Tertiary Magmatic Evolution of the Maricunga Mineral Belt in Chile

Kay, Suzanne Mahlburg; Mpodozis, Constantino; Tittler, Andrew; Cornejo, Paula

doi:10.1080/00206819409465506

Cited by 78 publications

(50 citation statements)

References 28 publications

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“…Overall, the trace element characteristics of these Del Crestón andesites are those expected in a backarc setting behind a main volcanic front to the west (Kay et al, 1994). Their basic features are similar to those of Early Miocene volcanic rocks described by Kay et al (1988Kay et al ( , 1991 near 32.58 -338S latitude over the shallow subduction zone (Table 1).…”

Section: Geochemistry Of the Del Crestón Hornblende-bearing Andesite mentioning

confidence: 89%

Early Miocene andesite conglomerates in the Sierra de Famatina, broken foreland region of western Argentina, and documentation of magmatic broadening in the south Central Andes

Dávila

Astini

Jordan

et al. 2004

Journal of South American Earth Sciences

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Section: Geochemistry Of the Del Crestón Hornblende-bearing Andesite mentioning

confidence: 89%

Early Miocene andesite conglomerates in the Sierra de Famatina, broken foreland region of western Argentina, and documentation of magmatic broadening in the south Central Andes

Dávila

Astini

Jordan

et al. 2004

Journal of South American Earth Sciences

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“…Figure modified from Richards et al (2001). Mpodozis et al, 1995; Maricunga belt) crustal thickening, epithermal Au-Ag; deposits: compressional tectono-magmatic faults; intersection with NW-SE Kay et al, 1994Kay et al, , 1999 followed by uplift Clark et al, 1990; orogeny; 59-55 volcanics major tectono-magmatic cycle, intersection of major NW-SE Sandeman et al, 1995; Incaic I orogeny followed by shallowing of Incapuquio fault system and Zweng and Clark, 1995; subduction angle NNE-trending faults of the There is disagreement between Benevides-Cáceres (1999) and Noble and McKee (1999) over the timing of the Quechua orogenic pulses; the dates of Noble and McKee (1999) are reported here to be consistent with the dates of porphyry systems; (Benevides-Cáceres, 1999: 17 Ma Quechua I orogeny; smaller pulses at 8-7 Ma, 5-4 Ma, 2-1.6 Ma.) broadly compressional stress, primitive arc magmas pool at the base of the crust of the overriding plate and begin to develop a relatively narrow but linearly extensive MASH zone along the length of the proto-arc.…”

Section: Tectono-magmatic Cycles and Porphyry Cu Deposit Formationmentioning

confidence: 95%

Tectono-Magmatic Precursors for Porphyry Cu-(Mo-Au) Deposit Formation

2003

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Porphyry Cu-(Mo-Au) deposits are relatively rare but reproducible products of subduction-related magmatism. No unique processes appear to be required for their formation, although additive combinations of common tectono-magmatic processes, or optimization of these processes, can affect the grade and size as well as the location of the resulting deposits. These various contributing processes are reviewed, from partial melting in the mantle wedge overlying the subducting plate, through processes of magma interaction with the lithosphere, to mechanisms for magma emplacement and volatile exsolution in the upper crust. Specific ore-forming processes, such as magmatic-hydrothermal fluid evolution, are not discussed.Hot, hydrous, relatively oxidized, sulfur-rich mafic magmas (predominantly basalts) generated in the metasomatized mantle wedge above a subducting oceanic slab rise buoyantly to the base of the overlying crust where they stall due to density contrasts. Because these magmas are oxidized, sulfur is dominantly present as sulfate, and chalcophile elements such as Cu and Au are incompatible (i.e., they are retained in the melt). As these magmas begin to crystallize they release heat which causes partial melting of crustal rocks. Mixing between crustal-and mantle-derived magmas yields evolved (andesitic to dacitic), volatile-rich, metalliferous, hybrid magmas, which are of sufficiently low density to rise through the crust. Magma ascent is driven primarily by buoyancy forces and is dominantly a fracture-controlled phenomenon. As such, crustal stress and strain patterns play an important role in guiding the ascent of magma from the lower crust. In particular, translithospheric, orogen-parallel, strike-slip structures serve as a primary control on magma emplacement in many volcanic arcs worldwide. A feedback mechanism operates, whereby preexisting faults facilitate magma ascent, the heat from which further weakens the crust and focuses strain. Certain structural geometries, such as fault jogs, step-overs, and fault intersections, offer low-stress extensional volumes during transpressional strain. Such sites represent vertical conduits of relatively high permeability, up which magmas will preferentially ascend. Large upper crustal plutonic complexes may therefore be localized within these structural settings. Having delivered a sufficient volume of evolved, fertile arc magma to a focused position in the upper crust, magmatic fractionation, recharge, and volatile exsolution lead to the development of ore-forming magmatic-hydrothermal systems. To a first approximation, the size of the resulting deposit will be limited by the magma volume delivered to the upper crustal magma chamber. System-specific details such as magmatic-hydrothermal evolution, the nature of the country rocks, and subsequent erosional and weathering history will ultimately control the value of the deposit, but these factors fall outside the scope of this paper.

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“…Early models for explaining crustal thicknesses in the Central Andes appealed to subduction-related subcrustally derived magmas as the principal cause (Reymer Kay et al (1994aKay et al ( , 1994b, Soler & Jimenz (1993), and Richter et al (1995). "APVC" refers to Altiplano-Puna Volcanic Complex of de Silva (1989 Thorpe et al 1981).…”

Section: Role Of Magmatism In Crustal Thickeningmentioning

confidence: 99%

The Evolution of the Altiplano-Puna Plateau of the Central Andes

Allmendinger

Jordan²,

Kay³

et al. 1997

Annu. Rev. Earth Planet. Sci.

815

658

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▪ Abstract The enigma of continental plateaus formed in the absence of continental collision is embodied by the Altiplano-Puna, which stretches for 1800 km along the Central Andes and attains a width of 350–400 km. The plateau correlates spatially and temporally with Andean arc magmatism, but it was uplifted primarily because of crustal thickening produced by horizontal shortening of a thermally softened lithosphere. Nonetheless, known shortening at the surface accounts for only 70–80% of the observed crustal thickening, suggesting that magmatic addition and other processes such as lithospheric thinning, upper mantle hydration, or tectonic underplating may contribute significantly to thickening. Uplift in the region of the Altiplano began around 25 Ma, coincident with increased convergence rate and inferred shallowing of subduction; uplift in the Puna commenced 5–10 million years later.

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Tertiary Magmatic Evolution of the Maricunga Mineral Belt in Chile

Cited by 78 publications

References 28 publications

Early Miocene andesite conglomerates in the Sierra de Famatina, broken foreland region of western Argentina, and documentation of magmatic broadening in the south Central Andes

Early Miocene andesite conglomerates in the Sierra de Famatina, broken foreland region of western Argentina, and documentation of magmatic broadening in the south Central Andes

Tectono-Magmatic Precursors for Porphyry Cu-(Mo-Au) Deposit Formation

The Evolution of the Altiplano-Puna Plateau of the Central Andes

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