- Früh-Green, Gretchen Scientist
We are conducting comparative studies that focus on geochemical and microbial processes during serpentinization and the precipitation of carbonate (±brucite) in two high alkaline, ultramafic environments: the active marine Lost City hydrothermal system on the Mid-Atlantic Ridge (MAR, 30°N), and high alkaline, Ca-OH springs associated with present-day serpentinization and carbonate deposits in the Voltri Massif (Liguria, N. Italy). Since 2009 we have sampled fluids and carbonates at twelve alkaline (pH 10-11.6) springs and investigated volatile content, organic and stable isotope geochemistry, and microbiology.
Our field studies are designed to evaluate carbon cycling and microbial metabolisms and thus have focused on co-registered rock and fluid sampling for biological and chemical analyses. We have conducted laboratory analyses to fully characterize the carbon content of the serpentinites, the springs, and the carbonate deposits. By comparing a modern marine system with a modern meteoric environment, we aim to evaluate the importance of abiotic versus biotic processes in the origin of organic compounds associated with serpentinization and to address the question as to whether Lost City is a good bio-geochemical analogue for present-day serpentinization processes on land and in ancient marine systems.