Petrography of the impact breccias of the Enkingen (SUBO 18) drill core, southern Ries crater, Germany: New estimate of impact melt volume

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Research Article| January 01, 2012 Petrography of the impact breccias of the Enkingen (SUBO 18) drill core, southern Ries crater, Germany: New estimate of impact melt volume W.U. Reimold; W.U. Reimold † 1Museum für Naturkunde–Leibniz Institute for Evolution and Biodiversity Research at Humboldt University Berlin, Invalidenstrasse 43, 10115 Berlin, Germany †E-mail: uwe.reimold@mfn-berlin.de Search for other works by this author on: GSW Google Scholar B.K. Hansen; B.K. Hansen 1Museum für Naturkunde–Leibniz Institute for Evolution and Biodiversity Research at Humboldt University Berlin, Invalidenstrasse 43, 10115 Berlin, Germany Search for other works by this author on: GSW Google Scholar J. Jacob; J. Jacob 1Museum für Naturkunde–Leibniz Institute for Evolution and Biodiversity Research at Humboldt University Berlin, Invalidenstrasse 43, 10115 Berlin, Germany Search for other works by this author on: GSW Google Scholar N.A. Artemieva; N.A. Artemieva 1Museum für Naturkunde–Leibniz Institute for Evolution and Biodiversity Research at Humboldt University Berlin, Invalidenstrasse 43, 10115 Berlin, Germany2Russian Academy of Sciences, Institute for Dynamics of Geospheres, Leninsky Prospect, 38, Housing 1, Moscow 119334, Russia Search for other works by this author on: GSW Google Scholar K. Wünnemann; K. Wünnemann 1Museum für Naturkunde–Leibniz Institute for Evolution and Biodiversity Research at Humboldt University Berlin, Invalidenstrasse 43, 10115 Berlin, Germany Search for other works by this author on: GSW Google Scholar C. Meyer C. Meyer 1Museum für Naturkunde–Leibniz Institute for Evolution and Biodiversity Research at Humboldt University Berlin, Invalidenstrasse 43, 10115 Berlin, Germany Search for other works by this author on: GSW Google Scholar GSA Bulletin (2012) 124 (1-2): 104–132. https://doi.org/10.1130/B30470.1 Article history received: 21 Dec 2010 rev-recd: 30 Mar 2011 accepted: 04 Apr 2011 first online: 08 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 W.U. Reimold, B.K. Hansen, J. Jacob, N.A. Artemieva, K. Wünnemann, C. Meyer; Petrography of the impact breccias of the Enkingen (SUBO 18) drill core, southern Ries crater, Germany: New estimate of impact melt volume. GSA Bulletin 2012;; 124 (1-2): 104–132. doi: https://doi.org/10.1130/B30470.1 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 A new drill core (SUBO 18) that intersects a continuous sequence of impact breccias has been obtained at the town of Enkingen at the southern edge of the Ries inner crater. Detailed petrographic analysis of this core provides important new information regarding the nature and origin of within-crater suevite, which is not only relevant for the understanding of the formation of the Ries impact structure but has strong implications for impact breccia deposition in general. In the Enkingen core, below 21 m of crater sediment, ∼90 m of impact breccia have been sampled. Most of this material is what in the past has been referred to as suevite—defined as groundmass of clastic material entraining cogenetic melt fragments and target rock clasts. Only the bottommost 10 m of core are melt-dominated impact breccia. Any relatively thick melt rock intersection along this core is revealed to be composed of individual centimeter- to decimeter-sized melt bodies best described as "agglomerate" due to its close resemblance to volcaniclastics of that type. Detailed macro-, meso-, and microscopic petrographic analysis has established that the SUBO 18 impact breccias cannot be divided into distinct units. The groundmass is extensively altered to phyllosilicate (smectite or chlorite) or carbonate minerals. Results of a detailed scanning electron microscopic investigation of the groundmasses of samples from all parts of this sequence emphatically support the traditional definition of suevite, irrespective of scale. Modal analysis at macroscopic to submicroscopic scales has shown that the overall, average melt content of Enkingen suevite is on the order of 49 vol%. This exceeds by far previous estimates and brings the Ries crater melt volume in line with values traditionally suggested from crater and melt volume scaling for similar-sized impact structures in crystalline and mixed targets. You do not have access to this content, please speak to your institutional administrator if you feel you should have access.

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