Neoproterozoic glacial origin of the Great Unconformity

C. Brenhin Keller, Jon M. Husson, Ross N. Mitchell, William F. Bottke, Thomas M. Gernon, Patrick Boehnke, Elizabeth A. Bell, Nicholas L. Swanson-Hysell, Shanan E. Peters

Research output: Contribution to journalArticlepeer-review

119 Scopus citations

Abstract

The Great Unconformity, a profound gap in Earth’s stratigraphic record often evident below the base of the Cambrian system, has remained among the most enigmatic field observations in Earth science for over a century. While long associated directly or indirectly with the occurrence of the earliest complex animal fossils, a conclusive explanation for the formation and global extent of the Great Unconformity has remained elusive. Here we show that the Great Unconformity is associated with a set of large global oxygen and hafnium isotope excursions in magmatic zircon that suggest a late Neoproterozoic crustal erosion and sediment subduction event of unprecedented scale. These excursions, the Great Unconformity, preservational irregularities in the terrestrial bolide impact record, and the first-order pattern of Phanerozoic sedimentation can together be explained by spatially heterogeneous Neoproterozoic glacial erosion totaling a global average of 3–5 vertical kilometers, along with the subsequent thermal and isostatic consequences of this erosion for global continental freeboard.

Original languageEnglish (US)
Pages (from-to)1136-1145
Number of pages10
JournalProceedings of the National Academy of Sciences of the United States of America
Volume116
Issue number4
DOIs
StatePublished - Jan 22 2019
Externally publishedYes

Bibliographical note

Publisher Copyright:
© 2019 National Academy of Sciences. All Rights Reserved.

Keywords

  • Cambrian explosion
  • Glacial erosion
  • Great Unconformity
  • Snowball Earth
  • Zircon

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