Submarine rhyolitic volcanism in a Jurassic proto-marginal basin; southern Andes, Chile and Argentina

Hanson, Richard E.; Wilson, T. J.

doi:10.1130/spe265-p13

Cited by 36 publications

(31 citation statements)

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“…The early extensional regime involved a rifting phase, related to the development of silicic volcanism in a wide region of southern South America (Bruhn, 1979;Hanson and Wilson, 1991) and to the opening of Rocas Verdes Marginal Basin, partially floored by oceanic crust (Katz, 1972;Dalziel et al, 1974). In the northern cratonic side of the marginal basin an Aptian-Maastrichtian succession of marine sedimentary rocks was deposited during tectonic quiescence (Biddle et al, 1986;Galeazzi, 1998); while in the southern edge of the basin a compressive regime prevailed since at least late Cretaceous .…”

Section: Regional Geologymentioning

confidence: 98%

Structure and evolution of the Fuegian Andes foreland thrust-fold belt, Tierra del Fuego, Argentina: Paleogeographic implications

Carbonell

Olivero

Dimieri

2008

Journal of South American Earth Sciences

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Section: Regional Geologymentioning

confidence: 98%

Structure and evolution of the Fuegian Andes foreland thrust-fold belt, Tierra del Fuego, Argentina: Paleogeographic implications

Carbonell

Olivero

Dimieri

2008

Journal of South American Earth Sciences

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“…Late Cretaceous lower-greenschist to upperamphibolite metamorphic mineral assemblages occur in both Paleozoic basement and Jurassic-Early Cretaceous cover rocks and reflect burial, prograde metamorphism, and subsequent uplift and exhumation of the Cordillera Darwin metamorphic complex and its cover during the Andean orogeny (Nelson et al, 1980;Kohn et al, 1993Kohn et al, , 1995Klepeis et al, 2010;Maloney et al, 2011;discussed in "Patagonian Fold-andThrust Belt, Magallanes Foreland Basin, and Mechanical Stratigraphy" section). Dalziel and Cortés, 1972;Natland, 1974;Bruhn et al, 1978;Dalziel, 1981;Gust et al, 1985;Hanson and Wilson, 1991;Pankhurst et al, 2000Pankhurst et al, , 2003. In southern Patagonia, Upper Jurassic mafic meta-igneous complexes, known as the Sarmiento and Tortuga complexes (Fig.…”

Section: Cordillera Darwin Metamorphic Complexmentioning

confidence: 98%

Along-strike variation in crustal shortening and kinematic evolution of the base of a retroarc fold-and-thrust belt: Magallanes, Chile 53°S-54°S

Betka¹,

Klepeis²,

Mosher³

2015

Geological Society of America Bulletin

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The Late Cretaceous closure of the Late Jurassic-Early Cretaceous Rocas Verdes basin resulted in the development of the Patagonian fold-and-thrust belt and Magallanes foreland basin between 50°S and 54.5°S. New geologic maps, structural data, and two retrodeformed, line-balanced cross sections from the Magallanes region of Chile (53°S-54°S) constrain the kinematic evolution and along-strike correlations of deformation that occurred at the base of the fold-and-thrust belt near the brittle-ductile transition. The stratigraphic architecture of the predecessor basin controlled the position of regional décollement levels. During the initial stage of closure (Albian-Campanian), the floor of the Rocas Verdes basin was imbricated and thrust onto the continental margin to form a regional décollement within Jurassic-Lower Cretaceous shale. Continued shortening resulted in the deepening of the décollement to a ductile shear zone that formed <1 km below the basement-cover contact. Ductile polyphase folding accommodated basement shortening and was mechanically decoupled from the overlying fold-and-thrust belt below the lower décollement. Ramps that cut Jurassic volcanic deposits linked the lower and upper décollements and transferred displacement into the nascent foreland basin. A second stage of shortening, characterized by basement-involved reverse faults that cut the early décollements, reflects complete closure of the Rocas Verdes basin by the Maastrichtian-Eocene. Coniacian to Eocene shortening estimates indicate a northwestsoutheast increase from 26% to 37% over 100 km along strike and are consistent with regional models of the Patagonian fold-andthrust belt. The results provide an important example of the kinematic evolution of the base of a retroarc fold-and-thrust belt in an "Andean-style" orogen.

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“…The eruption of large volumes of rhyolitic tuffs and the deposition of silicic volcaniclastic sediment of the Upper Jurassic Tobifera Formation accompanied rifting [Natland et al, 1974;Gust et al, 1985;Hanson and Wilson, 1991;Pankhurst et al, 2003], which occurred at least from ∼152 to ∼142 Ma . By the Early Cretaceous, the extension had formed the Rocas Verdes basin, a rift basin floored by quasi-oceanic crust [Katz, 1973;Dalziel et al, 1974, Dalziel, 1981Fildani and Hessler, 2005;Calderón et al, 2007].…”

Section: Late Jurassic Riftingmentioning

confidence: 99%

Continental underthrusting and obduction during the Cretaceous closure of the Rocas Verdes rift basin, Cordillera Darwin, Patagonian Andes

et al. 2010

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The Patagonian Andes record a period of Cretaceous‐Neogene orogenesis that began with the compressional inversion of a Late Jurassic rift called the Rocas Verdes basin. Detrital zircon ages from sediment that filled the southern part of the basin provide a maximum depositional age of ∼148 Ma, suggesting that the basin opened approximately simultaneously along its length during the Late Jurassic. Structural data and U‐Pb isotopic ages on zircon from granite plutons near the Beagle Channel (55°S) show that basin inversion involved two stages of shortening separated by tens of millions of years. An initial stage created a small (∼60 km wide) thrust wedge that placed the basaltic floor of the Rocas Verdes basin on top of adjacent continental crust prior to ∼86 Ma. Structures and metamorphic mineral assemblages preserved in an exhumed middle to lower crustal shear zone in Cordillera Darwin suggest that this obduction was accompanied by south directed subduction of the basaltic crust and underthrusting of continental crust to depths of ∼35 km beneath a coeval volcanic arc. A subsequent stage of out‐of‐sequence thrusting, culminating in the Paleogene, shortened basement and Upper Jurassic igneous rock in the internal part of the belt by at least ∼50 km, forming a bivergent thrust wedge. This latter period coincided with the exhumation of rocks in Cordillera Darwin and expansion of the fold‐thrust belt into the Magallanes foreland basin. This orogen provides an important example of how orogenesis initiated and led to continental underthrusting and obduction of basaltic crust during closure of a quasi‐oceanic rift basin.

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Submarine rhyolitic volcanism in a Jurassic proto-marginal basin; southern Andes, Chile and Argentina

Cited by 36 publications

References 0 publications

Structure and evolution of the Fuegian Andes foreland thrust-fold belt, Tierra del Fuego, Argentina: Paleogeographic implications

Structure and evolution of the Fuegian Andes foreland thrust-fold belt, Tierra del Fuego, Argentina: Paleogeographic implications

Along-strike variation in crustal shortening and kinematic evolution of the base of a retroarc fold-and-thrust belt: Magallanes, Chile 53°S-54°S

Continental underthrusting and obduction during the Cretaceous closure of the Rocas Verdes rift basin, Cordillera Darwin, Patagonian Andes

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