The Paleoproterozoic snowball Earth: A climate disaster triggered by the evolution of oxygenic photosynthesis

Abstract

Although biomarker, trace element, and isotopic evidence have been used to claim that oxygenic photosynthesis evolved by 2.8 giga-annum before present (Ga) and perhaps as early as 3.7 Ga, a skeptical examination raises considerable doubt about the presence of oxygen producers at these times. Geological features suggestive of oxygen, such as red beds, lateritic paleosols, and the return of sedimentary sulfate deposits after a Ϸ900-million year hiatus, occur shortly before the Ϸ2.3-2.2 Ga Makganyene ''snowball Earth'' (global glaciation). The massive deposition of Mn, which has a high redox potential, practically requires the presence of environmental oxygen after the snowball. New age constraints from the Transvaal Supergroup of South Africa suggest that all three glaciations in the Huronian Supergroup of Canada predate the Snowball event. A simple cyanobacterial growth model incorporating the range of C, Fe, and P fluxes expected during a partial glaciation in an anoxic world with high-Fe oceans indicates that oxygenic photosynthesis could have destroyed a methane greenhouse and triggered a snowball event on timescales as short as 1 million years. As the geological evidence requiring oxygen does not appear during the Pongola glaciation at 2.9 Ga or during the Huronian glaciations, we argue that oxygenic cyanobacteria evolved and radiated shortly before the Makganyene snowball.oxygen ͉ Makganyene glaciation ͉ Huronian glaciations ͉ cyanobacteria

Paleoproterozoic glaciation: Evidence from carbon isotope record of the Hutuo Group, Wutai Mountain area of Shanxi Province, China

“…The rise of atmospheric oxygen decreased atmospheric methane concentration [4]. Meanwhile, increasing fixation of atmospheric CO 2 into rock (carbonates) via growth of stromatolites may also have helped the drawdown of greenhouse gas, an important trigger for global glaciation.…”

“…Both the Paleoproterozoic and Neoproterozoic witnessed the assembly and breakup of supercontinents [5], as well as extensive glaciations [4], which were associated with extreme carbon isotope variations [20]. Before glaciation, the marine carbonates have been shown to be enriched in 13 C, and after glaciation, depleted 13 C [20].…”

“…the Makganyene diamictite) [3], North America (e.g. the Huronian diamictite) [4], and Fennoscandia (Finland, Norway, Sweden and Denmark), suggesting a global glaciation event [2,3]. The cause of this "snowball" Earth event has been linked to the Great Oxidation event [5].…”

“…The cause of this "snowball" Earth event has been linked to the Great Oxidation event [5]. It is believed that the methane-rich Paleoproterozoic atmosphere may have kept the Earth surface temperature above the freezing point [6], and subsequent increasing in atmospheric oxygen may have reduced methane concentrations, ultimately triggering the Paleoproterozoic global glaciation [4,7].…”

Osmium evidence for synchronicity between a rise in atmospheric oxygen and Palaeoproterozoic deglaciation

“…E arth's atmosphere is suggested to have shifted from anoxic to oxic in early Palaeoproterozoic during ~2.45-2.2 billion years ago (Ga) [1][2][3][4][5][6][7][8] . Any increase in O 2 would have resulted in reduced atmospheric methane levels, triggering glaciations 2 .…”