Tuesday, November 29, 2011

LROC: Dionysius Detour

A high albedo granular flow traveled down the wall of Dionysius crater. Why is the flow curving around the crater floor? LROC Narrow Angle Camera (NAC) M111484008R, orbit 1563, October 29, 2010; incidence angle 26.934° with a resolution of 0.51 meter per pixel from 48.11 kilometers. Image filed of view is 500 meters. View the full size LROC Featured Image HERE [NASA/GSFC/Arizona State University].
Drew Enns
LROC News System

Craters on the Moon often develop granular flows on their walls as loose material slides towards the bottom.

As this process occurs the granular flows must overcome any obstacles in their path to reach the crater floor.  Dionysius, an 18 kilometer crater on the western edge of Mare Tranquillitatis, is no exception.

The curved termination of the talus is the result of series of granular flows with an impact melt mound blocking the immediate path of the flow.

LROC Wide Angle Camera image (604 nm) of Dionysius with the subject impact melt marked with the small yellow arrow. LROC WAC observation M148871990C, orbit 6778, December 13, 2010; resolution 59.4 meters per pixel from 43.19 kilometers altitude [NASA/GSFC/Arizona State University].
Because the granular flow cannot go over the mound, it is being redirected along the mound's slope until it reaches the crater floor. The result is a spectacular arc that acts as a geologic contact between the granular flow on one side and impact melt on the other!

Are any other geologic features redirecting the granular flow in the full NAC frame?

Related Posts:
Lunar landslides!
Impact melt in Anaxagoras crater

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