Oceanic core complex

An ocean-floor dome exposing deep crustal and mantle rocks, formed when long-lived, low-angle normal faults exhume them at slow-spreading ridges.

Oceanic detachment fault: A long-lived, low-angle normal fault that exposes deep rocks at a mid-ocean ridge. Its slip exhumes the rocks that form an oceanic core complex.
Mid-ocean ridge: A submarine mountain chain where tectonic plates diverge and new oceanic lithosphere forms. Oceanic core complexes develop within this spreading environment.
Atlantis Massif: A prominent oceanic core complex near the Mid-Atlantic Ridge, west of the Atlantis Transform Fault. Its exposed rocks and hydrothermal field are extensively studied.
Magmatic accretion: The addition of magma-derived rock to Earth’s crust during tectonic spreading. Core complexes record fault-driven exposure where magmatic construction is incomplete.
Footwall exhumation: The upward exposure of rocks carried in the footwall of a fault. This process brings deep crust and mantle to the seafloor.
Slow spreading ridge: A mid-ocean ridge with a low rate of plate separation, commonly marked by deep axial valleys. Its uneven magma supply and faulting permit core-complex formation.
Kane Megamullion: A large oceanic core complex near the Kane Transform Fault on the Mid-Atlantic Ridge. It provides a well-mapped example of detachment-related seafloor relief.
Volcanic ridge: A ridge built chiefly by volcanic eruptions and accumulated lava. Its volcanic construction contrasts with the deep-rock exposure of core complexes.
Magma-starved ridge: A spreading ridge segment where magma supply is insufficient to accommodate most plate separation. Limited magma favors tectonic extension on long-lived faults.
Oceanic crust: The basaltic and gabbroic upper layer of oceanic lithosphere. Core complexes can expose lower crust beneath the volcanic seafloor.

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