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Published May 2015 | public
Journal Article

The Architecture, Chemistry, and Evolution of Continental Magmatic Arcs

Abstract

Continental magmatic arcs form above subduction zones where the upper plate is continental lithosphere and/or accreted transitional lithosphere. The best-studied examples are found along the western margin of the Americas. They are Earth's largest sites of intermediate magmatism. They are long lived (tens to hundreds of millions of years) and spatially complex; their location migrates laterally due to a host of tectonic causes. Episodes of crustal and lithospheric thickening alternating with periods of root foundering produce cyclic vertical changes in arcs. The average plutonic and volcanic rocks in these arcs straddle the compositional boundary between an andesite and a dacite, very similar to that of continental crust; about half of that comes from newly added mafic material from the mantle. Arc products of the upper crust differentiated from deep crustal (>40 km) residual materials, which are unstable in the lithosphere. Continental arcs evolve into stable continental masses over time; trace elemental budgets, however, present challenges to the concept that Phanerozoic arcs are the main factories of continental crust.

Additional Information

© 2015 Annual Reviews. First published online as a Review in Advance on February 27, 2015. We acknowledge funding from the National Science Foundation Petrology and Geochemistry program (EAR-1019525 and EAR-0907880 to M.N.D. and EAR-1049884 to G.B.) and from the Romanian Executive Agency for Higher Education, Research, Development and Innovation Funding (UEFISCDI) (project PN-II-ID-PCE-2011-3-0217).

Additional details

Created:
August 22, 2023
Modified:
October 23, 2023