Subsurface morphology and scaling of lunar impact basins
Subsurface morphology and scaling of lunar impact basins
复制标题
DOI：
10.1002/2016je005038
复制
发表时间：
2016-09-01
影响因子：
4.8
通讯作者：
Zuber, M. T.
中科院分区：
文献类型：
--
作者：
Miljkovic, K.;Collins, G. S.;Zuber, M. T.
在月球形成后的第一个十亿年里，撞击轰击至少产生了几十个盆地。重力恢复和内部实验室（GRAIL）使命以比以往任务高得多的空间分辨率绘制了这些撞击结构的重力场图，从而能够对整个地球仪进行详细的地下和形态分析。GRAIL衍生的地壳厚度图被用来定义在月球撞击盆地中心观察到的地壳变薄区域，这比基于地形特征的盆地尺寸测量不那么明确。月球撞击盆地的形成是使用iSALE-2D水动力学代码进行数值模拟的，其中包括月球演化最初10亿年的大范围撞击和目标条件。在调查范围内的撞击器和目标的条件下，目标温度的盆地地下形态的主导作用。模型结果还用于更新适用于月球环境的现有撞击比例关系（根据假定的目标温度）。我们新的温度相关的影响缩放关系提供了估计的影响条件和瞬态陨石坑直径的大多数撞击盆地绘制的GRAIL。由于月球撞击盆地的形成与太阳系演化的第一个类似于7亿年的时间有关，当时的撞击通量比现在大得多，我们修订的撞击比例关系可以帮助进一步分析和理解早期太阳系中月球和类地行星的撞击程度。
Impact bombardment during the first billion years after the formation of the Moon produced at least several tens of basins. The Gravity Recovery and Interior Laboratory (GRAIL) mission mapped the gravity field of these impact structures at significantly higher spatial resolution than previous missions, allowing for detailed subsurface and morphological analyses to be made across the entire globe. GRAIL-derived crustal thickness maps were used to define the regions of crustal thinning observed in centers of lunar impact basins, which represents a less unambiguous measure of a basin size than those based on topographic features. The formation of lunar impact basins was modeled numerically by using the iSALE-2D hydrocode, with a large range of impact and target conditions typical for the first billion years of lunar evolution. In the investigated range of impactor and target conditions, the target temperature had the dominant effect on the basin subsurface morphology. Model results were also used to update current impact scaling relationships applicable to the lunar setting (based on assumed target temperature). Our new temperature-dependent impact-scaling relationships provide estimates of impact conditions and transient crater diameters for the majority of impact basins mapped by GRAIL. As the formation of lunar impact basins is associated with the first similar to 700 Myr of the solar system evolution when the impact flux was considerably larger than the present day, our revised impact scaling relationships can aid further analyses and understanding of the extent of impact bombardment on the Moon and terrestrial planets in the early solar system.