Magnesian anorthosites and a deep crustal rock from the farside crust of the moon

Hiroshi Takeda*, A. Yamaguchi, D. D. Bogard, Y. Karouji, M. Ebihara, M. Ohtake, K. Saiki, T. Arai

*この研究の対応する著者

研究成果: Article査読

72 被引用数 (Scopus)

抄録

Among over thirty lunar meteorites recovered from the hot deserts and Antarctica, Dhofar 489 is the most depleted in thorium (0.05 ppm), FeO, and rare earth elements (REE). Dhofar 489 is a crystalline matrix anorthositic breccia and includes clasts of magnesian anorthosites and a spinel troctolite. The Mg / (Mg + Fe) mol% (Mg numbers = 75-85) of olivine and pyroxene grains in this meteorite are higher than those of the Apollo ferroan anorthosites. Such materials were not recovered by the Apollo and Luna missions. However, remote sensing data suggest that the estimated concentrations of Th and FeO are consistent with the presence of such samples on the farside of the Moon. The differentiation trend deduced from the mineralogy of the anorthositic clasts define a magnesian extension of the ferroan anorthosite (FAN) trend constructed from the Apollo samples. The presence of magnesian anorthositic clasts in Dhofar 489 still offers a possibility that the farside trend with magnesian compositions is more primitive than the FAN trend, and may require a revision of this classical differentiation trend. The Ar-Ar age of Dhofar 489 is 4.23 ± 0.034 Gyr, which is older than most Ar ages reported for highland rocks returned by Apollo. The old Ar-Ar age of impact formation of this breccia and the presence of a fragment of spinel troctolite of deep crustal origin suggest that a basin forming event on the farside excavated the deep crust and magnesian anorthosites before formation of Imbrium.

本文言語English
ページ(範囲)171-184
ページ数14
ジャーナルEarth and Planetary Science Letters
247
3-4
DOI
出版ステータスPublished - 2006 7 30
外部発表はい

ASJC Scopus subject areas

  • 地球物理学
  • 地球化学および岩石学
  • 地球惑星科学(その他)
  • 宇宙惑星科学

フィンガープリント

「Magnesian anorthosites and a deep crustal rock from the farside crust of the moon」の研究トピックを掘り下げます。これらがまとまってユニークなフィンガープリントを構成します。

引用スタイル