Geological investigations of the lunar surface using Clementine multispectral analyses

Several regions of the lunar surface (highland and maria) are studied using the Clementine multispectral data. Two large farside impact craters, King (120° E 5.5° N) and Tsiolkovsky (128° E, 22° S), are examined in detail and compared to provide an indication of the lateral diversity of the lunar crust. The Clementine data show a varied composition between the two sites. King may have excavated a large cryptomare deposit within the upper crust, while Tsiolkovsky formed in more anorthositic highland crust. The north wall of King is further complicated by the presence of a feldspathic intrusion, cut by more localised mafic dykes. On a vertical scale, the highland crust shows a more uniform trend of increasing anorthosite with depth. These results highlight the lateral diversity of the upper crust on a local scale, and show a more uniform vertical trend in composition in this region. The observed lateral heterogeneity appears to be the result of the presence of cryptomaria and stalled intrusions in the upper crust. Techniques are developed and tested to allow for the mapping and characterisation of lunar basalts, and the calculation of thickness limits. These are applied to the Marius Hills, Flamsteed, Damoiseau and Cavalerius regions of southern Oceanus Procellarum, and have resulted in the detection of three previously unrecognised basalts, and the characterisation of three basalts that had not been spectrally classified previously. Basalt thickness ranges from tens to hundreds of metres in localised regions bordering the highlands. Further from the highlands, the basalts are consistently greater than several hundred metres thick. It has been found that the oldest flows are typically lower in TiO2 content (very low titanium to 4 wt%) than the more recent volcanic episodes (6 to 11 wt%). These results are applied to the regional stratigraphy of the Oceanus Procellarum Group