ENHANCEMENT OF OH/H2O ASSOCIATED WITH THE COMPTON-BELCOVICH VOLCANIC COMPLEX ON THE FARSIDE OF THE MOON: ENDOGENIC OR EXOGENIC LUNAR WATER?
Spectral data from M3 reveal the presence of a strong 3.0µm absorption (suggesting the presence of OH/H2O) band directly associated with the regolith in Compton-Belcovich, significantly stronger than the background regolith outside of the volcanic feature. Data from the Diviner instrument on the Lunar Reconnaissance Orbiter (LRO) show that the Compton-Belcovich is silicic in composition. Investigations of other silicic volcanic sites by other authors has shown that those other sites are also enhanced in OH/H2O implying that perhaps the source of the water may be internal. However, we must also consider that the hydration is due to preferential retention of OH/H2O by the silicic mineralogy at these volcanic sites. Data from Deep Impact flybys of the Moon suggested that there was preferential trapping of OH/H2O in the highlands relative to the mare; perhaps we are detecting a variation of that at Compton-Belcovich. The Compton-Belcovich volcanic complex is also observed to be mantled by a block-poor deposit, illustrated by data from the Mini-RF instrument on LRO.