Dang, These Features on Mars are Groovy!

3D-DanielsonCrater_H1.jpg

[/caption]

The term 'yardangs' almost sounds like a fictional word from a Barsoomian tale of creatures living on Mars. However, this is a real word, a geologists' term for narrow, wind-eroded ridges. These are common land features in the desert regions of Earth, eolian features created by wind and dust. With Mars' dusty soil and frequent winds, these landforms are common on the Red Planet, too. The abrasive dust is blown by wind, impacting on the bedrock, slowly removing parts of the surface, like a sand-blaster. If the winds blow in the same direction for a long enough period, 'wind-lanes' are made. These features are called yardangs.

These latest images from the Mars Express mission show yardangs on the floor of Danielson crater, and scientists think this crater may provide evidence that the planet underwent significant periodic fluctuations in its climate due to changes in its rotation axis.

On June 19, 2011, Mars Express took a look at the region pictured here -- Arabia Terra region of Mars -- imaging Danielson and the smaller Kalocsa crater with its high-resolution stereo camera.

In the case of Danielson crater, scientists think the sediments were cemented in by water, possibly from an ancient deep groundwater reservoir, before being eroded by the wind.

[caption id="attachment_95724" align="aligncenter" width="580" caption="Danielson and Kalocsa craters as seen by Mars Express. Credit: ESA/DLR/FU Berlin (G. Neukum)"]

[/caption] The orientation of the yardangs leads scientists to theorize that strong north–northeasterly winds (from the lower right in the image) both deposited the original sediments and then caused their subsequent erosion in a later drier period of Martian history.

A 30 km-long field of darker dunes can be seen bisecting the yardangs and is thought to have formed at a later epoch.

Some scientists believe that this indicates periodic fluctuations in the climate of Mars, triggered by regular changes in the planet's axis of rotation. The different layers would have been laid down during different epochs.

But Kalocsa crater shows a completely different topography, with no layered sediments. This is thought to be due to the higher altitude of its floor, with the crater not tapping in to the suspected underlying ancient water reservoir.

However, another hypothesis is that this crater is younger than its neighbor, created when water was not present anymore.

Dang.

Source:

ESA

Nancy Atkinson

Nancy Atkinson

Nancy Atkinson is a space journalist and author with a passion for telling the stories of people involved in space exploration and astronomy. She is currently retired from daily writing, but worked at Universe Today for 20 years as a writer and editor. She also contributed articles to The Planetary Society, Ad Astra (National Space Society), New Scientist and many other online outlets.

Her 2019 book, "Eight Years to the Moon: The History of the Apollo Missions,” shares the untold stories of engineers and scientists who worked behind the scenes to make the Apollo program so successful, despite the daunting odds against it. Her first book “Incredible Stories From Space: A Behind-the-Scenes Look at the Missions Changing Our View of the Cosmos” (2016) tells the stories of 37 scientists and engineers that work on several current NASA robotic missions to explore the solar system and beyond.

Nancy is also a NASA/JPL Solar System Ambassador, and through this program, she has the opportunity to share her passion of space and astronomy with children and adults through presentations and programs. Nancy's personal website is nancyatkinson.com