Paper No. 6
Presentation Time: 3:10 PM
RECENT ANALOGS FOR SNOWBALL EARTH SEDIMENTS AND STRATIGRAPHY DISCOVERED BENEATH ANTARCTIC ICE SHELVES: CHANGING PARADIGMS AND CHALLENGING NAYSAYERS
Despite nearly 50 years of intense scientific investigation since the IGY vast areas of the Antarctic continental margin remain unexamined and this is particularly so for regions beneath ice shelves and ice sheets. As new areas open up for scientific exploration, due to advanced technology and/or climatically induced ice shelf collapse, newly examined deposystems are providing useful facies context for ancient strata, including those of Neoproterozoic age (i.e. Cryogenian to Ediacaran). While the Snowball Earth hypothesis rests on the agreement of a diverse set of geochemical, sedimentologic, and geochronology data sets, acceptance of the concept has been challenged based upon sedimentologic arguments—arguments which utilize general assumptions about: ice rafting, facies succession, biota, and glacial thermal regime. Detailed examples based upon sub ice shelf sediments from Antarctica are used to demonstrate that general principles, employed by some investigators to detract from a coherent interpretation of Cryogenian strata, are invalid and in need of revision. Furthermore, specific facies context for Neoproterozoic successions in East Greenland, Svalbard, Namibia, and Australia are used to exemplify how new discoveries made in Antarctica can provide more realistic interpretations of such ancient strata. The Antarctic realm is the best analogy we have for conditions proposed to be in existence in an ice bound earth, and we are just beginning to uncover the hidden worlds beneath the ice and the light they can shed into deep time.