The two white arrows point to a likely outcrop of bedrock in this wrinkle ridge. LROC NAC M109141090L, image is 0.5 m/pixel, incidence angle is 21° [NASA/GSFC/Arizona State University].
Today's image is from a small section of the 396 km long wrinkle ridge Dorsum Buckland, which is named after William Buckland, an English geologist who wrote the first full account of a fossil dinosaur! The boulders you see here are on top of the ridge. There are other areas on the long ridge that have similar blocks, but at this spot you can see what might be bedrock eroding out of the ridge as well (white arrows). Wrinkle ridges in the mare form due to compressional stresses probably caused by the weight of many layers of extruded basalts. The boulders may have eroded out of the fractured basalt that forms the ridge. Think about this: If the boulders and the ridge are made from the same material, then why do the boulders have a higher albedo? Or do they boulders have a more complicated origin? Certainly the darker outcrop and the brighter boulders would be easy to sample by future lunar explorers! We may have to wait until then to know for certain.
WAC 100 m/pixel monochrome mosaic of the area around part of Dorsum Buckland (outlined in white lines). The arrow points to the location of today's featured image [NASA/GSFC/Arizona State University].
Browse the full NAC frame to get a better look at this amazing wrinkle ridge.