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Kepler (D=31 km, d=2.7 km) is a Copernican complex crater situated in Oceanus Procellarum (8.1ºN 322ºE), W of Copernicus and SE of Aristarchus. It lies on Imbrium ejecta within Procellarum KREEP Terrain, and is surrounded by the youngest lava flows on the Moon. Kepler’s ray system makes it one of the most conspicuous craters, yet it remains poorly studied. We carry out an integrated study using mainly LROC and Kaguya TC imagery with M3 spectral data, focusing on impact melt distribution.
Kepler has smooth (N and W) and hummocky (S and E) floor units, interpreted to host most of the impact melt-bearing material retained in the crater. Other melt-rich units inside the crater include terrace ponds and wall lobes in the upper crater wall. Spectroscopically the exposed wall displays a crystalline, low-Ca pyroxene-dominated (noritic) signature, while the floor is distinct from the rest of the crater, with an immature, less-crystalline, high-Ca pyroxene-dominated (gabbroic) signature.
The exterior melt-bearing deposits are present as rim veneer and flows, as well as exterior ponds. The ponds display asymmetric distribution, being mainly present in the N and W sectors, similar to the smooth floor unit. This N and W dominance can also be seen in the distribution of the most prominent rays. These observations imply an oblique impact from the SE.
Sampling the Kepler impact melt-rich materials and the surrounding geologic units will provide crucial data points in the Copernican cratering flux, early geochemical evolution of the Moon, basin processes, as well as long-lived volcanism.
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