DOI: 10.1073/pnas.97.4.1400. Paleoproterozoic snowball Earth: Extreme climatic and geochemical global change and its biological consequences

Paleoproterozoic snowball Earth: Extreme climatic and geochemical global change and its biological consequences

10.1073/pnas.97.4.1400

Crossref journal-article

Proceedings of the National Academy of Sciences

Proceedings of the National Academy of Sciences (341)

Abstract

Geological, geophysical, and geochemical data support a theory that Earth experienced several intervals of intense, global glaciation (“snowball Earth” conditions) during Precambrian time. This snowball model predicts that postglacial, greenhouse-induced warming would lead to the deposition of banded iron formations and cap carbonates. Although global glaciation would have drastically curtailed biological productivity, melting of the oceanic ice would also have induced a cyanobacterial bloom, leading to an oxygen spike in the euphotic zone and to the oxidative precipitation of iron and manganese. A Paleoproterozoic snowball Earth at 2.4 Giga-annum before present (Ga) immediately precedes the Kalahari Manganese Field in southern Africa, suggesting that this rapid and massive change in global climate was responsible for its deposition. As large quantities of O 2 are needed to precipitate this Mn, photosystem II and oxygen radical protection mechanisms must have evolved before 2.4 Ga. This geochemical event may have triggered a compensatory evolutionary branching in the Fe/Mn superoxide dismutase enzyme, providing a Paleoproterozoic calibration point for studies of molecular evolution.

Bibliography

Kirschvink, J. L., Gaidos, E. J., Bertani, L. E., Beukes, N. J., Gutzmer, J., Maepa, L. N., & Steinberger, R. E. (2000). Paleoproterozoic snowball Earth: Extreme climatic and geochemical global change and its biological consequences. Proceedings of the National Academy of Sciences, 97(4), 1400â1405.

Authors 7

Joseph L. Kirschvink (first)
Eric J. Gaidos (additional)
L. Elizabeth Bertani (additional)
Nicholas J. Beukes (additional)
Jens Gutzmer (additional)
Linda N. Maepa (additional)
Rachel E. Steinberger (additional)

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Dates

Type	When
Created	23 years, 1 month ago (July 26, 2002, 10:35 a.m.)
Deposited	3 years, 2 months ago (June 7, 2022, 1:12 a.m.)
Indexed	16 minutes ago (Aug. 29, 2025, 10:46 p.m.)
Issued	25 years, 6 months ago (Feb. 15, 2000)
Published	25 years, 6 months ago (Feb. 15, 2000)
Published Online	25 years, 6 months ago (Feb. 15, 2000)
Published Print	25 years, 6 months ago (Feb. 15, 2000)

Funders 0

None

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  ]
}