This 4-kilometer wide, 40-meter deep circular feature in the southern polar region of Mars might not be an impact crater, but a formation caused by a gradual caving in and later collapse.

ID: ESP_056512_0930
date: Thursday, 16 August 2018
altitude: 246 km (152.52 mi)

https://uahirise.org/hipod/ESP_056512_0930
NASA/JPL-Caltech/University of Arizona
#Mars #science #NASA