Dormant volcanic vent on Mars
Click for original image.
Cool image time! The photo to the right, rotated, cropped, and reduced to post here, was taken on November 19, 2022 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). It shows what the science team labels “Intersecting Fissures.”
These fissures stand out distinctly on this terrain. If you look at an MRO context camera image, showing a wider view, you can see that the surrounding plain is relatively featureless, with few craters. Except for some strange and inexplicable dark streaks close by to the east, some mottled but flat terrain to the north, and a long but very faint similar east-west fissure to the south, this runelike fissure is the only major topological feature for miles around.
That context camera image also shows that this fissure sits on top of a very faint bulge, with hints that material had flowed downhill from the fissure’s western and southern outlets. Located very close to the equator, it is unlikely that any of those flow features are glacial, and in fact they do not have that appearance in the context camera picture. Instead, they have the look of Martian lava, fast-moving and far less viscous than Earth-lava, and thus able to cover large areas much more quickly.
Thus, all the evidence says that this feature is a dormant volcanic vent, sitting on a flood lava plain. And the overview map below cements this conclusion.
The white dot to the east of the volcano Pavonis Mons marks the location of this vent. As you can see, it sits inside the Tharsis Bulge, home for four of Mars’s largest volcanoes. The entire surface for hundreds and hundreds and hundreds of miles is volcanic flood lava, laid down over many eruptions more than a billion years ago.
The unknown right now is the number of those eruptions, and their timing over the eons. At present all we can do is study the surface of the Tharsis Bulge, and determine where the most recent flood lava events took place at each location, such as this particular vent in the photo above. Nor can we date these events very precisely, as this dating depends mostly on crater counts. Fewer craters suggests a more recent event, based on the known impact rates over time.
To map out over time the eruption history of Mars’s volcanoes will require many deep core samples, across a wide area of the Tharsis Bulge. And yes, that can’t really happen until humans finally get there and are able to quickly go from place to place.
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 photo to the right, rotated, cropped, and reduced to post here, was taken on November 19, 2022 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). It shows what the science team labels “Intersecting Fissures.”
These fissures stand out distinctly on this terrain. If you look at an MRO context camera image, showing a wider view, you can see that the surrounding plain is relatively featureless, with few craters. Except for some strange and inexplicable dark streaks close by to the east, some mottled but flat terrain to the north, and a long but very faint similar east-west fissure to the south, this runelike fissure is the only major topological feature for miles around.
That context camera image also shows that this fissure sits on top of a very faint bulge, with hints that material had flowed downhill from the fissure’s western and southern outlets. Located very close to the equator, it is unlikely that any of those flow features are glacial, and in fact they do not have that appearance in the context camera picture. Instead, they have the look of Martian lava, fast-moving and far less viscous than Earth-lava, and thus able to cover large areas much more quickly.
Thus, all the evidence says that this feature is a dormant volcanic vent, sitting on a flood lava plain. And the overview map below cements this conclusion.
The white dot to the east of the volcano Pavonis Mons marks the location of this vent. As you can see, it sits inside the Tharsis Bulge, home for four of Mars’s largest volcanoes. The entire surface for hundreds and hundreds and hundreds of miles is volcanic flood lava, laid down over many eruptions more than a billion years ago.
The unknown right now is the number of those eruptions, and their timing over the eons. At present all we can do is study the surface of the Tharsis Bulge, and determine where the most recent flood lava events took place at each location, such as this particular vent in the photo above. Nor can we date these events very precisely, as this dating depends mostly on crater counts. Fewer craters suggests a more recent event, based on the known impact rates over time.
To map out over time the eruption history of Mars’s volcanoes will require many deep core samples, across a wide area of the Tharsis Bulge. And yes, that can’t really happen until humans finally get there and are able to quickly go from place to place.
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
Nice one, Bob.