Late Archean Sulfidic Sea Caused by Continental Weathering?

A Late Archean Sulfidic Sea Stimulated by Early Oxidative Weathering of the Continents


1. Christopher T. Reinhard (1)

2. Rob Raiswell (2)

3. Clint Scott (1)

4. Ariel D. Anbar (3)

5. Timothy W. Lyons (1,*)


1 University of California–Riverside, Department of Earth Sciences, Riverside, CA 92521, USA.

2 University of Leeds, School of Earth and Environment, Leeds, UK LS2 9JT.

3 Arizona State University, School of Earth and Space Exploration and Department of Chemistry and Biochemistry, Tempe, AZ 85287, USA.

* To whom correspondence should be addressed. E-mail: timothyl@ucr.edu

Abstract:

Iron speciation data for the late Archean Mount McRae Shale provide evidence for a euxinic (anoxic and sulfidic) water column 2.5 billion years ago. Sulfur isotope data compiled from the same stratigraphic section suggest that euxinic conditions were stimulated by an increase in oceanic sulfate concentrations resulting from weathering of continental sulfide minerals exposed to an atmosphere with trace amounts of photosynthetically produced oxygen. Variability in local organic matter flux likely confined euxinic conditions to midportions of the water column on the basin margin. These findings indicate that euxinic conditions may have been common on a variety of spatial and temporal scales both before and immediately after the Paleoproterozoic rise in atmospheric oxygen, hinting at previously unexplored texture and variability in deep ocean chemistry during Earth’s early history.

I wonder how this dovetails (or doesn't) with "Anoxygenic photosynthesis modulated Proterozoic oxygen and sustained Earth's middle age." IDK why in the world the Lab doesn't have access to Science of all journals.

*shakes head*