A geochemical test of the Snowball Earth hypothesis.

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• Francis Macdonald, UC Berkeley
• Tuesday 05 November 2024, 12:00-13:00
• Department of Earth Sciences, Tilley Lecture Theatre.

If you have a question about this talk, please contact Dr Rachael Rhodes.

The Snowball Earth hypothesis predicts that the hydrological cycle was effectively shut down for millions of years, cutting off silicate weathering of the continental crust. In this scenario, the deep ocean should have equilibrated with the geochemistry of mantle through hydrothermal exchange at mid-ocean ridges. Here we report the discovery of mantle-like Sr isotope values in marine carbonate and barite that rest directly above ca. 717-661 Ma Sturtian glacial deposits in Oman. These new data and geochemical modeling support an extreme Snowball Earth scenario with near complete ice cover and reduced continental weathering for 56 Myr. The duration and extent of the Sturtian glaciation created a major bottleneck for the evolution of eukaryotes, clearing the way for the rise of algae and origin of animals.

This talk is part of the Department of Earth Sciences Seminars (downtown) series.

This talk is included in these lists:

• Department of Earth Sciences Seminars (downtown)
• Department of Earth Sciences seminars
• Department of Earth Sciences, Tilley Lecture Theatre
• ps635

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