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Updated: Jul 12, 2026
10:12
Synchrotron X-ray Microdiffraction and Fluorescence Imaging of Mineral and Rock Samples
Published on: June 19, 2018
Apollo 16 Geochemical X-ray Fluorescence Experiment: Preliminary Report.
Science (New York, N.Y.)
|July 21, 1972
Summary
Lunar surface mapping using Apollo 16 data reveals widespread differentiated highlands crust. Results indicate highland composition similar to anorthositic gabbros and feldspathic basalts, suggesting this premare crust exists at the Descartes site.
Area of Science:
- Lunar geology
- Planetary science
- Geochemistry
Background:
- Previous Apollo missions provided initial lunar surface composition data.
- Understanding lunar crustal composition is key to unraveling its geological evolution.
Purpose of the Study:
- To map the lunar surface composition using Apollo 16 data.
- To confirm and expand upon previous compositional findings.
- To investigate the composition of the Descartes landing site.
Main Methods:
- Orbital X-ray fluorescence spectroscopy during the Apollo 16 mission.
- Analysis of aluminum/silicon and magnesium/silicon intensity ratios.
- Mapping chemical composition along spacecraft ground tracks.
Main Results:
- Confirmed compositional observations from the Apollo 15 mission.
- Provided new compositional data for previously unmapped lunar features.
- Lunar highlands exhibit a differentiated crustal composition.
- Elemental ratios are consistent with anorthositic gabbros to gabbroic anorthosites or feldspathic basalts.
- X-ray data suggest premare crustal material at the Descartes landing site.
Conclusions:
- The lunar highlands represent a widespread differentiated crust.
- The composition of the highlands is consistent with specific igneous rock types.
- The Descartes region likely contains this ancient crustal material.
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