THE BECK SPRING DOLOMITE MOUNTAINS AND THE CA. 740-717 MA SARATOGA OROGENY

Proterozoic strata in Death Valley, CA conventionally have been interpreted as being deposited in a long-lived aulacogen that formed during the breakup of Rodinia. Recent geochronological and geological studies, however, have documented four discrete basin-forming events separated by major unconformities. Here, we present geological mapping, stratigraphic, sedimentological and structural data from the Saddle Peak Hills and the Kingston Range that document tectonism that post-dates the deposition of the Saratoga Spring Sandstone (Unit KP1) and is sealed by ca. 635 Ma Marinoan age glacial deposits (Unit KP4). We suggest that the Horse Thief Spring Fm, the Beck Spring Dolomite, and the Saratoga Spring Sandstone were accommodated by strike-slip motion and subsequently folded in a transpressional orogenic event that we refer to as the “Saratoga Orogeny”. This tectonism generated topography, which we refer to as the “Beck Mountains” that is responsible for the emplacement of large olistoliths (<1 km long) in the overlying glacial deposits of the Kingston Peak Formation (KP2-KP3). This tectonism may have been occurring at approximately the same time as ca. 780-635 Ma transpressional structures related to the Neoproterozoic Corn Creek Orogeny in NW Canada, representing a margin-wide transpressional event.