中国科学院地球化学研究所机构知识库

Imbrium basin is the most studied multi-ring structure on the moon. The ancient and young basalts on the moon are all distributed here. Therefore, Imbrium is an ideal area for the research on filling periods of mare basalt magmatism. In order to determine the evolution history of basaltic magma more reasonably in Mare Imbrium, a main combination of petrology, chronology and other analysis are made in this paper, aiming to make a re-division with the filling stages of mare basalt of Mare Imbrium. By making use of the Chang' E-1 IIM spectral dataset to draw distribution diagram of the rock type in this area, 5 different titanium contents of mare basalts are initially divided. Besides, with the help of LRO image data of wide viewing angle with high resolution of 100m, impact crater size and frequency distribution measurements (CSFD) are used to re-determine the age of the mare basalt in this area and 35 basalt units are divided, It is found that 3. 49 similar to 2. 23 Ga of the area has a filling activity of basaltic magma occurring in several stages. On the establishment of the relationship between different types of mare basalts, morphology and the model ages, this paper divides the basalt filling into four stages: very low titanium mare basalt (3. 49 similar to 3. 20 Ga), low titanium mare basalt (3. 29 similar to 2. 83 Ga), medium titanium mare basalt (3. 13 similar to 2. 52Ga), (very) high titanium mare basalt (2. 92 similar to 2. 23 Ga). The topographic features of the terrain and the different surface ages of the basalt units are negatively correlated. Therefore, in consideration of the stage division of basaltic magma in this area, not only the composition of mare basalt should be considered, but also the characteristics of the chronology and morphology which are closely related to basalt evolution should be combined with. Only by making use of morphology, composition data and chronology information as a common constraint can determine the stage division and evolution history of the basaltic magma.