Siberia: No Sign of a Snowball Earth Here

Testing the snowball Earth hypothesis for the Ediacaran

Authors:

a. Alexei V. Ivanov (a)
b. Anatoly M. Mazukabzov (a)
c. Arkady M. Stanevich (a)
d. Stanislav V. Palesskiy (b)
e. Olga A. Kozmenko (b)

Affiliations:

a. Institute of the Earth's Crust, Siberian Branch, Russian Academy of Sciences, Lermontov Street 128, Irkutsk 664033, Russia

b. Institute of Geology and Mineralogy, Siberian Branch, Russian Academy of Sciences, Academician Koptyug Boulevard 3, Novosibirsk 630090, Russia

Abstract:

Ediacaran Siberia was at tropical paleolatitudes when the glacigenic strata of the Goloustnaya Formation (Baikal Group, Siberia) were deposited at sea level. The presence of such deposits (at tropical latitudes) is at the core of the snowball Earth hypothesis, which is generally accepted for the previous Cryogenian glaciations. To test this hypothesis for the Ediacaran Period, we determined concentrations of platinum group elements (PGE) in the transitional unit between glacigenic conglomerates and postglacial cap carbonates of the Goloustnaya Formation. We speculate that if oceans were completely covered by ice during the glaciation, the ice prevented accumulation of PGE-rich cosmic dust and micrometeorites during that period, i.e., the snowball Earth stage. Such particles would have accumulated rapidly on the ocean floor at the ice-melting event, providing a geochemical signal; however, unlike the previous Cryogenian glaciations, this signal is at a background level, and we conclude that either the Ediacaran glaciation did not reach the snowball stage, or it was of very short duration.