10Be in Australasian microtektites compared to tektites: Size and geographic controls

Abstract

Research Article| August 08, 2018 10Be in Australasian microtektites compared to tektites: Size and geographic controls P. Rochette; P. Rochette 1Aix-Marseille Université, CNRS, IRD, INRA, Coll France, UM 34 CEREGE, Technopôle de l’Environnement Arbois-Méditerranée, BP80, 13545 Aix-en-Provence, France Search for other works by this author on: GSW Google Scholar R. Braucher; R. Braucher 1Aix-Marseille Université, CNRS, IRD, INRA, Coll France, UM 34 CEREGE, Technopôle de l’Environnement Arbois-Méditerranée, BP80, 13545 Aix-en-Provence, France Search for other works by this author on: GSW Google Scholar L. Folco; L. Folco 2Dipartimento di Scienze della Terra, Università di Pisa, Via S. Maria 53, 56126 Pisa, Italy Search for other works by this author on: GSW Google Scholar C.S. Horng; C.S. Horng 3Institute of Earth Sciences, Academia Sinica, P. O. Box 1-55, Nankang, Taipei 11529, Taiwan Search for other works by this author on: GSW Google Scholar G. Aumaître; G. Aumaître 1Aix-Marseille Université, CNRS, IRD, INRA, Coll France, UM 34 CEREGE, Technopôle de l’Environnement Arbois-Méditerranée, BP80, 13545 Aix-en-Provence, France Search for other works by this author on: GSW Google Scholar D.L. Bourlès; D.L. Bourlès 1Aix-Marseille Université, CNRS, IRD, INRA, Coll France, UM 34 CEREGE, Technopôle de l’Environnement Arbois-Méditerranée, BP80, 13545 Aix-en-Provence, France Search for other works by this author on: GSW Google Scholar K. Keddadouche K. Keddadouche 1Aix-Marseille Université, CNRS, IRD, INRA, Coll France, UM 34 CEREGE, Technopôle de l’Environnement Arbois-Méditerranée, BP80, 13545 Aix-en-Provence, France Search for other works by this author on: GSW Google Scholar Geology (2018) 46 (9): 803–806. https://doi.org/10.1130/G45038.1 Article history received: 16 Apr 2018 rev-recd: 18 Jul 2018 accepted: 23 Jul 2018 first online: 08 Aug 2018 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation P. Rochette, R. Braucher, L. Folco, C.S. Horng, G. Aumaître, D.L. Bourlès, K. Keddadouche; 10Be in Australasian microtektites compared to tektites: Size and geographic controls. Geology 2018;; 46 (9): 803–806. doi: https://doi.org/10.1130/G45038.1 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 High 10Be contents in tektites reported in literature are taken as evidence of a source material, melted at the impact site, enriched in atmospheric 10Be; i.e., a soil or sediment. In 0.8 Ma Australasian tektites, 10Be content increases with distance from the putative impact location in Indochina, with geographic averages from 69 × 106 atoms/g (Indochina) to 136 × 106 atoms/g (Australia). Here we report, for the first time, 10Be contents in microtektites collected from Antarctica and the South China Sea. We show that microtektites are ∼30 × 106 atoms/g richer in 10Be than tektites from the same geographic areas. Antarctic microtektites, with an average 10Be content of 184 × 106 atoms/g after correction for in situ production, are the richest impact glass ever measured. The simplest explanation for such systematic size and geographic trends is that the source depth of the melt within the target surface decreases with ejection velocity. Indeed, higher initial kinetic energy implies higher launch distances and higher fragmentation of the ejecta. Antarctic microtektite source depth may tentatively be restricted to the upper tens of centimeters at the impact site. Alternative models invoking a marine or loessic sediment source, or a secondary enrichment in the microtektite (either by atmospheric scavenging, selective fractionation by volatilization, or post-depositional contamination) fail to reproduce the observed relationships. You do not have access to this content, please speak to your institutional administrator if you feel you should have access.