Determining whether a Martian crater is impact or volcanic
Cool image time! The picture above, rotated, cropped, reduced, and sharpened to post here, was taken on March 22, 2023 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). The camera team labeled this “Crater rim and ejecta,” which subtly reveals the picture’s scientific purpose.
The white dot on the overview map to the right indicates the location of this 15-mile-wide unnamed crater, about 150 miles northwest of where the rover Opportunity landed and traveled south to the rim of Endeavour Crater. It also shows in the inset that the crater appears to sit in the center of an upraised mound, suggesting it was formed not by impact but by volcanic processes.
This picture however says otherwise. The many small mounds and mesas to the south of the crater rim are not what one would expect on the apron of a volcano. Instead, they suggest this crater is an impact, with those mounds the eroded ejecta from that impact, now also partly buried by dust. This hypothesis is strengthened by the data from Opportunity, which found a great deal of impact ejecta during its travels, possibly from the very event that created this crater.
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, rotated, cropped, reduced, and sharpened to post here, was taken on March 22, 2023 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). The camera team labeled this “Crater rim and ejecta,” which subtly reveals the picture’s scientific purpose.
The white dot on the overview map to the right indicates the location of this 15-mile-wide unnamed crater, about 150 miles northwest of where the rover Opportunity landed and traveled south to the rim of Endeavour Crater. It also shows in the inset that the crater appears to sit in the center of an upraised mound, suggesting it was formed not by impact but by volcanic processes.
This picture however says otherwise. The many small mounds and mesas to the south of the crater rim are not what one would expect on the apron of a volcano. Instead, they suggest this crater is an impact, with those mounds the eroded ejecta from that impact, now also partly buried by dust. This hypothesis is strengthened by the data from Opportunity, which found a great deal of impact ejecta during its travels, possibly from the very event that created this crater.
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
Maar craters are probably what held back impact theory–they look like impact craters.
A cinder cone in a Maar might double for a complex crater–who knows?
What should we call a Mars geologist?
Dejathorisist?
Martiusist?
Ariesologist?
The overview picture suggests a small volcanic vent, a “cinder cone“ being a circular mountain without a obvious lava flow… with one large difference, an impact crater where the caldera should be.
I also thought the rocks were consistent with ejecta.
The only other explanation of the flat top small mesas (because of circular shape on the downwind side) Is that these are old fused impact craters in volcanic dust. Millions of years has blown away the finer UV degraded material leaving behind these glassy hard structures that were once the bottom of a crater. Just a guess.
I gotta admit, a cool image would be one of one of the Viking landers on Mars now.
Catch Thirty-Thr33: See these images:
https://www.uahirise.org/ESP_046170_2025
https://www.uahirise.org/PSP_001501_2280
https://www.uahirise.org/PSP_001521_2025