Tag Archives: barchan dunes

Seeing Mars in a grain of sand

[Ed. note: The following is a guide to two recent special issues of the Journal of Geophysical Research; both collect papers reporting on studies of the Bagnold Dunes in Gale Crater. The guide complements the MSL report posted earlier here.] … Continue reading

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‘Ghost dune’ pits discovered on Mars

Scientists have discovered hundreds of crescent-shaped pits on Mars where sand dunes the size of the U.S. Capitol stood billions of years ago. The curves of these ancient dune impressions record the direction of prevailing winds on the Red Planet, … Continue reading

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HiRISE: Once in a blue dune

Sand dunes often accumulate in the floors of craters. In this region of Lyot Crater there is a field of classic barchan dunes. Just to the south of the group of barchan dunes is one large dune with a more … Continue reading

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HiRISE: Barchan Pac-Man

Barchan sand dunes are common on Mars and often form vast dune fields within very large (tens to hundreds of kilometers) impact basins. The regions upwind of barchans are usually devoid of sandy bedforms, so if you were walking in … Continue reading

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THEMIS: Frost-free dunes in north polar sand sea

THEMIS Image of the Day, March 16, 2018. This VIS image was collected at the height of summer. It is during this season that winds are able to move sand sized particles, slowly modifying the dunes. Olympia Undae is a … Continue reading

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THEMIS: Dunes in transition

THEMIS Image of the Day, March 15, 2018. This VIS image highlights the dune form/dune density aspects of Olypmia Undae. In the center there is a brighter, diagonal region of few dunes. These dunes are the arc or crescent shape … Continue reading

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THEMIS: Dunes, lacy and regular

THEMIS Image of the Day, March 14, 2018. This VIS image hightlights the density of dunes, the bottom third of the image has fewer dunes, spaced farther apart than the top two thirds of the image. The bottom of the … Continue reading

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THEMIS: Is that gypsum under the dunes?

THEMIS Image of the Day, March 13, 2018. This VIS image of Olympia Undae was collected during north polar summer. The dunes are now completely frost free and are dark in color due to being made of basaltic sand. The … Continue reading

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THEMIS: Edge of the great northern sand sea

THEMIS Image of the Day, March 12, 2018. This VIS image of Olympia Undae was collected during north polar summer. The dunes are now completely frost free and are dark in color due to being made of basaltic sand. The … Continue reading

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THEMIS: Amidst the sea of sand

THEMIS Image of the Day, March 9, 2018. This VIS image of Olympia Undae was collected during north polar spring. The crests of the dunes and other surfaces are light colored, indicative of a frost covering. The density of dunes … Continue reading

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