Detrital Zircon Record of a Mesozoic Collisional Forearc Basin in South Central Alaska: The Tectonic Transition From an Oceanic to Continental Arc
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AMER GEOPHYSICAL UNIONCitation
Stevens Goddard, A. L., Trop, J. M., & Ridgway, K. D. (2018). Detrital zircon record of a Mesozoic collisional forearc basin in south central Alaska: The tectonic transition from an oceanic to continental arc. Tectonics, 37, 529–557. https://doi.org/10.1002/2017TC004825Journal
TECTONICSRights
© 2018. American Geophysical Union. All Rights Reserved.Collection Information
This item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at repository@u.library.arizona.edu.Abstract
The collision of oceanic arcs with continental margins is an important mechanism for the growth of continents. Ancient forearc basin strata in collisional orogens provide a record of the upper crustal response to this tectonic process. In south central Alaska, Mesozoic forearc basin strata are exposed in a complete crustal section. U-Pb detrital zircon geochronology from the forearc basin strata was analyzed within a similar to 107Ma stratigraphic framework. The Jurassic strata contain unimodal detrital zircon populations that become progressively younger upsection and range from 175 to 151Ma. These strata are derived from the active oceanic Talkeetna arc. The Cretaceous strata were deposited above multiple unconformities that collectively represent as much as similar to 30Ma of nondeposition and/or erosion in the forearc basin. Erosion in the forearc basin and a general absence of detrital zircon ages between 140 and 120Ma are interpreted as a hiatus of magmatism triggered by collision of the oceanic arc with the former continental margin. The Cretaceous strata have two main detrital zircon populations: a Cretaceous population ranging from 90 to 68Ma that becomes progressively younger upsection and a Jurassic population with a broad range of peak ages from 194 to 144Ma. The Cretaceous population marks the establishment of an active Cretaceous continental arc following the collisional event, and the older population reflects continued erosion of the remnant Jurassic oceanic arc plutons. Our results show that detrital zircon geochronology provides a powerful approach for delineating stages of forearc basin collision and the erosion of multiple magmatic arcs.Note
6 month embargo; published online: 06 January 2018ISSN
0278-74071944-9194
Version
Final published versionSponsors
National Science Foundation [EAR-0910945, EAR-0910545]; NSF graduate research fellowshipAdditional Links
https://agupubs.onlinelibrary.wiley.com/doi/10.1002/2017TC004825ae974a485f413a2113503eed53cd6c53
10.1002/2017TC004825