Chemical Composition of the Lunar Surface in a Terra Region near the Crater Tycho

Science  15 May 1970:
Vol. 168, Issue 3933, pp. 825-828
DOI: 10.1126/science.168.3933.825


More precise and comprehensive analytical results for lunar surface material in a terra region have been derived from the data of the alpha-scattering experiment on Surveyor 7. The silicon content and the low sodium abundance are close to that of mare material. The abundances of titanium and iron are at least a factor of 2 lower, whereas the abundances of aluminum and calcium are significantly higher. The analytical results provide direct evidence for chemical differentiation in the moon and indicate a lunar crust of appreciably lower density than the whole moon and with lower density and higher albedo than lunar mare material.