Quick Search:    advanced search

GSW Home   GeoRef Home   My GSW Alerts   Contact GSW   About GSW   Journals List   Help

This Article Figures Only Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in ISI Web of Science Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via ISI Web of Science (4) Citing Articles via Google Scholar Google Scholar Articles by Clift, P. D. Articles by Kelemen, P. B. Search for Related Content GeoRef GeoRef Citation

Subduction erosion of the Jurassic Talkeetna-Bonanza arc and the Mesozoic accretionary tectonics of western North America

¹ School of Geosciences, University of Aberdeen, Aberdeen AB24 3UE, UK
² Department of Geology and Geophysics, University of New Orleans, New Orleans, Louisiana 70148, USA
³ Department of Geology, Western Washington University, Bellingham, Washington 98225, USA
⁴ University of California–Santa Cruz, Santa Cruz, California 95060,USA, and U.S. Geological Survey, 400 Natural Bridges Drive, Santa Cruz, California 95060, USA
⁵ Department of Geological Sciences, University of California–Santa Barbara, Santa Barbara, California 93106, USA
⁶ Lamont-Doherty Earth Observatory, Columbia University, P.O. Box 1000, 61 Route 9W, Palisades, New York 10964, USA

The Jurassic Talkeetna volcanic arc of south-central Alaska is an oceanic island arc that formed far from the North American margin. Geochronological, geochemical, and structural data indicate that the arc formed above a north-dipping subduction zone after ca. 201 Ma. Magmatism migrated northward into the region of the Talkeetna Mountains ca. 180 Ma. We interpret this magmatism as the product of removal of the original forearc while the arc was active, mainly by tectonic erosion. Rapid exhumation of the arc after ca. 160 Ma coincided with the sedimentation of the coarse clastic Naknek Formation. This exhumation event is interpreted to reflect collision of the Talkeetna arc with either the active margin of North America or the Wrangellia composite terrane to the north along a second north-dipping subduction zone. The juxtaposition of accreted trench sedimentary rocks (Chugach terrane) against the base of the Talkeetna arc sequence requires a change from a state of tectonic erosion to accretion, probably during the Late Jurassic (before 150 Ma), and definitely before the Early Cretaceous (ca. 125 Ma). The change from erosion to accretion probably reflects increasing sediment flux to the trench due to collision ca. 160 Ma.

Key Words: Alaska • terrane accretion • subduction • tectonic erosion • collision

This article has been cited by other articles:

				J. M. Amato, A. O. Boullion, A. M. Serna, A. E. Sanders, G. L. Farmer, G. E. Gehrels, and J. L. Wooden Evolution of the Mazatzal province and the timing of the Mazatzal orogeny: Insights from U-Pb geochronology and geochemistry of igneous and metasedimentary rocks in southern New Mexico GSA Bulletin, March 1, 2008; 120(3-4): 328 - 346. [Abstract] [Full Text] [PDF]

				J. M. Trop Latest Cretaceous forearc basin development along an accretionary convergent margin: South-central Alaska GSA Bulletin, January 1, 2008; 120(1-2): 207 - 224. [Abstract] [Full Text] [PDF]

				M. Rioux, B. Hacker, J. Mattinson, P. Kelemen, J. Blusztajn, and G. Gehrels Magmatic development of an intra-oceanic arc: High-precision U-Pb zircon and whole-rock isotopic analyses from the accreted Talkeetna arc, south-central Alaska GSA Bulletin, September 1, 2007; 119(9-10): 1168 - 1184. [Abstract] [Full Text] [PDF]

				A. E. Draut and P. D. Clift Sedimentary Processes in Modern and Ancient Oceanic Arc Settings: Evidence from the Jurassic Talkeetna Formation of Alaska and the Mariana and Tonga Arcs, Western Pacific Journal of Sedimentary Research, March 1, 2006; 76(3): 493 - 514. [Abstract] [Full Text] [PDF]