Duration and nature of the end-Cryogenian (Marinoan) glaciation

This is a Preprint and has not been peer reviewed. The published version of this Preprint is available: https://doi.org/10.1130/G38089.1.

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Authors

Anthony R. Prave, Daniel Condon , Karl Heinz Hoffmann, Simon , Anthony E. Fallick

Abstract

The end-Cryogenian glaciation (Marinoan) is portrayed commonly as the archetype of snowball Earth, yet its duration and character remain uncertain. Here we report U-Pb zircon ages for two ash beds from widely separated localities of the Marinoan-equivalent Ghaub Formation in Namibia: 639.29 ± 0.26 Ma and 635.21 ± 0.59 Ma. These findings verify, for the first time, the key prediction of the snowball Earth hypothesis for the Marinoan glaciation, i.e., longevity, with a duration of ≥4 m.y. They also show that the nonglacial interlude of Cryogenian time spanned 20 m.y. or less and that glacigenic erosion and sedimentation, and at least intermittent open-water conditions, occurred 4 m.y. prior to termination of the Marinoan glaciation.

DOI

https://doi.org/10.31223/osf.io/xgwa3

Subjects

Earth Sciences, Geology, Physical Sciences and Mathematics, Stratigraphy

Keywords

Geochronology, Snowball Earth, U-Pb, Cryogenian

Dates

Published: 2017-11-05 14:19

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License

Academic Free License (AFL) 3.0

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