Open AccessCoeval blueschist exhumation along thousands of kilometers: Implications for subduction channel processes
Author(s) -
Monié P.,
Agard P.
Publication year - 2009
Publication title -
geochemistry, geophysics, geosystems
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.928
H-Index - 136
ISSN - 1525-2027
DOI - 10.1029/2009gc002428
Subject(s) - subduction , geology , blueschist , geodynamics , slab , seismology , mantle (geology) , depth of focus (tectonics) , geophysics , tectonics , eclogite
We herein focus on understanding what controls the detachment and migration of oceanic crustal slices along subduction zones. We provide evidence for the coeval Middle to Late Cretaceous exhumation of oceanic blueschists in the same Neotethyan subduction zone, across more than 3000 km, from depths around 30–40 km, over a short time interval (∼25 Ma) compared to the duration of subduction (>100 Ma). We stress the importance of such a geodynamic process and suggest that this exhumation was promoted by a regional‐scale change in the long‐term interplate mechanical coupling. On the basis of geological and geophysical evidence, we propose that the upward migration of oceanic fragments in subduction zones is normally inhibited and only occurs discontinuously, as the subduction channel opens up in response to a major change in plate geodynamics, slab geometry and dynamics, mantle wedge and slab hydration, or a combination of these.