The broken edge of Mars’ largest volcanic ash field
Cool image time! The picture above, reduced and rotated to place north to the left, was taken on November 5, 2024 by the high resolution camera on Mars Reconnaissance Orbiter (MRO).
The science team labeled it “Stepped Features in Tartarus Skopulus”. The white dot on the overview map to the right marks the location, right at the equator on the northern edge of the Medusae Fossae Formation, the largest volcanic ash field on Mars, about the size of the subcontinent of India. As I wrote in a post in 2024:
It is believed that most of the planet’s dust comes from this ash field. It is also evident that the ash is a leftover from the time period more than a billion years ago when the giant volcanoes that surround this field were erupting regularly. The eruptions laid down vast flood lava plains that coat the surface for thousands of miles.
The ash either came from the eruptions themselves, or was created as the thin Martian wind eroded those flood lava plains, slowly stripping ash from the top. The ash then gathered within the black-outlined regions on the map.
In that 2024 post the cool image showed another location on the north edge of Medusae. In that case the prevailing wind had carved long parallel ridges as it pulled ash from the field.
Here, the wind appears to play no part, or if it did, it produced a very different terrain. At first glance it appears the stepped terraces formed as the ash field began to slide downhill to the north, spreading to crack along the curved lines. The inset especially suggests this explanation.
A closer look instead suggests these terraces each represent a different layer of ash placed down by a sequence of eruptions. Over time the prevailing winds, which here appear to generally blow to the south, stripped off the top of each layer, creating this stair-step landscape.
I however have no guess as to why the terraces are curved. Regardless, it is all strange, but quite beautiful in its own way.
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
Cool image time! The picture above, reduced and rotated to place north to the left, was taken on November 5, 2024 by the high resolution camera on Mars Reconnaissance Orbiter (MRO).
The science team labeled it “Stepped Features in Tartarus Skopulus”. The white dot on the overview map to the right marks the location, right at the equator on the northern edge of the Medusae Fossae Formation, the largest volcanic ash field on Mars, about the size of the subcontinent of India. As I wrote in a post in 2024:
It is believed that most of the planet’s dust comes from this ash field. It is also evident that the ash is a leftover from the time period more than a billion years ago when the giant volcanoes that surround this field were erupting regularly. The eruptions laid down vast flood lava plains that coat the surface for thousands of miles.
The ash either came from the eruptions themselves, or was created as the thin Martian wind eroded those flood lava plains, slowly stripping ash from the top. The ash then gathered within the black-outlined regions on the map.
In that 2024 post the cool image showed another location on the north edge of Medusae. In that case the prevailing wind had carved long parallel ridges as it pulled ash from the field.
Here, the wind appears to play no part, or if it did, it produced a very different terrain. At first glance it appears the stepped terraces formed as the ash field began to slide downhill to the north, spreading to crack along the curved lines. The inset especially suggests this explanation.
A closer look instead suggests these terraces each represent a different layer of ash placed down by a sequence of eruptions. Over time the prevailing winds, which here appear to generally blow to the south, stripped off the top of each layer, creating this stair-step landscape.
I however have no guess as to why the terraces are curved. Regardless, it is all strange, but quite beautiful in its own way.
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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