Compaction by impact of unconsolidated lunar fines

New Hugoniot and release adiabate data for 1.8 g cm-3 lunar fines (sample, 70051) in the approx. 2 to approx. 70 kbar range demonstrate that upon shock compression intrinsic crystal density (approx. 3.1 g cm-3) is achieved under shock stresses of 15 to 20 kbar. Release adiabate determinations indicate that measurable irreversible compaction occurs upon achieving shock pressures above approx. 4 kbar. For shocks in the approx. 7 to 15 kbar range, the inferred, post-shock, specific volumes observed decrease nearly linearly with increasing peak shock pressures. Upon shocking to approx. 15 kbar, the post-shock density is approximately that of the response to impact of unconsolidated regolith material on the Moon, it is inferred that the formation of appreciable quantities of soil breccia can be associated with the impact of meteoroids or ejecta at speeds of as low as approx. 1 km s-1