Major and Trace Element Variations and Lithologic Component Analysis in Apollo 17 Drive Tube 73001/2

Abstract Samples 73001 and 73002, which make up the lower and upper portions, respectively, of the double drive tube containing regolith (“soil”) collected on the “light mantle” at Station 3 during Apollo 17. Using a quadrupole inductively coupled plasma‐mass spectrometer (ICP‐MS) and fused‐bead electron‐probe microanalysis (FB‐EPMA), we determined the chemical composition of every 0.5 cm dissection interval of the entire 56.9 cm length of the double drive tube, which penetrated to a depth of 70.6 cm below the regolith surface. We used the chemical compositions to model the proportions of different lithologic components found at the Apollo 17 site. Elemental variations with depth were linked to different proportions of these components. Higher amounts of high‐Ti mare basalt near the 73002 surface (uniformly dark‐toned regolith from 0 to 1.5 cm) indicate mixing of local mare materials by small impact cratering. Decreasing proportions of high‐Ti mare basalt below 1.5 cm result from the mixing of dark and light regolith components during the dissection process on Earth. Below about 7.5 cm, compositions indicate consistent amounts of primarily highlands material (<5% high‐Ti mare basalt), which can be described as a mixture of noritic impact‐melt and anorthositic‐norite components. In detail, the modeled anorthositic‐norite component, which may represent the pre‐basin upper crust in this part of the Moon, ranges from 50 to 60 wt.%. The modeled noritic impact‐melt breccia component remains relatively uniform at 35–40 wt.% throughout the length of 73002 and increases to 45 wt.% at the bottom of 73001.