Gullies and glaciers in a crater on Mars
Click for full image.
Cool image time! The photo to the right, rotated, cropped, and reduced to post here, was taken on July 10, 2022 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). It shows the floor of 4-mile-wide Avire Crater, located at about 41 degrees south latitude inside the much larger 185-mile wide Newton Crater.
This picture was taken as part of a long term monitoring program of the many gullies that flow down the slopes of the crater’s interior rim. In fact, the gullies of this crater have so interested scientists that one even proposed [pdf] this location as a potential future rover landing site.
Avire Crater, a small … gullied crater within Newton Crater, provides many aspects ideal to a future rover mission. It has been previously hypothesized to be the location of a former paleolake with multiple episodes of ponding and deposition. Gullies occur almost continuously on the southwest wall clockwise to the northeastern wall. Dark-toned dunes are present in the northern portion of the crater, in some places obscuring gullies while cut by gullies in others. No changes in the extent or appearance of the dunes have been observed since they were first imaged … in January of 2000. The dunes lack superimposed craters, indicating that the gullies that cut through them are geologically very youthful. Layered lobate features are present at the base of the gullies on the northern wall, seen in many other craters on Mars (not always in association with gullies), which have been suggested to have formed as terminal moraines of ice-rich flows; in Avire, these features have also been suggested to be paleolake deposits. The crater floor is obscured by mid-latitude “fill” material, hypothesized to be partially comprised of ice based on morphologic evidence that the material has been partially removed.
As gullies, dunes, and “fill” material occur in many places on Mars, a single rover mission to a site containing these features would provide valuable information applicable to thousands of other locations across the planet.
The curved ridgeline in the crater floor is thought to be a moraine. The “fill” material to the south is essentially glacial in nature. Both, as well as the gullies, appear to have been shaped either a paleolake that once existed in the crater or by cyclical glacier activity. By going to this one crater, scientists could study all these different geological features at one time.
The black cross in the overview map to the right marks the location of this crater, inside Newton Crater. Located only about 200 to 800 miles from southwest edge of the lava flood plains laid down by Mars’ biggest volcanoes, this crater sits in the southern cratered highlands. Volcanic processes might helped form the bedrock, but those processes were not directly related to those big volcanoes. The dust forming the young dunes inside the crater however could easily have come from the Medusae Fossae Formation, the planet’s largest deposit of volcanic ash that fills the lowlands to the southwest of Olympus Mons for many hundreds of miles.
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 full image.
Cool image time! The photo to the right, rotated, cropped, and reduced to post here, was taken on July 10, 2022 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). It shows the floor of 4-mile-wide Avire Crater, located at about 41 degrees south latitude inside the much larger 185-mile wide Newton Crater.
This picture was taken as part of a long term monitoring program of the many gullies that flow down the slopes of the crater’s interior rim. In fact, the gullies of this crater have so interested scientists that one even proposed [pdf] this location as a potential future rover landing site.
Avire Crater, a small … gullied crater within Newton Crater, provides many aspects ideal to a future rover mission. It has been previously hypothesized to be the location of a former paleolake with multiple episodes of ponding and deposition. Gullies occur almost continuously on the southwest wall clockwise to the northeastern wall. Dark-toned dunes are present in the northern portion of the crater, in some places obscuring gullies while cut by gullies in others. No changes in the extent or appearance of the dunes have been observed since they were first imaged … in January of 2000. The dunes lack superimposed craters, indicating that the gullies that cut through them are geologically very youthful. Layered lobate features are present at the base of the gullies on the northern wall, seen in many other craters on Mars (not always in association with gullies), which have been suggested to have formed as terminal moraines of ice-rich flows; in Avire, these features have also been suggested to be paleolake deposits. The crater floor is obscured by mid-latitude “fill” material, hypothesized to be partially comprised of ice based on morphologic evidence that the material has been partially removed.
As gullies, dunes, and “fill” material occur in many places on Mars, a single rover mission to a site containing these features would provide valuable information applicable to thousands of other locations across the planet.
The curved ridgeline in the crater floor is thought to be a moraine. The “fill” material to the south is essentially glacial in nature. Both, as well as the gullies, appear to have been shaped either a paleolake that once existed in the crater or by cyclical glacier activity. By going to this one crater, scientists could study all these different geological features at one time.
The black cross in the overview map to the right marks the location of this crater, inside Newton Crater. Located only about 200 to 800 miles from southwest edge of the lava flood plains laid down by Mars’ biggest volcanoes, this crater sits in the southern cratered highlands. Volcanic processes might helped form the bedrock, but those processes were not directly related to those big volcanoes. The dust forming the young dunes inside the crater however could easily have come from the Medusae Fossae Formation, the planet’s largest deposit of volcanic ash that fills the lowlands to the southwest of Olympus Mons for many hundreds of miles.
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
Readers: the rules for commenting!
No registration is required. I welcome all opinions, even those that strongly criticize my commentary.
However, name-calling and obscenities will not be tolerated. First time offenders who are new to the site will be warned. Second time offenders or first time offenders who have been here awhile will be suspended for a week. After that, I will ban you. Period.
Note also that first time commenters as well as any comment with more than one link will be placed in moderation for my approval. Be patient, I will get to it.