A flood that would make even Noah turn and run

The orange band is a small-scale volcanic dike that filled a crack between older lavas about a billion years ago. This one is located at the mouth of the Lester River in Duluth, Minn. Photo: Bob King

Massive floods are not only common on Earth but 3.5 billion years ago they raged across the Martian landscape. One of the most dramatic issued from a breach in a rift called Mangala Fossae. ‘Mangala’ is the Sanskrit word for Mars and ‘fossae’ is Latin for ditch or trough.  This striking linear crack is located 16 degrees south of the Martian equator north and east of the edge of the vast volcanic plateau called the Tharis bulge.

What’s now a wide valley began as a narrow fault in the crust. Scientists believe that a surge of molten rock (magma) beneath the fault caused it to widen into a long, linear valley seen in the photo below. Surges of magma that squeezed between cracks in earlier lava flows are called volcanic dikes. Many can be seen along the rivers and rock outcroppings of Lake Superior’s North Shore.

The large crack in Mars crust at left is Mangala Fossae. Water beneath the surface burst forth when the crack widened, flooding nearly everything you see to the right or north. Multiple bursts of floodwaters carved a huge channel 550 miles long called Mangala Valles. The area in the yellow oval is shown in closeup below. Click photos to enlarge. Credit: NASA/JPL-Caltech/Arizona State University

But there’s more, much more. The cracking released a vast reserve of subsurface water that had been capped and contained either by frozen ground or thick layers of rock. Once the surface was broken, water gushed forth in a fashion similar to shaking a pop bottle and then untwisting the cap. After filling the trough, it breached the wall and flowed with cataclysmic fury across hundreds of miles of desert Martian landscape scouring everything in its path. What a terrifying sight to have seen if eyes had been around back then. The floodplain is named Mangala Valles (valley).

The yellow arrow points to the remains of the volcanic dike that caused the water flow leading to the creation of Mangala Valles. When the dike widened the valley, it broke into a subsurface reservoir of water, causing floods that opened the breach seen here. The blue arrow (right) points to water-cut terraces that suggest the valley saw multiple episodes of floods. This scene is about 6 miles wide. Credit: NASA/JPL-Caltech/Arizona State University

The breach measures five miles wide and 1,600 feet deep. Think of the power it must have taken to tear through all that rock. By counting craters, scientists have estimated that the first and largest flow happened 3.5 billion years ago. Crater-counting has been used across the solar system to get a handle on a body’s age. The more craters, the more ancient the landscape; the fewer the younger.  Judging by the terraces in the downstream walls of rock, smaller floods recurred 1 billion, 500 million and as recently as 200 million years ago, each leaving its own ‘water level mark’ on the hillsides.

Downstream in the valley floor, the floods thinned the material covering an underground aquifer. As the subsurface waters broke out, they joined the main flood. Scene is 4.1 miles wide. Credit: NASA/JPL-Caltech/Arizona State University

Even more evidence for floods are found in the quilted patterns of mesas and valleys in what’s termed ‘chaotic terrain’.  The crazy shapes are believe to form when powerful floodwaters scrape away much of the overlying rock in the floodplain. Without the confinement of that upper layer or rock (or ice), water may have bubbled out all over the place creating this strange scene of jumbled valleys and hilltops.

The Mangala flood scoured the channel deeper and carved hills and knobs into graceful streamlined shapes. This scene 9 miles wide. Credit: NASA/JPL-Caltech/Arizona State University

The Mangala flood tells us that despite current conditions, where liquid water can’t exist on Mars for long because of bitter cold temperatures and low atmospheric pressure, it once did pour across the landscape, creating vast floodplains as well as narrow, branching riverbeds. Since a growing crack in its surface was enough to liberate a flood, I wonder if a well-placed large meteorite strike might someday do the same. Will some future amateur astronomer catch an impact flash on Mars followed by a darkening of the surface as pressurized water once again seeks the light?

(Photos taken by Mars Reconnaissance Orbiter and the infrared camera on the Mars Odyssey orbiter. Thanks to NASA for the background information used to create this piece.)

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About astrobob

My name is Bob King and I work at the Duluth News Tribune in Duluth, Minn. as a photographer and photo editor. I'm also an amateur astronomer and have been keen on the sky since age 11. My modest credentials include membership in the American Association of Variable Star Observers (AAVSO) where I'm a regular contributor, International Meteorite Collectors Assn. and Arrowhead Astronomical Society. I also teach community education astronomy classes at our local planetarium.

6 thoughts on “A flood that would make even Noah turn and run

  1. There is another far better explanation that “water” on a planet with an atmospheric pressure that makes it impossible for liquid water,,, is the electric plasma scarring that is wide spread all across the universe. The “flows” that some describe can just as easily be the wind blown sand flows,,, it looks the exact same as water flowing people. When the “experts” get off the gravitational universe model they will also be dropping a lot of farcical fantasy theories that are required to make ‘it fit’ the observations.

    • Sam,
      No way windblown sand. There are far too many features indicating massive fluid movement. There’s a REMOTE chance it might be from a lava flood but sand has been ruled out. The flood after all originates from the rift, and rifts are regular features in tectonic zones both on Earth and Mars, particularly in the Tharsis region. Mangala Valles is only one of many water-created landscapes on the planet that show features mimicking those in massive floods and river morphologes right here on Earth. The “electric universe theory” as applied to crater and fault creation is complete speculation without an iota of evidence.

  2. Bob, is there any consensus on what changed Mars’ climate so drastically, that the telltale signs of water and an abundant atmosphere are all that’s left of a very different time?

    • Carol,
      Yes, a planet certainly needs an atmosphere to hold onto its water. The best current explanation was that Mars lost its magnetic field early in its history. Without a magnetosphere to protect the atmosphere, it was stripped away by the solar wind. Today only remnants of that field survive above certain regions of the planet’s surface. Since a magnetic field requires a circulating, metal-rich dynamo in a planet’s core, it would appear that the one in Mars shut off several billion years ago. Perhaps because Mars is considerably smaller than the Earth, the dynamo cooled and lost its effectiveness at maintaining a field. No one yet knows for sure.
      Venus also lacks a magnetic field, but holds onto a very thick atmosphere all the same because of its stronger gravitational pull. I also suspect that active volcanic outgassing helps to replenish its atmosphere, but that is speculation.

    • Brandon,
      There is no chance in heaven, hell or perhaps even purgatory this will happen. Its orbit is very well known. If it were to, damage would be local, not global.

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