Collapse Pit in Tractus Fossae (Original NASA/MGS/MSSS b/w Frame)

Caption NASA originale:"Extensional faulting, wherein some fraction of the Martian Crust is pulled apart and Faults are formed where the Bedrock breaks, has also led to formation of Collapse Pits in the Tractus Fossae Region. This MGS-MOC image shows one such pit and the layered bedrock exposed in its walls. Dark Streaks on the Slopes of the Pit result from Avalanches of dry, fine-grained debris (probably Dust, as these streaks are only found in the dust-mantled regions of Mars).
This Pit is located near 23,5° North Lat. and 103,8° West Long. Sunlight illuminates the scene from the lower left".