Experimental Investigation of Apollo 16 “Rusty Rock” Alteration by a Lunar Fumarolic Gas

The Apollo 16 sample 66095, named “Rusty Rock”, is enriched in volatile and moderately elements. impact melt breccia characterized by abundant Fe-rich sulfide chloride alteration phases, including FeS, ZnS, FeCl2. These phases have previously been interpreted to be the result of fumarolic breccia. Here we present results two different experimental approaches, which aim constrain temperature conditions process under Rock” formed. first set-up assumes that metals Zn, Cu, Fe were introduced into rock a C-O-S-Cl gas phase, sulfides chlorides deposited from this phase. This “gas deposition” experiment suggests assemblage formed over range 538–638 ± 5°C. second simulates scenario, where metal particles lunar react with Zn-C-O-S-Cl phase at six temperatures between 396 5°C 1,005 latter “metal reaction” resulted formation coatings on chips. FeCl2 (Zn,Fe)S abundantly coating chip reacted 580 10°C. Both experiments lead are agreement, providing 50°C for Moon, as observed Rock”.