Neoproterozoic glacial origin of the Great Unconformity

This is a Preprint and has not been peer reviewed. The published version of this Preprint is available: https://doi.org/10.1073/pnas.1804350116.

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Authors

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

Abstract

The Great Unconformity, a profound gap in Earths 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 three to five vertical kilometers, along with the subsequent thermal and isostatic consequences of this erosion for global continental freeboard.

DOI

https://doi.org/10.31223/osf.io/4k6pd

Subjects

Earth Sciences, Geochemistry, Geology, Glaciology, Physical Sciences and Mathematics

Keywords

Snowball Earth, Zircon, Cambrian explosion, glacial erosion, Great Unconformity

Dates

Published: 2019-01-07 11:06

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License

CC BY Attribution 4.0 International

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