A new analysis of Martian data once again suggests that an intermittent ocean once existed in the planet’s northern hemisphere, and that it was fed by catastrophic floods coming down from the volcanoes through Marineris Valles.
“Our simulation shows that the presence of the sea would have attenuated cataclysmic floods, leading to shallow spillovers that reached the Pathfinder landing site and produced the bedforms detected by the spacecraft,” said [lead scientist Alexis Rodriguez].
The team’s results indicate that marine spillover deposits contributed to the landscape that the spacecraft detected nearly 22 years ago, and reconcile the mission’s in situ geologic observations and decades of remote-sensing outflow channel investigations.
The sea bears an uncanny resemblance to the Aral Sea on Earth in that in both instances they lack distinct shoreline terraces. Its rapid regression over shallow submerged slopes resulted in rates of shoreline front retreat too fast for the terraces to form. The same process could partly account for the long-recognized lack of northern plains shorelines.
“Our numerical simulations indicate that the sea rapidly became ice-covered and disappeared within a few thousand years due to its rapid evaporation and sublimation. During this time, however, it remained liquid below its ice cover,” said PSI Senior Scientist Bryan Travis, a co-author in the paper.
The map above shows the outlet region to the west and north of Marineris Valles. (The paper from which it is adapted is available on line here.) It shows that inland sea, created by the catastrophic floods. Because it sits at a lower elevation than the plains to the north, the floods that entered it ponded there, where they dried up. Only when the floods were at their highest did the water spill out into the northern plains.
In reading the paper, it confirms many of the suppositions I myself have made in my frequent posts analyzing numerous Mars Reconnaissance Orbiter (MRO) images, such as the lack of a clear shoreline because the ocean was short-lived. As it dried up its edge left patches of shoreline, at different elevations and in pondlike patterns, almost like the beach debris left behind by the tide.
The paper also shows that some of my guesses were not quite correct. For example, this new analysis says that the catastrophic floods only partly carved out the chaos terrain of Hydraotes Chaos, rather than do it all as I supposed here. Instead, the floods contributed, but much of the erosion occurred when the short-lived inland sea existed here, eroding away at the mesas from all sides.
Read it all. Though this remains a simulation based on what is presently very incomplete data and thus has many uncertainties, it will give you a much deeper understanding of what we presently theorize about the past geological history of Mars.
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