THEORETICAL PREDICTION OF PHASE-RELATIONSHIPS IN PLANETARY MANTLES

Journal article

Calorimetric and phase equilibrium data were used to establish an internally consistent thermodynamic database for the Si-undersaturated part of the system Na2O-FeOnCaO-MgO-Al2O3-SiO2. This database has been used to calculate the stability fields of assemblages involving olivine, orthopyroxene, clinopyroxene, spinel, plagioclase, and garnet at high P and T. In the six-component system CaO-MgO-Al2O3-SiO2 the stable assemblages are ol-opx-cpx-plag at P < 8 kbar at 1300oC and <6 kbar at 900oC. Above these P, spinel replaces plagioclase until P of 16 kbar at 1300oC and 14 kbar at 900oC are reached. At higher P, garnet lherzolite (ol + opx + cpx + gt) is stable. Stable phase assemblages have also been calculated for Na- and Fe-bearing compositions postulated as possible martian mantles. -P.Br.

Authors: Wood, B; Holloway, J

• Publication status: Published
• Journal: JOURNAL OF GEOPHYSICAL RESEARCH
• Volume: 87
• Issue: Supplement
• Pages: A19-A30
• Publication date: 1982-01-01
• DOI: 10.1029/JB087iS01p00A19
• ISSN: 0148-0227
• Language: English