Crater Size-Frequency Distribution Measurements and Age Determination of Sinus Iridum

Impact cratering is an important process in planet formation and surface modification.It creats impact craters on the surface, which records and reveals the geological history of the planet. It is known that the younger a surface is, the less amount and smaller diameters the craters on that surface are. Therefore, model ages of a surface region of a solid celestial body can be estimated by measuring the crater size-frequency distribution. We summarized the principles and its application,and applied the method to the age determination of Sinus Iridum on the Moon using images obtained by Lunar Reconnaissance Orbiter Wide Angle Camera. Our results show that this region has three main geological units with model ages of 3.33 Ga, 3.21 Ga and 2.60 Ga, respectively.