AS15-0320(P)

The sinuous rilles here are part of a network controlled to some degree by fractures. In an area view (Figure 192) it may be seen that the east west segment at A parallels prominent linear trends of several rilles northeast of the Aristarchus Plateau. Fracturing alone, however, cannot explain the origin of the rilles. As shown by the larger rille (B), material has clearly been removed from the walls so that, despite their parallelism, they cannot be fitted together. In addition, a terrace occurs at C, suggesting two cycles of rille formation. The larger rille is nearly obliterated at its juncture with rille A, suggesting that formation of A may have been slightly later, and that some sort of fluid erosion and overbank flooding may have been involved.    -C.A.H.