347 Tectonics/Tectonophysics (Posters)

Wednesday, 28 September 2016
9:00 AM - 6:30 PM
Exhibit Hall E/F

STRATIGRAPHY AND GEOCHRONOLOGY OF THE MIDDLE?-LATE JURASSIC NACIENTES DEL TENO AND RIO DAMAS FORMATIONS—NEW INSIGHTS INTO VOLCANISM, SEDIMENTATION AND PALEOGEOGRAPHY

Paper number: 347-25
Program: Technical Sessions
Time: 9:00 AM – 6:30 PM

Authors

  • William Junkin Presenting Author
    University of California Santa Barbara, Santa Barbara, CA

Abstract

A subaerial volcanogenic pebble conglomerate in the Principal Cordillera of the Chilean Andes at 35.5°S provides the first strong evidence for the location of a late Middle?-early Late Jurassic, volumetrically important source of intermediate volcanic products. Most likely the source was located within a few kilometers west of the present-day continental divide and consisted of one or more andesitic stratovolcanoes. The pebble conglomerate shares a depositional contact with an overlying quartz rhyolite ignimbrite that yielded a U-Pb zircon age of 162 + 3.2 Ma, the first Jurassic rhyolite reported for the southern Central Andes. This age is inconsistent with the Triassic age previously assumed for local Mesozoic rhyolitic rocks, and thus requires revisions to stratigraphy used to model the development of the Andean back-arc basin and the overall magmatic and deformational evolution of the Mesozoic Central Andean Arc.

Geological Society of America Abstracts with Programs. Vol. 48, No. 7

doi: 10.1130/abs/2016AM-278059

© Copyright 2016 The Geological Society of America (GSA), all rights reserved. Permission is hereby granted to the author(s) of this abstract to reproduce and distribute it freely, for noncommercial purposes. Permission is hereby granted to any individual scientist to download a single copy of this electronic file and reproduce up to 20 paper copies for noncommercial purposes advancing science and education, including classroom use, providing all reproductions include the complete content shown here, including the author information. All other forms of reproduction and/or transmittal are prohibited without written permission from GSA Copyright Permissions.