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The lunar highland melt‐rock suite
Author(s) -
Vaniman D. T.,
Papike J. J.
Publication year - 1978
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/gl005i006p00429
Subject(s) - anorthosite , gabbro , geology , anorthite , plagioclase , geochemistry , basalt , layered intrusion , ilmenite , petrology , mineralogy , mafic , paleontology , quartz
Size can be used as a criterion to select 18 large (> 1 cm) samples from among 148 melt‐rock fragments of all sizes. This selection provides a suite of large samples which represent the important chemical variants among highland melt rocks; each large sample has enough material for a number of sample‐destructive studies, as well as for future reference. Cluster analysis of the total data base of 148 highland melt rocks shows six distinct groups: anorthosite, gabbroic anorthosite, anorthositic gabbro (“highland basalt”), low‐K Fra Mauro, intermediate‐K Fra Mauro, and high‐K. Large samples are available for four of the melt‐rock groups (gabbroic anorthosite, anorthositic gabbro, low‐K Fra Mauro, and intermediate‐K Fra Mauro). This sample selection reveals two sub‐groups of anorthositic gabbro (one anorthite‐poor with negative Eu anomaly and one anorthite‐rich without Eu anomaly). There is a sharp distinction between those Apollo 16 melt rocks and glasses which have both been classified as “gabbroic anorthosite”.