Water content of mantle garnets

Research Article| December 01, 1984 Water content of mantle garnets Roger D. Aines; Roger D. Aines 1Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, California 91125 Search for other works by this author on: GSW Google Scholar George R. Rossman George R. Rossman 1Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, California 91125 Search for other works by this author on: GSW Google Scholar Geology (1984) 12 (12): 720–723. https://doi.org/10.1130/0091-7613(1984)12<720:WCOMG>2.0.CO;2 Article history first online: 01 Jun 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation Roger D. Aines, George R. Rossman; Water content of mantle garnets. Geology 1984;; 12 (12): 720–723. doi: https://doi.org/10.1130/0091-7613(1984)12<720:WCOMG>2.0.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 Garnet megacrysts from Colorado Plateau diatremes (Green Knobs, Garnet Ridge) and the Wesselton kimberlite, South Africa, commonly contain a structural hydrous component. The Colorado Plateau samples range from 0.0 to 0.26 wt% H2O, and the Wesselton samples contain from 0.01 to 0.07%. Concentrations were measured using P2O5 cell coulometry, H2 gas manometry, and thermogravimetry. These were used to calibrate infrared integrated absorbance in the 3-µm region, which is a more sensitive measure of total O-H content than the other analytical methods. Infrared absorbance patterns were also used to differentiate structural hydrous component from water contained in alteration and included phases. The structure of the hydrous component in these garnets appears to be the classic H4O44− = SiO44−. Profiles at 100-µm intervals across these samples show flat concentration profiles or slightly increasing concentration toward the center. A large range of water content among samples appears to represent real differences in water fugacity at the point where the garnets equilibrated. Garnets in eclogite nodules from South Africa and the Solomon Islands were also studied but were either anhydrous or too badly altered to determine the content of structurally bound water. The high concentration of hydrous component in the Colorado Plateau samples is consistent with other indicators of high volatile content in that region of the mantle. The water content of mantle garnets may prove to be an accurate indicator of mantle-water fugacities. 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.