Petrogenesis of the Puerto Edén Igneous and Metamorphic Complex, Magallanes, Chile: Late Jurassic syn-deformational anatexis of metapelites and granitoid magma genesis

M. Calderón, F. Hervé, H. J. Massonne, C. G. Tassinari, R. J. Pankhurst, E. Godoy, T. Theye

Resultado de la investigación: Article

16 Citas (Scopus)

Resumen

A suite of schists, gneisses, migmatites, and biotite granitoids from the Puerto Edén Igneous and Metamorphic Complex (PEIMC) and biotite-hornblende granitoids of the South Patagonian batholith (southern Chile) has been studied. For that purpose, the chemistry of minerals and the bulk rock composition of major and trace elements including Rb-Sr and Sm-Nd isotopes were determined. Mineralogical observations and geothermobarometric calculations indicate high-temperature and low-pressure conditions (ca. 600-700 °C and 3 to 4.5 kbar) for an event of metamorphism and partial melting of metapelites in Late Jurassic times (previously determined by SHRIMP U-Pb zircon ages). Structures in schists, gneisses, migmatites and mylonites indicate non-coaxial deformation flow during and after peak metamorphic and anatectic conditions. Andalusite schists and sillimanite gneisses yield initial 87Sr/86Sr ratios of up to 0.7134 and εNd150 values as low as - 7.6. Contemporaneous biotite granitoids and a coarse-grained orthogneiss have initial 87Sr/86Sr ratios between 0.7073 and 0.7089, and εNd150 values in the range - 7.6 to - 4.4. This indicates that metamorphic rocks do not represent the natural isotopic variation in the migmatite source. Thus, a heterogeneous source with a least radiogenic component was involved in the production of the biotite granitoids. The PEIMC is considered as a segment of an evolving kilometre-sized and deep crustal shear zone in which partial melts were generated and segregated into a large reservoir of magmas forming composite plutons in Late Jurassic times. A biotite-hornblende granodiorite and a muscovite-garnet leucogranite show initial 87Sr/86Sr ratios of 0.7048 and 0.7061, and εNd100 values of - 2.6 and - 1.8, respectively, and are thus probably related to Early Cretaceous magmas not involved in the anatexis of the metasedimentary rocks.

Idioma originalEnglish
Páginas (desde-hasta)17-38
Número de páginas22
PublicaciónLithos
Volumen93
N.º1-2
DOI
EstadoPublished - 1 ene 2007

Huella dactilar

anatexis
metapelite
petrogenesis
granitoid
biotite
Jurassic
magma
schist
hornblende
Rocks
Metamorphic rocks
leucogranite
orthogneiss
migmatite
andalusite
Garnets
Trace Elements
sillimanite
metasedimentary rock
batholith

ASJC Scopus subject areas

  • Geochemistry and Petrology

Citar esto

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title = "Petrogenesis of the Puerto Ed{\'e}n Igneous and Metamorphic Complex, Magallanes, Chile: Late Jurassic syn-deformational anatexis of metapelites and granitoid magma genesis",
abstract = "A suite of schists, gneisses, migmatites, and biotite granitoids from the Puerto Ed{\'e}n Igneous and Metamorphic Complex (PEIMC) and biotite-hornblende granitoids of the South Patagonian batholith (southern Chile) has been studied. For that purpose, the chemistry of minerals and the bulk rock composition of major and trace elements including Rb-Sr and Sm-Nd isotopes were determined. Mineralogical observations and geothermobarometric calculations indicate high-temperature and low-pressure conditions (ca. 600-700 °C and 3 to 4.5 kbar) for an event of metamorphism and partial melting of metapelites in Late Jurassic times (previously determined by SHRIMP U-Pb zircon ages). Structures in schists, gneisses, migmatites and mylonites indicate non-coaxial deformation flow during and after peak metamorphic and anatectic conditions. Andalusite schists and sillimanite gneisses yield initial 87Sr/86Sr ratios of up to 0.7134 and εNd150 values as low as - 7.6. Contemporaneous biotite granitoids and a coarse-grained orthogneiss have initial 87Sr/86Sr ratios between 0.7073 and 0.7089, and εNd150 values in the range - 7.6 to - 4.4. This indicates that metamorphic rocks do not represent the natural isotopic variation in the migmatite source. Thus, a heterogeneous source with a least radiogenic component was involved in the production of the biotite granitoids. The PEIMC is considered as a segment of an evolving kilometre-sized and deep crustal shear zone in which partial melts were generated and segregated into a large reservoir of magmas forming composite plutons in Late Jurassic times. A biotite-hornblende granodiorite and a muscovite-garnet leucogranite show initial 87Sr/86Sr ratios of 0.7048 and 0.7061, and εNd100 values of - 2.6 and - 1.8, respectively, and are thus probably related to Early Cretaceous magmas not involved in the anatexis of the metasedimentary rocks.",
keywords = "Gondwana, Late Jurassic, Metapelites, Migmatites, Sr-Nd isotopes",
author = "M. Calder{\'o}n and F. Herv{\'e} and Massonne, {H. J.} and Tassinari, {C. G.} and Pankhurst, {R. J.} and E. Godoy and T. Theye",
year = "2007",
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Petrogenesis of the Puerto Edén Igneous and Metamorphic Complex, Magallanes, Chile : Late Jurassic syn-deformational anatexis of metapelites and granitoid magma genesis. / Calderón, M.; Hervé, F.; Massonne, H. J.; Tassinari, C. G.; Pankhurst, R. J.; Godoy, E.; Theye, T.

En: Lithos, Vol. 93, N.º 1-2, 01.01.2007, p. 17-38.

Resultado de la investigación: Article

TY - JOUR

T1 - Petrogenesis of the Puerto Edén Igneous and Metamorphic Complex, Magallanes, Chile

T2 - Late Jurassic syn-deformational anatexis of metapelites and granitoid magma genesis

AU - Calderón, M.

AU - Hervé, F.

AU - Massonne, H. J.

AU - Tassinari, C. G.

AU - Pankhurst, R. J.

AU - Godoy, E.

AU - Theye, T.

PY - 2007/1/1

Y1 - 2007/1/1

N2 - A suite of schists, gneisses, migmatites, and biotite granitoids from the Puerto Edén Igneous and Metamorphic Complex (PEIMC) and biotite-hornblende granitoids of the South Patagonian batholith (southern Chile) has been studied. For that purpose, the chemistry of minerals and the bulk rock composition of major and trace elements including Rb-Sr and Sm-Nd isotopes were determined. Mineralogical observations and geothermobarometric calculations indicate high-temperature and low-pressure conditions (ca. 600-700 °C and 3 to 4.5 kbar) for an event of metamorphism and partial melting of metapelites in Late Jurassic times (previously determined by SHRIMP U-Pb zircon ages). Structures in schists, gneisses, migmatites and mylonites indicate non-coaxial deformation flow during and after peak metamorphic and anatectic conditions. Andalusite schists and sillimanite gneisses yield initial 87Sr/86Sr ratios of up to 0.7134 and εNd150 values as low as - 7.6. Contemporaneous biotite granitoids and a coarse-grained orthogneiss have initial 87Sr/86Sr ratios between 0.7073 and 0.7089, and εNd150 values in the range - 7.6 to - 4.4. This indicates that metamorphic rocks do not represent the natural isotopic variation in the migmatite source. Thus, a heterogeneous source with a least radiogenic component was involved in the production of the biotite granitoids. The PEIMC is considered as a segment of an evolving kilometre-sized and deep crustal shear zone in which partial melts were generated and segregated into a large reservoir of magmas forming composite plutons in Late Jurassic times. A biotite-hornblende granodiorite and a muscovite-garnet leucogranite show initial 87Sr/86Sr ratios of 0.7048 and 0.7061, and εNd100 values of - 2.6 and - 1.8, respectively, and are thus probably related to Early Cretaceous magmas not involved in the anatexis of the metasedimentary rocks.

AB - A suite of schists, gneisses, migmatites, and biotite granitoids from the Puerto Edén Igneous and Metamorphic Complex (PEIMC) and biotite-hornblende granitoids of the South Patagonian batholith (southern Chile) has been studied. For that purpose, the chemistry of minerals and the bulk rock composition of major and trace elements including Rb-Sr and Sm-Nd isotopes were determined. Mineralogical observations and geothermobarometric calculations indicate high-temperature and low-pressure conditions (ca. 600-700 °C and 3 to 4.5 kbar) for an event of metamorphism and partial melting of metapelites in Late Jurassic times (previously determined by SHRIMP U-Pb zircon ages). Structures in schists, gneisses, migmatites and mylonites indicate non-coaxial deformation flow during and after peak metamorphic and anatectic conditions. Andalusite schists and sillimanite gneisses yield initial 87Sr/86Sr ratios of up to 0.7134 and εNd150 values as low as - 7.6. Contemporaneous biotite granitoids and a coarse-grained orthogneiss have initial 87Sr/86Sr ratios between 0.7073 and 0.7089, and εNd150 values in the range - 7.6 to - 4.4. This indicates that metamorphic rocks do not represent the natural isotopic variation in the migmatite source. Thus, a heterogeneous source with a least radiogenic component was involved in the production of the biotite granitoids. The PEIMC is considered as a segment of an evolving kilometre-sized and deep crustal shear zone in which partial melts were generated and segregated into a large reservoir of magmas forming composite plutons in Late Jurassic times. A biotite-hornblende granodiorite and a muscovite-garnet leucogranite show initial 87Sr/86Sr ratios of 0.7048 and 0.7061, and εNd100 values of - 2.6 and - 1.8, respectively, and are thus probably related to Early Cretaceous magmas not involved in the anatexis of the metasedimentary rocks.

KW - Gondwana

KW - Late Jurassic

KW - Metapelites

KW - Migmatites

KW - Sr-Nd isotopes

UR - http://www.scopus.com/inward/record.url?scp=33845504723&partnerID=8YFLogxK

U2 - 10.1016/j.lithos.2006.03.044

DO - 10.1016/j.lithos.2006.03.044

M3 - Article

AN - SCOPUS:33845504723

VL - 93

SP - 17

EP - 38

JO - Lithos

JF - Lithos

SN - 0024-4937

IS - 1-2

ER -