Even if the continent wasn’t inhabited until 25,000 years ago, however, we’re still left with an immense span of time before the earliest evidence of mound-building in North America around 8,000 years ago. That’s an interval quite long enough for great innovations in human culture to have occurred, yet if they did occur, why do we find no trace of them?
We’ve already seen, and I think there’s no dispute about it, that a vast heritage of truth about Native American cultures, and what they really knew and believed, was utterly obliterated by the European conquest in the past 500 years. That’s one reason why the record is so patchy, with great chunks simply missing.
The second reason, as Tom Deméré explained (see part 2), is that archaeologists have, until recently, been unwilling to investigate older deposits because of a preexisting conviction that nothing would be found in them.
But there’s a third factor that may prove to be of far greater significance than the other two, and this has to do with the extinction-level cataclysm that the earth experienced 12,800 years ago. Although the entire globe was affected, all the evidence indicates that the epicenter was in North America. It’s giant ice cap, 2 kilometers deep and extending in that epoch as far south as Minnesota, was massively destabilized, and the destruction that followed was near total across an immense area where the archaeological record was effectively swept clean.
What happened in North America?
ELOISE
IT’S EARLY OCTOBER 2017, A roasting-hot midmorning, and we’ve just left Tucson, Arizona, for the 80-mile drive to Murray Springs, a very rich and complex Clovis site about 14 miles southwest of the town of Tombstone and 20 miles north of the Mexican border. Our route takes us via I-10 and AZ-90 through increasingly sere scrub and semidesert under a merciless sky, but when we arrive at Murray Springs itself, park, say hello to the rangers at the gate, and walk the couple of miles of the trail around the archaeological site we find ourselves in a sort of oasis with abundant mesquite growing tall enough along the edges of a sinuous arroyo—a flood channel—to offer some welcome shade. Although flash floods still rip through here from time to time it’s rumored that the present lush environment owes more to treated sewage being dumped in the area.
Santha and I are accompanied by geophysicist Allen West and his wife, Nancy. Working with Jim Kennett, an earth scientist and oceanographer at the University of California, and Richard Firestone, a nuclear analytical chemist at Lawrence Berkeley National Laboratory, West is one of the principal investigators in a loose alliance of more than sixty scientists from many different fields who have joined forces since 2007 to try to solve a profound mystery. It concerns the Younger Dryas, the interlude of cataclysmic global climate change coinciding with the Late Pleistocene Extinction Event in which thirty-five genera of North American megafauna (with each genus consisting of several species) were wiped out around 12,800 years ago. Sharing their fate were the Clovis people and their distinctive culture with its characteristic “fluted-point” weaponry.
We climb down to the floor of the arroyo, which is about 2 meters deep and 12 meters wide at this point, and begin to walk along it. After a few moments Allen stops. “It’s around here that they excavated Eloise,” he says. He’s referring to one of the mammoths ambushed and butchered at Murray Springs by the Clovis people some 12,800 years ago. He describes how Eloise’s skeleton was found intact except for the hind legs, which had been chopped off right after she was killed. One was moved up and placed alongside her head. Archaeologists found the other a few hundred meters away, close to the residue of an ancient campfire. Part of a broken Clovis point was also found by the campfire, while the rest of it was “in Eloise.”
The archaeologist who excavated the mammoth in the 1960s, and who would bring Allen West and Richard Firestone to the site many years later, was Vance Haynes, Regents Professor Emeritus at the University of Arizona and a senior member of the National Academy of Sciences. The reader will recall that his adamant defense of “Clovis First” was a significant factor in extending the life of that now thoroughly discredited theory and in inhibiting other research indicating a much earlier peopling of the Americas.
As the discoverer and principal excavator of Murray Springs, however, Haynes deserves credit for drawing attention to a very curious aspect of the site—a distinct dark layer of soil draped “like shrink-wrap,” as Allen West puts it, over the top of the Clovis remains and of the extinct megafauna—including Eloise.
Haynes has identified this “black mat” (his term) not only at Murray Springs but at dozens of other sites across North America,1 and was the first to acknowledge its clear and obvious association with the Late Pleistocene Extinction Event. He speaks of the “remarkable circumstances” surrounding the event, the abrupt die-off on a continental scale of all large mammals “immediately before deposition of the … black mat,” and the total absence thereafter of “mammoth, mastodon, horse, camel, dire wolf, American lion, tapir and other [megafauna], as well as Clovis people.”2
Haynes notes also that “The basal black mat contact marks a major climate change from the warm dry climate of the terminal Allerød to the glacially cold Younger Dryas.”3
From roughly 18,000 years ago, and for several thousand years thereafter, global temperatures had been slowly but steadily rising and the ice sheets melting. Our ancestors would have had reason to hope that earth’s long winter was at last coming to an end and that a new era of congenial climate beckoned. This process of warming became particularly pronounced after about 14,500 years ago. Then suddenly, around 12,800 years ago, the direction of climate change reversed and the world turned dramatically, instantly cold—as cold as it had been at the peak of the Ice Age many thousands of years earlier. This deep freeze—the mysterious epoch now known as the Younger Dryas—lasted for approximately 1,200 years until 11,600 years ago, at which point the climate flipped again, global temperatures shot up rapidly, the remnant ice sheets melted and collapsed into the oceans, and the world became as warm as it is today.4
In addition to Murray Springs, Vance Haynes reports finding:
At least 40 other localities in the United States with Younger Dryas age black mat deposits. … 5 This layer or mat covers the Clovis-age landscape or surface on which the last remnants of the terminal Pleistocene megafauna are recorded. Stratigraphically and chronologically the extinction appears to have been catastrophic, seemingly too sudden and extensive for either human predation or climate change to have been the primary cause. This sudden … termination … appears to have coincided with the sudden climatic switch from Allerød warming to Younger Dryas cooling. Recent evidence for extraterrestrial impact, although not yet compelling, needs further testing because a remarkable perturbation occurred … that needs to be explained.6
Haynes published these thoughts in the Proceedings of the National Academy of Sciences in May 2008. The “extraterrestrial” impact that he mentions (and finds “not yet compelling”) has nothing to do with “aliens” but refers to a serious scientific theory, the “Younger Dryas Impact Hypothesis,” that had received its first formal airing—also in PNAS—in October 2007.7 The paper was coauthored by Allen West, Richard Firestone, James Kennett, and more than twenty other scientists and presents evidence that multiple fragments of a giant comet—a swarm of fragments—struck the earth with disastrous consequences around 12,800 years ago. The effects were global but the epicenter of the cataclysm was over the North American ice cap, which the impacts destabilized, triggering the Younger Dryas deep freeze and the megafaunal extinctions.8
Haynes was right to say, in 2008, that this radical hypothesis needed further testing. It would receive it in the years ahead and become the focus of a furious debate that has divided scientists and continues to this day. On one side, many highly qualified and experienced specialists from many different fields are convinced that a comet swarm was indeed encountered around 12,800 years ago and that the result was a global catastrophe, with its most extreme effects felt in N
orth America. On the other side is a smaller but more vocal and highly influential group of skeptics who reject the theory. I reported the debate between the two factions in some detail in my book Magicians of the Gods so won’t repeat myself here. As I write these words in 2018, and despite a decade of unrelenting criticism and focused attempts at refutation, the upshot is that the Younger Dryas Impact Hypothesis [YDIH] has stood the test of time, gained increasingly wide acceptance among scientists, and remains by far the best single, coherent explanation for the cataclysmic events and extinctions—the “remarkable perturbation”—that did indeed occur around 12,800 ago.
Allen West is at the cutting edge of the research into this colossal mystery and the coauthor of more than forty scientific papers looking into it in depth.
I’m privileged to have him join me at Murray Springs.
BLACK MAT
ALLEN LEADS US OVER TO the side wall of the arroyo, explaining, as we walk, that the area would have had a very different appearance 12,800 years ago. In particular it would have been “much wetter,” with “a string of lakes” serving as watering holes for the megafauna that the Clovis hunters came here to kill. The arroyo itself is a relatively recent feature but a useful one because it slices vertically through a couple of meters of sediment laid down before and after the onset of the Younger Dryas and thus functions something like an archaeological trench, revealing the layers—and what’s in them—stacked one on top of the other.
A distinct black stratum, running horizontally like a layer in a cake, is visible on both walls of the arroyo about a meter below present ground level. It obviously lies across the whole landscape and has been exposed here by the flash floods that cut the arroyo—as though, to extend the analogy, a “slice” of the cake has been removed, allowing us a glimpse of its interior.
The stratum is about a hand’s-breadth thick.
“That’s the black mat,” Allen confirms.
It doesn’t look like a cataclysm, but appearances can be deceptive.
The first and most obvious sign of an impact by an asteroid or comet is a crater—or multiple craters in the case of a swarm. However, the earth’s surface is dynamic and craters can be obliterated by erosion or other geological processes, or covered over by later sediments or submerged by rising sea levels. In the case of impacts on the 2-kilometer-deep North American ice cap, as envisaged in the YDIH, the craters would have been excavated in ice that would have subsequently melted away, leaving little or no evidence on the ground beneath.
Scientists have therefore developed other measures, more subtle than looking for craters, to detect cosmic impacts in the geological record. Nanodiamonds, for example, are microscopic diamonds that form under rare conditions of great shock, pressure, and heat, and are recognized as being among the characteristic fingerprints—“proxies” in scientific language—of powerful impacts by comets or asteroids.9 Other proxies include meltglass (resembling trinitite), tiny carbon spherules that form when molten droplets cool rapidly in air, magnetic microspherules, charcoal, soot, platinum, carbon molecules containing the rare isotope helium-3, and magnetic grains with iridium.10
Certain of the glassy and metallic proxies require temperatures in excess of 2,200 degrees C to form and there is nothing in nature other than the heat and shock of a cosmic impact that can instantly generate such temperatures.11 Alternative explanations might be offered for some of the other proxies but when they occur together, and in abundance, a cosmic impact again fits the evidence better than anything else.12
Moreover, to this day, scientists know of only two layers of sediment “broadly distributed across several continents that exhibit coeval abundance peaks in a comprehensive assemblage of cosmic impact markers, including nanodiamonds, high-temperature quenched spherules, high-temperature melt-glass, carbon spherules, iridium and aciniform carbon.”13
These layers are found at the Cretaceous-Paleogene Boundary 65 million years ago, when it has long been agreed that a gigantic cosmic impact in the Gulf of Mexico caused the mass extinction of the dinosaurs, and at the Younger Dryas Boundary 12,800 years ago.14
I have a question for Allen. “Since the black mat was found draped directly on top of Eloise—like ‘shrink-wrap,’ you said—then presumably it must have begun to form very shortly after she was killed and butchered with most of her remains left lying on the spot?”
“What we see is that at the bottom of that black-mat layer, literally the first thing touching those bones, are spherules, iridium, platinum, and small pieces of melt-glass from the event. So it doesn’t mean the animal was alive when the event happened, but she had to have been alive very, very shortly, at most a few weeks, before it.”
I ask Allen to explain the black mat to me. “I understand that the lowest part of it is full of impact proxies laid down at the time the mat began to form but clearly they’re not the mat itself …”
“The black mat formed on top of the layer of proxies,” Allen replies. “Down here it has a lot of charcoal in it. But it also has algal remains so it’s not just fire. The Younger Dryas changed the climate and made the area much wetter. Algae began to grow along the edges of the lakes.” He puts a hand on the black stripe along the arroyo wall: “So the remains of about 1,000 years of dead algae, charcoal, and a lot of other stuff are all embedded in here, and at the bottom of it, where the impact happened, we find iridium, platinum, and a layer of melted spherules where the temperatures must have been so high that they would have melted a modern car into a pool of metal.”
“So are you saying that there was an impact right here? At Murray Springs?”
Allen replies that it’s not as simple as that. “The bigger impacts were farther north. Down here it’s more likely to have been an airburst—a fragment of the comet that literally blew up in the sky before hitting the ground …”
“And the effect of that would have been … what?”
“If you’d been standing here it would have seemed like the whole sky caught on fire with the center of it brighter than the sun. And the thing is it would have been totally silent. They would have heard nothing at first. Because the speed of sound is a lot slower than the speed of light.”
My imagination has gone into overdrive. “Could it have happened,” I ask, “while the Clovis hunters were actually butchering Eloise?”
Allen shakes his head. “We know it didn’t happen instantaneously,” he reminds me, “because they chopped her legs off and hauled one of them away and cooked it. But it could have happened later the same day and like I say it certainly happened within a couple of weeks. That’s based on modern data from elephant kills in Africa. The scavengers come in quickly and disarticulate the skeleton, and that didn’t happen with Eloise.”
This kill site sounds like unfinished business to me.
“That other haunch left up by Eloise’s head,” I reflect, “and the rest of her intact. Doesn’t that suggest that the hunters were still in the vicinity and meant to come back to finish butchering her, but for some reason never did?”
Allen joins in with the spirit of the thought. “Okay,” he says. “It’s pure speculation, obviously, because we’ll never know for sure the exact sequence of events here 12,800 years ago, but based on the evidence it’s not unreasonable to envisage the hunters sitting around, cooking mammoth haunch over their campfire when all of a sudden the sky explodes …”
“And that’s why they never go back for the rest of Eloise? Because they’re all dead?”
“Could be,” Alan agrees. He jabs a finger into the base of the black mat and continues.
“But what we can be certain of was that this moment marked the end of their story, and the end of an epoch, really. There’s not a single Clovis point found anywhere in North America that’s above that black mat. They’re all in it or below it. And there’s not a single mammoth skeleton anywhere in North America that’s above it. A huge part of the die-off could have been as a direct result of the impacts themselves, but impacts and airbur
sts south of the ice cap, particularly as far south as New Mexico, would also have set off wildfires. There’s overwhelming evidence that gigantic wildfires raged at the onset of the Younger Dryas—in fact, more soot has been found at the Younger Dryas Boundary than at the Cretaceous-Paleogene Boundary. We did the calculations and it looks like as much as 25 percent of the edible biomass and around 9 percent of the total biomass of the planet was on fire and destroyed within days or weeks of the YDB. So in many areas if the animals weren’t killed outright they wouldn’t have been able to forage enough food afterwards to survive. The grass would have burned up, leaves on trees were gone. … And you know, the other thing is that when comet fragments come in they’re traveling incredibly fast and they literally punch a hole in the atmosphere. They actually push the air aside and they bring in that super cold from space, and when they explode in the air that cold plume continues to the ground and you literally have things frozen in place if they were close enough to where the plume came down. It’s possible they were fried and then frozen all within a matter of seconds.”
MULTIPLE INJECTIONS OF PLATINUM
I ASK ALLEN HOW LONG, in his opinion, the multiple impacts that kicked off the Younger Dryas were sustained for. Was it an overnight affair? Was it a matter of days? Was it weeks?
He replies that there are levels of uncertainty, variables that will probably never be properly resolved, but that within those limits what the evidence points to is not days or weeks but a 21-year period of utter devastation, horror, and cataclysm unfolding between 12,836 years ago and 12,815 years ago, with a peak around 12,822 years ago.
This ability to zoom in at very high resolution on a time window just 21 years wide and almost 13,000 years in the past comes to us courtesy of an amazing scientific resource consisting of ice cores from Greenland. Extracted with tubular drills that can reach depths of more than 3 kilometers, these cores preserve an unbroken 100,000-year record of any environmental and climatic events anywhere around the globe that affected the Greenland ice cap. What they show, and what Allen is referring to, is a mysterious spike in the metallic element platinum—“a 21-year interval with elevated platinum,” as he puts it now—“so we know that was the length of the impact event because there’s very little way, once platinum falls on the ice sheet, that it can move around. It’s pretty well locked in place.”
America Before Page 37
