Geochemical Constraints on Past Water Inflow into Death Valley, California, from LA-ICP-MS Analysis of Fluid Inclusions in Halite

Authors: Kate Halpin, David Collins, Mebrahtu Weldeghebriel, Tim Lowenstein

Field of Study: Geological Sciences

Faculty Mentors: Tim Lowenstein

Easel: 43

Timeslot: Midday

Abstract: Fluid inclusions in halite record the ionic chemistry of ancient brines, offering a high-resolution proxy for paleolake conditions in closed-basin systems. Recent work has established hydrologic connectivity between Owens, Searles, Panamint, and Death Valleys in California during the penultimate glaciation. The mineral Northupite, documented at a depth of 113 m in Death Valley core DV93-1, provides evidence of alkaline overflow from Searles Valley into Death Valley ~130,000 years ago. This research applies laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) to fluid inclusions in halite above and below this horizon to document the crossing of chemical divides associated with basinal spillover events. Dissolved cations and anions serve as geochemical fingerprints that can identify water sources to reconstruct the timing and frequency of overflow events during Marine Isotope Stage 6 (~191,000-130,000 years ago) and Termination II. Results will constrain how closed-basin waters respond to deglacial transitions in the southwestern United States.