Not all supercontinents are created equal: Gondwana-Rodinia case study

Christopher J. Spencer*, Chris Hawkesworth, Peter A. Cawood, Bruno Dhuime

*Corresponding author for this work

Research output: Contribution to journalArticle (Academic Journal)peer-review

52 Citations (Scopus)

Abstract

The geologic records associated with the formation of the supercontinents Rodinia and Gondwana have markedly different seawater Sr and zircon Hf isotopic signatures. Rodinia-related (Grenville-Sveconorwegian-Sunsas) orogens display significantly less enriched crustal signatures than Gondwana-related (Pan-African) orogens. Seawater Sr isotope ratios also exhibit a more pronounced crustal signal during the span of the Gondwana supercontinent than at the time of Rodinia. Such isotopic differences are attributed to the age and nature of the continental margins involved in the collisional assembly, and specifically to the depleted mantle model ages, and hence the isotope ratios of the material weathered into the oceans. In our preferred model the isotopic signatures of Rodinia-suturing orogens reflect the closure of ocean basins with dual subduction zones verging in opposite directions, analogous to the modern Pacific basin. This would have resulted in the juxtaposition of juvenile continental and island arc terrains on both margins of the colliding plates, thus further reworking juvenile crust. Conversely, the assembly of Gondwana was accomplished primarily via a number of single-sided subduction zones that involved greater reworking of ancient cratonic lithologies within the collisional sutures. The proposed geodynamic models of the assembly of Rodinia and Gondwana provide a connection between the geodynamic configuration of supercontinent assembly and its resulting isotopic signature.

Original languageEnglish
Pages (from-to)795-798
Number of pages4
JournalGeology
Volume41
Issue number7
DOIs
Publication statusPublished - Jul 2013

Keywords

  • EAST-AFRICAN OROGEN
  • CONTINENTAL-CRUST
  • ISOTOPE DATA
  • EVOLUTION
  • GROWTH
  • CRATON
  • EVENTS
  • AMALGAMATION
  • PERSPECTIVE
  • GENERATION

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