Other
Scientific paper
Sep 1994
adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=1994gecoa..58.3855w&link_type=abstract
Geochimica et Cosmochimica Acta, vol. 58, Issue 18, pp.3855-3877
Other
20
Scientific paper
The mineral grossite (CaAl 4 O 7 ; Ca-dialuminate, also termed CA2) is a rare phase in terrestrial and extraterrestrial rocks. In meteorites, grossite was found in Ca,Al-rich inclusions (CAIs) from Allende (CV3), Vigarano (CV3), Leoville (CV3), Efremovka (CV3), Colony (CO3), Murchison (CM2), ALH 85085 (CH), Acfer 182 (CH), Acfer 059-E1 Djouf 001 (CR2), and the anomalous C-chondrite Adelaide. In Ca,Al-rich inclusions from most of these meteorites, grossite is an accessory phase; however, in many CAIs from ALH 85085, Acfer 182, and Acfer 059-E1 Djouf 001 it is a major phase. In this paper, we summarize the results of literature reports on grossite-bearing inclusions and focus, in detail, on the occurrence, mineralogy, and chemistry of CaAl 4 O 7 -containing Ca,Al-rich inclusions in Acfer 182 and Acfer 059-E1 Djouf 001. In these carbonaceous chondrites, abundant CAIs with high modal abundances of grossite (> 30 vol%, often >60 vol%) were discovered. To classify Ca,Al-rich inclusions with such high modal abundances of CaAl 4 O 7 we suggest to introduce a new type of Ca,Al-rich inclusion: grossite-rich inclusions. In Acfer 059-E1 Djouf 001 and Acfer 182, grossite-containing inclusions occur with different petrographic characteristics. The most common type consists of a core of grossite rimmed by melilite, Ca-pyroxene ± spinel ± hibonite. In an other type, anhedral, polycrystalline grossite complexes of irregular shape are enclosed in melilite. In some spherical CA2-inclusions abundant euhedral to subhedral grossite and/or hibonite crystals are embedded in melilite. In two inclusions, a core of hibonite is mantled by grossite. Additionally, some grossite-bearing inclusions with unique texture and/or mineralogy were found. One of these inclusions is rich in Zr,Y-rich perovskite and contains phases rich in the ultrarefractory elements Sc and/or Zr. Almost all of the grossite-containing inclusions are rich in Al 2 O 3 (>50 wt%), even if grossite is only a minor phase. Based on textural appearance and/or on REE contents in some inclusions (core minerals with Group II patterns) a condensation history for most inclusions is suggested. A single inclusion rich in perovskite and other phases containing high concentrations of ultrarefractory elements appears to have formed as an early condensate from the solar nebula.
Bischoff Adolf
Weber Dietmar
No associations
LandOfFree
The occurrence of grossite (CaAl 4 O 7 ) in chondrites does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with The occurrence of grossite (CaAl 4 O 7 ) in chondrites, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and The occurrence of grossite (CaAl 4 O 7 ) in chondrites will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-1789514