THEMIS: Yardangs in Candor Chasma

Yardangs in Candor Chasma (THEMIS_IOTD_20180112)THEMIS Image of the Day, January 12, 2018. This image shows part of eastern Candor Chasma. In the middle of the image is a set of linear ridges and valleys. These features are called yardangs and are created by uniform winds that winnow away materials.

Once the valleys are formed the wind then is funneled through the valley and erosion continues more in the valley than on the ridges. At the bottom of the valleys there are sand materials covering the slope between the valleys and the surrounding chasma floor. Beyond this coating of sand there are darker sand deposits where wind has accumulated the sand into larger dunes.

The brighter mesa on the right side of the image has also been wind eroded into yardangs, but are aligned in a different direction than the larger yardangs. This indicates that wind directions within the canyon have changed over time.

Candor Chasma is one of the largest canyons that make up Valles Marineris. It is approximately 810 km long (503 miles) and has is divided into two regions – eastern and western Candor. Candor is located south of Ophir Chasma and north of Melas Chasma. The border with Melas Chasma contains many large landslide deposits. The floor of Candor Chasma includes a variety of landforms, including layered deposits, dunes, landslide deposits and steep sided cliffs and mesas. Many forms of erosion have shaped Chandor Chasma. There is evidence of wind and water erosion, as well as significant gravity driven mass wasting (landslides).

NASA’s Mars Odyssey spacecraft has spent over 15 years in orbit around Mars, circling the planet more than 69,000 times. It holds the record for longest working spacecraft at Mars. THEMIS, the IR/VIS camera system, has collected data for the entire mission and provides images covering all seasons and lighting conditions.

Over the years many features of interest have received repeated imaging, building up a suite of images covering the entire feature. From the deepest chasma to the tallest volcano, individual dunes inside craters and dune fields that encircle the north pole, channels carved by water and lava, and a variety of other feature, THEMIS has imaged them all.

For the next several months the Image of the Day will focus on the Tharsis volcanoes, the various chasmata of Valles Marineris, and the major dunes fields. We hope you enjoy these images!

More THEMIS Images of the Day by geological topic.

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