Tectonic and chronostratigraphic implications of new 40Ar/39Ar geochronology and geochemistry of the Arman and Maltan-Ola volcanic fields, Okhotsk-Chukotka volcanic belt, northeastern Russia

Research Article| May 01, 2004 Tectonic and chronostratigraphic implications of new 40Ar/39Ar geochronology and geochemistry of the Arman and Maltan-Ola volcanic fields, Okhotsk-Chukotka volcanic belt, northeastern Russia Jeremy K. Hourigan; Jeremy K. Hourigan 1Department of Geological and Environmental Sciences, Stanford University, Stanford, California 94305, USA Search for other works by this author on: GSW Google Scholar Vyacheslav V. Akinin Vyacheslav V. Akinin 2North East Interdisciplinary Scientific Research Institute, Far East Branch, Russian Academy of Sciences, Magadan, Portovaya Ulitsa, 16, 685000, Russia Search for other works by this author on: GSW Google Scholar Author and Article Information Jeremy K. Hourigan 1Department of Geological and Environmental Sciences, Stanford University, Stanford, California 94305, USA Vyacheslav V. Akinin 2North East Interdisciplinary Scientific Research Institute, Far East Branch, Russian Academy of Sciences, Magadan, Portovaya Ulitsa, 16, 685000, Russia Publisher: Geological Society of America Received: 19 Feb 2003 Revision Received: 08 Aug 2003 Accepted: 28 Aug 2003 First Online: 02 Mar 2017 Online ISSN: 1943-2674 Print ISSN: 0016-7606 Geological Society of America GSA Bulletin (2004) 116 (5-6): 637–654. https://doi.org/10.1130/B25340.1 Article history Received: 19 Feb 2003 Revision Received: 08 Aug 2003 Accepted: 28 Aug 2003 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 Jeremy K. Hourigan, Vyacheslav V. Akinin; Tectonic and chronostratigraphic implications of new 40Ar/39Ar geochronology and geochemistry of the Arman and Maltan-Ola volcanic fields, Okhotsk-Chukotka volcanic belt, northeastern Russia. GSA Bulletin 2004;; 116 (5-6): 637–654. doi: https://doi.org/10.1130/B25340.1 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 Okhotsk-Chukotka volcanic belt is part of an extensive late Early to Late Cretaceous Andean-style magmatic arc that spans the entire eastern margin of the Asian continent. The belt itself stretches 3000 km from the Chukotka Peninsula to the Uda River and comprises ∼1.2 × 106 km3 of volcanic rock over a 500,000 km2 area. Despite its size and regional tectonic significance, the time span of magmatic activity is poorly constrained and the subject of significant debate, mostly in the Russian literature. In this paper, we provide new geochronologic control on the timing of inception and cessation of magmatism for the Arman and Maltan-Ola volcanic fields. These field localities were chosen because they are well studied, relatively accessible, and contain floral assemblages that have been used to correlate volcanic sequences at the regional scale. The majority of the volcanic sequence was emplaced between 85.5 ± 1.3 Ma and 74.0 ± 1.2 Ma, as shown by 17 new 40Ar/39Ar ages. The Coniacian– Santonian to Campanian age range indicated is 15 m.y. younger than the Albian to early Cenomanian age range given by a synthesis of floral stratigraphic, K-Ar, and Rb-Sr geochronologic data. The calc- alkaline part of the volcanic section spans an apparent age range of 85.5 ± 1.3 Ma to 80.7 ± 0.8 Ma. Capping basalts were emplaced between 77.5 ± 1.1 Ma and 74.0 ± 1.2 Ma and exhibit a within-plate geochemical signature, which we attribute to a temporally and geochemically distinct, possibly extension-related, phase of magmatism. The apparent northwestward migration of the arc front from the interior (seaward) zone (Taigonos Peninsula, Magadan batholith) in Albian–Cenomanian time to the Arman and Maltan-Ola volcanic fields in Coniacian–Santonian to Campanian time may be explained by shallowing of the subducting paleo-Pacific (Kula?) oceanic plate.The flat-lying nature of these volcanic rocks and the within-plate geochemical affinity of the capping basalt unit are inconsistent with prevailing tectonic models for the cessation of arc magmatism and formation of the Sea of Okhotsk which require the collision of a microcontinental block or oceanic plateau with the northeast Asian margin in the Late Cretaceous. You do not have access to this content, please speak to your institutional administrator if you feel you should have access.