In spring 2023 the Joides Resolution, the scientific drilling vessel of the International Ocean Discovery Program, recovered a more than 1.2 km long section of upper mantle lithologies at the Atlantis Massif, located at 30°N along the Mid-Atlantic Ridge. Ocean floor drilling recovered primarily serpentinized peridotites (~70%), and gabbroic intrusions and magmatic veins (~30%), thus recovering a unique sequence of upper mantle lithologies never sampled before.
Alteration of upper mantle rocks (peridotites) has wide-ranging implications for mineralogical, geochemical, biological to magmatic and tectonic processes. This includes that seawater-peridotite interaction influence ocean water chemistry over geological timescales, magmatic and ore forming processes in the volcanic arc, and through abiogenic production of hydrogen supports simple microbial lifeforms. Hence, these drill cores can provide insights into fluid-rock-microbe(-magma) interaction in the shallow upper mantle.
Specific research topics may be 1) to investigate the elemental exchange between mafic magmatic veins and surrounding host rock, including magmatic degassing, on providing energy sources for microorganisms and their influence on providing fluid pathways, and 2) investigating the extent and impact of seafloor (serpentinite) weathering on geochemical cycles and microbial communities. These projects will be carried out within a SNSF-funded project that supports two PhD students. Analytics may involve petrographic characterization of thin sections, Raman spectroscopy, X-ray powder diffraction, electron microprobe analyses and/or laser ablation mass spectrometry.
Students interested in this project or in any topic related to fluid-rock interaction processes and metamorphic petrology are welcome to discuss research possibilities with Esther Schwarzenbach.
Advisors: Prof. Esther Schwarzenbach
University: FR