IS THE NOONDAY DOLOMITE A CAP CARBONATE? STRATIGRAPHIC TIMING CONSTRAINTS FROM THE KINGSTON RANGE

Stratigraphic relations between the Kingston Peak and Noonday Dolomite in the Kingston Range, eastern California reveal a complex history between multiple phases of glaciation, tectonics and carbonate deposition associated with deglaciation from a “snowball” event. Glacigenic facies of the Kingston Peak formation are most commonly assigned to the older Sturtian glacial interval (~720 ma) and are unconformably overlain by the Noonday Dolomite, a unit commonly interpreted to be a postglacial cap carbonate based on its distinctive facies and stable isotope geochemistry. The unconformable stratigraphic relation, however, implies that the Noonday Dolomite is not genetically related to the Kingston Peak glaciation- an observation that contradicts current competing models of cap carbonate deposition which link the cap carbonate to postglacial processes. Detailed stratigraphic mapping in the Kingston Range reveals a more complicated stratigraphy in which a significant period of tilting and synsedimentary deposition postdates the youngest glacigenic facies in the Kingston Peak Formation. Thick (~500 m) association of monolithic talus and fanglomerate facies overlie glacigenic facies and are partially interbedded with the basal Noonday Dolomite. Laterally, fanglomerate sediments overlie a second stratigraphic interval of glacial deposits known as the Gunsight Diamictite (Wildrose Formation equivalent?) of possible Marinoan age. The thick succession of fanglomerate, postdating marine glacigenic facies, suggests an intense period of local faulting and uplift capable of removing several kilometers of the Kingston Peak Formation and the underlying Beck Spring Dolomite.