Thursday, July 29, 2010

Gullies along South Wall of Asimov Crater

This image shows part of the southern wall region of Asimov Crater (centered at -47S, 5E) in Noachis Terra, located west of Hellas Planitia. This ancient crater displays an intriguing large trough-shaped feature (a.k.a. Noachis ring trough) that encircles the entire inner crater wall.

In this image, the northern slope exhibits crisp-appearing gullies that appear to have sourced from jumbled, gravelly indistinct regions. Some tributaries seem to originate in fractured bedrock. The tributaries coalesce forming sinuous gullies that dissipate into the trough floor deposits. Frost or ice covers much of this south facing slope. In contrast, the south wall of Asimov Crater seems to lack the pristine gully morphology evident on the trough slope to the north, but contains more distinct rock layers near the rim. Gullies on the upper crater wall exhibit more of a debris chute morphology likely formed by the persistent erosion of the southern rim. These gullies coalesce into more channelized forms across the lower reaches, creating fans of sediment and debris before terminating on the crater floor below.

Photo credit: NASA/JPL/University of Arizona

No comments: