Thursday, November 15, 2012

Layers of Imbrium floor excavated at Piton B

Southern contact of Piton B crater wall and rim. From LROC Narrow Angle Camera (NAC) observation M168203756R, orbit 9922, August 17, 2011; 290 meter-wide field of view captured from a mere 28.75 kilometers, resolution 42 centimeters per pixel, centered near 39.292°N, 359.883°E. North is up [NASA/GSFC/Arizona State University].
Hiroyuki Sato
LROC News System

Piton B is a young, fresh crater (about 4.5 km diameter) located in northeast Mare Imbrium. Along the upper part of this young crater wall, you can find clear layering similar as seen in Meteor Crater at east of Flagstaff, Arizona. The opening image highlights such layerings observed at the southern crater wall of Piton B.

In the lower right corner of this image is a portion of the crater rim, downslope is toward the top. The relatively resistant layers discontinuously outline their horizontal expanses. Among them, the blocky outcrop at the center of this image shows the clearest bedding plane. 

The thinnest layers are roughly 3 to 4 meters thick, assuming a slope angle about 30°.

Context for the Featured Image field of view (white rectangle) in the full width of the left and right frame of LROC NAC observation M168203756 [NASA/GSFC/Arizona State University].
Layer thickness estimates from orbital views are not as accurate as geologists would make standing on the outcrop, but many measurements at multiple craters give a great estimate of the general layer thicknesses of the original lava flows. Knowing thickness of flows helps us understand the viscosity and flow rates of ancient mare volcanism.

Piton B (below center) in LROC Wide Angle Camera 100 meter resolution mosaic on LOLA laser altimetry based topography from a simulated perspective 14 km over the vast Imbrium floor. Beyond are Piton A and their namesake Piton Mons [NASA/GSFC/Arizona State University].
Explore the fresh crater wall of Piton B in full NAC frame yourself, HERE.

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