Portnyagin, Maxim and Manea, Vlad Constantin (2008) Mantle temperature control on composition of arc magmas along the Central Kamchatka Depression. Geology, 36 (7). pp. 519-522. ISSN 0091-7613. doi:10.1130/G24636A.1. https://resolver.caltech.edu/CaltechAUTHORS:20170408-140358225
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Abstract
Abundant volcanism in the Central Kamchatka Depression (CKD) adjacent to the Kamchatka–Aleutian Arc junction occurs where the Pacific slab edge is subducting beneath Kamchatka. Here we summarize published data on CKD rocks and demonstrate a systematic south-to-north change of their compositions from moderately fractionated basalt-andesite tholeiitic series to highly fractionated basalt-rhyolite calc-alkaline series including high-magnesian andesites near the slab edge. Localized slab melting at the slab edge cannot explain these regional geochemical variations. Instead, we propose that the thermal state of the mantle wedge can be the key factor governing the composition of CKD magmas. We integrate the results from petrology and numeric modeling to demonstrate the northward decrease of the mantle wedge temperatures beneath CKD volcanoes, which correlates with decreasing slab dip, length of mantle columns, and magma flux. We envision two petrogenetic models, which relate the composition of erupted magmas to the subduction parameters beneath the CKD. The first model suggests that mantle temperature governs melt-peridotite equilibria and favors generation of andesitic primary melts in cold mantle regions above the shallowly subducting Pacific slab edge. Alternatively, mantle temperature may control magmatic productivity along the CKD, which decreases sharply toward the slab edge and thus allows more extensive magma fractionation deeper in the crust and mixing of highly evolved and mantle-derived magmas to generate Si-rich “primitive” magmas. These results point to a possible casual link between deep mantle and shallow crustal magmatic processes. Similar effects of mantle temperature on the composition and productivity of arc magmatism are expected elsewhere, particularly in volcanic regions associated with significant slab dip variation along the arc.
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Additional Information: | © 2008 Geological Society of America. Manuscript received 23 November 2007. Revised manuscript received 29 February 2008. Manuscript accepted 4 March 2008. We thank L. Elkins-Tanton, M. Streck, and K. Putirka for constructive reviews, and V. Ponomareva and N. Mironov for helpful comments. This work was supported by the KALMAR and SFB-574 projects (M.P.) and PAPIIT #IN105607 (V.M.). Numerical simulations were performed at DGSCA-UNAM Supercomputer Center (KanBalam), Mexico. This is contribution 151 from the SFB-574 project. GSA Data Repository item 2008128, Appendix DR1 (numeric modeling procedure, supplementary figures, and mean compositions of CKD rocks), is available online at www.geosociety.org/pubs/ft2008.htm, or on request from editing@geosociety.org or Documents Secretary, GSA, P.O. Box 9140, Boulder, CO 80301, USA. | |||||||||||||||
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Subject Keywords: | Kamchatka; island arc; subduction; calc-alkaline; tholeiite; high-magnesian andesite; mantle wedge; mixing; numeric modeling | |||||||||||||||
Issue or Number: | 7 | |||||||||||||||
DOI: | 10.1130/G24636A.1 | |||||||||||||||
Record Number: | CaltechAUTHORS:20170408-140358225 | |||||||||||||||
Persistent URL: | https://resolver.caltech.edu/CaltechAUTHORS:20170408-140358225 | |||||||||||||||
Official Citation: | Mantle temperature control on composition of arc magmas along the Central Kamchatka Depression Maxim Portnyagin, Vlad Constantin Manea Geology Jul 2008, 36 (7) 519-522; DOI: 10.1130/G24636A.1 | |||||||||||||||
Usage Policy: | No commercial reproduction, distribution, display or performance rights in this work are provided. | |||||||||||||||
ID Code: | 75912 | |||||||||||||||
Collection: | CaltechAUTHORS | |||||||||||||||
Deposited By: | 1Science Import | |||||||||||||||
Deposited On: | 19 Apr 2017 18:49 | |||||||||||||||
Last Modified: | 15 Nov 2021 16:56 |
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