Daniel Lehman
An examination of the Warner valley in south central oregon - a mars analogue environment
BSES Senior Research Project 2007

Abstract
The Warner Valley is a closed-drainage basin located on the Oregon Basalt Plateau in south central Oregon. Numerous alkaline lakes, saline playas, and hydrothermal springs occur within this non-marine, evaporitic setting. This location represents a possible analogue for alkaline aqueous Precambrian Earth and Noachian Mars environments. My research in the Warner Valley focuses on sulfur isotopic signatures resulting from evporitic concentration of lake waters and associated microbial metabolisms during changing salinity. Extensive and diverse algal/bacterial mat communities were observed and collected along with sediment and water samples from two primary study sites. Sulfur isotopic analysis on these samples will provide critical information on current sulfur cycling in this basaltic terrestrial setting. In preparation for exploration of Mars, geochemical research on sulfur cycling in non-marine, evaporitic settings is needed to define the types of instruments and landing sites.
Sulfur isotopic composition of microbial mat and sediment samples were carried out by sequential extraction. Elemental sulfur, acid-volatile (monosulfides), acid-soluble (sulfates), and Cr-reducible (disulfide) phases were recovered in the forms of BaSO4 and Ag2S. Final analysis by a stable isotope mass-spectrometer has not been completed. Final sulfur isotopic compositions will contribute significantly to what may be and sulfur “fingerprint” at similar terrestrial environments or even martian in nature.

Figure 1. Warner Valley Oregon field site