EVALUATING EVIDENCE FOR LAKE LEVEL CHANGE FROM A NEAR SHORE SEDIMENT CORE IN LAKE MOJAVE (SILVER LAKE, CA)

The Mojave Desert’s limited water resources make it especially susceptible to climate change. Understanding the paleoclimatic history of pluvial lakes like Lake Mojave provides key insights into the region’s hydroclimatic future. Lake Mojave was a large desert lake system that formed after the draining of Lake Manix. Although well-studied (e.g., Wells et al., 2003), we apply a combination of physical, chemical, and biological analyses on a new core (SLDC18-3) to refine its history, focusing on the late-Glacial to Holocene transition (ca. 13-7 ka). SLDC18-3 is a ~10 m sediment core extracted from the southern end – modern fan-delta complex – of Silver Lake (formally the southern section of Lake Mojave). Initial results indicate an abrupt change from a perennial lake (fine-grained) to a Holocene ephemeral playa (coarse-grained) system. This change contrasts with core SLDC18-1 taken from the lake’s depocenter at the northern end of Lake Mojave, which suggests a more gradual transition from a perennial to ephemeral lake. This difference likely reflects the high energy dynamics of the near shore core site where generally shallower conditions favor sediment reworking and removal. The early Holocene shows evidence for variable sediment input and energy dynamics as expected in the shallower portion of the lake system. On-going work includes radiocarbon dates, ostracod counts, and additional grain size analyses, which will refine the timing of lake changes and characterize/identify depositional environments.