The Cryogenian record in the southern Kingston Range, California: The thickest Death Valley succession in the hunt for a GSSP

摘要

The Kingston Peak Formation of the Death Valley area, California, allows valuable insight into both regional Cordilleran stratigraphy and the number of glacial cycles preserved in the Cryogenian record. In the Kingston Range, the eponymous strata have been previously interpreted to record both Sturtian and Marinoan pan-glacial events. In the context of a search for a Global Boundary Stratotype Section and Point (GSSP) for the Cryogenian, we provide the first detailed description of the thickest diamictite-bearing interval in the western USA. Two clast-poor, muddy diamictite intervals within the succession-one at the base, and one near the top-have been used to support Sturtian and Marinoan events previously. However, new data from the southern part of the Kingston Range suggest that the upper diamictite interval is genetically related to underlying strata. The deposits are interpreted as glaciogenic debris flow deposits which probably represent the proximal tract of a subaqueous fan. Medial to distal portions of this fan are dominated by turbidites, which were transported down a consistent SE-oriented palaeoslope. Lowermost beds of the upper diamictite interval are intercalated with graded sandstones and sandy, matrix supported conglomerates. The graded beds (turbidites) and matrix-supported conglomerates (debrites) testify to a subaqueous setting, with the compositionally and texturally distinct diamictites indicating a glacial origin.