Trace and Rare Earth Element Geochemical Signatures Used to Assess the Sources of Silicate Materials in Atacama Desert Soils

The Atacama Desert of northern Chile is one of the driest deserts on Earth with precipitation levels as low as 2 mm y^-1. Soils in the driest parts of the Atacama record the effects of long-term hyperaridity, retaining atmospherically-derived elements in quantities rarely seen on Earth. Recent work has demonstrated that the hyper-arid environment allows Atacama soils to accumulate large amounts of sulfate (e.g. anhydrite, gypsum), nitrate (NaNO₃), and chloride (halite) that result in radical volumetric expansion of the soil. Possible salt sources include eolian redistribution from Atacama playas and/or marine aerosols. The objective of this work is to examine the trace and rare earth element (REE) chemistry of Atacama soils to assess the sources of silicate materials. Three soils developed on fluvial landforms were examined along a south to north transect (Copiapo > Altamira > Yungay) that coincides with decreasing moisture levels (~15mm to ~2 mm yr^-1, south to north) and with differing eolian sources. Trace and REE chemistry from material collected in soil parent materials, dust traps, and local stream beds will be compared to soils to assess the magnitude of local and distal eolian source contributions to Atacama soils.