Capturing the Mesoarchean Emergence of Continental Crust in the Coorg Block, Southern India

This is a Preprint and has not been peer reviewed. The published version of this Preprint is available: https://doi.org/10.1029/2018GL078114.

Downloads

Download Preprint

Supplementary Files
Authors

Nick Roberts , M Santosh

Abstract

The emergence of Earths continental crust above sea‐level is debated. To assess whether emergence can be observed at a regional scale, we present zircon U‐Pb‐Hf‐O isotope data from magmatic rocks of the Coorg Block, southern India. A 3.5 Ga granodiorite records the earliest felsic crust in the region. Younger phases of magmatism at 3.37‐3.27 Ga and 3.19‐3.14 Ga, comprising both reworked crust and juvenile material, record successive crustal maturation. We interpret an elevation in δ18O through time as an increase in both the amount of sediment recycling, and hence, crustal thickening, as well as an increase in the emerged area of continental crust available for weathering. Geochemical signatures do not point to any apparent change in geodynamic regime. We interpret the isotopic evolution of these rocks as solely reflecting regional emergence and thickening of the continental crust, assisted by the increasing strength of the lithosphere.

DOI

https://doi.org/10.31223/osf.io/hfvzp

Subjects

Earth Sciences, Geochemistry, Physical Sciences and Mathematics, Tectonics and Structure

Keywords

Continental Crust, India, Zircon, Hf isotopes, continental emergence, oxygen isotope

Dates

Published: 2018-07-17 15:29

Older Versions
License

CC BY Attribution 4.0 International

Add a Comment

You must log in to post a comment.


Comments

There are no comments or no comments have been made public for this article.