Pristine moon rocks - An alkali anorthosite with coarse augite exsolution from plagioclase, a magnesian harzburgite, and other odditiesResults are presented on the analyses of 18 samples of pristine rocks obtained from the primarily mare Apollo 12 site and from the primarily highland Apollo 14 site, as well as samples from the nonmare Apollo 15 site. It was found that, while two of anorthosites from Apollo 12 were similar in composition to most other anorthosites from the west-central near region, the texture of an alkali anorthosite featured a long and narrow crystal of augite surrounded by a single crystal of plagioclase, clearly suggesting that the augite formed by exsolution out of the plagioclase. Another Apollo 12 rocklet was an unusual magnesian harzburite, with subequal amounts of enstatite and olivine, traces of Cr-Fe spinel, and FeNi metal, but no plagioclase; the bulk composition was found to be remarkably Ir-rich (53 percent) for a pristine rock, and the texture was also unusual. Apollo 14 samples included several uncommonly Al-rich and REE-poor impact melt breccias.
Document ID
19900046405
Acquisition Source
Legacy CDMS
Document Type
Conference Paper
Authors
Warren, P. H. (California Univ. Los Angeles, CA, United States)
Jerde, E. A. (California Univ. Los Angeles, CA, United States)
Kallemeyn, G. W. (California, University Los Angeles, United States)