Late Triassic detrital zircons in meta-turbidites of the Chonos Metamorphic Complex, southern Chile

Date

2001

Authors

Herve, Francisco
Fanning, Christopher

Journal Title

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Volume Title

Publisher

University of Chile

Abstract

Sensitive High Resolution Ion MicroProbe (SHRIMP) U-Pb age determinations of detrital zircons from metasandstones of the Chonos Metamorphic Complex reveal a significant population of Late Triassic ages. One of the samples is immediately underlying the coquinaceous bed containing fossils which were initially identified as Late Silurian-Early Devonian, and more recently as Late Triassic faunas. The zircon data confirm the latter age as the depositional age of the fossil bearing rocks, excluding completely the possibility of a Paleozoic depositional age. Similar U-Pb detrital zircon ages are recorded in two other samples, one of which was collected in the vicinity of strata containing Lima sp., confirming that a Late Triassic depositional age is widespread in the Eastern belt of the Chonos Metamorphic Complex. However, in a fourth sample, the youngest detrital zircons are Carboniferous in age. Construction of the accretionary prism was thus active in the Late Triassic, and its metamorphism probably took place during the Jurassic, in contrast with a previously accepted Late Paleozoic age.

Description

Keywords

Keywords: sandstone; stratigraphy; Triassic; zircon; Chile Chonos Metamorphic Complex; Late triassic; Southern Chile; U-Pb ages

Citation

Source

Revista Geologica de Chile (discontinued title)

Type

Journal article

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