caa a22 4500 465790763 CHVBK 20180323112023.0 cr unu---uuuuu 170327e19900101xx s 000 0 eng 10.1007/BF00310641 doi (NATIONALLICENCE)springer-10.1007/BF00310641 Constraints on phase diagram topology for the system CaO−MgO−SiO2−CO2−H2O [Elektronische Daten] [Volkmar Trommsdorff, James Connolly] Published phase diagrams for the siliceous carbonate system CaO−MgO−SiO2−CO2−H2O are contradictory because of different estimates of the relative stability of magnesite. Experimental data on magnesite are too ambiguous to determine the validity of these estimates. Therefore, field evidence is used to select the correct phase diagram topology for siliceous carbonate and carbonate ultramafic rocks at pressures of about 2-5 kbar. The primary selection criterion is provided by the existence of the stable assemblage talc+dolomite+forsterite+tremolite+antigorite, which occurs in the Bergell contact aureole and Swiss Central Alps. Field evidence also is used to argue that the reaction magnesite+quartz=enstatite must occur at lower temperature than the reaction dolomite+quartz=diopside. T-X CO 2 and P CO 2-T phase diagrams consistent with these observations are calculated from experimental and thermo-dynamic data. For antigorite ophicarbonate rocks, remarkable agreement is obtained between the spatial distribution of low variance mineral assemblages and the calculated diagrams. Springer-Verlag, 1990 Trommsdorff Volkmar Institut für Mineralogie und Petrographie, Eidgenössische Technische Hochschule, CH-8092, Zürich, Switzerland aut Connolly James Institut für Mineralogie und Petrographie, Eidgenössische Technische Hochschule, CH-8092, Zürich, Switzerland aut Contributions to Mineralogy and Petrology Springer-Verlag 104/1(1990-01-01), 1-7 0010-7999 104:1<1 1990 104 410 https://doi.org/10.1007/BF00310641 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/BF00310641 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Trommsdorff Volkmar Institut für Mineralogie und Petrographie, Eidgenössische Technische Hochschule, CH-8092, Zürich, Switzerland aut NATIONALLICENCE 700 1- Connolly James Institut für Mineralogie und Petrographie, Eidgenössische Technische Hochschule, CH-8092, Zürich, Switzerland aut NATIONALLICENCE 773 0- Contributions to Mineralogy and Petrology Springer-Verlag 104/1(1990-01-01), 1-7 0010-7999 104:1<1 1990 104 410 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer