Crustal thickening and clay

Controls on O isotope variation in global magmatism and siliciclastic sedimentary rocks

Justin L. Payne*, Martin Hand, Norman J. Pearson, Karin M. Barovich, David J. McInerney

*Corresponding author for this work

Research output: Contribution to journalArticle

16 Citations (Scopus)

Abstract

New compilations of global O isotope data from zircon and siliclastic sedimentary rocks highlight an increasing range in δ18O values in both systems since the late Archean. This is consistent with an increased clay component in sedimentary rocks and subsequent incorporation into igneous rocks. Each of these factors can arguably be achieved by increased crustal thickening in the late Archean resulting in greater burial and melting of supracrustal rocks and increased chemical weathering and recycling of upper crustal rocks. Despite the suggested change in tectonic regimes in the late Archean, stochastic modelling in this study demonstrates that δ18O data do not provide evidence for a secular decrease in the proportion of mantle-derived magmas in granitoid rocks. Instead, best-fit models indicate that juvenile input and reworking of supracrustal material vary with respect to the short term (100-200 Myr) tectonic cycles preserved in the continental crust. Hence, major step changes in global tectonic regimes in the post-Hadean, such as the initiation of subduction in the mid- to late Archean, are not supported by global zircon O isotope datasets and instead minor, progressive changes are indicated for Earth's tectonic regimes.

Original languageEnglish
Pages (from-to)70-76
Number of pages7
JournalEarth and Planetary Science Letters
Volume412
DOIs
Publication statusPublished - 5 Feb 2015

Keywords

  • Archean magmatism
  • Clay production
  • Continental growth
  • Oxygen isotopes
  • Zircon

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