Model for the origin of the Yakutat block, an accreting terrane in the northern Gulf of Alaska

Research Article| December 01, 1983 Model for the origin of the Yakutat block, an accreting terrane in the northern Gulf of Alaska Terry R. Bruns Terry R. Bruns 1U.S. Geological Survey, 345 Middlefield Road, Menlo Park, California 94025 Search for other works by this author on: GSW Google Scholar Author and Article Information Terry R. Bruns 1U.S. Geological Survey, 345 Middlefield Road, Menlo Park, California 94025 Publisher: Geological Society of America First Online: 01 Jun 2017 Online ISSN: 1943-2682 Print ISSN: 0091-7613 Geological Society of America Geology (1983) 11 (12): 718–721. https://doi.org/10.1130/0091-7613(1983)112.0.CO;2 Article history First Online: 01 Jun 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation Terry R. Bruns; Model for the origin of the Yakutat block, an accreting terrane in the northern Gulf of Alaska. Geology 1983;; 11 (12): 718–721. doi: https://doi.org/10.1130/0091-7613(1983)112.0.CO;2 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietyGeology Search Advanced Search Abstract A composite oceanic and continental terrane, the Yakutat block, is currently colliding with and accreting to North America in the northern Gulf of Alaska. Marine geophysical data indicate that the block has moved with the Pacific plate during Pliocene and Quaternary time, but are indeterminant about its previous movement history. A model that explains some observed geologic and structural features of the block is that it originated as a result of subduction of the Kula-Farallon spreading center beneath North America. In this model, the spreading center that formed the basaltic basement of the Yakutat block was offset from a spreading center to the south by a left-lateral transform fault 400–500 km long. Subduction of the northern spreading center about 45 m.y. ago sliced off part of the North America continental margin, attached it to the Kula plate, and initiated northward movement of the composite terrane as the Yakutat block. During Eocene and Oligocene time, migration of the southern spreading center toward North America truncated the Yakutat block on the south and left a fossil fracture zone that is now seen as the Transition fault. The southern spreading center subducted about 25 m.y. ago, and the Yakutat block has since traveled with the Pacific plate to southern Alaska. This content is PDF only. Please click on the PDF icon to access. First Page Preview Close Modal You do not have access to this content, please speak to your institutional administrator if you feel you should have access.