A Complex Microbiota from Snowball Earth Times: Microfossils from the Neoproterozoic Kingston Peak Formation, Death Valley, USA
A complex microbiota from snowball Earth times: Microfossils from the Neoproterozoic Kingston Peak Formation, Death Valley, USA Frank A. Corsetti*†, Stanley M. Awramik‡, and David Pierce‡ *Department of Earth Sciences, University of Southern California, Los Angeles, CA 90089; and ‡Department of Geological Sciences, Preston Cloud Research Laboratory, University of California, Santa Barbara, CA 93106 Communicated by John C. Crowell, University of California, Santa Barbara, CA, January 29, 2003 (received for review October 7, 2002) A thin carbonate unit associated with a Sturtian-age (Ϸ750–700 did they experience severe or moderate extinction during the million years ago) glaciogenic diamictite of the Neoproterozoic glacial events? Did surviving clades undergo radiation after Kingston Peak Formation, eastern California, contains microfossil the glacial events, as might be predicted with such an environ- evidence of a once-thriving prokaryotic and eukaryotic microbial mental crisis (e.g., ref. 7)? Can we observe evidence of the community (preserved in chert and carbonate). Stratiform stroma- environmental filter (3) or ‘‘bottlenecks’’ (7) that have been tolites, oncoids, and rare columnar stromatolites also occur. The hypothesized? microbial fossils, which include putative autotrophic and hetero- Here, we report the implications of diverse fossil microbiotas trophic eukaryotes, are similar to those found in chert in the from the Death Valley region, California, found immediately underlying preglacial units. They indicate that microbial life preceding and within (or possibly capping) demonstrably glacial adapted to shallow-water carbonate environments did not suffer strata deposited during one of the Neoproterozoic snowball the significant extinction postulated for this phase of low-latitude Earth episodes. Although diverse microbiotas are known from glaciation and that trophic complexity survived through snowball strata that immediately postdate snowball events (e.g., Tindir Earth times.
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