Impact craters on Mars (IMAGE) Curtin University Caption One of the 521 large craters that has been dated in the study. The formation age of this 40km crater has been estimated using the number of small craters accumulated around it since the impact occurred. A portion of these small craters are shown on the right panel and all of them have been detected using the algorithm. In total, more than 1.2 million craters were used to date the Martian craters. Credit Curtin University Usage Restrictions Only for use with this research study License Original content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.