Iapygia quadrangle
The Iapygia quadrangle is one of a series of 30 quadrangle maps of Mars used by the United States Geological Survey (USGS) Astrogeology Research Program. The Iapygia quadrangle is also referred to as MC-21 (Mars Chart-21). It was named after the heel of the boot of Italy. That name was given by the Greeks It is part of a region of Italy named Apulia. The name Iapygia was approved in 1958. The Iapygia quadrangle covers the area from 270° to 315° west longitude and from 0° to 30° south latitude on Mars. Parts of the regions Tyrrhena Terra and Terra Sabaea are found in this quadrangle. The largest crater in this quadrangle is Huygens. Some interesting features in this quadrangle are dikes. the many layers found in Terby crater, and the presence of carbonates on the rim of Huygens crater. Dikes Near Huygens, especially just to the east of it, are a number of narrow ridges which appear to be the remnants of dikes, like the ones around Shiprock, New Mexico. The dikes were once under the surface, but have now been eroded. Dikes are magma-filled cracks that often carry lava to the surface. Dikes by definition cut across rock