*     *     *

The large mammals of the Pleistocene had just made it through about 100,000 years of ice-age cold and they had survived previous glacial/warming transitions before. This time was different, and most of those animals suddenly went extinct. Human populations across the continent all but disappeared as well, at a time that should have been ideal for continued growth and expansion. The warming trend came to an abrupt end over a very few years as the climate chilled rapidly. A mysterious black “mat” formed at the same time. No Clovis artifacts or skeletal remains of the large mammals have ever been found within that black-mat layer or above it. None of the more recent Paleoindian artifacts have ever been found below. What remains of that time-of-change today is a challenging mystery.

The more we learn of this period, the less we actually know for certain. Of course, the same can often be said about other times including the present. Perhaps we can draw parallels between the explosive climate and environmental changes so long ago and the changes we face today: challenges we now interpret with a mixture of science, supposition, belief, hope, fear, denial and always through the personal filters of our own biases. We humans, along with all of our living neighbors, exist in a fragile, ever changing environment that is occasionally buffeted by sudden, catastrophic shifts followed by yet another new equilibrium.

When first excavated in 1932, the exquisitely crafted, bi-facially fluted hunting implements of the Clovis people were thought to have been made by the first humans to populate North America. These ancient people were believed to have crossed the Bering Land Bridge fr
om Asia about 13,500 years ago. Their unique hunting points have since been found at over 50 sites across all of North America.

    It turns out the Clovis were not the first to arrive. Older, pre-Clovis human sites have since been found across the continent dating back nearly 50,000 years. Among the Clovis sites, some of those in what is now the southeast United States are older than those in the west, and the very oldest of the distinctive artifacts come from a site in southern Chile, throwing into question an orderly migration from Asia to Alaska and then across America. Another curiosity is that identical flaking and grinding techniques were used thousands of years earlier in southern France, Spain and Portugal, but not in Asia. Could the Clovis people have somehow migrated across the Atlantic from what is now Europe, perhaps along a northern route following the edge of the much denser ice packs of the time? Or, might they have come up from Australia traveling northward through South America? Another possibility is that the unique tools may represent a technology that was widely traded among Paleolithic cultures, or that individuals independently discovered the same special techniques in isolated locations over the span of many thousands of years.



CLOVIS TOOLS. Archaeologist Douglas Bamforth holds one of the Clovis tools

uncovered in 2008 when a fountain was being installed in a Boulder, Colorado yard.

(Photo by Glenn J. Asadawa, University of Colorado.)


Each discovery brings more mystery. By whatever means the special tools came to be in North America, they served those we now call the Clovis well for over 350 years near the end of the ice age, which was at least the fifth in repeating cycles of warming and cooling of the Earth. The climate prior to the extinctions seems to have been cooler and wetter than today — but with at least two periods of extended drought. As the glaciers retreated, sea levels rose and the “land bridge” between Asia and North America disappeared under water.

But, there was still much ice covering most of present-day Canada and dipping into the northern U.S. At the height of the ice age, Chicago’s skyscrapers (had they existed) would have been buried under at least a mile of ice.

Then it happened.

 

ARTICLE LINKS
Click on Titles to Explore . . .

Where Do We Go From Here?
Most of us will do anything we can to avoid the loss of stability — indeed, the pain — of crisis. Yet, it is within this this time of disruption that a new beginning can be found.

Flowing With The Four Winds
Show Up
Be Receptive
Speak Your Own Truth
Don’t Be Attached to the Outcome

Driving Into a Prehistoric Dawn
This article is the start of a series
that takes a long view of our place
in history triggered by a personal experience of touching the distant past.

Something Strange Happened
Scientists debate the possible causes and meanings of a major crisis that occurred about 13,000 years ago. This second article in the series explores what is known of the rapid changes of that time, and explores possible causes.

What Might They (Someday) Think of Us?
After looking back to prehistoric events, consider now how our present time may be viewed from the far distant future.

Somewhere
The series concludes by checking in on some special artifacts of our own time awaiting discovery by those 13,000 years in the future.

Eating Away at Plastic Pollution
A Canadian teen gets tired of plastic bag clutter and finds a way to help nature 

Friendly Skies of Rufus 
Customer satisfaction may be at an all time low, but sometimes one person really can make a difference.

Future Articles . . .
The Hero’s Journey
Do we answer the Call of the Hero’s Journey or slip back into a continuing complacency?  The choice is ours as a society, and especially as individuals in choosing who we are and who we shall become.

Unintended Consequences
Galileo cautioned that protective efforts may lead to even greater damage. 

Moderation 
Today’s solution may become tomorrow’s problem.

New Neural Networks

Bottom/Up Planning

The Problem with Panic
The responses that cause panic attacks today helped our ancestors survive and get us this far, but times have changed

Copyright 2011 by Gil Campbell. The contents of the joyofcrisis.com website are copyrighted with all rights reserved. However, we have a very liberal policy of sharing information and allowing duplication.
We ask that attribution be provided whenever possible, and we appreciate your contacting us for any and all reasons at editor@joyofcrisis.comWhere_Do_We_Go.htmlWhere_Do_We_Go.htmlFour_Winds.htmlFour_Winds.htmlPrehistoric_Dawn.htmlPrehistoric_Dawn.htmlWhat_Might_They.htmlWhat_Might_They.htmlWhat_Might_They.htmlSomewhere.htmlPlastic_Pollution.htmlPlastic_Pollution.htmlRufus_Factor.htmlRufus_Factor.htmlmailto:editor@joyofcrisis.comshapeimage_4_link_0shapeimage_4_link_1shapeimage_4_link_2shapeimage_4_link_3shapeimage_4_link_4shapeimage_4_link_5shapeimage_4_link_6shapeimage_4_link_7shapeimage_4_link_8shapeimage_4_link_9shapeimage_4_link_10shapeimage_4_link_11shapeimage_4_link_12shapeimage_4_link_13shapeimage_4_link_14shapeimage_4_link_15shapeimage_4_link_16

LONE SURVIOR. Only the Bison remains of all the large Pleistocene mammals of North America.

THE BLACK MAT OF MURRAY SPRINGS, AZ. The very dark layer is the precise dividing boundary between the Pleistocene and Holocene Epochs. Clovis tools and the bones of mammoths are found in the lower sediments but not within the black boundary or above.

(Photo by Douglas Kennett)

GLASS-LIKE CARBON. The glassy, top surface of this specimen, found in one of the Carolina Bays, is thought to have formed when cellulose was heated at 3200º C. The bottom portion has been identified as unburned Yellow Pine wood. The sample is consistent with material that would be left if a tree were impacted by a fast-moving, high-temperature shockwave. Such an intense blast would be immediately followed by a temporary vacuum. Further burning was prevented because of the lack of oxygen. (Firestone, 2009)

METEOR CRATER. This Arizona landmark was formed when a school-bus sized iron meteorite crashed into the Earth. (Photo: U.S. Geological Survey)

TUNGUSKA EVENT. Trees were scorched and flattened in a “butterfly pattern” by the shockwave caused as an extraterrestrial object exploded high in the atmosphere above a remote area in Siberia. Had the object arrived just five hours later, the city of St. Petersburg, Russia, would have been destroyed.

COMET FRAGMENTS. Above, Shoemaker-Levy breaking apart as it approaches Jupiter. (Composite Hubble photograph). Right, fragments of the comet enter the upper atmosphere of Jupiter. (Hubble photograph, NASA)

DIRECTIONS TO US. The cover of Voyager spacecraft compartment containing recorded sounds, pictures and greetings from the people of Earth. The starburst pattern at the lower left shows relative distances from our sun to easily identifiable quasars.

Voyager I, launched in 1977, is now the furthest man-made object from Earth, currently about 10 billion miles away in the far reaches of the outer solar system beyond Pluto.

(NASA photo)

To Learn More . . .

www.pbs.org/wgbh/nova/clovis Online viewing of “Last Extinction” program, links to debate of various theories, and a computer animation of the effects of an airburst.


www.perigeezero.org A presentation of a “Unified theory of cultural heritage and geological history,” including evaluation of Carolina Bays evidence and a Google map linking bay orientation to a possible Great Lakes impact site.

We have no eyewitness accounts of what happened to the Clovis. Even with new discoveries and exploratory techniques — such as tracing the spread of ancestral RNA — the human journey through antiquity will always include both science and mythology. Indeed, the controversial Firestone and West also speculate that the collective memory of such momentous events as atmospheric explosions may survive in human mythology, perhaps as the Thunderbird of Native American culture.

This time of climate change and extinction is now known as the boundary between the 2.6 million years of the Pleistocene and the current, interglacial Holocene epochs. Within about 100 years of the event, human populations rebounded and were developing anew. The Clovis culture was gone but was then replaced by the Folsom culture, people who hunted bison instead of mammoths and left behind their own distinctive artifacts. The remaining ice sheets retreated as the Earth continued to warm, a trend which has extended to the present with only minor fluctuations.

After a few thousand years, agriculture and animal domestication slowly replaced the hunter-gatherer lifestyle for much of humanity. Stone tools gave way to metal — initially copper and iron — and then bronze, the first of many more man-made materials to come. Over time, roving clans settled into villages. Later consolidation and population growth led to towns, cities and now the suburbs. Pyramids were built and then skyscrapers. Human curiosity has continued to drive people to explore. Others again came to the “New World,” perhaps first in Viking longboats, then with Columbus, followed by Pizarro and Cortez seeking their mythological streets of gold. As so often happens, the newcomers killed and mated with the original inhabitants, overpowering the existing cultures through military strength and foreign beliefs. The transformation was not just one way, however, as even the conquerors were  changed into something new.

Barely a moment later, mankind discovered the awesome power of the atom, Neil Armstrong stepped onto the surface of the moon, Carl Sagan launched humanity’s greetings toward the stars, and our challenges became ever more complex.


Gil Campbell

Diamonds are formed when carbon is subjected to intense heat and pressure, usually over very long periods of time. However, nanodiamonds have a different molecular structure (hexagonal) and are formed quickly under extreme conditions such as that caused by an extraterrestrial collision with the Earth or the atmosphere. Nanodiamonds are typically found inside meteorites and at impact craters, but have not been associated with volcanic eruptions.

There is nothing unusual about space objects colliding with the Earth. Indeed, over 80 tons of extra-terrestrial materials fall on our planet every day, primarily as fine dust. After years of controversy, science has now pretty conclusively established that dinosaurs and about half of all animal species of the time were destroyed 65 million years ago by the impact of an asteroid that was over seven miles in diameter leaving a crater 120 miles wide and 1.5-mile-deep in the Yucatan Peninsula of Mexico. Earlier extinctions have also been linked to possible collisions, and there is believed to have been an atmospheric explosion of a comet over Asia 750,000 years ago. (To view a computer simulation of that event, go to the NOVA link at the end of this article.) In more recent times, the dramatic Meteor Crater in Arizona was formed when a 60,000-ton iron meteorite crashed into the Earth between 20,000 and 50,000 years ago. Very recently, on June 30, 1908, a presumed comet or low-density asteroid exploded over the remote region of Tunguska in Siberia leveling tens of thousands of trees, scorching the land, sending out a shockwave that circled the Earth twice, and putting so much dust into the atmosphere that people 6,000 miles away in London could read newspapers at night from the diffused light.

Critics of the Clovis-impact hypothesis cite a shortage of independently replicated and verified results, the lack of a definitive impact crater matching such a huge event, insufficient charcoal in lake sediments, and the possibility that evidence might have been overly concentrated by water seepage. Some also question Firestone and West for previously speculating about solar flares, galactic waves and algal nerve toxins as extinction causes.

The Clovis debate will continue for years. The lack of a “smoking gun” crater argues against a large, solid asteroid, but not necessarily against a comet — which is composed of ice and frozen gases as well as rocks — or even a loosely formed asteroid which would also break up high above the surface. No definitive crater has been found related to the Tunguska event either. Perhaps even more telling: the much larger Shoemaker-Levi comet impacting Jupiter in 1994 broke into over 20 pieces as it approached that planet. Had the collision been with Earth, it is possible that none of those fragments would have actually produced a crater, although the atmospheric explosions would have spread fiery destruction over vast areas, just as the proponents of the Clovis-impact hypothesis assert.

One particularly interesting Clovis site is Murray Springs in the southern Arizona town of Sierra Vista. It was here that Clovis artifacts, mammoth tracks and fossilized remains of large mammals were discovered in direct contact with the black mat. The upper surface of a mammoth fossil in that excavation was found to be highly magnetic and radioactive but the lower surfaces of the same fossil were not, leading to speculation that the mammoth was suddenly buried while actually in the process of being butchered.

Other possibly supporting evidence includes strange geologic structures called Carolina Bays that are found along the eastern U.S. seaboard from New England to Florida.


CAROLINA BAYS. Not easily identified until the advent of aerial photography,

these tear-drop shaped depressions may have resulted as a splatter pattern from debris

ejected when an object collided with the Laurentide ice sheet. Most of the 500,000

Carolina Bays are aligned toward the Great Lakes, while others point toward Hudson Bay.


While a high altitude airburst of a comet would have thrown extra-terrestrial material across the continent, these structures may represent a splatter pattern of material ejected from an actual collision. The alignment of the Bays points toward the Great Lakes and Hudson Bay indicating a possible collision with the Laurentide ice-sheet. Fifteen of these structures were investigated by Richard Firestone and found to contain markers similar to Clovis sites, including nanodiamonds.

 

Perhaps there was a different reason for those extinctions. Greenland ice core evidence shows that the 3000-year warming trend at the close of the ice age came to an abrupt end with average temperatures suddenly dropping 10º to 20º F. over just a few decades and possibly in only a few years. This extreme cooling ushered in a 1,400-year return to near ice age temperatures known as the Younger Dryas period. The new cold may have been too much for the already stressed animals and humans. This climate change affected most of the planet including Europe and Asia, with evidence of the shift found as far away as New Zealand. Some researchers even estimate that this climate disruption may have delayed human development by well over a millennium.

What caused the sudden reversal from 3,000 years of fairly steady warming to a return of ice age temperatures? Even if humans had managed to hunt all of the large mammals to extinction — all at once across the entire continent — they could not possibly have caused the new deep freeze. The Earth has experienced ice ages since long before the dinosaurs with five warming/cooling seesaws in just the past half million years. The sudden flip into the Younger Dryas cooling, however, was unique. Research by Wallace S. Broecker, an earth scientist at Columbia University, supports a now widely accepted theory: rapid climate change was caused by the disruption of the Great Atlantic Thermohaline Conveyor. This is the ocean current that cycles warm gulf-stream water from the tropics up to the northern latitudes. Such a disruption could have occurred had there been a sudden, large influx of fresh water into the Atlantic.

The source of that surge? The steady melting of ice sheets had formed a giant lake — Lake Agassiz — that was some 700 miles wide. Broecker proposes that geologic structures holding that water may have broken loose sending a huge pulse of fresh water through what is now the St. Lawrence Valley and into the Atlantic. The less dense fresh water then disrupted deep-water circulation and cut off the northward flow of warm salt water.

LAKE AGASSIZ. This illustration shows the full extent of the fluctuating meltwater body that

overflowedseveral times over a period of 5,000 years as the Laurentide ice sheet retreated.

Arrows indicate various flood routes. (Illustration from Levington and Teller, 2003

The sudden cooling would then have reinforced itself by causing more sea ice to form, further blocking the flow of warm water to the north. Although the disruption of the Atlantic Conveyor is now widely accepted as the cause of the Younger Dryas cooling, questions remain about the exact source of the fresh water. Also, evidence of a sufficient flood channel has not been identified, although more recent channels are clearly visible across eastern Canada. According to Broecker, the newer channels may have obliterated earlier evidence, or the “big flush” might have flowed under the remaining ice sheets. Very recently, Mark Bateman of the University of Sheffield, UK, identified the Mackenzie River as the likely path flood waters followed into the Arctic Ocean.

Another recent hypothesis may actually tie together the extinctions, loss of human populations, and the sudden climate change all in one concise, but controversial package. In May, 2007, Arizona geophysicist Allen West, James Kennett of the University of California, Santa Barbara, and Richard Firestone of Lawrence Berkeley National Laboratory, presented evidence to the American Geophysical Union that a comet had broken up in the atmosphere with the force of multiple nuclear detonations, instantly igniting anything that could burn as a superheated shockwave rushed across North America. Their evidence is found within the very base of that mysterious black mat that is often just above Clovis artifacts. They initially investigated sediments at Clovis and other sites across North America and in Europe, and have since analyzed more.

The black mat itself is a thin, carbon-rich layer composed of organic matter, especially dried algae strands, essentially pond scum that was left by stagnant water. At the very base of this layer is a narrow band coinciding with the beginning of the Younger Dryas. That band contains charcoal, soot, carbon spherules, and glass-like carbon, all materials associated with intense wild fires. The same layer also contains nanodiamonds, magnetic grains, and higher-than-normal levels of iridium, uranium, and thorium as well as a unique isotope of extra-terrestrial helium that is trapped within carbon fullerenes. The highest concentrations of these materials are found at the northern sites, and the same band has been identified in Greenland ice.

 

In a geologic flash — and perhaps literally in a flash — some 35 species of large mammals, including American camels and horses, mastodons, woolly mammoths, rhinos, giant ground sloths, tapirs, dire wolves, short-faced bears and saber-toothed cats all went extinct across North America.The only large survivor was the bison. In 1967, Archeologist Paul Martin proposed his “overkill” hypothesis that the Clovis hunters were responsible for the extinctions through their hunting. Another researcher, Ross MacPhee, countered that the extinctions could have been caused by a new “hyper-disease” spread through contact with colonizing humans. Both theories point toward the Clovis hunters as being responsible for the extinctions and the destruction of their own environment. Surviving humans reverted to the earlier, more sustainable hunter-gatherer lifestyles until agriculture finally came along at least a thousand years later.

Something

Strange Happened

12,900 Years Ago

What is now known as The Last Great Ice Age was drawing to a close. Mammoths, mastodons and other large mammals roamed the continent we have since named North America. The climate had been warming for about 3,000 years and an advanced prehistoric human culture — the Clovis — had been thriving for 350 to 500 of those years.

Then, in just a geologic heartbeat everything changed.

NEXT:  What Might They (Someday) Think of Us?

There are some special artifacts of today waiting

to be found in the far distant future.


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Another time of change completely beyond the

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