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The transition to a sulphidic ocean approximately 1.84 billion years ago.
Nature. 2004 Sep 09; 431(7005):173-7.Nat

Abstract

The Proterozoic aeon (2.5 to 0.54 billion years (Gyr) ago) marks the time between the largely anoxic world of the Archean (> 2.5 Gyr ago) and the dominantly oxic world of the Phanerozoic (< 0.54 Gyr ago). The course of ocean chemistry through the Proterozoic has traditionally been explained by progressive oxygenation of the deep ocean in response to an increase in atmospheric oxygen around 2.3 Gyr ago. This postulated rise in the oxygen content of the ocean is in turn thought to have led to the oxidation of dissolved iron, Fe(II), thus ending the deposition of banded iron formations (BIF) around 1.8 Gyr ago. An alternative interpretation suggests that the increasing atmospheric oxygen levels enhanced sulphide weathering on land and the flux of sulphate to the oceans. This increased rates of sulphate reduction, resulting in Fe(II) removal in the form of pyrite as the oceans became sulphidic. Here we investigate sediments from the approximately 1.8-Gyr-old Animikie group, Canada, which were deposited during the final stages of the main global period of BIF deposition. This allows us to evaluate the two competing hypotheses for the termination of BIF deposition. We use iron-sulphur-carbon (Fe-S-C) systematics to demonstrate continued ocean anoxia after the final global deposition of BIF and show that a transition to sulphidic bottom waters was ultimately responsible for the termination of BIF deposition. Sulphidic conditions may have persisted until a second major rise in oxygen between 0.8 to 0.58 Gyr ago, possibly reducing global rates of primary production and arresting the pace of algal evolution.

Authors+Show Affiliations

Danish Center for Earth System Science, Institute of Biology, University of Southern Denmark, Campusvej 55, 5230 Odense M, Denmark. s.poulton@biology.sdu.dkNo affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

15356628

Citation

Poulton, Simon W., et al. "The Transition to a Sulphidic Ocean Approximately 1.84 Billion Years Ago." Nature, vol. 431, no. 7005, 2004, pp. 173-7.
Poulton SW, Fralick PW, Canfield DE. The transition to a sulphidic ocean approximately 1.84 billion years ago. Nature. 2004;431(7005):173-7.
Poulton, S. W., Fralick, P. W., & Canfield, D. E. (2004). The transition to a sulphidic ocean approximately 1.84 billion years ago. Nature, 431(7005), 173-7.
Poulton SW, Fralick PW, Canfield DE. The Transition to a Sulphidic Ocean Approximately 1.84 Billion Years Ago. Nature. 2004 Sep 9;431(7005):173-7. PubMed PMID: 15356628.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - The transition to a sulphidic ocean approximately 1.84 billion years ago. AU - Poulton,Simon W, AU - Fralick,Philip W, AU - Canfield,Donald E, PY - 2004/04/27/received PY - 2004/07/29/accepted PY - 2004/9/10/pubmed PY - 2004/10/1/medline PY - 2004/9/10/entrez SP - 173 EP - 7 JF - Nature JO - Nature VL - 431 IS - 7005 N2 - The Proterozoic aeon (2.5 to 0.54 billion years (Gyr) ago) marks the time between the largely anoxic world of the Archean (> 2.5 Gyr ago) and the dominantly oxic world of the Phanerozoic (< 0.54 Gyr ago). The course of ocean chemistry through the Proterozoic has traditionally been explained by progressive oxygenation of the deep ocean in response to an increase in atmospheric oxygen around 2.3 Gyr ago. This postulated rise in the oxygen content of the ocean is in turn thought to have led to the oxidation of dissolved iron, Fe(II), thus ending the deposition of banded iron formations (BIF) around 1.8 Gyr ago. An alternative interpretation suggests that the increasing atmospheric oxygen levels enhanced sulphide weathering on land and the flux of sulphate to the oceans. This increased rates of sulphate reduction, resulting in Fe(II) removal in the form of pyrite as the oceans became sulphidic. Here we investigate sediments from the approximately 1.8-Gyr-old Animikie group, Canada, which were deposited during the final stages of the main global period of BIF deposition. This allows us to evaluate the two competing hypotheses for the termination of BIF deposition. We use iron-sulphur-carbon (Fe-S-C) systematics to demonstrate continued ocean anoxia after the final global deposition of BIF and show that a transition to sulphidic bottom waters was ultimately responsible for the termination of BIF deposition. Sulphidic conditions may have persisted until a second major rise in oxygen between 0.8 to 0.58 Gyr ago, possibly reducing global rates of primary production and arresting the pace of algal evolution. SN - 1476-4687 UR - https://www.unboundmedicine.com/medline/citation/15356628/The_transition_to_a_sulphidic_ocean_approximately_1_84_billion_years_ago_ L2 - https://doi.org/10.1038/nature02912 DB - PRIME DP - Unbound Medicine ER -