Free gas at the base of the gas hydrate zone in the vicinity of the Chile triple junction

Abstract

Research Article| October 01, 1993 Free gas at the base of the gas hydrate zone in the vicinity of the Chile triple junction Nathan L. B. Bangs; Nathan L. B. Bangs 1Institute for Geophysics, University of Texas at Austin, 8701 Mopac Expressway, Austin, Texas 78759 Search for other works by this author on: GSW Google Scholar Dale S. Sawyer; Dale S. Sawyer 2Department of Geology and Geophysics, Rice University, P.O. Box 1892, Houston, Texas 77251 Search for other works by this author on: GSW Google Scholar Xenia Golovchenko Xenia Golovchenko 3Lamont-Doherty Earth Observatory, Columbia University, Palisades, New York 10964 Search for other works by this author on: GSW Google Scholar Author and Article Information Nathan L. B. Bangs 1Institute for Geophysics, University of Texas at Austin, 8701 Mopac Expressway, Austin, Texas 78759 Dale S. Sawyer 2Department of Geology and Geophysics, Rice University, P.O. Box 1892, Houston, Texas 77251 Xenia Golovchenko 3Lamont-Doherty Earth Observatory, Columbia University, Palisades, New York 10964 Publisher: Geological Society of America First Online: 02 Jun 2017 Online ISSN: 1943-2682 Print ISSN: 0091-7613 Geological Society of America Geology (1993) 21 (10): 905–908. https://doi.org/10.1130/0091-7613(1993)021<0905:FGATBO>2.3.CO;2 Article history First Online: 02 Jun 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn Email Permissions Search Site Citation Nathan L. B. Bangs, Dale S. Sawyer, Xenia Golovchenko; Free gas at the base of the gas hydrate zone in the vicinity of the Chile triple junction. Geology 1993;; 21 (10): 905–908. doi: https://doi.org/10.1130/0091-7613(1993)021<0905:FGATBO>2.3.CO;2 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 At Ocean Drilling Program Site 859 in the vicinity of the Chile triple junction, the source of the bottom simulating reflection (BSR) at the base of the gas hydrate layer has, for the first time, been logged to reveal the nature of the impedance contrasts producing the reflection. We estimate from the P-wave velocity (Vp) that hydrate occupies no more than 18% of the pore space just above the BSR and is not concentrated enough to cause the reflections. The BSR is caused by a sharp drop in Vp, and presumably density, from ∼1950 to 1600 m/s (on average) within an 8 m interval. Seismic modeling of wave form and amplitude vs. offset of the BSR at Site 860 indicates that the BSR is produced by a 12 m interval with low Vp and shear-wave velocities that are consistent with small quantities of free gas (∼1% of pore space) in the interval. First Page Preview Close Modal You do not have access to this content, please speak to your institutional administrator if you feel you should have access.