Geologic maps of early Apollo landing sites of set C

Comparison of the five potential early Apollo landing sites of set C reveals significant geologic similarities and differences. No two sites are identical; the geology of each should be considered in the interpretation of returned lunar samples and observations. Geologic maps of each site have been prepared at scales of 1:5,000, 1:25,000, and 1:100,000.

Features emphasized on the 1:5,000-scale maps are common to all the sites and include mainly the widespread lunar regolith and small craters of varied age and origin. Because they cover the lunar surface and because mobility will be limited on early missions, these ubiquitous features will be the main objects of scientific inquiry during the first manned landings.

Regional geologic differences among the sites are more apparent on the 1:25,000- and 1:100,000-scale maps. Mare materials in sites 2 and 3 belong mainly to the Imbrian System; the materials in site 3 appear to be younger than those in site 2. Mare materials in sites 4 and 5 belong entirely to the Eratosthenian System. Most materials in site 1 have been assigned to the Copernican System. They consist of a young mantle of relatively low-cohesion material that covers an older cratered terrain, probably part of the terrae. Typical mare material occurs only in the eastern extremity of site 1. Ray materials and secondary impact craters related to large rayed primary impact craters are present in several of the sites.