I have previously discussed the evidence that at the end of the Pleistocene some
catastrophic force caused the death and destruction across South America.
Throughout the Atacama desert, people have found small shards of glass strewn
across miles of desert and it appears like the formation of these might also
be linked to the destruction caused during the Pleistocene. Let's dive in and find out more...
The Atacama Desert is a desert plateau in South America covering 1600km on the Pacific coast,
west of the Andes Mountains. It sits at an altitude of 2500 meters or 8000 feet and is one of
the driest places on earth. But it was not always like this in the not too recent, geologically
speaking, time the land was much lower and probably harboured a more favourable climate.
I have previously looked at the extensive evidence that lake Titicaca now the highest lake in the
world, once sat at sea level. The evidence of ancient agricultural terraces above the snow line
which once used to be much lower. We also saw that a vast number of large mammal remains
exist in South America, dated to the end of the Pleistocene, which show an extraordinary
level of preservation. The cause of death likely due some catastrophe that links other similar
finds in other parts of the world also dating to similar timeframes. Could these glass fragments
in any way be linked to the events of the uplifting of the plateau and the mass extinctions?
It is believed that the landscape of the Atacama desert changed about 10 to 15 million years ago
during the uplifting of the Andes. Prior to this, they know that rainfall was much higher
but then dramatically changed as the Andes rose up cutting off the moist air halting rainfall,
and preserving the soil virtually undisturbed for millions of years. A new piece of work
examines the glassy ejecta that are thought to be associated with impact craters.
The paper examines the discovery of a 650km^2 area that contained glass strewn-field
in the central depression of the Atacama desert. These are cm-sized splash form objects
that are thought to form through the high temperature melting of local magmatic
rocks with what they identify as variable iron meteorite contamination. Their analysis showed
that the likely formation age of these was about 8 million years ago. When they tried to identify
a potential impact crater non could be found. They collected over 23,000 samples across an
area of roughly 650 square kilometers. Samples were encountered lying on the desert surface,
and more abundant, up to several tens per meter squared, in gravel concentrations.
Some samples have textures suggesting formation by accretion of molten beads of
a few hundreds of micrometers in size. Some have a whirling texture indicating strong deformation
in a liquid state. In most magnetic samples, about 10% of all of them, iron oxides can be observed
as dendritic assemblages of micrometer-sized crystallites forming threads or globules.
Their analysis showed that the samples must have been exposed to temperatures in excess of 1700C
and the low water content excludes a volcanic origin.
The most likely cause in their mind was therefore a hyper velocity impact.
They acknowledge that these temperatures could be reached with lightning
however but point out that the texture and shape would rule this out as a possibility.
Composition in major and trace elements suggests a relatively homogenous lithology for the target
rocks, superimposed with Fe, Ni, and Co extraterrestrial contamination. When they
analysed the composition of the target rock that might have created the glass they were not able
match the composition to any known specimens in their existing database. When they then examined
the likely candidate for the impactor they could only conclude that it was likely an iron impactor
and they estimate that the composition of the impactor was 94% Iron, 5.4% Nickel
and 0.45% Cobalt. This allowed them to narrow down the group of meteorites to the IIAB iron group.
This is not the only evidence of glass found on the Atacama desert. Another set were discovered
about ten years ago and seemed to be located in a vast corridor stretching 75 km in length.
The shards of glass are very different to the previous example. They are up to 50cm across
and come in many different twisted shapes. Their features are both rough and smooth and
look as if they have been folded and twisted into shape. Some of these showed that the surface had
been sheared, twisted, rolled, and folded many times before finally being quenched.
Analysis of the samples indicated that they formed roughly 12,000 years ago.
Early hypotheses suggested that they might have formed as the result of a large meteor
exploding in the atmosphere. This would have thrown fragments of hot, fiery rock
on the desert surface, with the extra-terrestrial shrapnel melting the sand and soil on the spot.
An alternative idea suggested that they could have formed through heat from natural surface fires,
in a different age and climate when the desert was covered in more abundant vegetation.
Further analysis of the glass showed that it contained elements that are not normally found
on Earth. Minerals in the glass called zircons had decomposed to form a different mineral, this would
have required extremely hot temperatures of over 1600C. This is far hotter than wildfires can get.
Further investigation of the minerals in the glass showed that they were some exotic ones that only
tend to occur in meteorites. One of the minerals they identified was cubanite which had previously
been identified by NASA's Stardust mission, which collected samples from the comet Wild 2 in 2004.
Whatever caused the event the timing seems to coincide
with the mass disappearance of the megafauna in South America,
the supposed arrival of ancient hunter-gatherers in the area, and changes in climate as well.
So what can we make of these seemingly unrelated events? The timing of the first events
comes after they believe the Andes were uplifted, raising the Cordillera
and causing the inter Andean sea to vanish. This caused massive changes to the climate as
the warm moist air was blocked by the high Andes. Turning the Atacama into a desert.
The second event comes much later but seems to coincide with mass extinction in South America.
In both cases, the glass seems to exhibit strange swirling and folding patterns
and indicated that considerable deformation took place while the glass was in a molten state.
Their analysis of the target rock in the first case was not able to find a match
which is rather odd as you would expect it to match the material on the ground? In both cases,
they find the presence of exotic materials in the glass and speculate that their origin has
to be extraterrestrial. A meteor exploding above the surface would throw hot pieces of exotic rock
onto the surface of the desert across a wide area and cause the sand to melt forming the glass.
This would also neatly explain why no crater was ever found.
But does it explain the contorted and twisted shape of the glass fragments?
Could a series of electrical discharges explain this? Lightning does strike sand and
creates fulgurites. These have a very different appearance to these glass shards and fragments.
What if the discharge was much bigger than simple lightning? We know from electrical discharge
experiments that large discharges can create shapes that match what we call meteor craters.
These discharges are so violent that they in part melt the surface but also cause an explosive event
ejecting this molten material outwards. The molten partially ionised rock and sand would then twist
and follow the strong electric and magnetic fields that are created causing them to twist and fold as
they were ejected outwards and started cooling. The idea that one of the minerals found in the
glass is also seen in a comet may be yet more proof of this idea. If comets are electrical
bodies where arc discharges occur as they move closer to the Sun, these exotic elements may
well be created in the discharge through the transmutation of the elements present on the
surface. Could a similar process be occurring in the formation of the glass in the Atacama desert?
The problem is that this would require a crater which is not obvious in either case.
In the latter case, the scientist consider the event to be caused by what they call an
airburst meteor. This happens when the meteor suddenly explodes close to the surface.
An alternative way of considering these events is that the reason the meteor suddenly explodes
is because of a massive discharge from the Earth to the foreign object. The would happen because
the object was not at the same potential as the Earth. This could explain why no crater can be
found and the distorted shapes of the glass shards and may also explain why it was not
possible to find a match for the rock type in the first example as transmutation may have occurred.
The size of the fragments in both cases were very different which does tend to indicate a different
process for each. I'm also intrigued by the timing of both of these events. One coming just
after the uplifting of the Andes and the sudden changes to that area and one coming around the
time of mass extinctions in South America. If we examine the evidence of the old agricultural beds
which appear to have been uplifted to above perpetual snow level this once more raises
the question of whether these events occurred much more recently than 10-15 million years ago
or whether civilisation is much older than we recognise. Andy Hall's work might hold some
clues to understanding what might have gone one. Dr. Mark Boslough has simulated the effect of an
air-burst meteor and found that its solid matter atomises to form a bight ball of plasma
which essentially blow torches the earth. When the shock-wave rebounds violently upwards,
rising winds shear a column of updraft opposite the downward blast. Dr. Boslough
theorises that this supersonic updraft, vacuums molten ejecta into the strike zone,
leaving characteristic air-burst marks - a linear hill with a sharply peaked ridge and distinctive
triangular buttresses on the flanks, surrounded by an outwardly blasted zone of molten ejecta.
Scanning the landscape of the Atacama we find some examples of these features
across part of the Atacama. Although near the site
where they collected the shards no obvious signs of this can be found
In the later event, a single meteor explosion close to the surface over a small constrained area
cannot be responsible for the mass destruction we see around the same time all across the planet. So
was this just a rogue meteor? Or was it part of a much larger field of meteors? If the latter is the
case we would expect to see many more craters than we do. If they were all airburst then we would
expect to find glass shards almost everywhere. One of the reasons we find them in the Atacama
may be simply that this desert has remained almost untouched for thousands of years, with
no rainfall and no life to disturb the shards. Maybe they do exist elsewhere but have since been
disturbed and moved through the normal erosion and deposition process that take place on earth.
Of course the assumption is that these were created by a single airburst meteor.
Andy Hall's work may indicate that these smaller patches of triangular formations
which occur at different angles may be related not through many different meteors but instead
through the idea of surface conductive fault currents. Through some geomagnetic event,
Earth's normal current discharges through the atmosphere which normally we see in the form of
thunderstorms, earthquakes, and volcanoes, overloads, and essentially short-circuits.
Sheets of lightning and plasma bolides, arcing through surface conductive paths above the ground,
left these blisters. It would not follow a straight path. Magnetic fields around the plasma
current induce rotation along the horizontal axis modifying the speed of the winds. It blows the
ejecta blanket asymmetrically, and it may carve a valley longitudinally down the center of the hill.
These magnetic fields may well have twisted and distorted
the smaller fragments which later cooled as the distorted glass shards we find on the Atacama?
The other open question is if the older event is in any way related to the uplifting of the
whole area? What mechanisms are there to account for such a change of elevation.
If the area was uplifted due to a movement of the crust, like in Hapgood's model, or even if it is
uplifted through the action of the plates does this have an effect of the net charge on the
surface and the telluric currents that would flow. If you remember back to the Electronic Tectonics
where I covered Charles Chandler's concept you will realise that an uplifting like this
has to cause massive changes to the charge flowing
to or from the surface. What effect would this have? There are many pieces to this puzzle.