Abstract
The compositions of orthopyroxene, associated with magnetite and quartz in the system FeO-MgO-MnO-SiO2 were determined experimentally at temperatures of 700, 750, 800°C and pressures ranging between 3 and 5 kbar. On the basis of data obtained the value of the Guggenheim parameter of orthopyroxene solid solution was calculated: AFe. Mn = 2400 ±500 cal. For rocks rich in MnO, a modified version of orthopyroxene-magnetite-quartz oxygen barometer is suggested.
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Graphchikov, A.A. Orthopyroxene-magnetite-quartz oxygen barometer for Mnbearing rocks (experimental calibration). Proc. Indian Acad. Sci. (Earth Planet Sci.) 101, 191–199 (1992). https://doi.org/10.1007/BF02840352
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DOI: https://doi.org/10.1007/BF02840352