【学术交流】The lunar regolith: what can it reveal about......
2019/4/15 18:55:45学术委员会 中国科学院紫金山天文台

     报告题目：The lunar regolith: what can it reveal about the history of theMoon?

     报告人：Greg Michael (Freie Universit?t Berlin Germany)

     时间：4月17日(周三)下午2点

     地点：紫台仙林园区 2-208 会议室

     摘要：The lunar regolith is a fragmental mixture generated by a longsequence of impacts at all scales. The Apollo and Luna samples of brecciatedrocks contain impact melt clasts which can be dated by radioisotope methodsback to the earliest times of the surface history. It is clear from the numberof ancient clasts that such material is a ubiquitous fraction of the surfaceregolith. It follows that if traces of ancient impact events have survived withmeasurable abundance, all the intervening events should also have left theirmark. By modelling the impact history of the Moon, we estimate the present-dayabundance of material at the surface which would carry a measurableradioisotope age resulting from specific impact events.

     A new development in dating planetarysurfaces from their impact crater populations allows meaningful age estimatesbased on fewer superposed craters than previously. The method makes it possible to date smallerfeatures, and it is applied here to constrain the ages of several-km impactcraters in the vicinity of the planned Chang’E-5 landing site. A smallcomponent of ejecta from some of these craters could be present in the returnedregolith core, and knowledge of their timing could help to identify the source.

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