Role of arc processes in the formation of continental crust

Online Access: Get full text
doi: 10.1146/annurev-earth-040809-152345
Author(s): Jagoutz, Oliver; Kelemen, Peter B.
Author Affiliation(s): Primary:
Massachusetts Institute of Technology, Department of Earth, Atmospheric and Planetary Sciences, Cambridge, MA, United States
Lamont-Doherty Earth Observatory, United States
Volume Title: Annual Review of Earth and Planetary Sciences
Source: Annual Review of Earth and Planetary Sciences, Vol.43, p.363-404. Publisher: Annual Reviews, Palo Alto, CA, United States. ISSN: 0084-6597 CODEN: AREPCI
Note: In English. 227 refs.; illus., incl. 1 table, strat. cols., geol. sketch maps
Summary: We review data and recent research on arc composition, focusing on the relatively complete arc crustal sections in the Jurassic Talkeetna Arc (south central Alaska) and the Cretaceous Kohistan Arc (northwest Pakistan), together with seismic data on the lower crust and uppermost mantle. Whereas primitive arc lavas are dominantly basaltic, the Kohistan crust is clearly andesitic and the Talkeetna crust could be andesitic. The andesitic compositions of the two arc sections are within the range of estimates for the major element composition of continental crust. Calculated seismic sections for Kohistan and Talkeetna provide a close match for the thicker parts of the active Izu Arc, suggesting that it, too, could have an andesitic bulk composition. Because andesitic crust is buoyant with respect to the underlying mantle, much of this material represents a net addition to continental crust. Production of bulk crust from a parental melt in equilibrium with mantle olivine or pyroxene requires processing of igneous crust, probably via density instabilities. Delamination of dense cumulates from the base of arc crust, foundering into less dense, underlying mantle peridotite, is likely, as supported by geochemical evidence from Talkeetna and Kohistan. Relamination of buoyant, subducting material-during sediment subduction, subduction erosion, arc-arc collision, and continental collision-is also likely.
Year of Publication: 2015
Research Program: IODP Integrated Ocean Drilling Program
ODP Ocean Drilling Program
Key Words: 05 Petrology, Igneous and Metamorphic; 18 Geophysics, Solid-Earth; Alaska; Andesites; Arcuate structures; Asia; Atlantic Ocean; Atlantis Massif; Body waves; Calc-alkalic composition; Chemical composition; Continental crust; Crust; Crust-mantle boundary; Dacites; Delamination; Density; Elastic waves; Expeditions 304/305; Genesis; IODP Site U1309; Igneous rocks; Indian Peninsula; Integrated Ocean Drilling Program; Island arcs; Kohistan Arc; Leg 176; Lower crust; Magmatism; Mantle; Mid-Atlantic Ridge; Mohorovicic discontinuity; North Atlantic; ODP Site 735; Ocean Drilling Program; Oceanic crust; P-waves; Pakistan; Plate tectonics; Plutonic rocks; Properties; Relamination; Seismic waves; Spatial distribution; Subduction; Subduction zones; Talkeetna Arc; Temporal distribution; Thickness; Trace elements; Transformations; United States; Upper mantle; Velocity structure; Volcanic rocks
Coordinates: N350000 N363000 E0750000 E0710000
N611500 N620000 W1450000 W1483000
Record ID: 2016082288
Copyright Information: GeoRef, Copyright 2019 American Geosciences Institute. Reference includes data supplied by Annual Reviews, Palo Alto, CA, United States