Tectonic implications of a paleomagnetic study of the Sarmiento Ophiolitic Complex, southern Chile

Rapalini, Augusto E.; Calderón, Mauricio; Singer, Silvia; Hervé, Francisco; Cordani, Umberto G.

doi:10.1016/j.tecto.2008.01.005

Cited by 19 publications

(16 citation statements)

References 29 publications

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“…5i) The Andean GDUs have now collided with SAM, and GDUs in the region of Tierra del Fuego collide with those from the northern Antarctic Peninsula, implying rotation, potentially enhanced at local scale (e.g. Rapalini et al, 2001Rapalini et al, , 2008Grunow, 1993) but not resolved at the scale of our model. The movement remains transpressive.…”

Section: Ma (Fig 5d)mentioning

confidence: 92%

Geodynamic reconstructions of the South America–Antarctica plate system

Vérard

Flores

Stampfli

2012

Journal of Geodynamics

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Section: Ma (Fig 5d)mentioning

confidence: 92%

Geodynamic reconstructions of the South America–Antarctica plate system

Vérard

Flores

Stampfli

2012

Journal of Geodynamics

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“…The presence of a flexural strength discontinuity associated with lithospheric thinning can impact subsidence patterns by promoting a relatively fixed foredeep depocenter and long-wavelength deflection (Figure 11f). Efficient erosion may have also contributed to a fixed deformation front [e.g., Simpson, 2006;Cruz et al, 2010], as suggested by exhumation of the Tobífera thrust sheets and sediment input to the foredeep [Rapalini et al, 2008;Romans et al, 2010]. In this view, inhibited lateral cratonward migration of the deformation front may have pinned the foredeep position by the inherited lithotectonic and erosional regime.…”

Section: Implications For Flexural Models Of Successor Foreland Basinsmentioning

confidence: 99%

Influence of attenuated lithosphere and sediment loading on flexure of the deep-water Magallanes retroarc foreland basin, Southern Andes

2014

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Flexural subsidence in foreland basins is controlled by applied loads-such as topography, water/sediment, and subcrustal forces-and the mechanical properties of the lithosphere. We investigate the controls on subsidence observed within the Upper Cretaceous Magallanes retroarc foreland basin of southern South America to evaluate the impact of lateral variations in flexural rigidity due to Late Jurassic extension. Conventional elastic models cannot explain the observed basin deflection and thick accumulation of deep-water Cenomanian-Turonian basin strata. However, models in which the lithosphere has been previously thinned and deflects under topographic and sedimentary loads successfully reproduce regional subsidence patterns. Results satisfy paleobathymetric observations in the Magallanes Basin and suggest that lithospheric thinning is necessary to produce both long-wavelength and deep subsidence during Late Cretaceous basin evolution. Results indicate that elastic thickness decreases westward from~45-25 km in the distal foreland to~37-15 km beneath the foredeep. These findings are consistent with a westward reduction in crustal thickness associated with the Jurassic extensional history of the Patagonian lithosphere. Our results also show that sediment loading exerts an important control on regional deflection patterns and promotes a wider region of subsidence and reduced forebulge uplift. We propose that lateral variations in mechanical properties and large sediment loads restrict depocenter migration and may cause the foredeep to remain fixed for prolonged periods of time. These findings confirm that loading of thinned lithosphere imposes different mechanical controls on the flexural profile and have potential implications for other retroarc foreland basins characterized by earlier extensional histories.

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“…Most published paleomagnetic studies are on rocks from the Pacific side of the Patagonian orogenic belt or south of Lago Fagnano [Burns et al, 1980;Cunningham et al, 1991;Dalziel et al, 1973;Rapalini et al, 2001Rapalini et al, , 2008. There is only one paleomagnetic and AMS study in the Magallanes FTB [Maffione et al, 2010] with 22 sites sampled in sedimentary rocks cropping out near the Atlantic coast of Tierra del Fuego (Figure 1).…”

Section: Magnetic Propertiesmentioning

confidence: 99%

The curved Magallanes fold and thrust belt: Tectonic insights from a paleomagnetic and anisotropy of magnetic susceptibility study

et al. 2014

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The Magallanes fold and thrust belt (FTB) presents a large-scale curvature from N-S oriented structures north of 52°S to nearly E-W in Tierra del Fuego Island. We present a paleomagnetic and anisotropy of magnetic susceptibility (AMS) study from 85 sites sampled in Cretaceous to Miocene marine sediments. Magnetic susceptibility is lower than 0.0005 SI for 76 sites and mainly controlled by paramagnetic minerals. AMS results indicate that the sedimentary fabric is preserved in the undeformed areas of Tierra del Fuego and the more external thrust sheets units, where an incipient lineation due to layer parallel shortening is recorded. Prolate AMS ellipsoids, indicating a significant tectonic imprint in the AMS fabric, are observed in the internal units of the belt. AMS results show a good correlation between the orientation of the magnetic lineation and the fold axes. However, in Península Brunswick, the AMS lineations are at~20°counterclockwise to the strike of the fold axes. Pretectonic stable characteristic remanent magnetizations (ChRM) were determined in seven sites. A counterclockwise rotation (21.2°± 9.2°) is documented by ChRM data from four sites near the hinge of the belt in Península Brunswick and near Canal Whiteside while there is no evidence of rotation near the nearly E-W oriented Vicuña thrust within Tierra del Fuego. The curved shape of the Cenozoic Magallanes FTB is not related to vertical axis rotation, and thus, the Magallanes FTB can be considered as a primary arc.

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Tectonic implications of a paleomagnetic study of the Sarmiento Ophiolitic Complex, southern Chile

Cited by 19 publications

References 29 publications

Geodynamic reconstructions of the South America–Antarctica plate system

Geodynamic reconstructions of the South America–Antarctica plate system

Influence of attenuated lithosphere and sediment loading on flexure of the deep-water Magallanes retroarc foreland basin, Southern Andes

The curved Magallanes fold and thrust belt: Tectonic insights from a paleomagnetic and anisotropy of magnetic susceptibility study

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