Stability of dolomite in a hydrous mantle, with implications for the mantle solidus

Research Article| July 01, 1978 Stability of dolomite in a hydrous mantle, with implications for the mantle solidus David H. Eggler David H. Eggler 1Geophysical Laboratory, Carnegie Institution of Washington, Washington, D.C. 20008 Search for other works by this author on: GSW Google Scholar Author and Article Information David H. Eggler 1Geophysical Laboratory, Carnegie Institution of Washington, Washington, D.C. 20008 Publisher: Geological Society of America First Online: 02 Jun 2017 Online ISSN: 1943-2682 Print ISSN: 0091-7613 Geological Society of America Geology (1978) 6 (7): 397–400. https://doi.org/10.1130/0091-7613(1978)6<397:SODIAH>2.0.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 David H. Eggler; Stability of dolomite in a hydrous mantle, with implications for the mantle solidus. Geology 1978;; 6 (7): 397–400. doi: https://doi.org/10.1130/0091-7613(1978)6<397:SODIAH>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 The stability of dolomite, limited by the reaction enstatite + dolomite = diopside + forsterite + CO2, has been studied in the system CaO-MgO-SiO2-CO2-H2O at 26 and 31 kbar. The decarbonation curves (contoured for vapor composition) can be extended to a wider range of pressures with thermodynamic functions.At 31 kbar a portion of the decarbonation curve is intersected by the peridotite solidus. This solidus curve is univariant (independent of volatile composition) because the composition of vapor is buffered by the reaction shown above, within a range of CO2/(CO2 + H2O). This range, called the zone of invariant vapor composition (ZIVC), widens considerably with increasing pressure.An analogous ZIVC-type solidus can be calculated that is applicable, at pressures greater than about 22 kbar, to natural peridotite compositions containing small amounts of CO2 and H2O (dolomite peridotite). The solidus is equally applicable to dolomite-phlogopite peridotite, because the phlogopite content of the mantle is insufficient to buffer the vapor composition.At pressures below about 22 kbar, dolomite is not stable in the melting range of peridotite. The vapor composition is then buffered by an amphibole reaction at a relatively high (but unknown) value of CO2 /(CO2 + H2O). The change in reaction is accompanied by a relatively sudden increase in the solidus temperature. 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.