Chapter 41 Glaciogenic and related strata of the Neoproterozoic Kingston Peak Formation in the Panamint Range, Death Valley region, California

Abstract

Abstract Glaciogenic deposits in the Death Valley region occur within the Neoproterozoic Kingston Peak Formation (Fm.). In the Panamint Range, immediately west of Death Valley, the formation is as much as 1000 m thick and is continuously exposed for nearly 100 km along the strike of the range. Although the strata are variably metamorphosed and locally exhibit pronounced ductile strain, original sedimentary textures are well preserved in many places. Diamictite occurs in two distinct intervals, a lower one comprising the Limekiln Spring and Surprise members, and an upper one, the Wildrose Sub-member of the South Park Member. Lonestones, bullet-shaped and striated clasts, and rare dropstones within these members, along with the impressive lateral continuity of diamictic units, support a glacial origin. Both diamictic intervals are succeeded by well-defined carbonates, the oldest is the Sourdough Member of the Kingston Peak Fm. and the younger one is the Sentinel Peak Member of the overlying Noonday Dolomite. The stratigraphic succession between the Sourdough Member and the Wildrose Sub-member (i.e. the Middle Park, Mountain Girl and Thorndike sub-members of the South Park Member) is c. 300 m thick and includes lithologies recording deposition in braided fluvial to platform carbonate settings. Lithostratigraphic and chemostratigraphic profiles of δ 13 C for the Sourdough (–3‰ to +2‰, increasing upward) and Sentinel Peak (–3‰ ±1‰) members suggest correlation with, respectively, the older Cryogenian (commonly referred to as ‘Sturtian’ in previous literature) and younger Cryogenian (commonly referred to as ‘Marinoan’ in previous literature) cap-carbonate sequences recognized worldwide. Potentially economic uranium deposits (secondary brannerite) occur in graphitic schist of the Limekiln Spring Member and sub-economic uranium and thorium (hosted by detrital monazite) occur within quartz-pebble conglomerate in the South Park Member. The Kingston Peak Fm. strata in the Panamint Range contain no fossils, radiometric age control or primary magnetizations.