Metamorfismo y deformación de la Formación Tobífera en la cordillera Riesco, región de Magallanes, Chile: Evidencias para su evolución tectónica

Resultado de la investigación: Article

12 Citas (Scopus)

Resumen

The Tobífera Formation (150 Ma) was in part deposited contemporaneously with the Sarmiento Ophiolitic Complex during the rifting stage of the Rocas Verdes Basin. Later, the Cretaceous Zapata, Punta Barrosa and Cerro Toro Formations were deposited conformably on top of the Tobifera. In Cordillera Riesco, it is composed of siliceous tuffs, siliceous welded tuffs, quartzose black shales and siltstones. It is affected by a mylonitic deformation that developed different ductile reverse kinematic indicators, with a minor dextral component which suggest a reverse- dextral movement of the fault zone. The metamorphic mineralogy indicates that the greenschist facies conditions were reached for the matrix forming minerals, and prehnite-actinolite facies in mineral associations in retrograde cross-cutting veinlets. Geothermobarometric calculations indicate that this mylonite zone reached 6.3 ± 1.1 kb and 399 ± 64°C. These values suggest that these rocks reached a depth between 19 and 26 km, maybe during a reverse subduction episode in the area. Deformed clasts of Tobifera Formation in conglomerates of Cerro Toro Formation indicate the exhumation of the Tobifera Formation before or during the Late Cretaceous. The present configuration of the structures in Cordillera Riesco is possibly determined by westward rotations occurred in the Magallanes fold and thrust belt.

Idioma originalSpanish
Páginas (desde-hasta)762-774
Número de páginas13
PublicaciónRevista de la Asociacion Geologica Argentina
Volumen60
N.º4
EstadoPublished - oct 2005

Huella dactilar

cordillera
tectonic evolution
metamorphism
Cretaceous
prehnite
mylonite
fold and thrust belt
mineral
greenschist facies
siltstone
exhumation
clast
conglomerate
rifting
fault zone
mineralogy
subduction
kinematics
matrix
basin

ASJC Scopus subject areas

  • Geology

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title = "Metamorfismo y deformaci{\'o}n de la Formaci{\'o}n Tob{\'i}fera en la cordillera Riesco, regi{\'o}n de Magallanes, Chile: Evidencias para su evoluci{\'o}n tect{\'o}nica",
abstract = "The Tob{\'i}fera Formation (150 Ma) was in part deposited contemporaneously with the Sarmiento Ophiolitic Complex during the rifting stage of the Rocas Verdes Basin. Later, the Cretaceous Zapata, Punta Barrosa and Cerro Toro Formations were deposited conformably on top of the Tobifera. In Cordillera Riesco, it is composed of siliceous tuffs, siliceous welded tuffs, quartzose black shales and siltstones. It is affected by a mylonitic deformation that developed different ductile reverse kinematic indicators, with a minor dextral component which suggest a reverse- dextral movement of the fault zone. The metamorphic mineralogy indicates that the greenschist facies conditions were reached for the matrix forming minerals, and prehnite-actinolite facies in mineral associations in retrograde cross-cutting veinlets. Geothermobarometric calculations indicate that this mylonite zone reached 6.3 ± 1.1 kb and 399 ± 64°C. These values suggest that these rocks reached a depth between 19 and 26 km, maybe during a reverse subduction episode in the area. Deformed clasts of Tobifera Formation in conglomerates of Cerro Toro Formation indicate the exhumation of the Tobifera Formation before or during the Late Cretaceous. The present configuration of the structures in Cordillera Riesco is possibly determined by westward rotations occurred in the Magallanes fold and thrust belt.",
keywords = "Deformation, Metamorphism, Tectonic, Tob{\'i}fera formation",
author = "Gonzalo Galaz and Francisco Herv{\'e} and Mauricio Calder{\'o}n",
year = "2005",
month = "10",
language = "Spanish",
volume = "60",
pages = "762--774",
journal = "Revista de la Asociacion Geologica Argentina",
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TY - JOUR

T1 - Metamorfismo y deformación de la Formación Tobífera en la cordillera Riesco, región de Magallanes, Chile

T2 - Evidencias para su evolución tectónica

AU - Galaz, Gonzalo

AU - Hervé, Francisco

AU - Calderón, Mauricio

PY - 2005/10

Y1 - 2005/10

N2 - The Tobífera Formation (150 Ma) was in part deposited contemporaneously with the Sarmiento Ophiolitic Complex during the rifting stage of the Rocas Verdes Basin. Later, the Cretaceous Zapata, Punta Barrosa and Cerro Toro Formations were deposited conformably on top of the Tobifera. In Cordillera Riesco, it is composed of siliceous tuffs, siliceous welded tuffs, quartzose black shales and siltstones. It is affected by a mylonitic deformation that developed different ductile reverse kinematic indicators, with a minor dextral component which suggest a reverse- dextral movement of the fault zone. The metamorphic mineralogy indicates that the greenschist facies conditions were reached for the matrix forming minerals, and prehnite-actinolite facies in mineral associations in retrograde cross-cutting veinlets. Geothermobarometric calculations indicate that this mylonite zone reached 6.3 ± 1.1 kb and 399 ± 64°C. These values suggest that these rocks reached a depth between 19 and 26 km, maybe during a reverse subduction episode in the area. Deformed clasts of Tobifera Formation in conglomerates of Cerro Toro Formation indicate the exhumation of the Tobifera Formation before or during the Late Cretaceous. The present configuration of the structures in Cordillera Riesco is possibly determined by westward rotations occurred in the Magallanes fold and thrust belt.

AB - The Tobífera Formation (150 Ma) was in part deposited contemporaneously with the Sarmiento Ophiolitic Complex during the rifting stage of the Rocas Verdes Basin. Later, the Cretaceous Zapata, Punta Barrosa and Cerro Toro Formations were deposited conformably on top of the Tobifera. In Cordillera Riesco, it is composed of siliceous tuffs, siliceous welded tuffs, quartzose black shales and siltstones. It is affected by a mylonitic deformation that developed different ductile reverse kinematic indicators, with a minor dextral component which suggest a reverse- dextral movement of the fault zone. The metamorphic mineralogy indicates that the greenschist facies conditions were reached for the matrix forming minerals, and prehnite-actinolite facies in mineral associations in retrograde cross-cutting veinlets. Geothermobarometric calculations indicate that this mylonite zone reached 6.3 ± 1.1 kb and 399 ± 64°C. These values suggest that these rocks reached a depth between 19 and 26 km, maybe during a reverse subduction episode in the area. Deformed clasts of Tobifera Formation in conglomerates of Cerro Toro Formation indicate the exhumation of the Tobifera Formation before or during the Late Cretaceous. The present configuration of the structures in Cordillera Riesco is possibly determined by westward rotations occurred in the Magallanes fold and thrust belt.

KW - Deformation

KW - Metamorphism

KW - Tectonic

KW - Tobífera formation

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