Detachments in Oceanic Lithosphere: Deformation, Magmatism, Fluid Flow, and Ecosystems

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Abstract

[1] AGU Chapman Conference on Oceanic Detachments; Agros, Cyprus, 8–15 May 2010; Oceanic detachments are large-offset normal faults along the flanks of mid-ocean ridges. They represent a mode of accretion of the oceanic lithosphere that is fundamentally different from classical “magmatic” models, resulting in lithospheric composition and structure that are strikingly different from the Penrose model established 40 years ago of a layered magmatic crust. Oceanic detachments, which exhume deep lithosphere, forming oceanic core complexes (OCCs), are scientifically interesting because they represent tectonic windows to deep-seated rocks and processes (mantle flow, melt generation and migration, strain localization, and crustal accretion) at mid-ocean ridges; a fundamental process in the generation of oceanic lithosphere along sizeable sections of slow and ultraslow spreading centers; a system sustaining both long-lived, high-temperature hydrothermal circulation and low-temperature, hydrogen-rich, serpentinite-related systems with their associated mineral deposits and ecosystems; a fault zone, containing weak hydrous alteration phases, that efficiently localizes strain, and that has associated footwall flexure and rotation; and a key to understanding continental core complexes as well as detachments at extensional, magma-poor continental margins.

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