Saturday, October 17, 2009

Fresh rim, oldest rocks at Slipher S

Approximately 550 meter strip of the fresh rim and inner wall of 26 km-wide Slipher S, on the northern far side (49.2°N, 158.7°) [NASA/GSFC/ASU].

Samuel Lawrence
LROC News System

"The distinctive wave-like texture may look a little bit like a terrestrial beach, but it's actually impact ejecta on the rim of the crater Slipher S, on the lunar far side at the edge of larger and older Slipher.

"Notice there are only a few small craters dotting the surface, so the rim is well preserved.

"To a lunar geologist the lack of impact degradation on a surface like this indicates a relatively young age, currently mapped as an Eratosthenian-aged crater. You are actually looking at some of the deepest materials excavated by this crater. When impact craters form, the rocks excavated from the deepest parts of the crater actually fall near the rim. In effect nature is providing a drill hole to the subsurface, bringing deeper material to the surface.

"Sending future human lunar explorers to document and sample the materials found on the rims of fresh craters (like this one) will provide key insights into the stratigraphy and geology of the lunar crust."

Below: Stepping back to glance at the full width of the uncalibrated swatch of the LROC Narrow Angle Camera (NAC) image, approximately 3 km in width. Browse the full NAC image, HERE [NASA/GSFC/Arizona State University].

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