ore‐forming fluid of the Jinman–Liancheng vein Cu deposit in the Lanping Basin, western Yunnan, China

et al. 2015

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Extensive quartz-carbonate-Cu sulfide veins occur in clastic rocks and are spatially related to Paleocene granites in the western border of the Lanping Basin, western Yunnan, China. Abundant aqueous-carbonic fluid inclusions occur in these veins but their origin is debated. In the Jinman-Liancheng deposit, individual primary inclusion groups contain either exclusively liquid-rich inclusions (Gl), or coexisting liquid-rich and vapor-rich inclusions (Glv). Microthermometry and estimate of CO 2 content indicate that type Gl inclusions either have homogenization temperatures (Th) 238-263°C and contain c. 3.9-5.5 mole % CO 2 , or have Th 178-222°C and contain c. 1.6-3.2 mole % CO 2 . Type Glv inclusions are thought to represent samples of fluid unmixing that occurred at 183-218°C. At that time, the liquid phase in the unmixing fluid may contain c. 2.0-3.3 mole % CO 2 . As such, the correlation of CO 2 content with Th for type Gl inclusions is thought to be caused by fluid unmixing with decreasing temperature and subsequent CO 2 escape. indicate that the carbon and sulfur can be derived from (degassed) magma and/or nonmagmatic sources. The CO 2 -rich and magmatic-water-derived fluid at Jinman-Liancheng differs from the CO 2 -poor and basinally derived fluid in sediment-hosted stratiform Cu (SSC) deposits, which suggests that there are no genetic linkages between the vein Cu and SSC deposits in the Lanping Basin.

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The Sediment-Hosted Stratiform Copper Ore System

Cited by 95 publications

References 0 publications

Rare earth element fractionation in heterogenite (CoOOH): implication for cobalt oxidized ore in the Katanga Copperbelt (Democratic Republic of Congo)

Rare earth element fractionation in heterogenite (CoOOH): implication for cobalt oxidized ore in the Katanga Copperbelt (Democratic Republic of Congo)

Modelo de formación de los yacimientos estratoligados de Cu en lechos rojos de Las Vigas (Chihuahua, México)

Fluid inclusion and isotopic constraints on the origin of ore‐forming fluid of the Jinman–Liancheng vein Cu deposit in the Lanping Basin, western Yunnan, China

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