Ghost Crater in Southern Mare Crisium
December 7, 2012
This wrinkle ridge is part of a larger circular network of wrinkle ridges in southern Mare Crisium. Wrinkle ridges are the result of tectonic stresses which have compressed layers of material. On the Moon, these layers are made up of mare lava flows stacked one on top of the other. When there exists uneven topography, such as a buried (ghost) crater below the lava flows, the lava may deform and produce wrinkle ridges. Deformation occurs preferentially over the buried crater rim, and a circular wrinkle ridge is formed, hinting at the ghost crater beneath. Ghost craters are valuable scientific tools as they can provide minimum thicknesses of mare units. Knowing the diameter of a crater can quickly yield the depth of the crater, thanks to observations and tests performed by scientists. If we know the diameter of the ghost crater, we can estimate the minimum thickness of a given mare unit! This ghost crater is 16 km and using Pike's equations the crater depth should be 1.7-2.4 km.