Introduction

Active seafloor hydrothermal systems occur at the interface between the high temperature interior of the Earth and the cold hydrosphere. Across this interface there are large gradients in temperature, redox conditions, pH and other fluid chemistry. These gradients result in formation of a diverse range of minerals, and the minerals form a wide variety of structures. The structures harboring the steepest gradients are the "black smokers" where hydrothermal fluid, at a maximum temperature near 400 deg.C, is injected directly into cold, 2 deg.C seawater. Since the discovery of these vents about twenty years ago, an enormous amount has been learned about the geochemistry, mineralogy, fluid flow regimes, and biology in these systems. The natural systems are very complex, and that complexity sometimes makes it difficult to isolate or identify specific processes.

We have formed a research group whose members have a wide range of backgrounds to study hydrothermal processes experimentally. Our goals are to understand the interactions between geochemistry, mineralogy, surface catalysis, abiotic organic synthesis, and microbial ecology. We are primarily using laboratory systems that simulate various aspects of the pressure, temperature and chemical environments found in seafloor hydrothermal systems on Earth. Additionally we are investigating possible differences between hydrothermal systems on the present Earth, the early Earth, Mars and Europa.

• Dawn Ashbridge, graduate student in Geology, BS in Biology
• Karl Booksh, Prof. of Chemistry (Analytical)
• Brandon Canfield, graduate student in Chemistry, BS in Biology
• Eileen Dunn, Technologist/engineer
• Pete Dalla-Betta, RIDGE program post-doc, Ph. D. in microbiology
• Tamara Diedrich, graduate student in Geology, BS in Geology
• Darcy Gentleman, graduste student in Chemistry, BS in Planetary Science
• John Holloway, Prof. of Geology , and Chemistry & Biochemistry (Geochemistry)
• Michelle Nahorniak, graduate student in Chemistry (Analytical)
• Peggy O'day, Prof of Geology (Aqueous and environmental geochemistry)
• Julia Muccino, Prof. of Civil Engineering (Computational fluid dynamics)
• Ken Voglesonger, graduate student in Geology, BS in Environmental Geosciences
• Lynda Williams, Faculty research associate, Center for Solid State Science, Ph. D. in clay mineral geochemistry

Research Projects

Artificial black smoker system (ABS): One way to determine details of processes occurring at seafloor vents would be to use an artificial laboratory-scale system in which chemical and physical conditions could be varied to suit the experiment, and external and in situ measurements could be recorded continuously. The system required to do these experiments is complex and is in a state of continuous development. Stay tuned.

Catalytic Reactor Vessel System (CRV): This system is designed to measure the catalytic effect of selected mineral surfaces on the systhesis of organic compounds from CO2, H2, and H2O. The system design allows experiments to be conducted in the gas phase, the liqued phase, the gas + liquid region, or the supercritical fluid region. To date we have found that methyl alcohol (methanol) can be synthesized in the gas phase region at 360êC and 150 bars.

Fiber Optic Chemical Sensors: We are developing and testing two types of fiber optic probe for use in in situ analysis of seafloor hydrothermal fluids. One technique uses Surface Plasmon Resonance (SPR) to determine the refractive index of the fluid. The refractive index can be related to total salt content. The second technique is Raman spectroscopy, which can be used to determine the kind, and amount of a number of aqueous molecules and polyatomic ions. We are just beginning this project.

Page last updated April 19, 2002. Comments and Suggestions to Darren Locke