Petrogenesis of slab-derived trondhjemite-tonalite-dacite/adakite magmas

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Authors:Drummond, Mark S.; Defant, Marc J.; Kepezhinskas, Pavel K.
Author Affiliations:Primary:
University of Alabama at Birmingham, Department of Geology, Birmingham, AL, United States
U. S Geological Survey, United States
University of St. Andrews, United Kingdom
University of South Florida, United States
Volume Title:third Hutton symposium on the Origin of granites and related rocks
Volume Authors:Brown, M., editor; Candela, P. A.; Peck, D. L.; Stephens, W. E.; Walker, R. J.; Zen, E-an
Source:Special Paper - Geological Society of America, Vol.315, p.205-215; The third Hutton symposium on the Origin of granites and related rocks, College Park, MD, Aug. 27-Sept. 2, 1995, edited by M. Brown, P. A. Candela, D. L. Peck, W. E. Stephens, R. J. Walker and E-an Zen. Publisher: Geological Society of America (GSA), Boulder, CO, United States. ISSN: 0072-1077. ISBN: 0-8137-2325-9
Publication Date:1996
Note:In English. 115 refs.Copubl. with R. Soc. of Edinburgh; illus., incl. 1 table
Summary:Trondhjemite-tonalite-dacite magmas (high-Al TTD/adakite) with a unique compositional character can be generated by high-P partial melting of a basaltic source under garnet amphibolite to eclogitic conditions. Under the elevated geotherms of the Archaean, the production of high-Al TTD is considered to be a major continental crust-forming mechanism, whereas in Cainozoic tectonic regimes where young, hot oceanic crust has subducted, melting of the subducted slab can occur. The approximate upper age limit for slab melt generation is considered to be 25 m.y., on the basis of natural occurrences of adakites. Intermediate to felsic arc volcanic and plutonic rocks from an overthickened continental arc setting have some similarities with adakites due to plagioclase instability and involvement of garnet in their petrogenesis. However, adakites have lower Sr isotopic compositions, lower LIL element concentrations, a positive Sr anomaly and common presence of a mantle component in the slab melts. Adakites and transitional adakites show progressive enrichment in Cr and Ni due to mantle contamination. [R.A.H.]
Subjects:Adakites; Archean; Basalts; Cenozoic; Crust; Dacites; Dehydration; Diorites; Genesis; Igneous rocks; Inclusions; Magmas; Mantle; Melting; Melts; Metasomatism; Mid-ocean ridge basalts; Oceanic crust; P-T conditions; Partial melting; Plate convergence; Plate tectonics; Plutonic rocks; Precambrian; Subduction; Tonalite; Trondhjemite; Veins; Volcanic rocks; Xenoliths; Asia; Commonwealth of Independent States; Kamchatka Russian Federation; Russian Federation; Igneous activity
Abstract Numbers:97M/917
Record ID:1997012350
Copyright Information:GeoRef, Copyright 2019 American Geosciences Institute. Reference includes data from Mineralogical Abstracts, United Kingdom, Twickenham, United Kingdom
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