Buoyant mantle upwelling and crustal production at oceanic spreading centers: On-axis segmentation and off-axis melting
نویسندگان
چکیده
منابع مشابه
Oceanic slab melting and mantle metasomatism.
Modern plate tectonic brings down oceanic crust along subduction zones where it either dehydrates or melts. Those hydrous fluids or melts migrate into the overlying mantle wedge trigerring its melting which produces arc magmas and thus additional continental crust. Nowadays, melting seems to be restricted to cases of young (< 50 Ma) subducted plates. Slab melts are silicic and strongly sodic (t...
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a r t i c l e i n f o Keywords: East Pacific Rise mid-ocean ridge oceanic crust off-axis magmatism waveform modeling Formation of oceanic crust along the East Pacific Rise is thought to be complete within a few kilometers of the rise axis. Here, however, we present evidence for magmatism 20 km from the spreading center in 300-ka-old crust. Seismic data reveal an intrusive complex ~ 2 km beneath...
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We review physical and chemical constraints on the mechanisms of melt extraction from the mantle beneath mid-ocean ridges. Compositional constraints from MORB and abyssal peridotite are summarized, followed by observations of melt extraction features in the mantle, and constraints from the physical properties of partially molten peridotite. We address two main issues. (1) To what extent is melt...
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Large-scale tectonic processes introduce a range of crustal lithologies into the Earth's mantle. These lithologies have been implicated as sources of compositional heterogeneity in mantle-derived magmas. The model being explored here assumes the presence of widely dispersed fragments of residual eclogite (derived from recycled oceanic crust), stretched and stirred by convection in the mantle. H...
متن کاملWhy meter-wide dikes at oceanic spreading centers?
Numerical models show that maximum dike width at oceanic spreading centers should scale with axial lithospheric thickness if the pre-diking horizontal stress is close to the Andersonian normal faulting stress and the stress is fully released in one dike intrusion. Dikes at slow-spreading ridges could be over 5 m wide and maximum dike width should decrease with increasing plate spreading rate. H...
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ژورنال
عنوان ژورنال: Journal of Geophysical Research: Solid Earth
سال: 1997
ISSN: 0148-0227
DOI: 10.1029/96jb03807