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Mudball: Surface dust and Snowball Earth deglaciation Dorian S. Abbot1,2

Summary: Mudball: Surface dust and Snowball Earth deglaciation
Dorian S. Abbot1,2
and Raymond T. Pierrehumbert3
Received 4 March 2009; revised 2 October 2009; accepted 15 October 2009; published 3 February 2010.
[1] Recent modeling results have raised doubts about the ability to deglaciate from a
global glaciation at atmospheric carbon dioxide levels that are realistic for a
Neoproterozoic Snowball Earth. Here we argue that over the lifetime of a Snowball event,
ice dynamics should lead to the development of a layer of continental and volcanic dust at
the ice surface in the tropics that would significantly lower the tropical surface albedo
and encourage deglaciation. This idea leads to the prediction that clay drapes found on top
of Neoproterozoic glaciations should be thicker in tropical than extratropical regions. We
test this idea by running the FOAM general circulation model (GCM) with an added
tropical dust layer of different sizes and albedos and find that the tropical dust layer causes
Snowball deglaciation at pCO2 = 0.010.1 bar in a reasonable regime of these parameters.
We find similar, though more nuanced, results from a limited number of test cases
using National Center for Atmospheric Research's CAM GCM.
Citation: Abbot, D. S., and R. T. Pierrehumbert (2010), Mudball: Surface dust and Snowball Earth deglaciation, J. Geophys. Res.,
115, D03104, doi:10.1029/2009JD012007.
1. Introduction
[2] During the Neoproterozoic era ($1000 to $542 Ma),


Source: Abbot, Dorian Schuyler - Department of Geophysical Sciences, University of Chicago


Collections: Geosciences