Sinuous ridge inside Martian canyon
Click for original image.
Cool image time! The picture to the right, cropped, reduced, and sharpened to post here, was taken on February 7, 2023 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). It shows what the camera team labels a “sinuous ridge within valley.”
The location is at 30 degrees south latitude, right on the edge of the southern of the two 30-60 degree mid-latitude bands where orbital images show many glacial features. Closer to the equator and there is little or no evidence of near surface ice on Mars. Farther from the equator from this latitude and the evidence of near surface ice increases, becoming very dominant the closer to the poles you get.
At this spot, it appears there is little near surface ice. The channel has ripple sand dunes inside it, and the sinuous ridge appears to be bedrock. Similarly, the plateau above the channel also appears like bedrock, the craters showing no evidence of splatter that is common where there is near surface ice.
What made the channel? And what made that a sinuous ridge inside it?
The white cross north of Hellas Basin on the overview map to the right marks the location of this channel, which appears to be part of a major but unnamed drainage down into Hellas. To the south the canyons Dao, Harmakhis, and Reull all have lots of glacial features within them, and actually appear to be in the process of being carved out by those glaciers, when those presently inactive glaciers have been active in the past.
It is therefore very probable that this channel was carved by glacial activity also in the past, but because of its proximity to the equator that ice is now long gone.
The sinuous ridge suggests the remains of a much earlier channel, created first. Its floor got packed hard so that it became more resistant to erosion. When the larger later glacier carved out the larger channel, it removed the material around this older small channel, leaving behind that sinuous ridge.
At least, that’s my theory, which is also the guess of an amateur.
On Christmas Eve 1968 three Americans became the first humans to visit another world. What they did to celebrate was unexpected and profound, and will be remembered throughout all human history. Genesis: the Story of Apollo 8, Robert Zimmerman's classic history of humanity's first journey to another world, tells that story, and it is now available as both an ebook and an audiobook, both with a foreword by Valerie Anders and a new introduction by Robert Zimmerman.
The ebook is available everywhere for $5.99 (before discount) at amazon, or direct from my ebook publisher, ebookit. If you buy it from ebookit you don't support the big tech companies and the author gets a bigger cut much sooner.
The audiobook is also available at all these vendors, and is also free with a 30-day trial membership to Audible.
"Not simply about one mission, [Genesis] is also the history of America's quest for the moon... Zimmerman has done a masterful job of tying disparate events together into a solid account of one of America's greatest human triumphs."--San Antonio Express-News
Click for original image.
Cool image time! The picture to the right, cropped, reduced, and sharpened to post here, was taken on February 7, 2023 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). It shows what the camera team labels a “sinuous ridge within valley.”
The location is at 30 degrees south latitude, right on the edge of the southern of the two 30-60 degree mid-latitude bands where orbital images show many glacial features. Closer to the equator and there is little or no evidence of near surface ice on Mars. Farther from the equator from this latitude and the evidence of near surface ice increases, becoming very dominant the closer to the poles you get.
At this spot, it appears there is little near surface ice. The channel has ripple sand dunes inside it, and the sinuous ridge appears to be bedrock. Similarly, the plateau above the channel also appears like bedrock, the craters showing no evidence of splatter that is common where there is near surface ice.
What made the channel? And what made that a sinuous ridge inside it?
The white cross north of Hellas Basin on the overview map to the right marks the location of this channel, which appears to be part of a major but unnamed drainage down into Hellas. To the south the canyons Dao, Harmakhis, and Reull all have lots of glacial features within them, and actually appear to be in the process of being carved out by those glaciers, when those presently inactive glaciers have been active in the past.
It is therefore very probable that this channel was carved by glacial activity also in the past, but because of its proximity to the equator that ice is now long gone.
The sinuous ridge suggests the remains of a much earlier channel, created first. Its floor got packed hard so that it became more resistant to erosion. When the larger later glacier carved out the larger channel, it removed the material around this older small channel, leaving behind that sinuous ridge.
At least, that’s my theory, which is also the guess of an amateur.
On Christmas Eve 1968 three Americans became the first humans to visit another world. What they did to celebrate was unexpected and profound, and will be remembered throughout all human history. Genesis: the Story of Apollo 8, Robert Zimmerman's classic history of humanity's first journey to another world, tells that story, and it is now available as both an ebook and an audiobook, both with a foreword by Valerie Anders and a new introduction by Robert Zimmerman.
The ebook is available everywhere for $5.99 (before discount) at amazon, or direct from my ebook publisher, ebookit. If you buy it from ebookit you don't support the big tech companies and the author gets a bigger cut much sooner.
The audiobook is also available at all these vendors, and is also free with a 30-day trial membership to Audible.
"Not simply about one mission, [Genesis] is also the history of America's quest for the moon... Zimmerman has done a masterful job of tying disparate events together into a solid account of one of America's greatest human triumphs."--San Antonio Express-News
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