The Cerro Negro Mine, Chile: Manto-Type Copper Mineralization in a Volcaniclastic Environment

Elgueta, Sara; Hodgkin, A.; Rodríguez, Encarnación Puga; Schneider, Albrecht

doi:10.1007/978-3-642-88282-1_35

Cited by 6 publications

(3 citation statements)

References 6 publications

(5 reference statements)

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“…Thus, the types 2 and 3 deposits exhibit epigenetic modes of occurrence. In the case of the type 1 deposits, the mineralized zones are intimately associated with other modes of orebodies, such as veinlets and breccia fillings as the mineralization channel ways, and generally occur in permeable horizons favorable to mineralization (Camus, 1990; Elgueta et al , 1990). These features suggest that the type 1 deposits could also be epigenetic.…”

Section: Characteristics Of Alteration and Primary Mineralizationmentioning

confidence: 99%

“…Normally, host rocks in the vicinity of orebodies have experienced hydrothermal alteration genetically linked to primary copper mineralization. This event is commonly characterized by extensive sodic alteration (albitization) and consecutive calcic alteration of epidote, calcite, chlorite, sericite, Ca-amphibole (actinolite) and quartz ( Elgueta et al , 1990;Klohn et al , 1990;Wolf et al , 1990;Oyarzun et al , 1998;Kojima et al , 2003;Cisternas & Hermosilla, 2006 ). Moreover, pervasive potassic alteration as observed in the iron oxide -copper -gold (IOCG) deposits occurs in the Mantos Blancos deposit.…”

Section: Characteristics Of Alteration and Primary Mineralizationmentioning

confidence: 99%

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Genetic Aspects of the Manto‐type Copper Deposits Based on Geochemical Studies of North Chilean Deposits

2009

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Recent studies on mineralogy, geochronology, fl uid inclusion and stable isotope (Pb, Os, S, C, O, Sr) characteristics were reviewed to determine constraints for genetic models of the Chilean manto-type copper deposits. The Chilean manto-type deposits are divided into the two geologic categories of the northern areas (AricaIquique, Tocopilla -Taltal) and the central areas (Copiapó, La Serena, Santiago). The former is distributed in the coastal range composed of Jurassic andesite-dominated volcano-sedimentary piles and younger plutonic intrusions, and yields chalcocite (-digenite) and bornite as the principal hypogene copper sulfi des. The latter is hosted mostly in Lower Cretaceous volcano-sedimentary sequences, and has chalcopyrite-rich mineral associations. The fl uid inclusion data indicate that the primary copper mineralization was commonly generated in the temperature range 150 -360°C under low-pressure conditions near the boiling curve, mediated with relatively saline brines. Generally, homogeneous Pb and S isotope compositions for primary copper minerals imply direct magma source or leaching of igneous rocks. Pb and Os isotope data published for some deposits, however, suggest that ore-forming metals were derived mainly from the volcano-sedimentary host rocks. The noticeably negative isotope ratios of primary sulfi de sulfur and hydrothermal calcite carbon of some central area deposits indicate infl ux of sedimentary rock components, and the high 87 Sr/ 86 Sr initial ratios of hydrothermal calcite from the Tocopilla -Taltal area deposits imply contribution of the contemporaneous seawater or marine carbonates. These isotopic constraints imply a formation mechanism in which the Chilean manto-type copper deposits formed epigenetically in the process of hydrothermal interaction of non-magmatic surfacederived brine with the volcano-sedimentary host rocks, which is inferred to have been induced by a deepseated plutonic complex as the possible heat source.

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Section: Characteristics Of Alteration and Primary Mineralizationmentioning

confidence: 99%

Section: Characteristics Of Alteration and Primary Mineralizationmentioning

confidence: 99%

Genetic Aspects of the Manto‐type Copper Deposits Based on Geochemical Studies of North Chilean Deposits

2009

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“…North of Aconcagua Valley, Carter and Aliste (1962) defined a calcareous unit resting on the Tabón Member as the Ñilhue Member. This consists of thin-bedded limestone layers containing fossils of mollusks, fresh water clams, plant remains, and wood fragments, indicating a fresh water origin (Carter & Aliste, 1962;Elgueta et al, 1990;Sánchez, 1968). At the type locality, the reported thickness of the Ñilhue Member is 825 m (Carter & Aliste, 1962); however, given the considerably smaller thickness observed in other regions during this study and the structural complexity observed in the Ñilhue area, this thickness is possibly exaggerated due to structural repetitions.…”

Section: ñIlhue Member: Limestonesmentioning

confidence: 99%

The First Andean Compressive Tectonic Phase: Sedimentologic and Structural Analysis of Mid‐Cretaceous Deposits in the Coastal Cordillera, Central Chile (32°50′S)

2020

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We document the effects of major mid-Cretaceous to Late Cretaceous compression within the volcanic arc of the western Gondwanan margin. The thinned Early Cretaceous Andean margin underwent rapid thickening and shortening-related exhumation of magmatic arc rocks during compressional inversion of late Early Cretaceous intra-arc basins. Clastic sedimentary and volcanic rocks recording this phase of initial Andean shortening correspond to the Las Chilcas Formation and are interpreted to have been deposited in a proximal retro-arc position. A detailed analysis of these deposits reveals multiple periods during sustained compressional deformation throughout the latest Early and Late Cretaceous, from 105 to 83 Ma. This deformation is evidenced by the exhumation of older units in the Coastal Cordillera, together with the development of contractional structures and a strong sedimentary response involving deposition of approximately 3 km of synorogenic nonmarine clastic deposits of the Las Chilcas Formation. The structures and associated deposits suggest that the strongest uplift and deformation period occurred from 100 to 95 Ma, whereas subsequent Late Cretaceous deformation was less pronounced, possibly a result of eastward migration of deformation. This tectonic phase coincided with similar coeval synorogenic deposits in Chile and other Andean regions, which have been attributed to initial Andean shortening resulting from a major plate reorganization.

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Geological Characteristics of Stratabound Deposits Associated with Lacustrine Sediments, Central Chile

Camus¹

1990

Stratabound Ore Deposits in the Andes

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The Cerro Negro Mine, Chile: Manto-Type Copper Mineralization in a Volcaniclastic Environment

Cited by 6 publications

References 6 publications

Genetic Aspects of the Manto‐type Copper Deposits Based on Geochemical Studies of North Chilean Deposits

Genetic Aspects of the Manto‐type Copper Deposits Based on Geochemical Studies of North Chilean Deposits

The First Andean Compressive Tectonic Phase: Sedimentologic and Structural Analysis of Mid‐Cretaceous Deposits in the Coastal Cordillera, Central Chile (32°50′S)

Geological Characteristics of Stratabound Deposits Associated with Lacustrine Sediments, Central Chile

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