Diacria Quadrangle - Physiography and Geology

Physiography and Geology

The Diacria quadrangle is located at the northwestern edge of the Tharsis volcanic plateau. Topographic, volcanic, and tectonic features associated with the large volcanoes Olympus Mons (south of map area) and Alba Mons (east of map area) characterize the southeastern and east central portions of the quadrangle. The northern and western areas of the quadrangle lie in the northern lowland plains of Mars and cover portions of Amazonis Planitia (in the south), Arcadia Planitia (west central) and Vastitas Borealis (in the north). The large crater Milankovič (118.4 km in diameter) is located in the north central portion of the quadrangle at 54.7° N, 213.3° E.

Elevation data from the Mars Orbital Laser Altimeter (MOLA) instrument on the Mars Global Surveyor spacecraft shows that the regional terrain slopes gently downward to the northwest, with the highest elevation about 3.5 km (3,500 m) above datum (Mars "sea level") on the western flank of the Alba Mons volcano in the southeastern portion of the quadrangle. The lowest points in the quadrangle are about 4.5 km below datum (-4,500 m) in Vastitas Borealis in the northwest corner. The regional relief is thus about 8 km, but at a local scale, slopes are very shallow; the portion of Amazonis Planitia in the south central part of the quadrangle contains some of the flattest terrain on the entire planet.