Late Jurassic bimodal magmatism in the northern sea-floor remnant of the Rocas Verdes basin, southern Patagonian Andes

Calderón, Mauricio; Fildani, Andrea; Hervé, Francisco; Fanning, Christopher; Weislogel, Amy L.; Cordani, Umberto G.

doi:10.1144/0016-76492006-102

Cited by 119 publications

(149 citation statements)

References 30 publications

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“…There, ophiolitic pillow lavas and tuffs, sheeted dykes and gabbros, which are exposed through north-trending thrusts, are associated with abundant silicic lavas and pyroclastic rocks interbedded in the western areas with marine sediments (Stern et al 1976;Mukasa and Dalziel 1996;Stern and de Wit 2003). Recent U-Pb zircon dates constrained the initiation of the 'rocas verdes' extensional basin age to 152-147 Ma (Calderón et al 2007). Basalt geochemistry indicates typical oceanic tholeiites to transitional-type basalts and associated differentiates (Stern et al 1976).…”

Section: Rocas Verdes Basinmentioning

confidence: 99%

The tectonic regime along the Andes: Present‐day and Mesozoic regimes

Ramos¹

2009

Geological Journal

217

138

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The analyses of the main parameters controlling the present Chile-type and Marianas-type tectonic settings developed along the eastern Pacific region show four different tectonic regimes: (1) a nearly neutral regime in the Oregon subduction zone; (2) major extensional regimes as the Nicaragua subduction zone developed in continental crust; (3) a Marianas setting in the Sandwich subduction zone with ocean floored back-arc basin with a unique west-dipping subduction zone and (4) the classic and dominant Chile-type under compression. The magmatic, structural and sedimentary behaviours of these four settings are discussed to understand the past tectonic regimes in the Mesozoic Andes based on their present geological and tectonic characteristics. The evaluation of the different parameters that governed the past and present tectonic regimes indicates that absolute motion of the upper plate relative to the hotspot frame and the consequent trench roll-back velocity are the first order parameters that control the deformation. Locally, the influences of the trench fill, linked to the dominant climate in the forearc, and the age of the subducted oceanic crust, have secondary roles. Ridge collisions of seismic and seismic oceanic ridges as well as fracture zone collisions have also a local outcome, and may produce an increase in coupling that reinforces compressional deformation. Local strain variations in the past and present Andes are not related with changes in the relative convergence rate, which is less important than the absolute motion relative to the Pacific hotspot frame, or changes in the thermal state of the upper plate. Changes in the slab dip, mainly those linked to steepening subduction zones, produce significant variations in the thermal state, that are important to generate extreme deformation in the foreland.

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Section: Rocas Verdes Basinmentioning

confidence: 99%

The tectonic regime along the Andes: Present‐day and Mesozoic regimes

Ramos¹

2009

Geological Journal

217

138

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“…It is not necessary to invoke a marginal basin in this setting, as this mixture of movements was an expression of major plate motions between east and west Gondwana; they are mirrored on the conjugate margin in the Weddell Sea (Kristoffersen and Haugland, 1986) and are independently predicted by completion of the plate circuit in Gondwana (Eagles and Vaughan, 2009). Although their plate kinematic histories are less well constrained, the Rocas Verdes basinal remnants preserved further west in the Tortuga and Sarmiento complexes of Tierra del Fuego may represent more westerly reaches of the same boundary, given their similar ages (Mukasa and Dalziel, 1996;Calderón et al, 2007).…”

Section: Basin Floormentioning

confidence: 96%

“…1). Although the similarities are strong, it should be noted they are not prescriptive as they are also shared with the majority of the southern Patagonian Andes (Katz, 1963;Kraemer and Riccardi, 1997;Stern and de Wit, 2003;Calderón et al, 2007). The continental basement in both areas consists of pre mid-Jurassic metasedimentary rocks from accretionary settings (Dalziel and Elliot, 1971;Dalziel et al, 1975;Dalziel, 1982;Storey et al, 1977).…”

Section: Tectonostratigraphymentioning

confidence: 99%

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South Georgia and Gondwana's Pacific Margin: Lost in translation?

Eagles

2010

Journal of South American Earth Sciences

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“…3) area include Paleozoic igneous and metamorphic rocks (Söllner et al, 2000;Hervé et al, 2010). These rocks are unconformably covered by volcanic and volcaniclastic rocks of the Tobífera Formation (Thomas, 1949;Flores et al, 1973), which filled grabens and hemigrabens in a volcano-tectonic rift formed in the region (SW Gondwana) during the Late Jurassic (Wilson, 1991;Calderón et al, 2007). The Tobífera Formation is unconformably covered by Lower Cretaceous sedimentary rocks deposited during continued extension, which led to the evolution of the prior volcano-tectonic rift into FIG.…”

Section: Stratigraphymentioning

confidence: 99%

Evaluación de variaciones en el grado de deformación y el estilo estructural a lo largo del frente de la faja corrida y plegada Fueguina, Argentina.

Carbonell

Dimieri

Olivero

2013

Andgeo

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ABSTRACT. The Fuegian thrust-fold belt (TFB) forms the thin-skinned outer wedge of the Andes in Tierra del Fuego. Using subsurface and outcrop data from two areas (Western and Eastern) of the TFB front in Argentina we aimed to verify and characterize the apparent structural variations along the strike. Both areas reveal pro-and retro-vergent faultrelated folds detached at similar horizons, with a youngest early to middle (?) Miocene deformation age. However, the Western Area has gentle, large-wavelength folds whereas the Eastern Area is characterized by a very tight structural geometry, with closer fold geometries. This difference manifests itself in the shortening of analogous structures: below 5.5% in the west as against ~22% in the Eastern Area. Our findings verify structural style variations along the strike and suggest that the Eastern Area endured higher strain. We evaluate two possible causes of this strain gradient, assuming homogeneous regional shortening: (i) lateral rheological variations at the base of the thrust wedge, namely the occurrence of more competent beds which would have restrained the propagation of the detachment toward the east; and (ii) the effect of strong buttressing in the eastern TFB exerted by the Río Chico arch basement promontory during deformation. Published results, together with our current subsurface and outcrop data, rule out significant rheological gradients in a preferred direction along the TFB. On the other hand, we present evidence of the nucleation of frontal thrusts above basement steps at the Río Chico arch western margin, which comprise local buttresses. We speculate that this buttressing was mantained along the TFB front and is enhanced toward the east, where forward TFB propagation was hindered due to the southern projection of the Río Chico promontory. This would explain the higher strain and more complex structural style in the Eastern Area. 439Torres Carbonell et al. / Andean Geology 40 (3): 438-457, 2013 RESUMEN. Evaluación de variaciones en el grado de deformación y el estilo estructural a lo largo del frente de la faja corrida y plegada Fueguina, Argentina. La faja corrida y plegada Fueguina (FCP) comprende el cinturón de piel fina en el antepaís de los Andes en Tierra del Fuego. Con la finalidad de verificar y caracterizar posibles variaciones estructurales a lo largo del frente de la FCP en Argentina, hemos analizado datos de subsuelo y superficie en dos áreas (occidental y oriental). Ambas revelan pliegues relacionados con fallas, tanto provergentes como retrovergentes, que despegan en niveles similares, y tienen una edad mínima miocena temprana a media (?). Sin embargo, en el área occidental el plegamiento es suave y de alta longitud de onda mientras que en el área oriental la estructura es muy apretada, con pliegues más cerrados. Esta diferencia se manifiesta al comparar el acortamiento en estructuras análogas: menor a 5,5% en el oeste contra ~22% en el área oriental. Por lo tanto, queda verificada la existencia de variaciones en el estilo estructur...

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Late Jurassic bimodal magmatism in the northern sea-floor remnant of the Rocas Verdes basin, southern Patagonian Andes

Cited by 119 publications

References 30 publications

The tectonic regime along the Andes: Present‐day and Mesozoic regimes

The tectonic regime along the Andes: Present‐day and Mesozoic regimes

South Georgia and Gondwana's Pacific Margin: Lost in translation?

Evaluación de variaciones en el grado de deformación y el estilo estructural a lo largo del frente de la faja corrida y plegada Fueguina, Argentina.

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