A lava flow on a Martian lava plain
Click for original image.
While much of surface of the Martian equatorial regions is comprised of volcanic flood lava, the place where it is most obvious and evident is on the flanks of the three giant volcanoes of the Tharsis Bulge. Here, lava did not simple spout from surface vents to flood low-lying large areas, filling those depressions quickly almost like water. Instead it issued from vents on the slopes of those mountains, or from their calderas at their peaks, and flowed downhill almost like tsunamis of magma.
The picture to the right, rotated, cropped, reduced, and sharpened to post here, is a great example. Taken on March 11, 2023 by the high resolution camera on Mars Reconnaissance Orbiter (MRO), it shows the foot of one such flow, frozen in place as it oozed down hill from the Arsia Mons, about 300 miles away to the northwest.
The green dot west of Claritas Fossae on the overview map to the right marks this location. Such downhill flows to the southeast are not unusual in this region. In fact, they are very common, showing that the volcanic events that caused them and built up Arsia Mons were many over time, with each placing another layer on top. Only when researchers can drill deep core samples at these locations to record those many layers will we finally be able to record the long volcanic history of Mars, and begin to understand the planet’s full geological history.
One intriguing aspect of this picture is only visible at full resolution. Take a look. For some reason the surface of this flood lava is covered with a fine stippling of tiny ridges, almost of which are oriented in a north-south direction. Are these dunes shaped by the prevailing winds? Erosion features in the lava? Your guess is as good as mine.
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.
While much of surface of the Martian equatorial regions is comprised of volcanic flood lava, the place where it is most obvious and evident is on the flanks of the three giant volcanoes of the Tharsis Bulge. Here, lava did not simple spout from surface vents to flood low-lying large areas, filling those depressions quickly almost like water. Instead it issued from vents on the slopes of those mountains, or from their calderas at their peaks, and flowed downhill almost like tsunamis of magma.
The picture to the right, rotated, cropped, reduced, and sharpened to post here, is a great example. Taken on March 11, 2023 by the high resolution camera on Mars Reconnaissance Orbiter (MRO), it shows the foot of one such flow, frozen in place as it oozed down hill from the Arsia Mons, about 300 miles away to the northwest.
The green dot west of Claritas Fossae on the overview map to the right marks this location. Such downhill flows to the southeast are not unusual in this region. In fact, they are very common, showing that the volcanic events that caused them and built up Arsia Mons were many over time, with each placing another layer on top. Only when researchers can drill deep core samples at these locations to record those many layers will we finally be able to record the long volcanic history of Mars, and begin to understand the planet’s full geological history.
One intriguing aspect of this picture is only visible at full resolution. Take a look. For some reason the surface of this flood lava is covered with a fine stippling of tiny ridges, almost of which are oriented in a north-south direction. Are these dunes shaped by the prevailing winds? Erosion features in the lava? Your guess is as good as mine.
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