Abstract

—High-pressure phases (ringwoodite, maskelynite, and jadeite) present as coarse-grained fragments in the shock-melt vein of the Dhofar 922 L6 chondrite were studied by scanning electron microscopy and Raman spectroscopy. Ringwoodite and jadeite crystallized from melted plagioclase and olivine fragments, respectively, at the cooling–decompression stage. We assume that the high contents of Fe and Mg in maskelynite–jadeite aggregates are due to a miscibility gap in the hedenbergite–jadeite and diopside–jadeite joins at ~600 and ~700 ºC, respectively. The PT conditions of the formation of shock-melt veins are estimated at >19 GPa and >2150–2300 ºC.

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