Geochemistry of Permian to Triassic igneous rocks from northern Chile (28º-30º15’S): Implications on the dynamics of the proto-Andean margin.

Coloma, Felipe; Valin, X.; Oliveros, Verónica; Vásquez, Paulina; Creixell, Christian; Salazar, Esteban; Ducea, Mihai N.

doi:10.5027/andgeov44n2-a03

Cited by 51 publications

(24 citation statements)

References 28 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The strong possibility that the subduction would have been active in northern Chile at least during the Late Triassic (Coloma et al., ; González et al., ; Oliveros et al., ; Poma et al., ; del Rey, Deckart, Arriagada, & Martínez, ), suggests that the slab‐pull would have played an important role as a driving mechanism of rifting at the southwestern margin of Gondwana during its early breakup. The oblique convergence required to sustain the sinistral transtension for the Domeyko Basin is in agreement with recent Triassic kinematic reconstructions (Matthews et al., ; Müller et al., ).…”

Section: Discussionmentioning

confidence: 99%

“…Even though continental subduction-related rifts are scarce in modern settings, they could have been far more common along the "Pangean rim of fire" developed during the Late Triassic (Hadlari, Midwinter, Poulton, & Matthews, 2017), where unique global tectonic conditions such as very low convergence rates and subduction of relatively old and cold oceanic plates Müller et al, 2016) would have favoured the development of continental rift basins (Schellart, 2005;Stephenson & Schellart, 2010) associated with contemporaneous arc magmatism along the northwestern (Busby-Spera, 1988) and southwestern (Coloma et al, 2017;González et al, 2018;Oliveros et al, 2017;Poma et al, 2014) Gondwana margins. The identification and study of those basins in the Triassic Gondwanean record is crucial to understand the processes that took place at the margin of the supercontinent during the early stages of its breakup (~200 Ma; Lamotte, Fourdan, Leleu, Leparmentier, & Clarens, 2015).…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

The synrift phase of the early Domeyko Basin (Triassic, northern Chile): Sedimentary, volcanic, and tectonic interplay in the evolution of an ancient subduction‐related rift basin

Espinoza

Montecino²,

Oliveros

et al. 2018

Basin Research

Self Cite

View full text Add to dashboard Cite

The geodynamic setting along the SW Gondwana margin during its early breakup (Triassic) remains poorly understood. Recent models calling for an uninterrupted subduction since Late Palaeozoic only slightly consider the geotectonic significance of coeval basins. The Domeyko Basin initiated as a rift basin during the Triassic being filled by sedimentary and volcanic deposits. Stratigraphic, sedimentological, and geochronological analyses are presented in order to determine the tectonostratigraphic evolution of this basin and to propose a tectonic model suitable for other SW Gondwana‐margin rift basins. The Domeyko Basin recorded two synrift stages. The Synrift I (~240–225 Ma) initiated the Sierra Exploradora sub‐basin, whereas the Synrift II (~217–200 Ma) reactivated this sub‐basin and originated small depocentres grouped in the Sierra de Varas sub‐basin. During the rift evolution, the sedimentary systems developed were largely controlled by the interplay between tectonics and volcanism through the accommodation/sediment supply ratio (A/S). High‐volcaniclastic depocentres record a net dominance of the syn‐eruptive period lacking rift‐climax sequences, whereas low‐volcaniclastic depocentres of the Sierra de Varas sub‐basin developed a complete rift cycle during the Synrift II stage. The architecture of the Domeyko Basin suggests a transtensional kinematic where N‐S master faults interacted with ~NW‐SE basement structures producing highly asymmetric releasing bends. We suggest that the early Domeyko Basin was a continental subduction‐related rift basin likely developed under an oblique convergence in a back‐arc setting. Subduction would have acted as a primary driving mechanism for the extension along the Gondwanan margin, unlike inland rift basins. Slab‐induced dynamic can strongly influence the tectonostratigraphic evolution of subduction‐related rift basins through controls in the localization and style of magmatism and faulting, settling the interplay between tectonics, volcanism, and sedimentation during the rifting.

show abstract

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

The synrift phase of the early Domeyko Basin (Triassic, northern Chile): Sedimentary, volcanic, and tectonic interplay in the evolution of an ancient subduction‐related rift basin

Espinoza

Montecino²,

Oliveros

et al. 2018

Basin Research

Self Cite

View full text Add to dashboard Cite

show abstract

“…This particular tectonic scenario is known as the 'Pre-Andean' cycle and has been traditionally interpreted as a period of arrested subduction and extensive crustal reworking and anatexis, due to basalt underplating at the base of the thinned lithosphere (Mpodozis and Kay 1992;Llambías and Sato 1995). More recently though, several authors have questioned this model in light of new geochemical, petrological, geochronological and geological data, arguing that subduction may have persisted throughout the Late Paleozoic and the Mesozoic, making southwestern Gondwana a long-lived convergent margin (del Rey et al 2016;Coloma et al 2017;González et al 2018;Oliveros et al 2020). Recent global reconstructions also support the idea of an active subduction zone for western Pangea and Gondwana since the Carboniferous (Matthews et al 2016;Riel et al 2018).…”

Section: The Gondwana Cycle and Pre-andean Stagementioning

confidence: 99%

“…Some Norian-Rhaetian intrusive units, however, are monzogranite (e.g. the Algodones, La Estrella and Pichilemu plutons; Vásquez et al 2011;Coloma et al 2017). Bimodal plutonic complexes such as the Limarí Complex (Parada et al 1999) have mafic and intermediate lithologies but also lack granite intrusive compositions.…”

Section: Early Andean Magmatism (200-100 Ma)mentioning

confidence: 99%

Igneous Rock Associations 25. Pre-Pliocene Andean Magmatism in Chile

Oliveros

Moreno-Yaeger

Flores

2020

View full text Add to dashboard Cite

Andean-type magmatism and the term ‘andesite’ are often used as the norm for the results of subduction of oceanic lithosphere under a continent, and the typical rock formed. Although the Andes chain occupies the whole western margin of South America, the most comprehensively studied rocks occur in the present-day Chilean territory and are the focus of this paper. Andean magmatism in this region developed from the Rhaetian-Hettangian boundary (ca. 200 Ma) to the present and represents the activity of a long-lived continental magmatic arc. This paper discusses Pre-Pleistocene volcanic, plutonic, and volcano-sedimentary rocks related to the arc that cover most of the continental mass of Chile (between the Pacific coast and the High Andes) between the latitudes of 18° and 50°S. They comprise most of the range of sub-alkaline igneous rocks, from gabbro to monzogranite and from basalt to rhyolite, but are dominated by the tonalite-granodiorite and andesite example members. Variations in the petrographic characteristics, major and trace element composition and isotopic signature of the igneous rocks can be correlated to changes in the physical parameters of the subduction zone, such as dip angle of the subducting slab, convergence rate and angle of convergence. Early Andean magmatic products (Jurassic to Early Cretaceous) are found along the Coastal Cordillera in the westernmost part of the Andes. The rock record of the subsequent stages (Late Cretaceous, Paleocene–Early Eocene, Middle Eocene–Oligocene, Miocene) is progressively shifted to the east, reflecting migration of the magmatic front towards the continent. Tectonic segmentation of the convergent margin, as attested by the magmatic record, may have occurred throughout the Andean life span but it is particularly evident from the Eocene onwards, where the evolution of the northern part of the Chilean Andes (north of 27°S latitude) is very different to that of the southern segment (south of 27°S latitude). RÉSUMÉLe magmatisme de type andin et le terme « andésite » sont souvent les appellations utilisées pour décrire les résultats de la subduction de la lithosphère océanique sous un continent, et la roche typique formée. Bien que la chaîne des Andes occupe toute la marge ouest de l'Amérique du Sud, les roches les plus étudiées se trouvent dans le territoire chilien actuel et sont l'objet de cet article. Le magmatisme andin dans cette région s'est développé depuis la limite rhéto-hettangienne (environ 200 Ma) jusqu'à aujourd'hui et représente l'activité d'un arc magmatique continental persistant. Cet article a pour sujet les roches volcaniques, plutoniques et volcano-sédimentaires du pré-Pléistocène liées à l'arc qui couvrent la majeure partie de la masse continentale du Chili (entre la côte du Pacifique et les Hautes Andes) entre les latitudes de 18° et 50°S. Elles comprennent la majeure partie de la gamme de roches ignées sous-alcalines, du gabbro à la monzogranite et du basalte à la rhyolite, mais sont dominées par des roches de type tonalite-granodiorite et andésite. Les variations des caractéristiques pétrographiques, de la composition des éléments majeurs et traces et de la signature isotopique des roches ignées peuvent être corrélées aux changements des paramètres physiques de la zone de subduction, tels que l'angle de pendage de la plaque plongeante, le taux de convergence et l'angle de convergence. Les premiers produits magmatiques andins (du Jurassique au Crétacé inférieur) se trouvent le long de la Cordillère de la Côte dans la partie la plus occidentale des Andes. La succession de roche des stades suivants (Crétacé supérieur, Paléocène – Éocène inférieur, Éocène moyen – Oligocène, Miocène) est progressivement déplacée vers l'est, reflétant la migration du front magmatique vers le continent. La segmentation tectonique de la marge convergente, comme l'attestent les enregistrements magmatiques, peut avoir eu lieu tout au long de la formation des Andes, mais elle est particulièrement évidente à partir de l'Éocène, où l'évolution de la partie septentrionale des Andes chiliennes (au nord de 27°S de latitude) est très différente de celle du segment méridional (sud de 27°S de latitude).

show abstract

“…1b), the former considered Late Permian in age by Marcos et al (1971). These volcanic rocks are now assigned to the Guanaco Sonso Formation, of Late Permian-Early Triassic age (Martin et al, 1999;Coloma et al, 2017), which is widespread along the Chilean side of the international border, west of Josemaría (Martínez et al, 2015a). In the western parts of the Josemaría area, the Guanaco Sonso Formation comprises rhyolitic volcaniclastic rocks, including welded ignimbrite flows (Figs.…”

Section: Premineral Lithologiesmentioning

confidence: 99%

Geology of the Josemaría Porphyry Copper-Gold Deposit, Argentina: Formation, Exhumation, and Burial in Two Million Years

Sillitoe¹,

Devine²,

Sanguinetti³

et al. 2019

Economic Geology

View full text Add to dashboard Cite

The Josemaría porphyry copper-gold deposit is located in the Frontal Cordillera of San Juan Province, Argentina, near the present-day northern limit of the Chilean-Pampean flat-slab segment of the central Andes, and midway between the Maricunga and El Indio metallogenic belts. The deposit is centered on small, multiphase dacite porphyry intrusions that were emplaced at the contact between rhyolitic volcanic and tonalitic plutonic rocks of Late Permian to Triassic age. The earlier, more intensely quartz ± magnetite-veined porphyry phases and contiguous wall rocks display a telescoped sequence of alteration-mineralization zones, from shallow advanced argillic (mainly quartz-pyrophyllite) and underlying sericitic to deeper chlorite-sericite and minor remnant potassic. All the alteration types are mineralized, but the highest copper and gold grades are present as a low-arsenic, high-sulfidation assemblage in the quartz-pyrophyllite and sericitic zones. The outermost parts of the copper-gold zone are overlapped by a pronounced molybdenum-bearing annulus.New U-Pb zircon ages show that the deposit was formed at ~25 to 24.5 Ma, partially unroofed during continued NNE-striking, high-angle reverse faulting, and then unconformably overlain by red-bed conglomerate and sandstone capped by andesitic and dacitic tuff and lava. The andesite reported an age of ~22.35 Ma. A second, discrete pulse of currently undated, advanced argillic alteration, accompanied by minor high-sulfidation enargite mineralization, locally affected the southern periphery of the deposit, including its postmineral cover. Following erosional removal of the volcano-sedimentary strata from the northern and central parts of the deposit, the NNE-trending fault zone underwent minor normal displacement and localized economically significant supergene chalcocite enrichment. However, probably because of the rapidity of deposit unroofing, supergene processes were barely able to keep pace with erosion, resulting in a thin supergene profile over much of the exposed deposit. The southern part of the deposit remains beneath the postmineral cover and, hence, escaped the enrichment.Josemaría is unusual among the many central Andean porphyry copper deposits formed during rapid uplift because it preserves evidence for not only alteration-mineralization telescoping but also exceptionally rapid postmineral exhumation and subsequent burial beneath thick volcano-sedimentary cover. Unroofing of porphyry copper deposits in 1 to 2 m.y. is more typical of the high erosion rates that characterize pluvial tropical climates than the semiarid conditions that prevailed during and since the formation of Josemaría. Shell postdoctoral research fellow, he has operated for over 45 years as an independent consultant to more than 300 mining companies, international agencies, and foreign governments. He has worked on a wide variety of precious-, base-, and lithophile-metal deposits and prospects in 100 countries worldwide, but focuses primarily on the epithermal gold and porphyry copper enviro...

show abstract

Geochemistry of Permian to Triassic igneous rocks from northern Chile (28º-30º15’S): Implications on the dynamics of the proto-Andean margin.

Cited by 51 publications

References 28 publications

The synrift phase of the early Domeyko Basin (Triassic, northern Chile): Sedimentary, volcanic, and tectonic interplay in the evolution of an ancient subduction‐related rift basin

The synrift phase of the early Domeyko Basin (Triassic, northern Chile): Sedimentary, volcanic, and tectonic interplay in the evolution of an ancient subduction‐related rift basin

Igneous Rock Associations 25. Pre-Pliocene Andean Magmatism in Chile

Geology of the Josemaría Porphyry Copper-Gold Deposit, Argentina: Formation, Exhumation, and Burial in Two Million Years

Contact Info

Product

Resources

About