In-situ spectroscopic investigation of high-pressure hydrated (Mg,Fe)SiO 3 glasses; OH vibrations as a probe of glass structure

Other| April 01, 1995 In-situ spectroscopic investigation of high-pressure hydrated (Mg,Fe)SiO3 glasses: OH vibrations as a probe of glass structure C. Closmann; C. Closmann University of California, Institute of Tectonics, Santa Cruz, CA, United States Search for other works by this author on: GSW Google Scholar Q. Williams Q. Williams Search for other works by this author on: GSW Google Scholar Author and Article Information C. Closmann University of California, Institute of Tectonics, Santa Cruz, CA, United States Q. Williams Publisher: Mineralogical Society of America First Online: 02 Mar 2017 Online ISSN: 1945-3027 Print ISSN: 0003-004X Copyright © 1995 by the Mineralogical Society of America American Mineralogist (1995) 80 (3-4): 201–212. https://doi.org/10.2138/am-1995-3-401 Article history First Online: 02 Mar 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn Email Permissions Search Site Citation C. Closmann, Q. Williams; In-situ spectroscopic investigation of high-pressure hydrated (Mg,Fe)SiO3 glasses: OH vibrations as a probe of glass structure. American Mineralogist 1995;; 80 (3-4): 201–212. doi: https://doi.org/10.2138/am-1995-3-401 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 SocietyAmerican Mineralogist Search Advanced Search Abstract We have investigated the structure of hydrated (Mg,Fe)SiO3 glasses both at high pressure and after quenching, using infrared spectroscopy. Glasses were synthesized by fusion at pressures of up to 41 GPa and probed in situ to 39 GPa. Strong H bonding, as manifested by the presence of distinct OH stretching bands between 2250 and 2600 cm−1, plays an important role in the speciation of OH groups at pressures between 15 and 25 GPa. At higher pressures, strong H bonding is also observed in the glasses but is completely unquenchable to ambient pressure; major structural changes are observed during decompression from pressures in excess of 20 GPa. Both the absence of a significant concentration of strongly H-bound OH groups and the similarity in frequency of the primary O-H stretching peak in the spectra of samples quenched from pressures above 30 GPa and those formed below 15 GPa indicate that similar structural features exist in glasses synthesized and quenched from these two separate pressure regimes. We infer that changes in Si coordination occur primarily between these two pressures and are largely unquenchable. Intratetrahedral H bonding is suggested as a possible mechanism for densification at pressures lower than ∼25 GPa. Estimated bond lengths for high-pressure hydroxylated species imply that the hydrous component in silicate melts undergoes significant densification with pressure, and that the volume of dissolved H2O in high-pressure silicate melts is controlled almost solely by the volume of O anions. This content is PDF only. Please click on the PDF icon to access. 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.