Concept
The Aeolis quadrangle is one of a series of 30 quadrangle maps of Mars used by the United States Geological Survey (USGS) Astrogeology Research Program. The Aeolis quadrangle is also referred to as MC-23 (Mars Chart-23). The Aeolis quadrangle covers 180° to 225° W and 0° to 30° south on Mars, and contains parts of the regions Elysium Planitia and Terra Cimmeria. A small part of the Medusae Fossae Formation lies in this quadrangle. The name refers to the name of a floating western island of Aeolus, the ruler of the winds. In Homer's account, Odysseus received the west wind Zephyr here and kept it in bags, but the wind got out. It is famous as the site of two spacecraft landings: the Spirit rover landing site () in Gusev crater (January 4, 2004), and the Curiosity rover in Gale Crater () (August 6, 2012). A large, ancient river valley, called Ma'adim Vallis, enters at the south rim of Gusev Crater, so Gusev Crater was believed to be an ancient lake bed. However, it seems that a volcanic flow covered up the lakebed sediments. Apollinaris Patera, a large volcano, lies directly north of Gusev Crater. Gale Crater, in the northwestern part of the Aeolis quadrangle, is of special interest to geologists because it contains a high mound of layered sedimentary rocks, named "Mount Sharp" by NASA in honor of Robert P. Sharp (1911–2004), a planetary scientist of early Mars missions. More recently, on 16 May 2012, "Mount Sharp" was officially named Aeolis Mons by the USGS and IAU. Some regions in the Aeolis quadrangle show inverted relief. In these locations, a stream bed may be a raised feature, instead of a valley. The inverted former stream channels may be caused by the deposition of large rocks or due to cementation. In either case erosion would erode the surrounding land but leave the old channel as a raised ridge because the ridge will be more resistant to erosion Yardangs are another feature found in this quadrangle. They are generally visible as a series of parallel linear ridges, caused by the direction of the prevailing wind.
