A review of the geology of the Argentinian Fuegian Andes

Olivero, Eduardo B.; Martinioni, Daniel Roberto

doi:10.1016/s0895-9811(01)00016-5

Cited by 110 publications

(107 citation statements)

References 32 publications

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“…In the study area subsurface, this succession is a very homogeneous shaly package (Flores et al, 1973;Biddle et al, 1986;Olivero and Martinioni, 2001) subdivided into several units known by both informal and formal nomenclature, as depicted in figure 3. None of these Cretaceous units crop out at the TFB front.…”

Section: Stratigraphymentioning

confidence: 99%

“…This basin formed due to foreland flexure during closure of the Late Cretaceous back-arc basin and subsequent growth of the Fuegian Andes (Biddle et al, 1986;Wilson, 1991;Olivero and Martinioni, 2001). While the Upper Cretaceous rocks are lithologicaly not very different from the Lower Cretaceous rocks (Flores et al, 1973;Olivero and Martinioni, 2001), the Cenozoic package, with a minimum thickness of 3,000 m at its thickest portions, is composed of interbedded conglomerates, sandstones and mudstones. These deposits form marine clastic wedges that evolved in synchrony with the advance of the TFB (Olivero and Malumián, 2008;Ponce et al, 2008;Torres Carbonell et al, 2009;Martinioni, 2010;Torres Carbonell, 2010).…”

Section: Stratigraphymentioning

confidence: 99%

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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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Section: Stratigraphymentioning

confidence: 99%

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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“…Craton-ward turbiditic and distal platform facies are interbedded with tuffs (Olivero and Martinioni 2001;Olivero et al 2009), while in the inner facies pillow lavas, lava flows and volcanic breccias are indicating the proximity to the magmatic arc (Suárez and Pettigrew 1976;Dalziel 1988). …”

Section: Rocas Verdes Basinmentioning

confidence: 99%

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

Ramos¹

2009

Geological Journal

227

139

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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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“…The main units exposed in this area belong to the Lemaire and Yahgán formations. The Lemaire Formation (Olivero et al, 1999;Olivero and Martinioni, 2001) consists of acidic to mesosilic volcanic-pyroclastic rocks and basalts, and associated sedimentary rocks. This volcano-sedimentary complex has been interpreted as the record of the Late Jurassic extensional regime that led to the formation of the Rocas Verdes marginal basin (Katz, 1972;Dalziel et al, 1974).…”

Section: Geological Framework Of the Southernmost Andesmentioning

confidence: 99%

“…This volcano-sedimentary complex has been interpreted as the record of the Late Jurassic extensional regime that led to the formation of the Rocas Verdes marginal basin (Katz, 1972;Dalziel et al, 1974). It is characterized as a submarine complex that includes sedimentary rocks (conglomerates, chert, and black radiolarian and carbonaceous mudstones), acid volcanic and volcaniclastic rocks and basaltic facies representing the oceanic crust of the basin (Bruhn, 1979;Hanson and Wilson, 1991;Olivero and Martinioni, 2001). The main outcrops are found along a discontinuous WNW belt from Sierra Alvear to Isla de los Estados and in a restricted area at Bahía Ensenada.…”

Section: Geological Framework Of the Southernmost Andesmentioning

confidence: 99%

Fabrica Magnetica y Microestructuras a traves de los Andes de Tierra del Fuego, Argentina.

Esteban

Tassone

Menichetti

et al. 2011

Andgeo

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ABSTRACT. An anisotropy of magnetic susceptibility (AMS) transect was carried out across the Fuegian Andes, in Argentina, with the aim of studying its tectonic evolution. Two-hundred and forty oriented samples were collected from 27 sites distributed between the Paso Garibaldi to the north and the Canal Beagle to the south. The study was restricted to the Upper Jurassic Lemaire Formation, with a single site located in the Lower Cretaceous Yahgán Formation. Studied rocks comprised basaltic, andesitic, volcaniclastic and sedimentary rocks affected by low-grade metamorphism. AMS measurements were complemented with thin section analyses of representative samples in order to characterize the microstructures and metamorphic assemblages. In general, the magnetic fabric shows dominant oblate shapes and a large variation in the anisotropy degree from 1.04 up to 2. The anomalously high values were observed to be associated to growth of secondary pyrrhotite, which was identified by rock magnetic tests. Magnetic foliation was generally consistent with slaty cleaveage as observed in the field, confirming the tectonic origin of the magnetic fabric. Three geographic domains were distinguished in the study region on the basis of the pattern of the AMS axes distribution. In the northern domain, from Paso Garibaldi to Valle Carbajal, the orientation of the maximum susceptibility axis (k 1 ), or magnetic lineation, is N-S to NE-SW with moderate plunge towards the S-SW and coincides with previous determination of mineral lineations associated with the Andean deformation and very low grade metamorphism. The magnetic fabric pattern can be correlated with the main deformational phase responsible for the development of slaty cleavage (main Andean deformational phase) and the tectonic transport due to progression of the Fuegian fold and thrust belt in the Late Cretaceous. A different character is shown along the Valle Carbajal domain, where subvertical E-W magnetic foliation planes and roughly E-W to ESE-WNW subhorizontal magnetic lineations are more difficult to correlate with the main folding phase and suggest its relation to an E-W, possibly localized, strike-slip regime during the main deformational and metamorphic phase. The magnetic fabrics in the third domain, close to the Canal Beagle, displays a more heterogeneous character with both E-W and N-S striking foliations; in this case a population of subhorizontal E-W magnetic lineation (k 1 ) suggests the existence of a significant component of strike-slip deformation. Keywords: AMS, Microstructures, Mesozoic, Andean tectonics, Tierra del Fuego, Argentina. 65 Esteban et al./ Andean Geology 38 (1): 64-81, 2011 RESUMEN. Fábrica Magnética y Microestructuras a través de los Andes de Tierra del Fuego, Argentina.Se presentan los resultados de una transecta de Anisotropía de Susceptibilidad Magnética (ASM) realizada en los Andes Fueguinos, Argentina. Se midieron 240 muestras orientadas provenientes de 27 sitios de muestreo distribuidos entre Paso Garibaldi, al norte y el Canal Beagle al su...

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A review of the geology of the Argentinian Fuegian Andes

Cited by 110 publications

References 32 publications

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.

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.

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

Fabrica Magnetica y Microestructuras a traves de los Andes de Tierra del Fuego, Argentina.

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