Coprates Chasma

This THEMIS VIS image shows the northern interior wall of Coprates Chasma, one of the major canyons that form Valles Marineris. The cliff face seen in this image drops over 8 km from the plateau of Ophir Planum to the north (top) to the floor of Coprates. A complex set of ridges and chutes has been eroded into the layered rock that forms the canyon walls. Streamers of bright and dark material can be seen in many of the chutes, suggesting that loose material (sediment) is moving down the chutes toward the canyon floor. In many places this sediment has completely buried the wall. The uppermost layers near the rim of the canyon are brighter than the lower layers, suggesting that the upper layers are composed of different materials than occur further down the wall. Very few small impact craters can be seen in this image, indicating that the erosion and transport of material down the canyon wall and across the floor is occurring at a relatively rapid rate, so that any craters that form are rapidly buried or eroded.