Premium
Regolith Breccia Allan Hills A81005: Evidence of lunar origin, and petrography of pristine and nonpristine clasts
Author(s) -
Warren Paul H.,
Taylor G. Jeffrey,
Keil Klaus
Publication year - 1983
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/gl010i009p00779
Subject(s) - regolith , breccia , geology , achondrite , geochemistry , pyroxene , augite , geology of the moon , astrobiology , lunar soil , plagioclase , chondrite , petrography , basalt , meteorite , mineralogy , olivine , paleontology , physics , quartz
MnO/FeO ratios in pyroxene, texture (abundant brown, swirly glass, in general typical of lunar regolith breccias), and overall composition (∼75% plagioclase) all indicate that Allan Hills A81005 is of lunar origin. It is presumably from a heretofore unsampled region of the Moon. It differs in detail from other regolith samples, e.g., it has exceptionally low contents of Na and KREEP. A pristine clast contains exceptionally coarse augite, compared to similar Apollo samples. ALHA81005 is not perceptibly more shocked than typical Apollo regolith breccias. Therefore, its discovery on Earth lends further credence to suggestions that SNC achondrites were derived by impact ejection from Mars.