Wrinkle Ridge vs. Impact Crater

An impact crater, subsequently modified by a wrinkle ridge in Mare Imbrium. Field of view 3.2 meters wide from LROC Narrow Angle Camera (NAC) observation M1114391184R, LRO orbit 16466, February 1, 2013; 1.23 meters resolution [NASA/GSFC/Arizona State University].

Sarah Braden
LROC News System

Stratigraphic relationships in today's Featured Image tell a story of complex geologic events on the lunar surface.

Planetary geologists interpret images taken from orbit and piece together a narrative. Initially a bolide impacted the lunar surface, creating a crater.

Subsequently mare basalt flows buried parts of the impact crater. In the above image you can see darker material around the edges of the crater's rim and also areas where mare basalt material covered parts of the rim and the crater interior. Finally, tectonic deformation created a wrinkle ridge which is better seen in the context image and topography below. Boulders from the wrinkle ridge fell into the impact crater where the edge of the wrinkle ridge intersects with the crater's rim (upper right hand corner of the Featured Image). This impact crater has seen better days!

LROC Wide Angle Camera (WAC) context image. The crater from the Featured Image is in the center (SW of the arrow), and the red arrow denotes the wrinkle ridge. The dotted blue line shows the path of ejecta (ray) from Copernicus. Image field of view is 40.8 km across [NASA/GSFC/Arizona State University].

This region is located south of the crater Brayley D at the edge of Mare Imbrium. The crater in the Featured Image is ~2 km in diameter, and ~250 m deep (located at 18.240°N, 327.06°E). The wrinkle ridge is easier to see in the colorized topo image below. It extends from east to west across the mare.

LROC WAC topography showing the same region, contour interval is 140 meters elevation [NASA/GSFC/Arizona State University].

Explore the entire NAC frame to see more of the wrinkle ridge and surrounding mare, HERE.

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