EPSC Abstracts Vol. 6, EPSC-DPS2011-1095, 2011 EPSC-DPS Joint Meeting 2011 c Author(s) 2011 Absolute model ages of basalts in Mare Crisium H. Hiesinger (1), C. H. van der Bogert (1), D. Reiss (1), and M. S. Robinson (2) (1) Institut für Planetologie, Westfälische Wilhelms-Universität, Wilhelm-Klemm-Str. 10, 48149 Münster, Germany,
[email protected], (2) Arizona State University, Tempe, AZ, USA. Abstract presumably emplaced in two stages - first, around the We have dated several mare basalt units in Mare NE (Eimmart Basalts) and SE (Agarum Basalts) Crisium. On the basis of our crater size-frequency outer edge of the basin (Group IIB), and then in the distribution measurements (CSFD), we find Imbrian NNW of the basin (Group IIA; Swift Basalts). There and Eratosthenian ages for the investigated basalts. are several small occurrences of Group IIA Swift Basalts in the S, the easternmost of which contains 1. Introduction the Luna 24 landing site [1]. Group III basalts Mare Crisium is one of the most prominent lunar (Shapley Basalts) are the youngest basalts and are basins, located on the eastern nearside. According to exposed in the SSE of the basin. [1, 2], there are three major basalt groups within the While stratigraphic relationships among the Mare basin, i.e., an Fe- and Mg-rich high Ti basalt similar Crisium basalts were investigated in detail [e.g., 1], to Luna 16 samples (Group I), a very low Ti absolute and relative ages remain under discussion. ferrobasalt similar to Luna 24 samples (Group II), For example, the geologic map of [4] indicates that and a low Ti ferrobasalt similar to Apollo 12 samples most of northern Mare Crisium is covered by (Group III) (Fig.