• Lunar mare volcanism in the eastern nearside region derived from Clementine UV/VIS data

      Kodama, S.; Yamaguchi, Y. (The Meteoritical Society, 2003-01-01)
      Clementine UV/VIS multi-spectral data were used to map mare deposits in the eastern lunar nearside region (Mare Tranquillitatis, Mare Fecunditatis, Mare Serenitatis, Mare Crisium, Mare Nectaris) to understand the volcanic history of this region. An array of Clementine and Clementine-derived data were used to classify mare basalts; these include: 750 nm albedo, UV/VIS ratio, 1 micrometer absorption signatures, and Clementine derived FeO and TiO2 contents. We have successfully identified several new geological units and have determined their spectral characteristics. For example, the relatively younger low-Ti basalts were recognized in the eastern part of Mare Tranquillitatis. The central low-Ti basalts in Mare Serenitatis, which had been classed as mISP, were divided into 2 groups. In Mare Nectaris, 2 types of mare basalts were identified, while only 1 group was recognized in the previous study. The stratigraphy constructed from the spectral analysis indicates that the mare deposits tend to become younger in the northern maria, including Serenitatis and Crisium, and older in the southern maria, including Tranquillitatis, Fecunditatis, and Nectaris. According to the relationship between the titanium contents of the mare units and their stratigraphy, the titanium content decreases with time in the early stage but increases toward the end of volcanism in the Serenitatis and Crisium region, while it increases with time but finally decreases in the Tranquillitatis and Fecunditatis region. In connection with the distribution of mare basalts, a large amount of high-Ti mare basalts are found in Mare Tranquillitatis, especially in the western part, while other maria are covered by low-Ti basalts. The iron contents show a similar distribution to that of titanium.