Time scale of magma differentiation in arcs from protactinium-radium isotopic data

Abstract

Research Article| August 01, 2005 Time scale of magma differentiation in arcs from protactinium-radium isotopic data Yemane Asmerom; Yemane Asmerom 1 Department of Earth and Planetary Sciences, University of New Mexico, Albuquerque, New Mexico 87131, USA Search for other works by this author on: GSW Google Scholar S. Andrew DuFrane; S. Andrew DuFrane 1 Department of Earth and Planetary Sciences, University of New Mexico, Albuquerque, New Mexico 87131, USA Search for other works by this author on: GSW Google Scholar Samuel B. Mukasa; Samuel B. Mukasa 2Department of Geological Sciences, University of Michigan, Ann Arbor, Michigan 48109, USA Search for other works by this author on: GSW Google Scholar Hai Cheng; Hai Cheng 3 Department of Geology and Geophysics, University of Minnesota, Minneapolis, Minnesota 55455, USA Search for other works by this author on: GSW Google Scholar R. Lawrence Edwards R. Lawrence Edwards 3 Department of Geology and Geophysics, University of Minnesota, Minneapolis, Minnesota 55455, USA Search for other works by this author on: GSW Google Scholar Author and Article Information Yemane Asmerom 1 Department of Earth and Planetary Sciences, University of New Mexico, Albuquerque, New Mexico 87131, USA S. Andrew DuFrane 1 Department of Earth and Planetary Sciences, University of New Mexico, Albuquerque, New Mexico 87131, USA Samuel B. Mukasa 2Department of Geological Sciences, University of Michigan, Ann Arbor, Michigan 48109, USA Hai Cheng 3 Department of Geology and Geophysics, University of Minnesota, Minneapolis, Minnesota 55455, USA R. Lawrence Edwards 3 Department of Geology and Geophysics, University of Minnesota, Minneapolis, Minnesota 55455, USA Publisher: Geological Society of America Received: 18 Feb 2005 Revision Received: 25 Mar 2005 Accepted: 29 Mar 2005 First Online: 03 Mar 2017 Online ISSN: 1943-2682 Print ISSN: 0091-7613 The Geological Society of America, Inc. Geology (2005) 33 (8): 633–636. https://doi.org/10.1130/G21638AR.1 Article history Received: 18 Feb 2005 Revision Received: 25 Mar 2005 Accepted: 29 Mar 2005 First Online: 03 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 Yemane Asmerom, S. Andrew DuFrane, Samuel B. Mukasa, Hai Cheng, R. Lawrence Edwards; Time scale of magma differentiation in arcs from protactinium-radium isotopic data. Geology 2005;; 33 (8): 633–636. doi: https://doi.org/10.1130/G21638AR.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 SocietyGeology Search Advanced Search Abstract Absolute chronology of magma differentiation processes has been a long-desired goal, given its importance in understanding magma chamber dynamics and its connection to a fundamental understanding of the style and frequency of volcanic eruptions. Broad estimates of the duration of magma differentiation and overall crustal residence times have been made based on a variety of indirect approaches, such as physical models of magma chamber cooling, rates of crystal growth and settling, and long-lived radiogenic isotopes. In contrast, combined 231Pa-235U data may provide a robust measure of the time scale of magma differentiation. Based on 231Pa-235U, 230Th-238U and 226Ra-230Th data from Taal volcano, Luzon Arc, Philippine Archipelago, we show that 231Pa-235U data may provide a robust direct measure of the time scale of magma differentiation. A closed-system magma fractionation model gives a 231Pa-235U differentiation time scale in the range of 30 k.y., while the 226Ra-230Th time scale is considerably younger. The time scales are reconciled if we consider either fluid-mixing or magma-mixing models. The fluid-mixing model gives a time scale of differentiation similar to the 231Pa-235U closed-system time scale and is supported by the 230Th-238U data. The magma-mixing model gives a considerably longer time, in the range of 55 k.y. The combined observations support the robustness of the 231Pa-235U chronology, indicating a differentiation time scale in the range of 30 k.y., although this time scale for other volcanoes may vary depending on size and thermal state of the magma chamber. The 226Ra-230Th closed-system model ages, which yield much younger estimates for magma differentiation, are not likely to reflect time scales of magma differentiation. You do not have access to this content, please speak to your institutional administrator if you feel you should have access.