Debris flows converge at the bottom of a crater (32.660°S; 143.668°E). NAC frame M1107331321R, illumination is from the east-southeast, north is up, image is ~1.4 km wide [NASA/GSFC/Arizona State University].

Small crater floors are places where slopes facing different compass directions (azimuths) naturally approach each other. Steep, recently formed slopes will often produce debris flows that migrate part way or completely to the floor. The resulting zones of debris convergence can present interesting juxtapositions of coarse and fine deposits with variable light and shadow effects. On an airless body like the Moon, the patterns are frequently striking, and make for studies in artistic composition. The play of sunlight on these surfaces often create some surprising textural patterns and relationships.

Context NAC frame shows a larger portion of the crater; image is ~7 km wide [NASA/GSFC/Arizona State University].

This small, unnamed farside crater in the lunar highlands presents a nice example. High-reflectance ejecta in the WAC context image shows it to be the result of a relatively recent impact. Mass wasting events have generated debris flows that have different textures by the time they come to rest at or near the crater floor. Their different slopes produce different angles of illumination and different intensities of reflection. There are also examples of impact melt visible in the debris, best seen in the full NAC frame just south of the Featured Image boundary. What clues would you look for to help distinguish impact melt from fine-grained debris flows?

The WAC mosaic context image is just over 100 km wide [NASA/GSFC/Arizona State University].


Explore additional details in the full NAC frame below. Similar Featured Image posts have been presented as Diversity, Complicated Crater, and Rubble Pile on Fresh Crater Floor

Published by James Ashley on 8 August 2013