THEMIS Image of the Day, February 8, 2018. Tithonium Chasma has numerous large landslide deposits. At the bottom of this VIS image is the high plateau between Tithonium Chasma and Ius Chasma (off the bottom of the frame). The resistant material of the plateau surface forms the linear ridges of the canyon wall. Erosion of the walls cover the lower slopes. Large landslides have changed the walls and floor of the canyon.
A landslide is a failure of slope due to gravity. They initiate due to several reasons. A lower layer of poorly cemented/resistant material may have been eroded, undermining the wall above which then collapses; earth quake seismic waves can cause the slope to collapse; and even an impact event near the canyon wall can cause collapse. As millions of tons of material fall and slide down slope a scalloped cavity forms at the upper part where the slope failure occurred. At the material speeds downhill it will pick up more of the underlying slope, increasing the volume of material entrained into the landslide.
As the landslide material reaches the canyon bottom it spreads out and eventually comes to rest. The edge of the deposit is lobate, and may be affected by running up against pre-existing features on the canyon floor. Most Martian landslide have radial grooves on the slide surface.
Tithonium Chasma is at the western end of Valles Marineris. Valles Marineris is over 4000 kilometers long, wider than the United States. Tithonium Chasma is almost 810 kilometers long (499 miles), 50 kilometers wide, and over 6 kilometers deep. In comparison, the Grand Canyon in Arizona is about 175 kilometers long, 30 kilometers wide, and only 2 kilometers deep.
The canyons of Valles Marineris were formed by extensive fracturing and pulling apart of the crust during the uplift of the vast Tharsis plateau. Landslides have enlarged the canyon walls and created deposits on the canyon floor. Weathering of the surface and influx of dust and sand have modified the canyon floor.
NASA’s Mars Odyssey spacecraft has spent over 15 years in orbit around Mars, circling the planet more than 71,000 times. It holds the record for longest working spacecraft at Mars. THEMIS, the IR/VIS camera system, has collected data for the entire mission and provides images covering all seasons and lighting conditions.
Over the years many features of interest have received repeated imaging, building up a suite of images covering the entire feature. From the deepest chasma to the tallest volcano, individual dunes inside craters and dune fields that encircle the north pole, channels carved by water and lava, and a variety of other feature, THEMIS has imaged them all.
For the next several months the Image of the Day will focus on the Tharsis volcanoes, the various chasmata of Valles Marineris, and the major dune fields. We hope you enjoy these images!
More THEMIS Images of the Day by geological topic.