Tectonic controls and Cenozoic magmatism at the Torres del Paine, southern Andes (Chile, 51°10'S)

Five Miocene intrusive complexes are located along the N-trending, nearly trench-parallel San Lorenzo-Balmaceda Lineament in southern Patagonia. These complexes are characterized by mildly alkaline to calc-alkaline magmatism. The deformation and kinematics in the foreland of the granitoid-dominated...

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Autores principales:	Altenberger,Uwe, Oberhänsli,Roland, Putlitz,Benita, Wemmer,Klaus
Lenguaje:	English
Publicado:	Servicio Nacional de Geología y Minería (SERNAGEOMIN) 2003
Materias:	Cordillera de los Andes Torres del Paine Magmatism Deformation
Acceso en línea:	http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0716-02082003000100005
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spelling	oai:scielo:S0716-020820030001000052003-10-21Tectonic controls and Cenozoic magmatism at the Torres del Paine, southern Andes (Chile, 51°10'S)Altenberger,UweOberhänsli,RolandPutlitz,BenitaWemmer,Klaus Cordillera de los Andes Torres del Paine Magmatism Deformation Five Miocene intrusive complexes are located along the N-trending, nearly trench-parallel San Lorenzo-Balmaceda Lineament in southern Patagonia. These complexes are characterized by mildly alkaline to calc-alkaline magmatism. The deformation and kinematics in the foreland of the granitoid-dominated Torres del Paine laccolith (12±2 Ma) were studied in order to evaluate the influence of the pre- to syn-intrusive crustal stress field on magma emplacement. Compression and transpression led to large-scale folding, with fold wavelength of up to 10 km, and faulting of the Cretaceous flysch sedimentary rocks as well as alkaline gabbro sills. Geochronological data from folded gabbros point to an Oligocene minimum age for regional folding at 29.4±0.8 Ma. Reverse faults and convergent sinistral strike-slip faults occur as well as conjugate reverse faults. The shortening axes trend ENE- to E. These directions correlate with the oblique convergence between the Nazca- and the South America-plate. The magma ascent was parallel to the NNW-SSE striking Lago Grey-fault zone and probably coincides with the fossil intersection of the oceanic Madre de Dios transform fault. The intrusion correlates with a change from transpressional to transtensional dynamics as documented by a kinematic change from left-lateral convergent strike-slip faulting to left-lateral divergent strike-slip faulting. The changes in dynamics and kinematics correlate in time and space with a reorganisation of the plate tectonic situation during the Miocene. After the collision of the Chile ridge, separating the Nazca-plate from Antarctica, the situation in the south-western part of South America changed from rapid ENE-WSW-directed oblique convergence between the Nazca- and South America-plate, to an east-west-directed slow frontal convergence between the Antarctica and South America plates. The observed geometric divergence of the San Lorenzo-Balmaceda lineament and the apparent control of magma ascent through upper crustal faults may be explained by the interpretation of the SLB as a possible large-scale lower crustal strike slip zone and by shear partitioning from lower crust to upper crust.info:eu-repo/semantics/openAccessServicio Nacional de Geología y Minería (SERNAGEOMIN)Revista geológica de Chile v.30 n.1 20032003-07-01text/htmlhttp://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0716-02082003000100005en10.4067/S0716-02082003000100005
institution	Scielo Chile
collection	Scielo Chile
language	English
topic	Cordillera de los Andes Torres del Paine Magmatism Deformation
spellingShingle	Cordillera de los Andes Torres del Paine Magmatism Deformation Altenberger,Uwe Oberhänsli,Roland Putlitz,Benita Wemmer,Klaus Tectonic controls and Cenozoic magmatism at the Torres del Paine, southern Andes (Chile, 51°10'S)
description	Five Miocene intrusive complexes are located along the N-trending, nearly trench-parallel San Lorenzo-Balmaceda Lineament in southern Patagonia. These complexes are characterized by mildly alkaline to calc-alkaline magmatism. The deformation and kinematics in the foreland of the granitoid-dominated Torres del Paine laccolith (12±2 Ma) were studied in order to evaluate the influence of the pre- to syn-intrusive crustal stress field on magma emplacement. Compression and transpression led to large-scale folding, with fold wavelength of up to 10 km, and faulting of the Cretaceous flysch sedimentary rocks as well as alkaline gabbro sills. Geochronological data from folded gabbros point to an Oligocene minimum age for regional folding at 29.4±0.8 Ma. Reverse faults and convergent sinistral strike-slip faults occur as well as conjugate reverse faults. The shortening axes trend ENE- to E. These directions correlate with the oblique convergence between the Nazca- and the South America-plate. The magma ascent was parallel to the NNW-SSE striking Lago Grey-fault zone and probably coincides with the fossil intersection of the oceanic Madre de Dios transform fault. The intrusion correlates with a change from transpressional to transtensional dynamics as documented by a kinematic change from left-lateral convergent strike-slip faulting to left-lateral divergent strike-slip faulting. The changes in dynamics and kinematics correlate in time and space with a reorganisation of the plate tectonic situation during the Miocene. After the collision of the Chile ridge, separating the Nazca-plate from Antarctica, the situation in the south-western part of South America changed from rapid ENE-WSW-directed oblique convergence between the Nazca- and South America-plate, to an east-west-directed slow frontal convergence between the Antarctica and South America plates. The observed geometric divergence of the San Lorenzo-Balmaceda lineament and the apparent control of magma ascent through upper crustal faults may be explained by the interpretation of the SLB as a possible large-scale lower crustal strike slip zone and by shear partitioning from lower crust to upper crust.
author	Altenberger,Uwe Oberhänsli,Roland Putlitz,Benita Wemmer,Klaus
author_facet	Altenberger,Uwe Oberhänsli,Roland Putlitz,Benita Wemmer,Klaus
author_sort	Altenberger,Uwe
title	Tectonic controls and Cenozoic magmatism at the Torres del Paine, southern Andes (Chile, 51°10'S)
title_short	Tectonic controls and Cenozoic magmatism at the Torres del Paine, southern Andes (Chile, 51°10'S)
title_full	Tectonic controls and Cenozoic magmatism at the Torres del Paine, southern Andes (Chile, 51°10'S)
title_fullStr	Tectonic controls and Cenozoic magmatism at the Torres del Paine, southern Andes (Chile, 51°10'S)
title_full_unstemmed	Tectonic controls and Cenozoic magmatism at the Torres del Paine, southern Andes (Chile, 51°10'S)
title_sort	tectonic controls and cenozoic magmatism at the torres del paine, southern andes (chile, 51°10's)
publisher	Servicio Nacional de Geología y Minería (SERNAGEOMIN)
publishDate	2003
url	http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0716-02082003000100005
work_keys_str_mv	AT altenbergeruwe tectoniccontrolsandcenozoicmagmatismatthetorresdelpainesouthernandeschile5110s AT oberhansliroland tectoniccontrolsandcenozoicmagmatismatthetorresdelpainesouthernandeschile5110s AT putlitzbenita tectoniccontrolsandcenozoicmagmatismatthetorresdelpainesouthernandeschile5110s AT wemmerklaus tectoniccontrolsandcenozoicmagmatismatthetorresdelpainesouthernandeschile5110s
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Tectonic controls and Cenozoic magmatism at the Torres del Paine, southern Andes (Chile, 51°10'S)

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