Late Paleozoic to Jurassic silicic magmatism at the Gondwana margin: Analogy to the Middle Proterozoic in North America?

Kay, Suzanne Mahlburg; Ramos, Víctor A.; Mpodozis, Constantino; Sruoga, Patricia

doi:10.1130/0091-7613(1989)017<0324:lptjsm>2.3.co;2

Cited by 342 publications

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“…6). This stratigraphic variation enables us to deduce that the Lautaro Basin has undergone at least two extensional phases, which is consistent with the interpretations from Kay et al (1989), Mpodozis and Kay (1990) and Suárez and Bell (1992). b.…”

Section: Restored Section and Tectonic Shorteningsupporting

confidence: 72%

The Lautaro Basin: A record of inversion tectonics in northern Chile

Martínez

Arriagada

Mpodozis

et al. 2012

andgeo

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ABsTrACT. The Triassic and Jurassic tectonic history of northern Chile has been dominated by extension, although clear evidence about the nature and geometry of the extensional basins and subsequent inversion structures has been adequately illustrated in only a few cases. In this contribution we present a structural study of the Lautaro Basin located at the western edge of the Frontal Cordillera in the Atacama region of northern Chile. The Lautaro Basin is a Jurassic half-graben, filled by at least 2,600 m of marine deposits of the Lautaro Formation and developed on top of, at least 2,000 m of Triassic volcanic successions of the La Ternera Formation, also accumulated during an earlier period of extensional deformation. Detailed field mapping and construction of a regional balanced cross-section, supported by good exposures along the Copiapó River valley, allow reconstruction of the structural style of both the Jurassic and Triassic extensional depocenters. New structural data have shown that the Lautaro Basin has a complex structural framework reflected in two major Mesozoic extensional periods, overprinted by Cenozoic inversion involving thin-and thick-skinned tectonics. Shortening was accommodated by a combination of inversion of pre-existing normal faults, buttresses, development of footwall short-cuts, and both thin and thick-skinned thrusting. New estimates of shortening are up to 13.1 km (30%), while Mesozoic extension is estimated to be 3 km (7%). resuMen. La Cuenca Lautaro: un registro de inversión tectónica en el norte de Chile. Durante el Triásico y Jurá-sico la evolución tectónica del norte de Chile fue dominada por extensión cortical. No obstante, evidencias claras acerca del estilo estructural y subsecuente inversión de las cuencas asociadas con el evento extensional, han sido ilustradas en pocos casos. En este trabajo, se presenta un estudio estructural de la Cuenca Lautaro, localizada en el borde occidental de la Cordillera Frontal, en la región de Atacama del norte de Chile. La Cuenca Lautaro, es un hemigraben que aloja al menos 2.600 m de depósitos marinos de la Formación Lautaro, acumulados sobre al menos 2.000 m de sucesiones volcánicas triásicas de la Formación La Ternera. Los excelentes afloramientos de la región permitieron construir una sección balanceada y restaurar el estilo estructural de los depocentros extensionales triásicos y jurásicos. Los resultados obtenidos muestran que la Cuenca Lautaro tiene una arquitectura estructural compleja, reflejada en dos episodios extensionales mayores. Posteriormente, se sobreimpone al menos un evento de inversión tectónica que desarrolla una tectónica mixta de piel fina y piel gruesa. El acortamiento se acomoda por una combinación de inversión de fallas preexistentes, desarrollo de fallas de atajo y corrimientos de piel fina y piel gruesa, que involucran bloques rígidos o 'buttresses'. Las estimaciones de acortamiento son de 13,1 km (30%), mientras que la extensión mesozoica es de 3 km (7%).

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Section: Restored Section and Tectonic Shorteningsupporting

confidence: 72%

The Lautaro Basin: A record of inversion tectonics in northern Chile

Martínez

Arriagada

Mpodozis

et al. 2012

andgeo

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“…According to Martin et al (1999) Furthermore, Kay et al (1989) have suggested that the Late PaleozoicJurassic silicic magmatism erupted at the southwestern margin of GondwanaSouth America-was formed in an extensional setting without subduction.…”

Section: Accepted Manuscriptmentioning

confidence: 99%

Lower Pliensbachian caldera volcanism in high-obliquity rift systems in the western North Patagonian Massif, Argentina

Benedini

Gregori

Strazzere

et al. 2014

Journal of South American Earth Sciences

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“…Volcanism continued with the Early to Late Jurassic Chon Aike Province, that covers a wide area of Patagonia, from approximately 40ºS to 55ºS, and constitutes one of the world's most voluminous volcanic silicic provinces (Kay et al, 1989;Pankhurst et al 1998Pankhurst et al , 2000Riley and Leat, 1999;Riley et al, 2001). Volcanism spanned more than 30 Ma, but based on SHRIMP U-Pb zircon, Rb-Sr whole-rock and 40 Ar/ 39 Ar data, three episodes of peak activity have been recognized (Feraud et al, 1999;Pankhurst et al, 2000): a Toarcian-Aalenian episode, between 188-178 Ma, a Bajocian-Bathonian episode, between 172 and 162 Ma and an Oxfordian-Kimmeridgian episode, between 157 and 153 Ma.…”

Section: Fig 1 Sketch Geologic Map Of Patagonia Modified Aftermentioning

confidence: 99%

Cuenca de retroarco toarciana en Patagonia central (Chubut), Argentina: cierre, migracion del arco y ambiente tectonico durante el Jurasico Medio.

Suárez¹,

Márquez²

2007

Andgeo

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The Chubut Basin (new name for the 'Liassic Western Chubut Basin' of other authors), developed during the Early Jurassic in the western part of central extra-Andean Patagonia in Argentina (42º30'S and 44º30'S), accumulated shallow marine and continental sedimentary beds, with pyroclastic input, of the Osta Arena Formation and equivalent units. To the west it was bounded by a coeval subduction-related magmatic arc (Subcordilleran Plutonic Belt) and a subduction complex of Late Triassic-Early Jurassic age (Chonos Metamorphic Complex). In turn, the eastern basin floor developed over the remnants of a previous Late Triassic-earliest Jurassic magmatic arc (Batholith of Central Patagonia) and over neopaleozoic sedimentary rocks of an accretionary prism. To the east, the basin was limited by a Toarcian volcanic system associated to the Karroo plume. The western magmatic arc continued to the north, where it is represented by the Icalma Member of the Nacientes del Biobío Formation, bounding this time the Neuquén Basin developed to the east. The closure of the Toarcian basin in the Middle Jurassic coincides in time with a migration to the southwest of the Toarcian magmatic arc, from a position in central extra-Andean Patagonia and a NNW orientation, to a location in the Patagonian Cordillera and a north-south orientation. Synchronously, rift-related anatectic silicic volcanism developed east of the basin. Hence, a major change in tectonic setting took place during the Middle Jurassic. It is here proposed that the migration of the arc was related to the growth of a plume under north-eastern Patagonia.

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Late Paleozoic to Jurassic silicic magmatism at the Gondwana margin: Analogy to the Middle Proterozoic in North America?

Cited by 342 publications

References 0 publications

The Lautaro Basin: A record of inversion tectonics in northern Chile

The Lautaro Basin: A record of inversion tectonics in northern Chile

Lower Pliensbachian caldera volcanism in high-obliquity rift systems in the western North Patagonian Massif, Argentina

Cuenca de retroarco toarciana en Patagonia central (Chubut), Argentina: cierre, migracion del arco y ambiente tectonico durante el Jurasico Medio.

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