Published January 15, 2025 | Published
Journal Article Open

Melting the Marinoan Snowball Earth: The impact of deglaciation duration on the sea-level history of continental margins

  • 1. ROR icon California Institute of Technology
  • 2. ROR icon University of California, Santa Cruz
  • 3. ROR icon Oregon State University

Abstract

The termination of the Marinoan Snowball Earth (∼635 Ma) represents a significant transition in Earth's climate. Cap carbonate strata, and underlying glaciogenic deposits, record global deglaciation and preserve diverse relative sea-level histories, representing the intersection of global mean sea-level rise with regional forcings such as glacial isostatic adjustment and sedimentation. For example, at cap carbonate outcrops in the Naukluft Mountains of central Namibia, facies transitions reveal two intervals of water-depth deepening and shallowing. While many factors may have contributed to this deglacial pattern of relative sea-level change, here we consider the possibility that this, and other, non-monotonic sea-level histories, were driven by glacial isostatic adjustment. We modeled relative sea-level change due to glacial isostatic adjustment for a globally synchronous and continuous Marinoan deglaciation, and explored how the duration of deglaciation impacts the range of resulting relative sea-level patterns across continental margins. Short Snowball deglaciation durations, on the order of ∼2 kyr, result in exclusive relative sea-level rise, or relative sea-level rise followed by relative sea-level fall but cannot drive two distinct phases of relative sea-level fall. However, longer duration Snowball deglaciations, of ∼10–30 kyr, can drive two distinct intervals of relative sea-level rise and fall across much of the width of a continental margin, which may have contributed to the stratal patterns observed in Naukluft Mountains cap carbonate, though we cannot exclude that the pattern arises from changes in sediment supply or other factors. This work underlines the need for better constraints on the areal distribution and volume of Marinoan ice sheets from field observations, as well as plausible deglacial durations from global climate models.

Copyright and License

© 2024 The Authors. Published by Elsevier B.V.

This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).

Acknowledgement

We thank Andrew Merdith for generously providing the paleogeographic reconstructions we used in the sea-level models. We also appreciate conversations regarding climate modeling with Greta Shum. This work was financially supported by the National Science Foundation Graduate Research Fellowship Program (NSF GRFP). We are grateful for constructive comments from the two anonymous reviewers, which strengthened this manuscript.

Funding

This work was financially supported by the National Science Foundation Graduate Research Fellowship Program (NSF GRFP). 

Data Availability

Paleogeographies, ice histories, and predicted relative sea level output are available at 10.5281/zenodo.13990992.

Supplemental Material

Supplementary materials (DOCX).

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Additional details

Created:
November 27, 2024
Modified:
November 27, 2024