053 - Copernicus Crater (mosaic)

Mosaic of the lunar crater Copernicus produced using images obtained by the Clementine UV/VIS camera. This 95-km crater, believed to be approximately 800 million years old, is located near the center of the lunar nearside and exhibits prominent rays extending in all directions. The right section of the image is a color composite mosaic of the eastern half of Copernicus. This color mosaic was prepared using images obtained through filters of three different colors chosen to allow small lunar color differences to be mapped in a geologic context. In this image, the color assignments are: red (750/415 nm), green ( 750/950 nm), and blue (415/750 nm). The left section of the image is a mosaic of the same area prepared using frames obtained through a single filter (750 nm). This mosaic is displayed as a mirror image to the color composite to allow easy comparison of geologic features and their color.

Extensive large- and small-scale heterogeneity of materials excavated by this large crater is readily evident from the color composite mosaic. Bright blue tones typically suggest fresh material similar to Apollo 16 rocks and breccias, mottled red-orange tones indicate material similar to Apollo 16 soils, vivid red is associated with deposits of impact melt (seen most prominently in the northwestern part of the crater floor), and green-yellow tones along the southern wall imply a higher abundance of iron-bearing materials.

Impact craters can be used as windows into the interior and this multispectral image of Copernicus provides dramatic new information about how materials are excavated, melted, mixed, and deposited in a major impact event. The extensive heterogeneity around the wall of the crater indicates materials are not intimately mixed in spite of the huge energy involved during crater formation. Similarly, impact melt (target rock melted during the impact event) is not distributed uniformly, but can be seen to be concentrated in large sections of the floor and in small areas along ledges of the walls.