Erosion revealing ridges on Mars?
Click for original image.
Cool image time! The picture to the right, rotated, cropped, reduced, and sharpened to post here, was taken on June 30, 2023 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). The science team calls the features here “narrow ridges”, but what makes these criss-crossing ridges interesting is their location within the picture.
They appear only inside the hollows and depressions, as if erosion had stripped out a top layer of softer material to reveal these ridges, made of a harder material. The almost random but straight orientations of the ridges also suggest they formed along faults or cracks, which also suggests we are seeing dikes where lava was pushed up from below.
Whether the eroded softer material is lava or volcanic ash is unclear, though it certainly resembles the ash layers seen in the giant Medusa Fossae Formation ash field on the opposite side of Mars.
As always, a wider look helps clarify things.
The rectangle inside the inset on the overview map to the right marks the area of this cool image. That inset also shows the large area surrounding that image, showing that it covers the transition between a high and low plain. The drop is only about 600 feet, but clearly something removed the softer material on that lower plain.
The location, in Arabia Terra in a region called Meridiani Planum (because it is the zero point on Mars for both longitude and latitude), is also known to have areas of flood lava, though no distinct upraised volcanoes. Instead, it appears that the lava here extruded up through smaller vents, not dissimilar to the cracks and faults that likely mark the locations of these ridges.
It is also possible that instead of erosion, the higher regions are simply areas that were covered by a flood of lava, with the ridges might be lava dikes that the lava never reached to engulf. See this June 2021 cool image for an example.
It is also possible none of my guesses here are right. The amount of data is too limited to come to any firm conclusions.
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. from any other book seller, or direct from my ebook publisher, ebookit.
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 June 30, 2023 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). The science team calls the features here “narrow ridges”, but what makes these criss-crossing ridges interesting is their location within the picture.
They appear only inside the hollows and depressions, as if erosion had stripped out a top layer of softer material to reveal these ridges, made of a harder material. The almost random but straight orientations of the ridges also suggest they formed along faults or cracks, which also suggests we are seeing dikes where lava was pushed up from below.
Whether the eroded softer material is lava or volcanic ash is unclear, though it certainly resembles the ash layers seen in the giant Medusa Fossae Formation ash field on the opposite side of Mars.
As always, a wider look helps clarify things.
The rectangle inside the inset on the overview map to the right marks the area of this cool image. That inset also shows the large area surrounding that image, showing that it covers the transition between a high and low plain. The drop is only about 600 feet, but clearly something removed the softer material on that lower plain.
The location, in Arabia Terra in a region called Meridiani Planum (because it is the zero point on Mars for both longitude and latitude), is also known to have areas of flood lava, though no distinct upraised volcanoes. Instead, it appears that the lava here extruded up through smaller vents, not dissimilar to the cracks and faults that likely mark the locations of these ridges.
It is also possible that instead of erosion, the higher regions are simply areas that were covered by a flood of lava, with the ridges might be lava dikes that the lava never reached to engulf. See this June 2021 cool image for an example.
It is also possible none of my guesses here are right. The amount of data is too limited to come to any firm conclusions.
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. from any other book seller, or direct from my ebook publisher, ebookit. 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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