Article,
Subduction zones
Reviews of Geophysics, 40 (4): 1012+ (Dec 31, 2002)
DOI: 10.1029/2001RG000108
Abstract
Subduction zones are where sediments, oceanic crust, and mantle lithosphere
return to and reequilibrate with Earth's mantle. Subduction zones
are interior expressions of Earth's 55,000 km of convergent plate
margins and are the geodynamic system that builds island arcs. Excess
density of the mantle lithosphere in subduction zones provides most
of the power needed to move the plates while inducing convection
in the overriding mantle wedge. Asthenospheric mantle sucked toward
the trench by the sinking slab interacts with water and incompatible
elements rising from the sinking plate, and this interaction causes
the mantle to melt. These melts rise vertically through downwelling
mantle to erupt at arc volcanoes. Subduction zones are thus interior
Earth systems of unparalleled scale and complexity. Subduction zone
igneous activity formed most ore deposits and continental crust,
and earthquakes caused by the downgoing plate present a growing hazard
to society. This overview summarizes our present understanding of
subduction zones, using perspectives of the incoming plate, downgoing
plate, mantle wedge, and arc-trench complex. Understanding the operation
of subduction zones stands as one of the great challenges facing
the Earth sciences in the 21st century and will require the efforts
of global interdisciplinary teams.
