# Diacria quadrangle > Mediated Wiki article. Canonical URL: https://mediated.wiki/source/Diacria_quadrangle > Markdown URL: https://mediated.wiki/source/Diacria_quadrangle.md > Source: https://en.wikipedia.org/wiki/Diacria_quadrangle > Source revision: 1333173832 > License: Creative Commons Attribution-ShareAlike 4.0 International (https://creativecommons.org/licenses/by-sa/4.0/) Map of Mars Diacria quadrangle Elevation map of Diacria quadrangle from Mars Orbiter Laser Altimeter (MOLA) data Coordinates 47°30′N 150°00′W / 47.5°N 150°W / 47.5; -150 Eponym Diacria highlands around Marathon in Greece Image of the Diacria Quadrangle (MC-2). The southeastern part is marked by aureole deposits of the largest known volcano in the Solar System, [Olympus Mons](/source/Olympus_Mons). The **Diacria quadrangle** is one of a series of [30 quadrangle maps of Mars](/source/List_of_quadrangles_on_Mars) used by the [United States Geological Survey](/source/United_States_Geological_Survey) (USGS) [Astrogeology Research Program](/source/Astrogeology_Research_Program). The [quadrangle](/source/Quadrangle_(geography)) is located in the northwestern portion of Mars' western hemisphere and covers 180° to 240° east longitude (120° to 180° west longitude) and 30° to 65° north latitude. The quadrangle uses a [Lambert conformal conic projection](/source/Lambert_conformal_conic_projection) at a nominal scale of 1:5,000,000 (1:5M). The Diacria quadrangle is also referred to as **MC-2** (Mars Chart-2).[1] The Diacria quadrangle covers parts of [Arcadia Planitia](/source/Arcadia_Planitia) and [Amazonis Planitia](/source/Amazonis_Planitia). The southern and northern borders of the Diacria quadrangle are approximately 3,065 km (1,905 mi) and 1,500 km (930 mi) wide, respectively. The north to south distance is about 2,050 km (1,270 mi) (slightly less than the length of Greenland).[2] The quadrangle covers an approximate area of 4.9 million square km, or a little over 3% of Mars' surface area.[3] The *[Phoenix](/source/Phoenix_(spacecraft))* lander's landing site (68.22° N, 234.25° E) lies about 186 km (116 mi) north of the northeastern quarter of the Diacria quadrangle. The landscape viewed by the *Phoenix* lander is probably representative of a large portion of the terrain in the northern Diacria quadrangle. ## Etymology Diacria is the name of a [telescopic albedo feature](/source/Classical_albedo_features_on_Mars) located at 48° N and 190° E on Mars. The feature was named by Greek astronomer E. M. Antoniadi in 1930 after [Diacria](/source/Diacria), the highlands around [Marathon](/source/Marathon%2C_Greece) in north-west [Attica](/source/Attica), Greece. The name was approved by the [International Astronomical Union](/source/International_Astronomical_Union) (IAU) in 1958.[4] ## Physiography and geology The Diacria quadrangle is located at the northwestern edge of the [Tharsis](/source/Tharsis) volcanic plateau. Topographic, volcanic, and tectonic features associated with the large volcanoes [Olympus Mons](/source/Olympus_Mons) (south of map area) and [Alba Mons](/source/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](/source/Amazonis_Planitia) (in the south), [Arcadia Planitia](/source/Arcadia_Planitia) (west central) and [Vastitas Borealis](/source/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](/source/Mars_Orbital_Laser_Altimeter) (MOLA) instrument on the [Mars Global Surveyor](/source/Mars_Global_Surveyor) spacecraft shows that the regional terrain slopes gently downward to the northwest, with the highest elevation about 3.5 km (2.2 mi) 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.[5] 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.[6] ## Placeholder The western flank of the Alba Mons volcano makes up the eastern and southeastern edge of the quadrangle. In terms of area, Alba Mons (formerly, Alba Patera) is the largest volcanic feature on Mars. The flank has a very low slope (l° or less) and is characterized by lava flows and an outwardly radiating array of ridges and channels. Some of the channels have a drainage pattern that resembles that formed by rain water on the slopes of terrestrial volcanoes. However, many other channels on the flanks of Alba Mons were clearly formed by flowing lava.[7] The western flank of the volcano also contains some NW-SE trending [grabens](/source/Graben) ([Cyane Fossae](/source/Cyane_Fossae)). An image from High Resolution Imaging Science Experiment ([HiRISE](/source/HiRISE)) on the [Mars Reconnaissance Orbiter](/source/Mars_Reconnaissance_Orbiter) (MRO) beautifully shows a line of rimless pit craters in Cyane Fossae. The pits may have formed by the collapse of surface materials into open fractures created as magma intruded the subsurface rock to form [dikes](/source/Dike_(geology)).[8] ### Acheron Fossae Main article: [Acheron Fossae](/source/Acheron_Fossae) Near the southeast corner of the quadrangle (37° N, 225° E) lies a southward sloping, semicircular block of ancient, heavily cratered, highland crust that is dissected by numerous, [arcuate](https://en.wiktionary.org/wiki/arcuate) troughs ([Acheron Fossae](/source/Acheron_Fossae)). ### Lycus Sulci (Olympus Mons Aureole) Lycus Sulci (24.6° N, 219° E) is the name applied to the northwestern portion of a larger terrain feature that partially encircles Olympus Mons and extends up to 750 km from the giant [shield volcano's](/source/Shield_volcano) base. This feature, called the Olympus Mons aureole, consists of several large lobes and has a distinctive corrugated or grooved surface texture. East of Olympus Mons, the aureole is partially covered by lava flows, but where it is exposed it goes by different names ([Gigas Sulci](/source/Gigas_Sulci), for example). The origin of the aureole remains debated, but it was likely formed by huge landslides or gravity-driven [thrust sheets](/source/Thrust_fault) that sloughed off the edges of the Olympus Mons shield.[9] ### Erebus Montes Main article: [Erebus Montes](/source/Erebus_Montes) Erebus Montes, as seen by HiRISE. Grooves indicate movement. Westward from Lycus Sulci, across the flat plains of Amazonis Planitia, lies an elongated region of knobby terrain called [Erebus Montes](/source/Erebus_Montes) (Erebus Mountains). The region contains hundreds of clustered to isolated hillocks that stand 500 to 1,000 m above the surrounding plains. The presence of numerous partly filled "ghost" craters in the area indicates that the hills represent the high-standing remnants of ancient highland crust that was inundated by lava flows and (possibly) alluvial sediments from Tharsis in the southeast and the [Elysium](/source/Elysium_Planitia) volcanic province to the west.[10] ### Arcadia Planitia and Southern Vastitas Borealis North and east of the Erebus Montes are low-lying plains that characterize a large part of the Diacria Quadrangle and of the Martian northern hemisphere in general. Medium resolution [Mariner 9](/source/Mariner_9) and [Viking](/source/Viking_program) spacecraft images from the 1970s show that large portions of Arcadia Planitia have an overall mottled (blotchy light and dark) appearance. At higher resolution, landforms commonly consist of lobate flow fronts; small channel segments; [wrinkle ridges](/source/Wrinkle-ridge); [pedestal craters](/source/Pedestal_craters); and low, isolated volcano-like hills with summit craters.[11] MOLA images reveal numerous large, shallowly buried craters, suggesting that an old cratered surface lies under a layer of younger material. At the resolution of the Mars Orbital Camera (MOC) on the Mars Global Surveyor spacecraft (around several m per pixel), much of the northern plains has a distinctly stippled, pitted texture that causes the ground to resemble the surface of a basketball or orange rind. This texture is likely caused by a mantle of ice and dust covering the landscape. The small hollows and pits formed as the ice evaporated (sublimed). The geologic history and origin of the northern plains are complex and still poorly understood. Many of the landforms resemble [periglacial](/source/Periglacial) features seen on Earth, such as [moraines](/source/Moraines), [ice-wedged polygons](/source/Ice_wedge), and [pingos](/source/Pingo). Arcadia Planitia and Vastitas Borealis likely consist of a hodgepodge of old lava flows, ice-related features, and reworked sediments of diverse origin. Some theorize that the northern plains were once covered by oceans or large lakes. ## See also - [Dark slope streak](/source/Dark_slope_streak) - [Dust Devil Tracks](/source/Dust_Devil_Tracks) - [Expanded Craters](/source/Expanded_Craters) - [Fossa (geology)](/source/Fossa_(geology)) - [HiRISE](/source/HiRISE) - [HiWish program](/source/HiWish_program) - [Inverted relief](/source/Inverted_relief) - [List of quadrangles on Mars](/source/List_of_quadrangles_on_Mars) - [List of rocks on Mars](/source/List_of_rocks_on_Mars) - [Martian Gullies](/source/Martian_Gullies) - [Milankovic (Martian crater)](/source/Milankovic_(Martian_crater)) - [Outflow channels](/source/Outflow_channels) - [Valley networks (Mars)](/source/Valley_networks_(Mars)) - [*Phoenix* lander](/source/Phoenix_Lander) - [Polygonal patterned ground](/source/Polygonal_patterned_ground) - [Volcanism on Mars](/source/Volcanism_on_Mars) - [Water on Mars](/source/Water_on_Mars) ## References 1. **[^](#cite_ref-1)** Davies, M.E.; Batson, R.M.; Wu, S.S.C. "Geodesy and Cartography" in Kieffer, H.H.; Jakosky, B.M.; Snyder, C.W.; Matthews, M.S., Eds. *Mars.* University of Arizona Press: Tucson, 1992. 1. **[^](#cite_ref-2)** Distances calculated using NASA World Wind measuring tool. ["NASA WorldWind"](https://worldwind.arc.nasa.gov/.). 1. **[^](#cite_ref-3)** Approximated by integrating latitudinal strips with area of R^2 (L1-L2)(cos(A)dA) from 30° to 65° latitude; where R = 3889 km, A is latitude, and angles expressed in radians. See: ["Calculating area enclosed by arbitrary polygon on Earth's surface - Stack Overflow"](https://stackoverflow.com/questions/1340223/calculating-area-enclosed-by-arbitrary-polygon-on-earths-surface.). 1. **[^](#cite_ref-4)** USGS Gazetteer of Planetary Nomenclature. Mars. ["Planetary Names: Welcome"](https://planetarynames.wr.usgs.gov/.). 1. **[^](#cite_ref-5)** JMARS MOLA elevation database. Christensen, P.; Gorelick, N.; Anwar, S.; Dickenshied, S.; Edwards, C.; Engle, E. "New Insights About Mars From the Creation and Analysis of Mars Global Datasets;" American Geophysical Union, Fall Meeting 2007, (abstract #P11E-01). 1. **[^](#cite_ref-6)** Goddard Spaceflight Center. Global Slope and Roughness Maps of Mars from MOLA. [\[1\]](https://web.archive.org/web/20090321025947/http://ssed.gsfc.nasa.gov/tharsis/slopes.html). 1. **[^](#cite_ref-7)** Carr, M.H. *The Surface of Mars;* Cambridge University Press: New York, 2006. 1. **[^](#cite_ref-8)** University of Arizona HiRISE Website. ["HiRISE | High Resolution Imaging Science Experiment"](http://hirise.lpl.arizona.edu/PSP_010345_2150.). 1. **[^](#cite_ref-9)** Cattermole P. *Mars: the Mystery Unfolds;* Oxford University Press: New York, 2001. 1. **[^](#cite_ref-10)** Tanaka, K.L.; Skinner, J.A.; Hare, T.M. Geologic Map of the Northern Plains of Mars. Scientific Investigations Map 2888, U.S. Geological Survey, 2005. 1. **[^](#cite_ref-11)** Tanaka, K.L.; Scott, D.H.; Greely, R. "Global Stratigraphy" in Kieffer, H.H.; Jakosky, B.M.; Snyder, C.W.; Matthews, M.S., Eds. *Mars;* University of Arizona Press: Tucson, 1992. ## External links - [High resolution video](https://www.flickr.com/photos/136797589@N04/33566282890/) by Seán Doran of a flyover of crater Domoni (51.7° N, 125.6° W) - [Chris McKay: Results of the Phoenix Mission to Mars and Analog Sites on Earth](https://www.youtube.com/watch?v=1plIgTG9x-A) Wikimedia Commons has media related to [Diacria quadrangle](https://commons.wikimedia.org/wiki/Category:Diacria_quadrangle). v t e Quadrangles on Mars MC-01 Mare Boreum (features) MC-02 Diacria (features) MC-03 Arcadia (features) MC-04 Acidalium (features) MC-05 Ismenius Lacus (features) MC-06 Casius (features) MC-07 Cebrenia (features) MC-08 Amazonis (features) MC-09 Tharsis (features) MC-10 Lunae Palus (features) MC-11 Oxia Palus (features) MC-12 Arabia (features) MC-13 Syrtis Major (features) MC-14 Amenthes (features) MC-15 Elysium (features) MC-16 Memnonia (features) MC-17 Phoenicis Lacus (features) MC-18 Coprates (features) MC-19 Margaritifer Sinus (features) MC-20 Sinus Sabaeus (features) MC-21 Iapygia (features) MC-22 Mare Tyrrhenum (features) MC-23 Aeolis (features) MC-24 Phaethontis (features) MC-25 Thaumasia (features) MC-26 Argyre (features) MC-27 Noachis (features) MC-28 Hellas (features) MC-29 Eridania (features) MC-30 Mare Australe (features) v t e Mars Outline of Mars Geography Atmosphere Circulation Climate Dust devil tracks Methane Regions Arabia Terra Cerberus (Mars) Cydonia Eridania Lake Iani Chaos Olympia Undae Planum Australe Planum Boreum Quadrangles Sinus Meridiani Tempe Terra Terra Cimmeria Terra Sabaea Tharsis Undae Ultimi Scopuli Vastitas Borealis Physical features "Canals" (list) Canyons Catenae Chaos terrain Craters Fossae Gullies Mensae Labyrinthi Mountains by height Observed rocks Outflow channels Plains Valley network Valleys Gravity Geology Brain terrain Carbonates Chaos terrain Color Composition Concentric crater fill Dark slope streak Dichotomy Fretted terrain Geysers Glaciers Groundwater Gullies Lakes Lava tubes Lobate debris apron Marsquake Meteorites on Earth on Mars Mud cracks North Polar Basin Ocean hypothesis Ore resources Polar caps polar wander Recurring slope lineae (RSL) Ring mold craters Rootless cones Seasonal flows Soil Spherules Surface "Swiss cheese" feature Terrain softening Tharsis bulge Volcanism Water Yardangs History Pre-Noachian Noachian Hesperian Amazonian Observation history Classical albedo features Astronomy Moons Phobos Stickney crater Limtoc crater Monolith Deimos Swift crater Voltaire crater Transits Solar eclipses on Mars Satellite transits Phobos Deimos Planetary transits Earth Mercury Asteroids Impacts Mars-crossers 2007 WD5 Trojans 5261 Eureka 1998 VF31 1999 UJ7 2007 NS2 Comets C/2013 A1 (Siding Spring) General Orbit Exploration Concepts Flyby Orbiter Landing Rover Sample return Human mission Permanent settlement Colonization Terraforming Missions List of missions to Mars Advocacy The Mars Project The Case for Mars Inspiration Mars Foundation Mars Institute Mars Society Mars race Related Artificial objects on Mars Memorials on Mars Fiction List of films set on Mars Martian scientist Mythology Flag of Mars Life on Mars Sub-Earth Timekeeping on Mars Sol (day on Mars) Darian calendar Category Solar System portal [Portal](https://en.wikipedia.org/wiki/Wikipedia:Contents/Portals): - [Solar System](https://en.wikipedia.org/wiki/Portal:Solar_System) --- Adapted from the Wikipedia article [Diacria quadrangle](https://en.wikipedia.org/wiki/Diacria_quadrangle) by Wikipedia contributors ([contributor history](https://en.wikipedia.org/wiki/Diacria_quadrangle?action=history)). 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