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File:Proctor Crater Dune Field.jpg

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Summary

Description
English: This observation shows the edge of a dark dune field on the floor of Proctor Crater, a 150-kilometre diameter crater in the Southern highlands of Mars.

The dark dunes are composed of basaltic sand that has collected on the bottom of the crater. Dark dune slip faces (the steeper sides of the dunes) are located on the east side of the dunes and are believed to have formed in response to fall and winter westerly winds caused by geostrophic forces (winds balanced by Coriolis and pressure gradient forces). Superimposed on their surface are smaller secondary dunes that are commonly seen on terrestrial dunes of this size.

Many smaller and brighter bed forms, most likely small dunes or granule ripples, cover the substrate between the larger dark dunes as well as most of the floor of Proctor Crater. The dark dunes overlie the small bright bed-forms indicating that they formed more recently. In several areas, however, the dark dunes appear to influence the orientation of the small bright dunes, possibly by wind flowing around the larger ones, suggesting that both dark and bright bed-forms are coeval. The dunes in Proctor Crater may be active today, moving in response to Martian winds.
Русский: Oгромные песчаные дюны на дне марсианского кратера Проктор. Фотография была получена с помощью камеры HiRISE, установленной на борту спутника Марс Реконесанс Орбитер (Mars Reconnaissance Orbiter, MRO) — роботизированного космического аппарата, летающего по орбите вокруг Марса. Тёмные волнообразные дюны, скорее всего, сформировались позже, чем более светлые камни под ними. Считается, что они медленно смещаются под действием вездесущих ветров. Дюны возникают вследствие сложного взаимодействия песчаной марсианской поверхности и сильных ветров. Подобные образования были замечены в кратере Проктор космическим аппаратом Маринер-9 более 35 лет назад.
Date
Source HiRISE
Author NASA/JPL/University of Arizona

Local Mars time: 3:30 PM. Latitude (centered): -47.0 °. Longitude (East): 30.7 °. Range to target site: 281.8 km. Original image scale range: 28.2 cm/pixel (with 1 x 1 binning) so objects ~85 cm across are resolved. Map projected scale: 25 cm/pixel and north is up. Map projection: EQUIRECTANGULAR. Emission angle: 27.7 °. Phase angle: 22.7 °. Solar incidence angle: 47 °, with the Sun about 43 ° above the horizon. Solar longitude: 254.6 °, Northern Autumn.

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Public domain This file is in the public domain in the United States because it was solely created by NASA. NASA copyright policy states that "NASA material is not protected by copyright unless noted". (See Template:PD-USGov, NASA copyright policy page or JPL Image Use Policy.)
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10 June 2007

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current12:58, 22 November 2010Thumbnail for version as of 12:58, 22 November 20102,560 × 1,920 (4.34 MB)Originalwana{{Information |Description={{en|1=This observation shows the edge of a dark dune field on the floor of Proctor Crater, a 150-kilometre diameter crater in the Southern highlands of Mars. The dark dunes are composed of basaltic sand that has collected

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