October 4, 2014 | David F. Coppedge

Canyons on Earth, Mars Reinterpreted as Flood-Caused

Catastrophic floods formed canyons long thought to have been formed by slow, gradual processes.

On Earth

The Atacama Desert is one of the driest places on Earth today, but it was the scene of catastrophic floods in the past.  A new paper in Icarus (the leading solar system journal) takes a look at amphitheater-headed canyons in the Chilean desert.  Previously, they were explained by sapping, the failure of cliffs due to springs.  Finding a flood model more appropriate, the geologists extend their finding to the planet Mars:

Understanding planetary landforms, including the theater-headed valleys (box canyons) of Mars, usually depends on interpreting geological processes from remote-sensing data without ground-based corroboration. Here we investigate the origin and development of two Mars-analog theater-headed valleys in the hyperarid Atacama Desert of northern Chile. Previous workers attributed these valleys to groundwater sapping based on remote imaging, topography, and publications on the local geology. We evaluate groundwater sapping and alternative hypotheses using field observations of characteristic features, strength measurements of strata exposed in headscarps, and estimates of ephemeral flood discharges within the valleys… Flood discharge estimates of cubic meters to tens of cubic meters per second, derived using the Manning equation, are consistent with the size of transported clasts and show that the ephemeral streams are geomorphically effective, even in the modern hyperarid climate. We interpret that headscarp retreat in the Quebrada de Quisma is due to ephemeral flood erosion of weak Miocene epiclastic strata beneath a strong welded tuff, with erosion of the tuff facilitated by vertical jointing.

On Mars

A separate paper in Icarus re-evaluated “some of the largest channels in the Solar System” that have been the subject of intense interest since the 1970s.  Some of the narrow canyons in the southern circum-Chryse area have landforms in the 10-meter to 100-meter (football field size) range.  Previous studies proposed catastrophic floods, lava flows, debris flows and even glaciers.  Dates assumed for the canyons were in the 3-billion-year range.  The new study not only weighs in favor of catastrophic floods, but re-dates them far more recent:

These terrains include landforms consistent in shape, dimension and overall assemblage to those produced by catastrophic floods, and at one location, to glacial morphologies. Impact crater statistics for four of these surfaces, located within upstream, midstream and downstream outflow channel surfaces, yield an age estimate of ∼600 myr. This suggests that the southern circum-Chryse outflow channels were locally resurfaced by some of the most recent catastrophic floods on the planet, and that these floods coexisted within regional glacier environments as recently as during the Middle Amazonian.

We’ve noted in previous entries that crater-count dating is notoriously unreliable (3/02/14, 5/22/12, 4/03/11, etc.).  Still, this re-evaluation forces geologists to consider a date that is one fifth of the previously assumed date.  For more on floods as a cause of canyons, see 5/03/1412/19/13 and 5/23/08.

Dating a Martian (Surface)

Sun: There are other indications Mars cannot be even as old as 600 million years.  For one, Mars is subjected to coronal mass ejections without the protection of a global magnetic field.  PhysOrg discussed how the sun could have eroded the Martian atmosphere over hundreds of millions of years — far less than the billions assumed — yet a thicker atmosphere is necessary to account for surface water capable of causing the catastrophic flooding that the scientists proposed for the canyons at Chryse.  A video animation in the article shows a hypothetical watery Martian landscape drying out into the windy desert we see today, as its atmosphere depletes under a merciless sun.

Wind: Another article on PhysOrg discusses the sandblasting effect of constant wind.  “Winds on Mars can be strong and can reach hurricane speed (more than 120 kilometres per hour or 75 miles per hour),” said Francois Ayoub of Caltech.  He added that at the study site (a 15-square mile area at Nil Patera, observed for one Martian year), such winds were a daily occurrence.  “High winds are a near-daily force on the surface of Mars, carving out a landscape of shifting dunes and posing a challenge to exploration,” the article begins.  This was a surprise:

But data about the strength, frequency and origin of winds has been sketchy, and many specialists had expected that gusts strong enough to move sand would be rare on a planet with such a thin atmosphere.

“We observed that martian sand dunes are currently migrating and that their migration speed varies with the season, which is at odds with the common view of a static martian landscape and very rare sand-moving winds,” study co-author Francois Ayoub of the California Institute of Technology’s planetary sciences division told AFP.

The study shows that even in today’s thin Martian atmosphere (about 1% the density of Earth’s), the winds are strong enough to form and move the large sand dunes seen at many locations on Mars.  Wouldn’t billions of years of wind have eroded every landform, including the canyons and volcanoes, into small particles, long before now?  In 2/03/11, we quoted a leading Mars geologist wondering about this: “There’s a good question why Mars isn’t a billiard-ball planet covered by a kilometer of dust,” Phil Christensen said.  To keep Mars old, he proposed an ad hoc speculation that dust formation only occurs in cycles 2% of the time.

These questions never seem to faze the astrobiologists.  NASA’s Astrobiology Magazine tried recently to revive interest in possible indications of life in Martian meteorites, just like one dubbed ALH 84001 did when featured at a famous 1996 press conference that gave birth to the new “science” of astrobiology — still looking for pertinent subject matter to scientifically study.

Who is surprised?  It’s always the secular geologists and planetary scientists.  Why are they surprised?  Because they are moyboys, wedded to belief in millions and billions of years.  Do you see any actual, empirical, observation, scientific facts in these stories that would lead one to believe in such unfathomably long periods of time?  No?  Do you, instead, see more evidence for quick-acting processes over short periods of time?  Yes?  As you read this, are you sitting within the atmosphere of a beautifully-designed planet filled with life?  Does it look anything like Mars or Venus?  Why do you think that is?  Do you feel that science should follow the evidence where it leads?



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