continental crust


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continental crust

[¦känt·ən¦ent·əl ′krəst]
(geology)
The basement complex of rock, that is, metamorphosed sedimentary and volcanic rock with associated igneous rocks mainly granitic, that underlies the continents and the continental shelves.
References in periodicals archive ?
Previous studies have suggested that the slow, steady collision between the Nazca Plate, made of dense oceanic crust, and the South American plate, of lighter, continental crust, gradually lifted the Andes.
Many arc systems, especially those capped by thick continental crust, have mafic magmas derived from the mantle, intermediate to felsic magmas formed by fractionation of a more mafic parent, and felsic magmas that are derived by partial melting of the crust.
Island arcs capped by mafic crust tend to be dominated by mafic to intermediate magmas; those capped by continental crust have a higher proportion of intermediate to felsic lavas, and are compositionally similar to continental arcs (e.
The composition of the continental crust corresponds to a semi-liquid version of the oceanic crust melted by 10 to 30 percent of its original state.
Oceanic islands represent a small proportion of the Earth's surface yet their volcanic rocks are amongst the most studied; this is because they occur far from continental crust that might contaminate rising magma, and they are unaffected by orogenic, metamorphic and tectonic processes (Basaltic Volcanism Study Project = BVSP, 1981, p.
If the wide transition zone in the Newfoundland Basin proves to be floored by continental crust that has thinned, faulted, and eroded in a subaerial environment, a fundamental new class of crust will be documented that must be accounted for in future models of continental breakup.
Lead author Steven Shirey at the Carnegie Institution's Department of Terrestrial Magnetism explained: "The Wilson cycle is responsible for the growth of the Earth's continental crust, the continental structures we see today, the opening and closing of ocean basins through time, mountain building, and the distribution of ores and other materials in the crust.
Separated from contaminating continental crust, and unaltered by mountain-building metamorphic and tectonic processes (Basaltic Volcanism Study Project = BVSP, 1981, p.
Raghavan and his colleagues obtain similar conclusions and go on to suggest that, because one site is on continental crust and the other at the interface between continental and oceanic crust, it may even be possible to probe some aspects of the distribution of radioactive elements beneath Earth's surface.
The continental crust formation modified the composition of the mantle and the atmosphere, it supports life and it remains a sink for carbon dioxide through weathering and erosion.
The opening papers recount Coward's career and assess his impact on the geological understanding of the deformation of the continental crust.
Bacteria and archaea may reach as far as 4 km below the continental crust and 7 km into the oceanic crust, says Fredrickson.

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