T19 Origin and Evolution of the Continental Crust: A Celebration of the Career of Paul Mueller

Sunday, 22 October 2017
8:00 AM - 12:00 PM
Skagit 2

AN ISOTOPIC PERSPECTIVE ON GROWTH AND DIFFERENTIATION OF PROTEROZOIC OROGENIC CRUST: FROM SUBDUCTION MAGMATISM TO CRATONIZATION

Paper number: T19-7
Program: Technical Sessions
Time: 9:30 AM – 9:45 AM

Authors

Abstract

The in situ chemical differentiation of continental crust ultimately leads to the long-term stability of the continents. This process, more commonly known as ‘cratonization’, is driven by deep crustal melting with the transfer of melts to shallower regions resulting in a strongly chemically stratified crust, with a refractory, dehydrated lower portion overlain by a complementary enriched upper portion. Since the lower to mid portions of continental crust are rarely exposed, investigation of the cratonization process must be through indirect methods. In this study we report in situ Hf and O isotope compositions of both magmatic and inherited zircons from several well-dated felsic magmatic suites in the Capricorn Orogen of Western Australia to highlight the differentiation history (i.e. cratonization) of this portion of late Archean to Proterozoic orogenic crust. The Capricorn Orogen shows a distinct tectonomagmatic history that evolves from an active continental margin through to intraplate reworking, ultimately leading to thermally stable crust that responds similarly to the adjacent Archean Pilbara and Yilgarn Cratons. The data define not only the source components from which the magmas were derived, but a range of physical and chemical processes that operated during magma transport and emplacement. These data also identify a previously unknown crustal reservoir in the Capricorn Orogen that may represent the remnants of an Ophthalmian-aged magmatic arc.

Geological Society of America Abstracts with Programs. Vol. 49, No. 6

doi: 10.1130/abs/2017AM-304863

© Copyright 2017 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.