Gabbro Discovery in Discovery Deep: First Plutonic Rock Samples From the Red Sea Rift Axis

Plutonic rocks such as gabbros provide information on magmatic and tectonic processes which occur beneath a mid-ocean rift axis well the formation of oceanic crust. Igneous rocks, reported from Red Sea Rift valley, have been limited to extrusive basalts so far. The only deeper crustal found in area are flanks interpreted late-stage continental magmatism. Here, we present geochemistry first recovered gabbro fragments Rift, sampled crater structure within brine-filled Discovery Deep at Rift. Petrology show characteristics typical ridge formed shallow crystallization depth. Clinopyroxene core mineral data fall two groups, thus pointing multiphased history, including different magma batches joint fractional crystallization. Geobarometry, based clinopyroxene cores, suggests lower pressures than similar geobarometric for gabbroic samples Zabargad (8–9 kbar) Brother’s Islands (2.5–3.5 flanks. However, evolved whole rock composition, its multiphase thickness crust, current location samples, uncertainties barometer, estimates likely overestimated. Instead, propose that these originate upper part fully developed crust central High-resolution bathymetry sparker seismic reveal is characterized by significant normal fault strong reflector near axis, interpret potential sill intrusion an approximate depth 400 m. Based lack progressive alteration sampling sediment-free structure, emplacement has be geologically recent. We either xenolith transported eruptive volcanism crater, potentially related visible depth, or intrusive gabbro, was uplifted deposited talus fan adjacent fault, exposed volcanic crater.