U-Pb Geochronology and Hf-O Isotopes of zircons from the Pennsylvanian Coastal Batholith, South-Central Chile

Deckart, Katja; Hervé, Francisco; Fanning, C. Mark; Ramirez, Valeria; Calderon, Mauricio; Godoy, Estanislao

Abstract

The Coastal Batholith of south-central Chile between latitudes 33 degrees and 40 degrees S is composed of calc-alkaline granitoids emplaced in a relatively restricted time period. New SHRIMP U-Pb zircon ages on eight quartzdioritic to granitic rocks collected over a distance of 800 km yielded ages between 300 and 320 Ma, Pennsylvanian ( late Carboniferous). Lu-Hf isotopic analyses on the same zircon grains have initial epsilon Hf-(i) values from +1.67 to -5.64. The delta O-18 ratios for that grains range from 6.4 to 8.6 parts per thousand. These new isotopic data point to a relative homogeneous source with prominent components of the continental crust. The calculated Mesoproterozoic Depleted Mantel model ages, in addition to the short span of intrusive ages give insights to the position of the proto-Gondwana margin and the changing subduction mechanism at the end of late Paleozoic time.

Más información

Título según WOS: U-Pb Geochronology and Hf-O Isotopes of zircons from the Pennsylvanian Coastal Batholith, South-Central Chile
Título según SCIELO: U-Pb Geochronology and Hf-O Isotopes of zircons from the Pennsylvanian Coastal Batholith, South-Central Chile
Título de la Revista: Andean geology
Volumen: 41
Número: 1
Editorial: Servicio Nacional de Geología y Minería (SERNAGEOMIN)
Fecha de publicación: 2014
Página de inicio: 49
Página final: 82
Idioma: English
DOI:

10.5027/andgeoV41n1-a03

Notas: ISI, SCIELO