Tractus Fossae and Tractus Catena

This VIS image shows part of both Tractus Fossae and Tractus Catena, some of many north/south trending tectonic graben located south of Alba Mons. The deeper depression running vertically on the left side of the image is Tractus Catena. While the other grabens to the right side are Tractus Fossae. The term fossae is defined as a long, narrow depressions, whereas the term catena is defined as a chain of craters. The circular depressions within in the Tractus Catena graben lead to the descriptor name catena. However, in this case the craters are a result of roof collapse into an underlying open space such as a lava tube, rather than a set of impact craters. Orbit Number: 78231 Latitude: 26.5131 Longitude: 257.336 Instrument: VIS Captured: 2019-08-03 20:38 https://photojournal.jpl.nasa.gov/catalog/PIA23457