Increased Continental Weathering at High latitudes During Late Neoproterozoic?

Late Neoproterozoic Baltic paleosol: Intense weathering at high latitude?

Authors:

Liivamägi et al

Abstract:

The Neoproterozoic was a time when repeated global cooling events, interrupted by supergreenhouse phases, preceded environmental change toward a modern oxygen-rich atmosphere and the eventual emergence of animal life. Cyclically increased atmospheric CO2 levels intensified weathering of continental silicates, but little is known about the influence of Neoproterozoic climates on soil morphogenesis, which acts as a direct proxy of conditions at the time of formation. However, being typically fragmented in time and space, these mineralic soils (paleosols) had a low preservation potential. An exceptionally well preserved Neoproterozoic deeply weathered paleosol on the Baltica paleocontinent provides n ew information on weathering during the Precambrian. The kaolinite-Fe-oxyhydroxide composition of this paleosol is indicative of intense weathering in a stable landscape at a time when Baltica was positioned between intermediate to high southern latitudes. It is plausible that this paleosol developed over long steady-state weathering under temperate climatic conditions, or alternatively during an intensified weathering event triggered by elevated CO2 levels and transient greenhouse climatic conditions at the termination of Ediacaran glaciations, or possibly the Ediacaran Shuram-Wonoka isotope event.