Eocene arc petrogenesis in central chile (C. 33.6° s) and implications for the late cretaceous–miocene andean setting: Tracking the evolving tectonic regime

Marcia Muñoz-Gómez, Constanza Fuentes, Francisco Fuentes, Felipe Tapia, Mathieu Benoit, Marcelo Farías, C. Mark Fanning, Andrés Fock, Reynaldo Charrier, Daniel Sellés, Daniela Bustamante

Research output: Contribution to journalArticlepeer-review

1 Citation (Scopus)

Abstract

The scarce Eocene geological record in the Andean region of Central Chile (c. 33.6° S) is represented by the Estratos del Cordón de los Ratones unit. This is a c. 450 m thick, mainly volcanic, continental series with a bimodal character that hosts numerous subvolcanic intrusions. The igneous products show compositional features indicating a co-genetic character for the whole suite, relatively juvenile mantle signatures and arc-like affinities. This, along with age determinations of c. 42 Ma, indicate that the unit corresponds to the middle Eocene arc in the region. The geochemical data obtained complement the evolving arc magmatic record throughout Andean evolution. This allows us to track: (1) the earliest Late Cretaceous orogenic event; (2) neutral tectonic conditions from the latest Cretaceous to mid-Eocene times; (3) the Oligocene–early Miocene extensional episode; and (4) the onset of the prevailing compression. The record also indicates that the extensional event started no earlier than the mid-Eocene, with the deposition of the Estratos del Cordón de los Ratones, and no later than the earliest Oligocene. In addition, orogenic processes developed from early Miocene times are highlighted relative to those developed during the early Late Cretaceous, at least in the arc region.

Original languageEnglish
Pages (from-to)258-275
Number of pages18
JournalJournal of the Geological Society
Volume177
Issue number2
DOIs
Publication statusPublished - 1 Jan 2019

ASJC Scopus subject areas

  • Geology

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