A geological survey of basalts in Mare Humorum, southeast Oceanus Procellarum and Mare Serenitatis

• Main Author: Hackwill, Terence Martyn
• Published: University College London (University of London) 2007
• Subjects: 552
• Online Access: http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.498596

Clementine multi-spectral data have been used to investigate the geological history of lunar basalts in Mare Humorum, southeast Oceanus Procellarum and Mare Serenitatis. These data have enabled 109 discrete basaltic units to be identified in Mare Humorum and southeast Oceanus Procellarum, while 48 units have been identified in and around Mare Serenitatis. The ages of a number of these units have been inferred by correlating their crater densities with the densities of units from which returned radiometrically-dated samples were collected. Histograms are presented showing that the most extensive volcanic activity in these areas occurred in the Upper Imbrian Period. The depth of basalt has been estimated at locations where an impact has penetrated through to the underlying highland material. The minimum depth of basalt has been inferred from the depth/diameter relationship for a number of impacts which have only penetrated the basalt. These actual and minimum depths have been used to infer the cross sections of Mare Humorum and Mare Serenitatis. These profiles have been used to estimate the minimum volume of basalt in each basin. Evidence is presented from Clementine TiO2 wt% data that vertical, rather than lateral transport of ejecta, is a more efficient method of contaminating basalts with highland material. It is suggested that vertical contamination produces a coarse correlation between the depth of basalt and TiO2 wt%. The possibility of using TiO2 wt% data to imply the depth of a sequence of basaltic lava flows is examined. The extent of lava flows from a number vents in the Herigonius region has been investigated using variations in TiO2 wt% on the walls of rilles. It is also shown that particular sections of the rilles were probably fed from separate sources and these have been identified.