Whole-rock 40Ar/39Ar geochronology, geochemistry, and stratigraphy of intraplate Cenozoic volcanic rocks, central Mongolia

Research Article| April 25, 2018 Whole-rock 40Ar/39Ar geochronology, geochemistry, and stratigraphy of intraplate Cenozoic volcanic rocks, central Mongolia Leonard D. Ancuta; Leonard D. Ancuta † 1Department of Earth and Environmental Sciences, Lehigh University, Bethlehem, Pennsylvania 18015, USA †Corresponding author: lancuta24@gmail.com Search for other works by this author on: GSW Google Scholar Peter K. Zeitler; Peter K. Zeitler 1Department of Earth and Environmental Sciences, Lehigh University, Bethlehem, Pennsylvania 18015, USA Search for other works by this author on: GSW Google Scholar Bruce D. Idleman; Bruce D. Idleman 1Department of Earth and Environmental Sciences, Lehigh University, Bethlehem, Pennsylvania 18015, USA Search for other works by this author on: GSW Google Scholar Brennan T. Jordan Brennan T. Jordan 2Department of Sustainability and Environment, University of South Dakota, Vermillion, South Dakota 57069, USA Search for other works by this author on: GSW Google Scholar GSA Bulletin (2018) 130 (7-8): 1397–1408. https://doi.org/10.1130/B31788.1 Article history received: 02 Mar 2017 rev-recd: 30 Sep 2017 accepted: 28 Feb 2018 first online: 25 Apr 2018 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn Email Tools Icon Tools Get Permissions Search Site Citation Leonard D. Ancuta, Peter K. Zeitler, Bruce D. Idleman, Brennan T. Jordan; Whole-rock 40Ar/39Ar geochronology, geochemistry, and stratigraphy of intraplate Cenozoic volcanic rocks, central Mongolia. GSA Bulletin 2018;; 130 (7-8): 1397–1408. doi: https://doi.org/10.1130/B31788.1 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search nav search search input Search input auto suggest search filter All ContentBy SocietyGSA Bulletin Search Advanced Search Abstract A new comprehensive suite of 235 whole-rock 40Ar/39Ar ages ranges from Holocene to ca. 30 Ma for Cenozoic volcanic rocks in central Mongolia. Their total preserved volume is ∼1540 km3, but prior to erosion, the volume may have been as high as 2900 km3. The 235 new stratigraphically referenced ages, combined with surface mapping, suggest that volcanic output began to increase in the early Miocene and peaked in the middle Miocene, with a gradual decrease in volume through the Holocene. Trace-element inversion modeling suggests that the volcanic rocks were derived by low degrees of partial melting of a garnet lherzolite source at a depth greater than 62 km. The low total volumes and the lack of an apparent age-progressive hotspot track suggest that the volcanism cannot be attributed to a deep mantle plume beneath central Mongolia. The long-term gradual increase and subsequent decrease in volcanic output may also rule out delamination as the cause of the volcanism. Instead, we favor a small-scale mantle upwelling to explain the cause of the intraplate volcanism in the region. This upwelling could have been the result of one or more different processes, including edge-driven convection, redirection of asthenospheric flow by the thick lithosphere of the Siberian craton to the north, shear-driven upwelling, delamination, drips, or upwelling related to stagnant slabs in the mantle transition zone. You do not currently have access to this article.