Neoproterozoic glacial record in the Death Valley region, California and Nevada

Abstract

The Neoproterozoic succession in the Death Valley region contains a physical- and chemostratigraphic record of glaciation. Direct evidence for glaciation includes dropstones, glacially influenced diamictites, and cap carbonates in the Neoproterozoic Kingston Peak Formation. Within this formation, glacially influenced deposits and cap carbonates occur at two distinct horizons, suggesting at least two glacial episodes. Cap-like carbonates and sequence boundaries elsewhere in the succession may indicate additional glacial intervals. The basal Beck Spring Dolomite has fades and isotopic characteristics commonly associated with cap carbonates, and the rest of the succession is punctuated by numerous sequence boundaries including a prominent incised horizon in the uppermost Johnnie Formation. This horizon is locally overlain by carbonate with cap-like facies and isotopic characteristics. Together, these observations indicate at least two and possibly four distinct Neoproterozoic glaciations.