Chemistry and petrology of Apollo 12 drive tube 12027

Papike et al. (1982) have provided a summary of previous petrologic and chemical studies of the lunar regolith, taking into account samples from all of the Apollo and Luna sites. On the basis of these studies, an understanding is obtained of the processes which form and characterize the lunar regolith. It is found that comminution of local lithologies by meteorite impact and soil mixing are the most important regolith-forming processes. On the basis of grain size studies of Apollo 14 surface, trench, and drive tube soils, Simin et al. (1982) and Laul et al. (1982) concluded that comminution of local lithologies and vertical soil mixing processes are most important in the formation of the soils at that site. In the present investigation, this study of chemistry and petrology of lunar soils is extended to the Apollo 12 drive tube 12027. This drive tube provides an opportunity to study lunar soil from a depositional environment involving a location at the rim of a crater. The chemical and petrologic data are found to be consistent and suggest three stratigraphic units in the 12027 core.