MIXED CARBONATE-CLASTIC SEDIMENTATION IN THE LATE EDIACARAN REED DOLOMITE

The sedimentary record holds the key to understanding the Ediacaran-Cambrian transition, one of the most significant time intervals for the evolution of life in Earth’s history. While the Neoproterozoic-Cambrian proximal succession from the Death Valley region of CA and NV has been extensively studied, distal equivalents in the White-Inyo Mountains (and adjacent areas of CA and NV) have received relatively little attention. As a result, the detailed progression of depositional environments and the overall geometry of the northwest to westward-facing basin have not been well defined yet. Our research focuses on the late Ediacaran Reed Dolomite, which is a dolostone-dominated unit in the White-Inyo Mountains and a suggested equivalent to the Stirling Quartzite of the Death Valley region.

Here, we present a preliminary synthesis of detailed sedimentological and sequence stratigraphical analyses of the Reed Dolomite, with an emphasis on the middle Hines Tongue Member. Specifically, we demonstrate the facies changes throughout this mixed carbonate-siliciclastic member and its lateral variations across the White-Inyo region. In addition, results from carbon and oxygen stable isotope analyses of select sections are presented and discussed within the context of the depositional setting and regional chemostratigraphic correlations. With more Reed Dolomite sections soon to be measured, our results will help improve stratigraphic correlations between the White-Inyo and Death Valley regions and refine the architecture of the southwestern Laurentian margin at the Ediacaran-Cambrian transition.