TY - JOUR
T1 - Petrography of Yamato 984028 lherzolitic shergottite and its melt vein
T2 - Implications for its shock metamorphism and origin of the vein
AU - Ozawa, Shin
AU - Miyahara, Masaaki
AU - Ohtani, Eiji
AU - Kimura, Makoto
AU - Ito, Yoshinori
N1 - Funding Information:
We appreciate the opportunity provided by the National Institute of Polar Research for us to study the chip sample from Y984028. We thank Prof. A. El Goresy for his helpful discussion and encouragement. An anonymous reviewer is acknowledged for constructive comments that improved an early version of the manuscript. S. O. is supported by a JSPS Research Fellowship for Young Scientists. E. O. was partly supported by Grants-in-aid for Scientific Research (Nos. 18654091 and 18184009 ) from the Ministry of Education, Culture, Sports, Science, and Technology (MEXT) , Japan, and the study was conducted as a part of the Tohoku University Global COE program “Global Education and Research Center for Earth and Planetary Dynamics”.
PY - 2011/1
Y1 - 2011/1
N2 - Yamato 984028 (Y984028) is a newly identified lherzolitic shergottite, recovered from the Yamato Mountains, Antarctica, in 1999. As part of a consortium study, we conducted petrographic observations of Y984028 and its melt vein in order to investigate its shock metamorphism. The rock displays the typical non-poikilitic texture of lherzolitic shergottite, characterized by a framework of olivine, minor pyroxene (pigeonite and augite), and interstitial maskelynite. Shock metamorphic features include irregular fractures in olivine and pyroxene, shock-induced twin-lamellae in pyroxene, and the complete conversion of plagioclase to maskelynite, features consistent with those found in other lherzolitic shergottites. The melt vein is composed of coarse mineral fragments (mainly olivine) entrained in a matrix of fine-grained euhedral olivine (with several modes of compositional zoning) and interstitial glassy material. Some coarse olivine fragments consist of an assemblage of fine-grained euhedral to subhedral olivine crystals, suggesting shock-induced fragmentation, recrystallization, and/or a process of sintering. The implication is that the fine-grained olivine crystals in the matrix of the melt vein represent complicated crystallization environments and histories.
AB - Yamato 984028 (Y984028) is a newly identified lherzolitic shergottite, recovered from the Yamato Mountains, Antarctica, in 1999. As part of a consortium study, we conducted petrographic observations of Y984028 and its melt vein in order to investigate its shock metamorphism. The rock displays the typical non-poikilitic texture of lherzolitic shergottite, characterized by a framework of olivine, minor pyroxene (pigeonite and augite), and interstitial maskelynite. Shock metamorphic features include irregular fractures in olivine and pyroxene, shock-induced twin-lamellae in pyroxene, and the complete conversion of plagioclase to maskelynite, features consistent with those found in other lherzolitic shergottites. The melt vein is composed of coarse mineral fragments (mainly olivine) entrained in a matrix of fine-grained euhedral olivine (with several modes of compositional zoning) and interstitial glassy material. Some coarse olivine fragments consist of an assemblage of fine-grained euhedral to subhedral olivine crystals, suggesting shock-induced fragmentation, recrystallization, and/or a process of sintering. The implication is that the fine-grained olivine crystals in the matrix of the melt vein represent complicated crystallization environments and histories.
KW - Chemical zoning
KW - Martian meteorites
KW - Melt vein
KW - Shock metamorphism
KW - Sintering
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U2 - 10.1016/j.polar.2010.08.002
DO - 10.1016/j.polar.2010.08.002
M3 - Article
AN - SCOPUS:78649666543
VL - 4
SP - 550
EP - 557
JO - Polar Science
JF - Polar Science
SN - 1873-9652
IS - 4
ER -