Open AccessMultiple sulfur isotope evidence for massive oceanic sulfate depletion in the aftermath of Snowball Earth
Author(s) -
Pierre Sansjofre,
Pierre Cartigny,
Ricardo I.F. Trindade,
Afonso César Rodrigues Nogueira,
Pierre Agrinier,
Magali Ader
Publication year - 2016
Publication title -
nature communications
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.559
H-Index - 365
ISSN - 2041-1723
DOI - 10.1038/ncomms12192
Subject(s) - sulfate , snowball earth , sulfur , geology , pyrite , carbonate , isotope , sulfur cycle , environmental chemistry , glacial period , chemistry , oceanography , geochemistry , paleontology , physics , organic chemistry , quantum mechanics
The terminal Neoproterozoic Era (850–542 Ma) is characterized by the most pronounced positive sulfur isotope ( 34 S/ 32 S) excursions in Earth's history, with strong variability and maximum values averaging δ 34 S∼+38‰. These excursions have been mostly interpreted in the framework of steady-state models, in which ocean sulfate concentrations do not fluctuate (that is, sulfate input equals sulfate output). Such models imply a large pyrite burial increase together with a dramatic fluctuation in the isotope composition of marine sulfate inputs, and/or a change in microbial sulfur metabolisms. Here, using multiple sulfur isotopes ( 33 S/ 32 S, 34 S/ 32 S and 36 S/ 32 S ratios) of carbonate-associated sulfate, we demonstrate that the steady-state assumption does not hold in the aftermath of the Marinoan Snowball Earth glaciation. The data attest instead to the most impressive event of oceanic sulfate drawdown in Earth's history, driven by an increased pyrite burial, which may have contributed to the Neoproterozoic oxygenation of the oceans and atmosphere.