月球虹湾-雨海盆地壳幔结构

为了探讨月球大型撞击盆地形成后的壳幔物质迁移, 采用新近的月球重力场数据研究壳幔界面的起伏情况, 这对撞击盆地的形成演化研究有重要意义.通过对虹湾-雨海盆地地区玄武岩引起的重力异常进行正演模拟, 发现该部分重力异常仅约占布格重力异常幅值的8%, 布格重力异常主要与壳幔界面起伏有关.对该地区不同解算高度的剩余布格重力异常进行场源边界提取, 发现虹湾-雨海西北部的壳幔界面随深度增加向雨海中心倾斜, 在此区域下方, 壳幔界面会有一个向虹湾方向的额外上隆, 可能为月幔物质曾向此方向涌动造成.分析表明这种月幔上涌情况可能在雨海撞击时形成, 或者可能是形成虹湾的撞击对雨海盆地壳幔结构产生了二次影响, 在虹湾地区的壳幔回弹过程中, 拖动雨海下方的物质向虹湾方向运移造成的. 

Crust-Mantle Structure beneath the Sinus Iridum-Mare Imbrium Basin of the Moon

In order to investigate the material migration of crust and mantle after the formation of large impact basins, a study on the undulation of crust-mantle interface, using new lunar gravity data is carried out. This has an important significance for the research of the formation and evolution of impact basin. The forward modeling of the gravity anomaly established by filling mare basalts in Sinus Iridum-Mare Imbrium basin area shows that the gravity anomaly only accounts for about 8% in the amplitude of total Bouguer gravity anomaly, while the rest 92% is mainly related to the perturbation of crust-mantle interface. The edge detection of the Bouguer gravity anomaly at different observing heights in Sinus Iridum-Mare Imbrium area indicates that the crust-mantle interface beneath the area of Sinus Iridum-Mare Imbrium northwest leans to the center of Mare Imbrium with increasing depth. It is concluded that extra mantle uplifts to Sinus Iridum area in the crust-mantle interface may have been caused by the impact forming Mare Imbrium basin. This or the later Sinus Iridum impact may have induced a second effect on the crust-mantle structure beneath Mare Imbrium basin. During the lunar mantle rebounds, there may have been a force dragging the mantle beneath the Mare Imbrium toward the Sinus Iridum area.