A sinuous Martian ridge of uncertain origin
Click for original image.
Cool image time! The picture to the right, rotated, cropped, reduced, and sharpened to post here, was taken on July 21, 2025 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). It was posted today by the camera team as a captioned image, with the caption as follows:
The sinuous ridge is approximately 10 meters wide and several kilometers long. The floor surrounding this ridge has been eroding laterally, forming pits and circular features suggestive of removal (sublimation) of subsurface ice. However, landforms such as channels or moraines that might suggest the presence of water or ice are lacking, so the ridge itself does not appear to have formed by fluvial or glacial processes.
Perhaps this curious feature is an exhumed dike formed from magma emanating from Alba Mons in subsurface fractures.
Alba Mons is a gigantic shield volcano to the west.
The white dot on the overview map to the right marks the location, in the cracked lava plains that extend along the 3,500-mile-long major fault line from which three of Mars’ biggest volcanoes erupted. In this region the land is made up of many parallel fractures running northeast to southwest, all aligned with that major fault. The inset shows that this sinuous ridge sits on the floor of its own such fracture, about five miles wide and about 2,100 feet deep at this point.
The location is at 35 degrees north latitude, far enough north so the near surface ice is possible. The eroded plateau north of this fracture in the inset suggests underground sublimation could have occurred here.
At the same time, this doesn’t explain the origin of the ridge. Usually such ridges are thought to be the hardened floors of river/glacial channels, more resistant to erosion than the surrounding terrain so they end up as positive features when the ground around them wears away. In this case however the science team seems unsure of this possibility.
And so, we have another geological mystery on Mars. Hardly unusual, but fun nonetheless.
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 print edition can be purchased at Amazon or from any other book seller. If you want an autographed copy the price is $60 for the hardback and $45 for the paperback, plus $8 shipping for each. Go here for purchasing details. 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, rotated, cropped, reduced, and sharpened to post here, was taken on July 21, 2025 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). It was posted today by the camera team as a captioned image, with the caption as follows:
The sinuous ridge is approximately 10 meters wide and several kilometers long. The floor surrounding this ridge has been eroding laterally, forming pits and circular features suggestive of removal (sublimation) of subsurface ice. However, landforms such as channels or moraines that might suggest the presence of water or ice are lacking, so the ridge itself does not appear to have formed by fluvial or glacial processes.
Perhaps this curious feature is an exhumed dike formed from magma emanating from Alba Mons in subsurface fractures.
Alba Mons is a gigantic shield volcano to the west.
The white dot on the overview map to the right marks the location, in the cracked lava plains that extend along the 3,500-mile-long major fault line from which three of Mars’ biggest volcanoes erupted. In this region the land is made up of many parallel fractures running northeast to southwest, all aligned with that major fault. The inset shows that this sinuous ridge sits on the floor of its own such fracture, about five miles wide and about 2,100 feet deep at this point.
The location is at 35 degrees north latitude, far enough north so the near surface ice is possible. The eroded plateau north of this fracture in the inset suggests underground sublimation could have occurred here.
At the same time, this doesn’t explain the origin of the ridge. Usually such ridges are thought to be the hardened floors of river/glacial channels, more resistant to erosion than the surrounding terrain so they end up as positive features when the ground around them wears away. In this case however the science team seems unsure of this possibility.
And so, we have another geological mystery on Mars. Hardly unusual, but fun nonetheless.
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 print edition can be purchased at Amazon or from any other book seller. If you want an autographed copy the price is $60 for the hardback and $45 for the paperback, plus $8 shipping for each. Go here for purchasing details. 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