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Acidalia Planitia is a plain on Mars. It is located between the Tharsis volcanic province and Arabia Terra to the north of Valles Marineris, centered at . Most of this region is found in the Mare Acidalium quadrangle, but a small part is in the Ismenius Lacus quadrangle. The plain contains the famous Cydonia region at the contact with the heavily cratered highland terrain. The plain is named after a corresponding albedo feature on a map by Giovanni Schiaparelli, which was in turn named after the mythological fountain of Acidalia. Some places in Acidalia Planitia show cones. Some researchers have suggested that these are mud volcanoes. ==Gullies== Martian gullies are small, incised networks of narrow channels and their associated downslope sediment deposits, found on the planet of Mars. They are named for their resemblance to terrestrial gullies. First discovered on images from Mars Global Surveyor, they occur on steep slopes, especially on the walls of craters. Usually, each gully has a dendritic ''alcove'' at its head, a fan-shaped ''apron'' at its base, and a single thread of incised ''channel'' linking the two, giving the whole gully an hourglass shape.〔Malin, M., Edgett, K. 2000. Evidence for recent groundwater seepage and surface runoff on Mars. Science 288, 2330–2335.〕 They are believed to be relatively young because they have few, if any craters. A subclass of gullies is also found cut into the faces of sand dunes which themselves considered to be quite young. On the basis of their form, aspects, positions, and location amongst and apparent interaction with features thought to be rich in water ice, many researchers believed that the processes carving the gullies involve liquid water. However, this remains a topic of active research. Image:24951bambergwidectx.jpg|Context for next image of Bamberg crater. Box shows where the next image came from. This is a CTX image from Mars Reconnaissance Orbiter. Image:ESP 024951gulliesandflow.jpg|Gullies and massive flow of material, as seen by HiRISE under HiWish program. Gullies are enlarged in next two images. Location is Bamberg crater. Image:24951gulliesclose.jpg|Close up view of some gullies, as seen by HiRISE under the HiWish program. Image:24951gullyclose.jpg|Close up view of another gully in same HiRISE picture. Picture taken under HiWish program. Image:26574gullies.jpg|Gullies, as seen by HiRISE under HiWish program. Image:ESP 027707_2195gullies.jpg|Gullies in a crater, as seen by HiRISE under HiWish program. Image:27707gulliesclose.jpg|Close-up of gullies in a crater from previous image. Image taken by HiRISE under HiWish program. Polygons are easily visible; they are believed to be from the freezing and thawing of ice in the ground. Image:PIA19914-MarsLandingSite-Ares4Mission-TheMartian-2015Film-20150714.jpg| ''Ares III'' Mission - Landing Site (Acidalia Planitia region). Image:Wikiacidaliumboundaries.jpg|MOLA map showing boundaries for Acidalia Planitia and other regions. Image:ESP 024701mudvolcanoes.jpg|Possible mud volcanoes near the edge of the ejecta of a nearby crater, as seen by HiRISE under the HiWish program. Image:ESP 040775 2235cones.jpg|Large field of cones that may be mud volcanoes, as seen by HiRISE under HiWish program Image:040775 2235conesclose.jpg|Close-up of possible mud volcanoes, as seen by HiRISE under HiWish program Note: this is an enlargement of the previous image. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Acidalia Planitia」の詳細全文を読む スポンサード リンク
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