Geocronología SHRIMP del basamento de la Cuenca de Magallanes, Tierra del Fuego: Plutonismo Cámbrico y metamorfismo Pérmico de alto grado

Francisco Hervé, Mauricio Calderón, C. Mark Fanning, Stefan Kraus, Robert J. Pankhurst

Resultado de la investigación: Article

24 Citas (Scopus)

Resumen

Five new SHRIMP U-Pb zircon ages are reported for gneisses and foliated plutonic rocks belonging to the Tierra del Fuego igneous and metamorphic basement complex (TFIMC), obtained from the bottom of borehole cores through the Magallanes Basin. Three of the samples yielded weighted mean 206Pb/238U ages (523±7 Ma, 522±6 Ma and 538±6 Ma), interpreted as indicating Early Cambrian igneous crystallization of the host rocks. A migmatitic gneiss shows peaks at ca. 950-1,100 Ma and 560-650 Ma from inherited zircon grains in addition to two grains with ages of ca. 525 Ma, suggesting involvement of Grenvillian and Brasiliano material in the protolith of a Cambrian migmatite. A cordierite-sillimanite-garnet gneiss contains igneous zircons of Cambrian age and a population of U-rich metamorphic Permian zircons, indicating that a Permian high-grade metamorphic and anatectic (P=2-3 kbar, T=730-770°C) event affected the Cambrian igneous rocks or sedimentary rocks derived from them. Cambrian/Ediacaran plutonic rocks are known from the basement of NW Argentina, the Sierra de la Ventana, the Cape Fold Belt in South Africa, and the Ross Orogen in Antarctica. The Permian metamorphic event is coeval with the deformation and low-grade metamorphism of the sedimentary successions that overlie the basement in many of these areas. In Tierra del Fuego at least 8 to 12 km of cover rocks were removed following the high-grade Permian metamorphic episode and the unconformable deposition of the Tobífera Formation volcanic rocks in the Middle to Late Jurassic. This eroded cover could have been an important source of detritus for the conglomeratic Permian and Triassic? successions of neighbouring regions in South America, Africa and Antarctica.

Idioma originalSpanish
Páginas (desde-hasta)253-275
Número de páginas23
PublicaciónAndean Geology
Volumen37
N.º2
EstadoPublished - 1 dic 2010

Huella dactilar

plutonism
chronology
Permian
metamorphism
Rocks
zircon
basin
plutonic rock
gneiss
Igneous rocks
Volcanic rocks
Sedimentary rocks
Garnets
Crystallization
Boreholes
Grenvillian orogeny
low grade metamorphism
Ediacaran
migmatite
cordierite

ASJC Scopus subject areas

  • Geology
  • Geochemistry and Petrology
  • Stratigraphy
  • Palaeontology

Citar esto

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title = "Geocronolog{\'i}a SHRIMP del basamento de la Cuenca de Magallanes, Tierra del Fuego: Plutonismo C{\'a}mbrico y metamorfismo P{\'e}rmico de alto grado",
abstract = "Five new SHRIMP U-Pb zircon ages are reported for gneisses and foliated plutonic rocks belonging to the Tierra del Fuego igneous and metamorphic basement complex (TFIMC), obtained from the bottom of borehole cores through the Magallanes Basin. Three of the samples yielded weighted mean 206Pb/238U ages (523±7 Ma, 522±6 Ma and 538±6 Ma), interpreted as indicating Early Cambrian igneous crystallization of the host rocks. A migmatitic gneiss shows peaks at ca. 950-1,100 Ma and 560-650 Ma from inherited zircon grains in addition to two grains with ages of ca. 525 Ma, suggesting involvement of Grenvillian and Brasiliano material in the protolith of a Cambrian migmatite. A cordierite-sillimanite-garnet gneiss contains igneous zircons of Cambrian age and a population of U-rich metamorphic Permian zircons, indicating that a Permian high-grade metamorphic and anatectic (P=2-3 kbar, T=730-770°C) event affected the Cambrian igneous rocks or sedimentary rocks derived from them. Cambrian/Ediacaran plutonic rocks are known from the basement of NW Argentina, the Sierra de la Ventana, the Cape Fold Belt in South Africa, and the Ross Orogen in Antarctica. The Permian metamorphic event is coeval with the deformation and low-grade metamorphism of the sedimentary successions that overlie the basement in many of these areas. In Tierra del Fuego at least 8 to 12 km of cover rocks were removed following the high-grade Permian metamorphic episode and the unconformable deposition of the Tob{\'i}fera Formation volcanic rocks in the Middle to Late Jurassic. This eroded cover could have been an important source of detritus for the conglomeratic Permian and Triassic? successions of neighbouring regions in South America, Africa and Antarctica.",
keywords = "Basement complex, Cambrian plutonism, Magallanes Basin, Permian metamorphism, U-Pb SHRIMP ages",
author = "Francisco Herv{\'e} and Mauricio Calder{\'o}n and {Mark Fanning}, C. and Stefan Kraus and Pankhurst, {Robert J.}",
year = "2010",
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language = "Spanish",
volume = "37",
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Geocronología SHRIMP del basamento de la Cuenca de Magallanes, Tierra del Fuego : Plutonismo Cámbrico y metamorfismo Pérmico de alto grado. / Hervé, Francisco; Calderón, Mauricio; Mark Fanning, C.; Kraus, Stefan; Pankhurst, Robert J.

En: Andean Geology, Vol. 37, N.º 2, 01.12.2010, p. 253-275.

Resultado de la investigación: Article

TY - JOUR

T1 - Geocronología SHRIMP del basamento de la Cuenca de Magallanes, Tierra del Fuego

T2 - Plutonismo Cámbrico y metamorfismo Pérmico de alto grado

AU - Hervé, Francisco

AU - Calderón, Mauricio

AU - Mark Fanning, C.

AU - Kraus, Stefan

AU - Pankhurst, Robert J.

PY - 2010/12/1

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N2 - Five new SHRIMP U-Pb zircon ages are reported for gneisses and foliated plutonic rocks belonging to the Tierra del Fuego igneous and metamorphic basement complex (TFIMC), obtained from the bottom of borehole cores through the Magallanes Basin. Three of the samples yielded weighted mean 206Pb/238U ages (523±7 Ma, 522±6 Ma and 538±6 Ma), interpreted as indicating Early Cambrian igneous crystallization of the host rocks. A migmatitic gneiss shows peaks at ca. 950-1,100 Ma and 560-650 Ma from inherited zircon grains in addition to two grains with ages of ca. 525 Ma, suggesting involvement of Grenvillian and Brasiliano material in the protolith of a Cambrian migmatite. A cordierite-sillimanite-garnet gneiss contains igneous zircons of Cambrian age and a population of U-rich metamorphic Permian zircons, indicating that a Permian high-grade metamorphic and anatectic (P=2-3 kbar, T=730-770°C) event affected the Cambrian igneous rocks or sedimentary rocks derived from them. Cambrian/Ediacaran plutonic rocks are known from the basement of NW Argentina, the Sierra de la Ventana, the Cape Fold Belt in South Africa, and the Ross Orogen in Antarctica. The Permian metamorphic event is coeval with the deformation and low-grade metamorphism of the sedimentary successions that overlie the basement in many of these areas. In Tierra del Fuego at least 8 to 12 km of cover rocks were removed following the high-grade Permian metamorphic episode and the unconformable deposition of the Tobífera Formation volcanic rocks in the Middle to Late Jurassic. This eroded cover could have been an important source of detritus for the conglomeratic Permian and Triassic? successions of neighbouring regions in South America, Africa and Antarctica.

AB - Five new SHRIMP U-Pb zircon ages are reported for gneisses and foliated plutonic rocks belonging to the Tierra del Fuego igneous and metamorphic basement complex (TFIMC), obtained from the bottom of borehole cores through the Magallanes Basin. Three of the samples yielded weighted mean 206Pb/238U ages (523±7 Ma, 522±6 Ma and 538±6 Ma), interpreted as indicating Early Cambrian igneous crystallization of the host rocks. A migmatitic gneiss shows peaks at ca. 950-1,100 Ma and 560-650 Ma from inherited zircon grains in addition to two grains with ages of ca. 525 Ma, suggesting involvement of Grenvillian and Brasiliano material in the protolith of a Cambrian migmatite. A cordierite-sillimanite-garnet gneiss contains igneous zircons of Cambrian age and a population of U-rich metamorphic Permian zircons, indicating that a Permian high-grade metamorphic and anatectic (P=2-3 kbar, T=730-770°C) event affected the Cambrian igneous rocks or sedimentary rocks derived from them. Cambrian/Ediacaran plutonic rocks are known from the basement of NW Argentina, the Sierra de la Ventana, the Cape Fold Belt in South Africa, and the Ross Orogen in Antarctica. The Permian metamorphic event is coeval with the deformation and low-grade metamorphism of the sedimentary successions that overlie the basement in many of these areas. In Tierra del Fuego at least 8 to 12 km of cover rocks were removed following the high-grade Permian metamorphic episode and the unconformable deposition of the Tobífera Formation volcanic rocks in the Middle to Late Jurassic. This eroded cover could have been an important source of detritus for the conglomeratic Permian and Triassic? successions of neighbouring regions in South America, Africa and Antarctica.

KW - Basement complex

KW - Cambrian plutonism

KW - Magallanes Basin

KW - Permian metamorphism

KW - U-Pb SHRIMP ages

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