Ancient volcanic vent 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 May 28, 2023 by the high resolution camera on Mars Reconnaissance Orbiter (MRO).
The picture label describes it as a “Low Shield Vent and Pit Northeast of Arsia Mons,” suggesting these depressions are volcanic in nature. We know the pit in the lower left is not an impact crater because it has no raised rim of ejecta. Instead, it looks like a collapsed sinkhole, formed when the ceiling above a void could no longer support its weight. Similar, the trench to the northeast is aligned with the downhill grade to the northeast, with its features suggesting a vent draining in that direction.
The ample dust inside the trench and pit suggest that it has been a very long time since this vent was active. Research suggests volcanic activity last occurred in this region from 10 to 300 million years ago, so that gives us a rough estimate of this vent’s age. Since then any dust that is blown into it will tend to become trapped there.
The white rectangle on the inset on the right of the overview map shows the area covered by the picture above, with the white dot on the map marking the location, about 250 miles from the caldera center of the giant volcano Arsia Mons. The black dots mark locations of pits described here previously as cool images.
Another reason scientists probably consider this a volcanic vent is the topography. The vent is at the top of a low rise, suggesting it is basically a small shield volcano on the flanks of a gigantic shield volcano.
The inset also reveals one other puzzling geological feature. The dark streaks on the right are likely areas of dark volcanic material exposed because the ubiquitous Martian dust has been blown away for some reason. That its eastern edge aligns perfectly with that long southwest-northeast trending fissure strongly suggests air is coming out of that fissure and is then blown to the northwest by the prevailing winds. If so, that also suggests that there are extensive underground voids linked to that long fissure. In other words, this is evidence of hidden lava tubes of some length and size.
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 or from any other book seller. If you want an autographed copy the price is $60 for the hardback and $45 for the paperback, plus $8 shipping for each. Go here for purchasing details. 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 May 28, 2023 by the high resolution camera on Mars Reconnaissance Orbiter (MRO).
The picture label describes it as a “Low Shield Vent and Pit Northeast of Arsia Mons,” suggesting these depressions are volcanic in nature. We know the pit in the lower left is not an impact crater because it has no raised rim of ejecta. Instead, it looks like a collapsed sinkhole, formed when the ceiling above a void could no longer support its weight. Similar, the trench to the northeast is aligned with the downhill grade to the northeast, with its features suggesting a vent draining in that direction.
The ample dust inside the trench and pit suggest that it has been a very long time since this vent was active. Research suggests volcanic activity last occurred in this region from 10 to 300 million years ago, so that gives us a rough estimate of this vent’s age. Since then any dust that is blown into it will tend to become trapped there.
The white rectangle on the inset on the right of the overview map shows the area covered by the picture above, with the white dot on the map marking the location, about 250 miles from the caldera center of the giant volcano Arsia Mons. The black dots mark locations of pits described here previously as cool images.
Another reason scientists probably consider this a volcanic vent is the topography. The vent is at the top of a low rise, suggesting it is basically a small shield volcano on the flanks of a gigantic shield volcano.
The inset also reveals one other puzzling geological feature. The dark streaks on the right are likely areas of dark volcanic material exposed because the ubiquitous Martian dust has been blown away for some reason. That its eastern edge aligns perfectly with that long southwest-northeast trending fissure strongly suggests air is coming out of that fissure and is then blown to the northwest by the prevailing winds. If so, that also suggests that there are extensive underground voids linked to that long fissure. In other words, this is evidence of hidden lava tubes of some length and size.
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 or from any other book seller. If you want an autographed copy the price is $60 for the hardback and $45 for the paperback, plus $8 shipping for each. Go here for purchasing details. 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