1. Title of the forum:
For a fundamental improvement of the lunar crater chronology
2. Names and affiliation information of confirmed conveners:
Zhiyong Xiao, Sun Yat-sen University
Stephanie C. Werner, University of Oslo (TBD)
Stuart J. Robbins, Southwest Research Institute, Boulder (TBD)
Caleb I. Fassett, NASA’s Goddard Space Flight Center (TBD)
Carolyn van der Bogert, University of Münster (TBD)
Greg Michael, Freie Universit？t Berlin (TBD)
3. Forum objectives, scientific relevance, timeliness, multi- and inter-disciplinarity, added-value and role of ISSI-BJ:
Statistics of impact craters is the dominating technique used to estimate relative and absolute model ages of exterrestrial bodies. This technique is built on the premise of known production rates of different-sized craters, which is largely supported by isotopic ages of sampled returned by the Apollo and Luna missions and observations of crater size-frequency distributions at the sampling regions. Prediction of impact flux based on orbital dynamics is a relatively independent approach, which also needs to be calibrated against observations by previous lunar explorations.
The first order reliability of crater statistics in estimating relative and absolute model ages has been well verified in many tests. However, debates and concerns about the accuracy of this technique exist pervasively. For examples, the provenance of samples returned by Apollo and Luna samples, even those thought to be related with Copernican-aged terrains, contains certain ambiguity, and we frequently see different interpretations about the source region/event; populations of impactors in the inner solar system might have been different at different planetary bodies, and/or at different geological times for a given planetary body; connections between observed crater populations and postulated impactor populations might not be straightforward due to difficulties caused by target properties, secondaries, and inadequate knowledge of impact cratering mechanics.
We are in the beginning of another golden age of lunar exploration. Our knowledge about lunar science has been substantially improved thanks to the many new missions performed in the first decade of the 21st century. The past five years have witnessed grand progress of the Chinese lunar exploration program, the ambitious plan of the Artemies Program, and numerous new powers determining to arrive the Moon. It can be imagined that more samples from a broader region of the Moon that have much clearer geological contexts, such as those returned by the Chang’E-5 mission, would become available in the coming few years. Therefore, lunar crater chronology would be fundamentally improved in the coming decade.
The aims of this ISSI-BJ forum are to discuss 1) the key scientific questions existed in the lunar impact history and crater chronology; 2) the scientific objectives and sampling requirements of future lunar explorations. Leading scholars from all fields related with the impact history of the Moon and terrestrial planets (e.g., planetary ge-ology, sample analyses, orbital dynamics, etc.) are invited to this forum.