Date of Award
Master of Science
Biosignatures have been extensively studied at hot springs sites, such as Yellowstone, because liquid water is fundamental to the existence of life but also owing to the influx of mineral nutrients in these environments. However, some hot springs have upper temperatures exceeding the boundaries capable of sustaining life in all the spring facies, particularly those nearest the vent. Cold springs provide the same nutrient-rich environment with more ambient temperatures potentially capable of sustaining a diverse consortium of microorganisms across the entirety of the system. Ten Mile Graben Cold Springs, located in Southern Utah, is one such site known for its biota and preservation potential. This study aimed to observe the possible effects of the microorganisms on aragonite and calcite precipitation. Scanning electron microscope imagery observed biogenic fabric such as botryoidal aragonite and aragonite microspheres; however, the δ13C enrichment values of +2.80‰ to +7.30‰ imply the springs were dominantly precipitated through CO2 degassing. This discrepancy in the chemical and morphological data has been observed at other astrobiology analog sites such as Yellowstone; therefore, travertine and tufa seemingly do not preserve isotopic chemical biosignatures.
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