@article{oai:nipr.repo.nii.ac.jp:00006012,
 author = {Tomiyama, Takayuki and Yamaguchi, Akira and Misawa, Keiji and Kojima, Hideyasu},
 journal = {Antarctic meteorite research},
 month = {Mar},
 note = {P(論文), Allan Hills (ALH-) 77252 is a regolith breccia consisting of various types of clasts differing in metamorphic grades (L3-6). Titanium/aluminum ratios of low-Ca pyroxene in ALH-77252 are bimodally distributed. In equilibrated clasts, Ti/Al ratios of low-Ca pyroxene are ∿0.5 which are quite different from those in unequilibrated clasts of ∿0.07. Among equilibrated and unequilibrated clasts, the Ti/Cr ratio of low-Ca pyroxene also shows large differences. Because titanium and aluminum are not diffusive elements in the pyroxene crystal structure, diffusional redistribution of titanium and aluminum in low-Ca pyroxene requires significantly higher metamorphic temperature than Fe-Mg homogenization, possibly above ∿800℃. Alternatively, if the source materials of L-group chondrites were initially different, the fingerprints of mineral properties resistant to thermal metamorphism remain unchanged. If this was the case, the distinctly higher Ti/Al ratios of low-Ca pyroxene in equilibrated clasts originated from the primary signatures of low-Ca pyroxene prior to thermal metamorphism.},
 pages = {78--96},
 title = {Minor element chemistry of low-Ca pyroxene in Allan Hills-77252, an L3-6 regolith breccia},
 volume = {15},
 year = {2002}
}