A Very Sinuous Rille

Two oxbow bends along the length of a sinuous rille located on a mare-filled crater floor. The tight twists and turns of the rille suggest that a very turbulent lava flow formed this rille. Subarea of uncalibrated LROC NAC frame M102672335L; image width is 1.56 km across and north is up [NASA/GSFC/Arizona State University].

Lillian Ostrach
LROC News System

The sinuous rille in today's Featured Image meanders, twisting and turning in very tight oxbows (the horseshoe-shaped channels), across a mare-filled crater floor. Sinuous rilles are believed to be of volcanic origin and have been the focus of both a previous LROC Featured Image and Apollo Featured Images (Vallis Schröeteri and Leveed Rille in Mare Cognitum). The tight, winding nature of this rille is consistent with erosion by a turbulent flow of low viscosity (very fluid), very hot lava. Within the turbulently flowing lava, eddies and vortices probably formed, which may have contributed to the erosion of the mare surface, creating twists that nearly touch and which rarely appear to merge (two such areas are designated by arrows). Browse the whole uncalibrated NAC Image, located to the northeast of Ulugh Beigh Crater on the northwestern boundary of Oceanus Procellarum.