Yamato-793605: A new lherzolitic shergottite from the Japanese Antarctic meteorite collection
スポンサーリンク
概要
- 論文の詳細を見る
Y-793605 is a new martian meteorite from Antarctica that can be classified as a lherzolitic shergottite. Y-793605 mainly shows a poikilitic texture (large pyroxene oikocryst with enclosed olivine and chromite), but partly contains non-poikilitic areas (mainly maskelynite, olivine, and pigeonite). Olivine in the non-poikilitic area is more Fe-rich and shows a narrower compositional distribution than that in the poikilitic area. Low-Ca pyroxenes in the non-poikilitic area are also more Fe-rich (En_<65>Fs_<28>Wo_7∿En_<60>Fs_<27>Wo_<13>) than those in the poikilitic area (En_<76>Fs_<21>Wo_3∿En_<66>Fs_<23>Wo_<11>). Augites in the poikilitic area are usually present rimming the oikocrysts (En_<52>Fs_<16>Wo_<32> to En_<49>Fs_<14>Wo_<37>). The crystallization sequence of minerals in Y-793605 is considered to have begun by initial crystallization of cumulus phases (olivine and chromite) from the parent magma. Then, low-Ca pyroxenes and later augite poikilitically enclosed cumulus phases, and became a large oikocryst. Due to accumulation of phases, small interstitial melts formed between the oikocryst boundaries, and plagioclase crystallized from the Ca-Fe-rich melt along with pigeonite. After minor augite crystallization in the non-poikilitic area, all phases experienced re-equilibration (e. g., homogenization of olivine). Y-793605 shows a close relationship to previously known lherzolitic shergottites ALH77005 and LEW88516. Especially, olivine composition of Y-793605 is nearly identical to that of LEW88516. Pyroxene and maskelynite compositions are almost the same among these three meteorites. Although it is hardly possible to consider that Y-793605 is paired with ALH77005 or LEW88516 in the sense that Y-793605 was in the same fall with them, it can be concluded that Y-793605 originated from the same igneous body or rock in Mars as ALH77005 and LEW88516.
- 国立極地研究所の論文
著者
-
Mikouchi Takashi
Mineralogical Institute Graduate School Of Science University Of Tokyo
-
Miyamoto Masamichi
Mineralogical Institute Graduate School Of Science University Of Tokyo
関連論文
- Metamorphic transformations of opaque minerals in some eucrites
- Mineralogy of the Asuka 87 and 88 eucrites and crustal evolution of the HED parent body
- Mineralogical consideration of possible microfossils in martian meteorite ALH84001
- Diffraction profile analysis of olivines in thin sections of meteorites by the micro-region Laue method using synchrotron radiation
- Mineralogical study of angrite Asuka-881371: Its possible relation to angrite LEW87051
- Modal mineral abundances and the differentiation trends in primitive achondrites
- Infrared diffuse reflectance spectra of weathered and unweathered CR2 chondrites: Comparison with asteroids
- Evaluation of diffusion coefficients of Fe-Mg and Ca in olivine
- Mineralogical comparison of Hammadah al Hamra 126 with some ureilites
- Yamato-793605: A new lherzolitic shergottite from the Japanese Antarctic meteorite collection
- Shocked plagioclase in the lunar meteorites Yamato-793169 and Asuka-881757: Implications for their shock and thermal histories
- Cooling rates of olivine xenocrysts in the EET79001 shergottite
- Chemical zoning of olivines in the Yamato-791717 CO3 chondrite
- Diffuse reflectance spectra for heated samples of an H5 chondrite: Importance of oxygen fugacity at heating
- Micro raman spectroscopy of diamonds in the Canyon Diablo iron meteorite: Implication for shock origin
- Comparisons of textural and chemical variations of minerals in some primitive achondrites and an H7 chondrite, with reference to their formation and cooling histories
- Lherzolitic Martian meteorites Allan Hills 77005, Lewis Cliff 88516 and Yamato-793605: Major and minor element zoning in pyroxene and plagioclase glass
- The variation of Zn content in spinel group minerals and daubreelites of primitive achondrites
- The Yamato-793605 martian meteorite consortium