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Spinel troctolite and anorthosite in apollo 16 samples
Science (New York, N.Y.)
|January 5, 1973
Summary
Two Apollo 16 lunar rocks, spinel troctolite and anorthosite, formed from the same high-alumina basalt magma. Troctolite crystallized first via settling, followed by anorthosite formation through flotation.
Area of Science:
- Lunar geology
- Petrology
- Cosmochemistry
Background:
- Apollo 16 samples provide insights into lunar crust formation.
- Primitive lunar cumulates represent early magmatic processes on the Moon.
Purpose of the Study:
- To analyze contrasting primitive lunar cumulate rock types from Apollo 16.
- To determine the origin and formation processes of spinel troctolite and anorthosite.
Main Methods:
- Petrographic analysis of lunar rock samples.
- Inferred formation mechanisms based on mineral assemblages and textures.
Main Results:
- Spinel troctolite and anorthosite exhibit distinct compositions and textures.
- Both rock types likely originated from a common high-alumina magnesian basaltic magma.
Conclusions:
- Troctolite likely formed earlier through crystal settling.
- Anorthosite possibly formed later via flotation processes from the same parent magma.
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