Spatial and temporal evolution of plume-ridge interaction and its geo- and biological impact on the Foundation Segment (Pacific-Antarctic Ridge) – SPRINTER

• Applicants: Dr. Philipp Brandl; Professorin Dr. Angelika Brandt; Professorin Dr. Mirjam Perner; Professorin Dr. Sylvia Gertrud Sander
• Subject Area: Geology ; Mineralogy, Petrology and Geochemistry ; Structural Biology
• Term: since 2026
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 564896340

Plume-ridge interactions are common in modern plate tectonics. Plumes are characterized by higher degrees of partial melting of enriched sources and a mantle flow regime that is distinct from mid-ocean ridges. The southern Pacific Foundation Plume is relatively weak but introduces a geochemical tracer into the adjacent Pacific-Antarctic Ridge (PAR). The detection of this signal in rocks of different ages makes it possible to reconstruct the interaction between the two systems over at least 5 million years. Brandl et al. (2024) have shown that, at least today, an asthenospheric flow controls the dispersion of plume material along the PAR. The geochemical signal of this interaction is preserved in rocks of the oceanic crust to the west of the PAR and we thus propose sampling perpendicular to the PAR axis. Furthermore, numerous felsic domes are found at the PAR and are associated with active hydrothermal venting. The geological setting and formation of these felsic rocks, and fauna of the associated vents are largely unknown. We plan to systematically explore this region using AUV and ROV. The interplay between differentiated host rocks and hydrothermal fluids, as well as their impact on hydrothermal precipitates, nutrients and microbial and faunal communities, is of particular importance. To date, there is little biological knowledge from the PAR between 34°S and 42°S, with some video footage from 37°47'S. These preliminary data indicate a distinct biogeographic vent region. Representative samples of fauna are yet to be taken but are integral to species identification and understanding relationships between species in different vent areas. Our proposed study aims at a holistic understanding of the Foundation-PAR plume-ridge interaction from the mantle and the crust to the hydro- and biospheres.

• DFG Programme: Infrastructure Priority Programmes
• Subproject of: SPP 2520: Infrastructure area - Research Vessels