This is a past event
Please join us for a research seminar presented by Gretchen Früh-Green, senior research scientist at the Institute of Geochemistry and Petrology of ETH Zurich. The Seminar will take place at 1pm on 2nd November in Meston Lecture Theatre 2. All are welcome to attend.
Abstract: Progressive interaction of seawater with mantle-dominated lithosphere during serpentinization is a fundamental process that controls rheology and geophysical properties of the oceanic lithosphere and has major consequences for heat flux, geochemical cycles and microbial activity in a wide variety of environments. At slow spreading ridge environments, serpentinization occurs along detachment faults (major, large-scale offset normal faults), as mantle rocks are uplifted to the seafloor and are incorporated in dome-shaped massifs known as oceanic core complexes. The processes controlling fluid flow and a deep biosphere are intimately linked, however, the spatial scale of lithological variability, the implications for geochemical cycles and the consequences for subsurface ecosystems supported by these systems remain poorly constrained. This lecture will provide an overview of mid-ocean ridge processes and will highlight recent results of IODP Expedition 357, which aimed to investigate the links between serpentinization processes and microbial activity in the shallow subsurface of the Atlantis Massif on the western flank of the Mid-Atlantic Ridge at 30°N. The Atlantis Massif is one of the best-studied oceanic core complexes and hosts the unique Lost City hydrothermal field on its southern wall. Serpentinization reactions in the underlying mantle rocks at Lost City produce high pH fluids that form large carbonate-brucite structures upon venting on the seafloor. The fluids have negligible dissolved carbonate and metals, but have high concentrations of hydrogen, methane and formate that support novel microbial communities. Exp. 357 used seabed rock drilling technology for the first time in the history of ocean drilling to recover ultramafic and mafic rock sequences along a detachment fault zone. The expedition also successfully applied new technologies that provide insight into active serpentinizing systems at slow-spreading ridges.
- Venue
- Meston Lecture Theatre 2