Possible serpentine relicts in lunar meteorites

S. I. Demidova, M. A. Nazarov, T. Ntaflos, F. Brandstätter

March 2015, Volume 23, Issue 2, pp 116-126


Recent studies of lunar rocks showed that water could be an important component of lunar magmas. However, mineralogical signs of aqueous alteration of lunar minerals have not been found yet. Two peculiar objects were identified in the Dhofar 302 and 961 lunar meteorites. Their compositional features suggest that their formation could be related to serpentine dehydration. These objects consist of olivine-orthopyroxene intergrowths. In the Dhofar 961 object pyroxene lamellae in olivine resemble exsolution features, while its olivine contains up to 0.5 wt % P2O5. Phosphoran olivines have never been observed in lunar rocks. The findings of these objects suggest possible participation of serpenitinization and deserpentinization in lunar petrogenesis. Significant chemical differences of objects from the Dhofar 302 and 961 meteorites indicate that different kind of rocks were subjected to serpentinization. Unlike the Dhofar 302 object, the serpentine precursor of the Dhofar 961 object should be formed in a KREEP-bearing source.