Tuesday, July 26, 2011

Rootless impact melt flows

Impact melt flows extending out of Eimmart A crater. LROC Narrow Angle Camera observation M152451994R, spacecraft orbit 7601, February 15, 2011; resolution is 0.5 meter per pixel, incidence angle of this 500 meter-wide field of view 44° from 44.74 kilometers [NASA/GSFC/Arizona State University].
Hiroyuki Sato
LROC News System

Today's Featured Image displays viscous flow features out of a fresh crater, likely the impact melt flows. The lower left bright portion corresponds to the crater cavity's inner slope, and the other area is outside the cavity with the slope in upper right direction.

The original source point of these flows are lost, probably due to slumping of the steep inner walls. When the rim failed and slid into the crater the head of the flows were truncated leaving a sharp edge, often with cracks parallel to the rim. Since the flows overlie the main ejecta blanket we can infer that the melt was thrown out late in the crater forming process. These cross-cutting or the overlapping relationships help scientists to understand the complicated process of impact cratering!  

LROC Wide Angle Camera (WAC) monochrome (643nm) image M119415370M, orbit 2732, January 29, 2010, from 46.4 km shows the vicinity of Eimmart A at 64.5 meters resolution [NASA/GSFC/Arizona State University].
Explore very fresh impact crater with impact melt flows in full NAC frame, HERE.

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