Late Proterozoic–Paleozoic evolution of the Arctic Alaska–Chukotka terrane based on U-Pb igneous and detrital zircon ages: Implications for Neoproterozoic paleogeographic reconstructions

Research Article| September 01, 2009 Late Proterozoic–Paleozoic evolution of the Arctic Alaska–Chukotka terrane based on U-Pb igneous and detrital zircon ages: Implications for Neoproterozoic paleogeographic reconstructions Jeffrey M. Amato; Jeffrey M. Amato † 1Department of Geological Sciences, New Mexico State University, Las Cruces, New Mexico 88003, USA †E-mail: amato@nmsu.edu Search for other works by this author on: GSW Google Scholar Jaime Toro; Jaime Toro 2Department of Geology and Geography, West Virginia University, Morgantown, West Virginia 26506, USA Search for other works by this author on: GSW Google Scholar Elizabeth L. Miller; Elizabeth L. Miller 3Department of Geological and Environmental Sciences, Stanford University, Stanford, California 94305, USA Search for other works by this author on: GSW Google Scholar George E. Gehrels; George E. Gehrels 4Department of Geosciences, University of Arizona, Tucson, Arizona 85721, USA Search for other works by this author on: GSW Google Scholar G. Lang Farmer; G. Lang Farmer 5Department of Geological Sciences, University of Colorado, Boulder, Colorado 80309, USA Search for other works by this author on: GSW Google Scholar Eric S. Gottlieb; Eric S. Gottlieb 1Department of Geological Sciences, New Mexico State University, Las Cruces, New Mexico 88003, USA Search for other works by this author on: GSW Google Scholar Alison B. Till Alison B. Till 6U. S. Geological Survey, Anchorage, Alaska 99508, USA Search for other works by this author on: GSW Google Scholar Author and Article Information Jeffrey M. Amato † 1Department of Geological Sciences, New Mexico State University, Las Cruces, New Mexico 88003, USA Jaime Toro 2Department of Geology and Geography, West Virginia University, Morgantown, West Virginia 26506, USA Elizabeth L. Miller 3Department of Geological and Environmental Sciences, Stanford University, Stanford, California 94305, USA George E. Gehrels 4Department of Geosciences, University of Arizona, Tucson, Arizona 85721, USA G. Lang Farmer 5Department of Geological Sciences, University of Colorado, Boulder, Colorado 80309, USA Eric S. Gottlieb 1Department of Geological Sciences, New Mexico State University, Las Cruces, New Mexico 88003, USA Alison B. Till 6U. S. Geological Survey, Anchorage, Alaska 99508, USA †E-mail: amato@nmsu.edu Publisher: Geological Society of America Received: 09 Jul 2008 Revision Received: 20 Oct 2008 Accepted: 22 Oct 2008 First Online: 02 Mar 2017 Online ISSN: 1943-2674 Print ISSN: 0016-7606 © 2009 Geological Society of America GSA Bulletin (2009) 121 (9-10): 1219–1235. https://doi.org/10.1130/B26510.1 Article history Received: 09 Jul 2008 Revision Received: 20 Oct 2008 Accepted: 22 Oct 2008 First Online: 02 Mar 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation Jeffrey M. Amato, Jaime Toro, Elizabeth L. Miller, George E. Gehrels, G. Lang Farmer, Eric S. Gottlieb, Alison B. Till; Late Proterozoic–Paleozoic evolution of the Arctic Alaska–Chukotka terrane based on U-Pb igneous and detrital zircon ages: Implications for Neoproterozoic paleogeographic reconstructions. GSA Bulletin 2009;; 121 (9-10): 1219–1235. doi: https://doi.org/10.1130/B26510.1 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 SocietyGSA Bulletin Search Advanced Search Abstract The Seward Peninsula of northwestern Alaska is part of the Arctic Alaska–Chukotka terrane, a crustal fragment exotic to western Laurentia with an uncertain origin and pre-Mesozoic evolution. U-Pb zircon geochronology on deformed igneous rocks reveals a previously unknown intermediate-felsic volcanic event at 870 Ma, coeval with rift-related magmatism associated with early breakup of eastern Rodinia. Orthogneiss bodies on Seward Peninsula yielded numerous 680 Ma U-Pb ages. The Arctic Alaska–Chukotka terrane has pre-Neoproterozoic basement based on Mesoproterozoic Nd model ages from both 870 Ma and 680 Ma igneous rocks, and detrital zircon ages between 2.0 and 1.0 Ga in overlying cover rocks. Small-volume magmatism occurred in Devonian time, based on U-Pb dating of granitic rocks.U-Pb dating of detrital zircons in 12 samples of metamorphosed Paleozoic siliciclastic cover rocks to this basement indicates that the dominant zircon age populations in the 934 zircons analyzed are found in the range 700–540 Ma, with prominent peaks at 720–660 Ma, 620–590 Ma, 560–510 Ma, 485 Ma, and 440–400 Ma. Devonian- and Pennsylvanian-age peaks are present in the samples with the youngest detrital zircons. These data show that the Seward Peninsula is exotic to western Laurentia because of the abundance of Neoproterozoic detrital zircons, which are rare or absent in Lower Paleozoic Cordilleran continental shelf rocks. Maximum depositional ages inferred from the youngest detrital age peaks include latest Proterozoic–Early Cambrian, Cambrian, Ordovician, Silurian, Devonian, and Pennsylvanian. These maximum depositional ages overlap with conodont ages reported from fossiliferous carbonate rocks on Seward Peninsula.The distinctive features of the Arctic Alaska–Chukotka terrane include Neoproterozoic felsic magmatic rocks intruding 2.0–1.1 Ga crust overlain by Paleozoic carbonate rocks and Paleozoic siliciclastic rocks with Neoproterozoic detrital zircons. The Neoproterozoic ages are similar to those in the peri-Gondwanan Avalonian-Cadomian arc system, the Timanide orogen of Baltica, and other circum-Arctic terranes that were proximal to Arctic Alaska prior to the opening of the Amerasian basin in the Early Cretaceous. Our Neoproterozoic reconstruction places the Arctic Alaska–Chukotka terrane in a position near Baltica, northeast of Laurentia, in an arc system along strike with the Avalonian-Cadomian arc terranes. Previously published faunal data indicate that Seward Peninsula had Siberian and Laurentian links by Early Ordovician time. The geologic links between the Arctic Alaska–Chukotka terrane and eastern Laurentia, Baltica, peri-Gondwanan arc terranes, and Siberia from the Paleoproterozoic to the Paleozoic help to constrain paleogeographic models from the Neoproterozoic history of Rodinia to the Mesozoic opening of the Arctic basin. You do not have access to this content, please speak to your institutional administrator if you feel you should have access.