Distribution Characteristics And Evolution Analysis Of Lunar Tectonic Features On Mare Tranquillitatis

The Moon is the Earth’s only natural satellite. As it’s closely related to the Earth,the origin and evolutionary history of the moon have always been the focuses ofhuman natural sciences. The lunar evolutionary history was distributed into six stages,including planetary formation stage, early melting stage, highland formation stage,huge impact basins formation, basalt filling activities and late tectonic activities stage.The Tranquillitatis basin is very widely spanned in geologic history with plentifulgeological structures in this area, which was formed by a huge impact event in thepre-Nectarian, then filled by mare basalts.In this paper, we taken Mare Tranquillitatis as the study area, its regionalgeology, morphology and chemical composition of rocks in were analysizedcomprehensively by the combinations of CE-1/CE-2CCD data, Clementinemultispectral data and the LROC/LOLA data of LRO. As a result, we defined themare basaltic units on the surface of Mare Tranquillitatis, then the surface ages ofthese basaltic units were determined from the Crater Size–Frequency Distributiondata. Meanwhile, we examined the spectral and morphometric properties of theimportant circular and linear structures in the study area. On the basis of regionalgeology, morphology, chemical compositions of rocks and regional stratigraphicrelationships, this investigation showed that:(1) In the investigated basin, the basaltic filling activities starting at about3.83Gaand ceasing at~3.5Ga, most basalts erupted during the Imbrian Period at3.6~3.8Ga,including Upper Imbrian epoch and Lower Imbrian epoch. The oldest mare basalts onthe surface of Mare Tranquillitatis is about Upper Imbrian epoch (about3.83Ga),while the most recently basaltic filling activities took place at about Lower Imbrian(about3.5Ga).(2)After the basaltic filling activities, the geological tectonic activities took placemost frequently on the investigated area were the impact events. Most cracters formedduring Eratosthenian (about0.8Ga~3.2Ga) and Copernican (about~0.8Ga).The typescraters on this area included bowl-shaped, flat-bottomed, central mound, complicated and residual craters, while the lunar mare dome fields near Cauchy, Arago and innorthern Mare Tranquillitatis can be divided into two main types: the intrusive domesand the effusive domes. Most lunar mare domes in this area formed duringEratosthenian (about0.8Ga~3.2Ga).(3) In conclusion, Mare Tranquillitatis has mainly experienced the followingevolutionary stages: huge impact basins formation, basalt filling activities and latetectonic activities stage. After an huge impact event at about4.2Ga, the study areaexperienced a series of mare basalts filling activities during3.5Ga~3.8Ga and a fewvolcanic activity during Eratosthenian. The internal energy of the Moon has drainedsince3.1Ga ago,So the geologic activity has almost ceased except some impacts fromexotic aerolite and the radial ridges mainly controlled by the basin structure.