@misc{10481/7315,
year = {2004},
url = {http://hdl.handle.net/10481/7315},
abstract = {K-Ar isotopic dating of very low-grade metamorphism affecting Triassic-Jurassic rocks in the Coastal Range of central Chile was carried out on whole rocks and their <2 mm size fractions. In the study area, a regional-burial low-grade metamorphism at anchizone conditions (T ≤ 190ºC) and low-pressure conditions (P ≥1.3 kbar) has been described. Observed temperatures are related to a contact metamorphism produced by nearby Jurassic intrusions, with a P-T estimate at the immediate contact zone of ~650-690ºC and 4 kbar. The whole-rock K-Ar age of 174?5 Ma is interpreted as belonging to the contact metamorphism due to the intrusion of Jurassic plutons (165±5 Ma to 175±5 Ma). A time-interval of ~20 Ma between the diagenesis (206 Ma) and the anchizonal very low-grade metamorphism (181-184 Ma) is obtained, and a rate of subsidence of ~120 m/Ma is proposed for these Triassic-Jurassic basins. A thermal influence on the burial, very low-grade, regional metamorphism is invoked.},
organization = {Departamento de Mineralogía y Petrología},
publisher = {Mineralogical Society},
keywords = {Pelites},
keywords = {Pelitas},
keywords = {K-Ar dating},
keywords = {Datación K-Ar},
keywords = {Very low-grade metamorphism},
keywords = {Metamorfismo de muy bajo grado},
keywords = {Costal Range},
keywords = {Cordillera de la Costa},
keywords = {Central Chile},
keywords = {Chile central},
title = {Significance of K-Ar dating of very low-grade metamorphism in Triassic-Jurassic pelites from the Coastal Range of central Chile},
author = {Belmar, Mauricio and Morata, Diego and Munizaga, Francisco and Pérez de Arce, Carlos and Morales, Salvador and Carrillo Rosúa, Francisco Javier},
}