Kerr Watch

Elapsed time since Richard Kerr failed to inform his Science readers of the confirmation of nanodiamonds at the YDB: 6 years, 2 months, and 1 day

NatGeo actually calls Wally Broecker to discuss evidence for cosmic impact at Younger Dryas start

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NatGeo 2007

NatGeo 2008

NatGeo 2013

Did a Comet Really Kill the Mammoths 12,900 Years Ago?

Did the planetary upheaval 12,900 years ago come from the heavens—or Earth?

Robert Kunzig

National Geographic
Published September 10, 2013

Why did mammoths, mastodons, and other mega-beasts vanish from North America?

Was it because:

1) humans killed them;

2) they couldn’t hack the climate after the Ice Age ended; or

3) an exploding comet ignited continent-wide wildfires, sent hundred-mile-an-hour winds and tornadoes howling across the land, and shattered the North American ice sheet, while also maybe gouging out the Great Lakes?

Let’s talk about option number three.

The idea that a comet struck Earth 12,900 years ago, at the beginning of a strange interlude of climate cooling called the Younger Dryas was first proposed in 2007. In the bitter scientific debate that has flared sporadically ever since, the latest evidence includes:

Tiny, glassy “spherules” of rock found in a Pennsylvania flowerbed by a woman who had seen a NOVA program about the comet hypothesis. In a paper that got wide coverage last week, Dartmouth researchers argue that those spherules were hurled to Pennsylvania by an impact in Quebec 12,900 years ago.

Traces of platinum deposited on the Greenland ice cap at about the same time. Harvard researchers argue that the platinum probably came from an extraterrestrial object—not a comet, however, but a rare type of iron-rich meteorite.

Spherules in Syria. In their latest paper, some of the original proponents of the impact hypothesis now say it deposited 10 million metric tons of spherules over an area of 20 million square miles, stretching from Syria through Europe to the west coast of North America.

Some opponents of the hypothesis—and there are many—want so badly for it to go away that they have attempted to declare it dead. “My only comment is that the pro-impact literature is, at this point, fringe science being promoted by a single journal,” one of them, Nicholas Pinter of Southern Illinois University, said last week. The journal in question is Proceedings of the National Academy of Science.

Other researchers are trying to keep an open mind.

“Most people were trying to disprove this,” said Wallace Broecker, a geochemist and climate scientist at Columbia University’s Lamont-Doherty Earth Observatory. “Now they’re going to have to realize there’s some truth to it”—though maybe only a spherule or two.

Why Care About the Younger Dryas?

Even if you’re inclined to let sleeping mammoths lie, this debate matters: It bears on the question of just how fragile Earth’s climate is. Does it need an extraterrestrial whack to go haywire, or can it do that on its own?

The alleged mammoth-killing impact is also alleged to have triggered the Younger Dryas. At the time, 12,900 years ago, the continental ice sheets were in full retreat from the last Ice Age, and the planet was nearly as warm as it is now.

Suddenly, in a matter of decades, glacial temperatures returned, and the ice advanced again. The cold lasted 1,500 years, then ended even more suddenly than it had begun.

In the 1980s Broecker helped bring the Younger Dryas to wide attention. He explained the sudden cold snap with a mechanism that’s internal to the climate system.

At the start of the Younger Dryas, he said, a conveyor belt of ocean currents that normally transports heat into the North Atlantic—the Gulf Stream is part of it—had gotten jammed by fresh meltwater flowing off the receding ice sheet. With no heat flowing north in the ocean, the North Atlantic region relapsed into bitter cold.

The Younger Dryas became the paradigm for the idea that Earth’s climate was an intrinsically flighty creature, capable of shifting abruptly to a radically different state. That idea has made the prospect of future climate change even more worrisome.

Conceivably a comet might have triggered the Younger Dryas by helping to break up the ice sheet and send meltwater into the North Atlantic. It would have had to have been a big comet, with about a million times the energy of the bolide that excavated Meteor Crater in Arizona, which is three-quarters of a mile wide.

See rest of story at NatGeo here

  • Trent Telenko

    There is the simple observation that humans did not hunt out elephants to extinction in Africa with bows and poisoned arrows far superior to that of the Clovis man.

    The American Indian didn’t hunt out the North American bison, either, after they got the horse from the Spanish.

    Why did anthropologists/paleontologists think that Clovis man was so much more special with the Mammoth?

  • Cevin Q

    Trent,
    One thing to consider is that the YDB event and subsequent climate change only drove the final nails into the coffin, so to speak, in terms of mega faunal extinctions in the new world.
    If we embrace the notion that culturally modern humans have much longer depth of occupation, in north America, then you have a framework by which human predation could lead to long term depression of mega faunal populations.
    There are a host of sites that indicate a human presence in NA goes much farther back than currently accepted.
    Calico hills and manix lake in ca, have yielded tools from strata up 200k years, valsequillo, in Mexico yielded objects of fantastic age. At Burnham ok and snow mass co there are mammoth kill sites up to 50k years old and here in central cal at the Witt site, there are human remains in excess of 17k years old and a mammoth tooth from the shell midden is an astounding 68k years old.
    In the past year I have become a follower of Russian anthropologist, Dr.German Dziebel, and his work in an american or Eurasian origin for modern humans.
    His blog,
    http://anthropogenesis.kinshipstudies.org/
    is a good source for the state of the art studies in genetics, linguistics, cultural anthropology and comparative mythology.
    The comments on the various articles are excellent.

  • Trent Telenko

    Cevin Q,

    The issue with the anthropologists/paleontologists is their knee reflex accusation of humans as evil at every opportunity. Humans are as much a part of the environment as other critters.

    Why is that so hard to accept?

    True, for a some of places with small and shallow ecosystems, we humans were an “invasive species” compared to local critters, and caused mass extinctions of some species like the Doe-Doe and Moas.

    Your point about along predator-prey relationship in North America between Humans and Mammoth actually argues against that. As North American sites of 68K BCE and 50K BCE Mammoth kills by humans argues for a 68 – 50 = 17K year minimum Predator/Prey relationship between early humans and Mammoth without extinction of the Mammoth. All prior to the YDB.

  • Steve Garcia

    Trent Telenko (September 11, 2013 at 6:30 am) –

    Dude, I asked that question the very first time I heard that Overkill thing. I wondered, “Are these guys idiots registered with the state as mental incompetents?”

    Then add in the IMPOSSIBILITY of it. . .

    1. A few thousand guys sweeping an entire continent of 8,000,000 square miles clear of EVERY large mammal.

    2. HOW were they supposed to prevent mammoths from circling around to areas already “swept clean”?

    Hos utterly STUPID could supposedly intelligent people BE?

  • Steve Garcia

    Trent: “The issue with the anthropologists/paleontologists is their knee reflex accusation of humans as evil at every opportunity.”

    Exactly. There are in the social sciences and natural science any number of people who have started from the position that we, human beings, should not be allowed to exist anymore – that we are a cancer o the planet and that the animals and plants should be allowed to live on without humans, unencumbered by us, the planetary cancer. They don’t see humans as part of the planet’s ecology, but as an invasive species.

    They select anything that is human about us – especially the ability to make and use tools – and demonize it as evil.

    An unsupported generality? Read “Confessions of a Greenpeace Dropout: The Making of a Sensible Environmentalist” by Greenpeace co-founder Patrick Moore.

    They are sad, sorry cases – haters of their own kind, really.

  • Cevin Q

    I personally don’t believe that a few groups of hunters on foot can rid an entire continent of some 35 genera of large mammals in only a few thousand years either.
    The point I was trying to make is that, with a possibility of a 200,000 year occupation, humans could have had a limiting effect on certain animal, that was exacerbated by the YDB event. After the initial massive die off due to instant loss of habitat, human predation finished off the survivors, in many portions of NA. The subsequent drought finished off those animal populations that survived in areas of refugium, such as central cal where the mega fauna survived for a few thousand more years.
    If you look at the larger animals that survived the YDB. event they are very adaptable feeders such as the coyote, timber wolf, black and brown bears, mt lions and deer and elk, and the American bison. They are also animals that are very mobile or can be found it isolated areas, such as remote mountain valleys, in the case of the American bison the event changed the landscape to their advantage, by transforming parkland/woodlands to grass prairie. Their population density also ensured their survival.
    Of the other species that did survive, many can be traced to areas that were far removed from the worst of the effects, or from enviroments that didn’t change much due to the subsequent resurgence of glaciation, such as carribou, elk and wolves.

  • Tom Holsinger

    Cevin,

    Bison also were enough smaller than the mammoths and whatnot that they could evolve to travel in really large herds. Note both the behavioral and head location differences between steppe bison and American bison. The latter have their heads set much closer to the ground so they can graze and keep watch simultaneously. Human predation in North America evolved American bison from steppe bison.

  • Steve Garcia

    Tom –

    “The latter have their heads set much closer to the ground so they can graze and keep watch simultaneously.”

    This is an assumption, a human reading the mind of evolution. Just because it is seen to allow that type to gaze and “keep watch simultaneously” does not in any way mean what you assert. If true, it should have happened to ALL the bison types “being preyed upon by those heinous Clovis” mofos.

    “Human predation in North America evolved American bison from steppe bison.”

    This would seem to be part of the Overkill hypothesis, and an extremely weak speculation at that. Evolution doesn’t act that fast, for such a gross difference. Humans were not – according to the “Clovis Done It” hypothesis.

    As to Clovis Overkill, do not forget that even within gradualists people have long been so unsatisfied with Overkill that many argue for climate change as being the culprit. Those people don’t even need a comet. But they also – by their very existence – argue that big bad humans were inadequate… even before Firestone et al came along.

    I love it when “greedy reductionism” (look it up) claims all sorts of corollary “evidence” for their paradigm. It has happened for a long time. I was reading a natural history textbook from about 1890 and laughed at just this sort of applying their then-modern understanding of things – things which are now known to be wrong – to this and that observation. Their certainty was humorous.

    They were guilty of greedy reductionism then – and CLovis First, Clovis Overkill, Global Warming all are guilty of it now.

    We who think the Younger Dryas Impactor “explains” a lot of things also need to not overstep what the evidence shows. Tying other things in with it is nice for discussion purposes – and helps some of us see the YDB as real, but when we apply it to ever-expanding circles of tangential things we are setting ourselves up for a rude awakening.

    Like all of them, we to whom the YDB seems to make a lot of sense also need to avoid being greedy reductionists. Just because something seems to correlate only means we have identified something worthy of inquiry. It may intuitively seem logical, but that is only the first step in making something part of science. And until it is, we need to try to be clear – especially to others – on what is our interpretation of things and what has been supported by evidence. Slap-dash application of our ideas all over the place would make us look silly – even if some of us might be scientists and are saying it all with a straight face… LOL

  • Trent Telenko

    Tom,

    Humans and mammoths co-existed in North America from 68K BCE to 12.6K BCE when the YDB event happened.

    There was a great deal of time for all the mega-critters of North America to evolve in response to human predation.

    The combination of the YDB event _and_ human predation adapted the American bison. Neither alone did it. There just wasn’t an ecological niche for them before the YDB event.

  • Gentlemen; I’ve been bouncing around other blog sites pertaining to the YDB era and have found this to be probably the only site that will even discuss opposing views without calling each other poopy heads. I was thinking about the idea that the YDB being a combination of both the impact and ocean current theories. At the time of the YDb the glaciers were in retreat, melt waters were accumulating behind ice dams morrainal dams etc. Along comes a comet swarm and strikes the various ice sheets causing instantaneous melting of ice at an astronomical rate. This releases incredible amounts of water that have to eventually make their way to the ocean. Also vast amounts of super heated steam is thrown into the atmosphere where it rises explosively and recondenses in the form of rain and snow. The snow accumulates at a much faster rate than any melting causing the climate to rapidly cool down and the ice to start advancing once again. Most of the fauna over a large portion of the earth has been wiped out allowing solar radiation to reflect back into space further cooling the earth. I think this is some kind of common ground for both theorists to work towards each other for common knowlege. Jim

  • Cevin Q

    Jim,
    I agree with the idea that the instigation of the YD WAS via multi mechanisms.
    As you noted the impacts or airbursts over the ice sheets would have melted vast quantities of ice, thus causing huge floods of meltwater into oceanic basins, and throwing great amounts of water into the atmosphere. This atmospheric water and ice would effectively block the sun for a period of time causing cooling.
    A couple aspects of the event haven’t been really discussed, namely the amount of smoke and dust from the fires in north America and the middle east, and how it would have affected remaining ice in the short term.
    Many years ago I read an article on how industrial soot and dust affected polar ice on the northern hemisphere. The authors found that even a light layer, fractions of a mm, will change the reflectivity of ice to an effective absorbant of IR radiation, thus causing melting even if air temps are low.
    They set up areas on the polar ice where they covered the ice with a very fine layer of powdered charcoal, just enough to slightly discolor the ice.
    The ice in the test areas melted rapidly, while the ice surrounding them remained frozen.
    The soot from the fires that formed the black mat would have settled around the world causing accelerated melting of remaing ice and re enforcing the effects of a meltwater pulse.
    So it isn’t necessarily needed for the impact itself to destroy the ice cap, the settled dust and soot would accelerate melting.
    One also has to consider the fact that there may have been multiple oceanic impacts as well. The almost inconceivable amount of water thrown into the atmosphere would have contributed to the melt as well, as it would the heat from the impacts remains longer in the atmosphere while raining out. In the upper atmosphere it would have mixed with the soot and dust from the fires and continental impacts before raining out.
    This event is remebered in the mythology of meso America, as the resinous black rain that fell
    after the gods destroy the first people.
    Some of the native Californians also rember these events through mythology, in the tales of the world being on fire and distinctly different flood stories.
    Among the northern miwok, who lived in the coast range near clear lake, weasel sets the world afire before a flood comes over the mountains and then it rains for many days, flooding the entire Sacramento/san Joaquin valley.
    With the people of yosemite, the earth shakes and groans before a great fire and smoke arise in the east that melts the glaciers in the mountains, causing great floods that drown the people of the valleys.
    This is the cool part I have actually been to the cave where it is said one of the seven ancient chiefs and his people survived the event. This notion of seven groups of survivors in seven caves can be found in the nahuatl mythology,illustrating the link between utian speaking people of cal and the nahuatl speakers of Mexico.

  • Tom Holsinger

    Steve,

    American bison did evolve that fast. This is simple paleontology. You can dispute the cause, but not the timeframe. American bison appeared 5000 – 10,000 years ago. It didn’t go straight from steppe bison to American bison – there were intervening species – but steppe bison disappeared in Eurasia about 11,000 years ago, and in North America about 4,000 – 8,000 years ago.

    This is not a case of “reading of the mind of evolution”. The energy costs of bobbing the massive bison heads up and down between feeding and searching are significant. The behavioral differences in herd sizes were truly fantastic – hundreds in a single herd versus millions.

    I agree with Trent that there were multiple causes of the Younger Dryas extinctions of megafauna. Human predation was one.

  • Tom Holsinger

    Cevin,

    I live in the northern San Joaquin Valley. Where is this cave? That would be a great place to visit. Thank you very much for the story.

  • Cevin Q

    Tom,
    Unfortunately I agreed not to divulge it’s exact location, out of respect for it’s sacred nature.
    I can say that if you drive the old toll road to Yosemite, it can be found on a ridge near a nice meadow.
    I’ve known about for about it for 6 years and there is still only one reference to it on the web, a early 1900’s collection of native cal mythology.
    I’ve only been to the rim of the entrance, as it takes climbing equipment to descend the 75-100′ to the cave floor .
    I was told there was a great deal of cultural material in the cave.

  • Tom; I agree with you that human predation did play a role in the mega fauna, but I think it was the last nail in the coffin. Before YDB I don’t think the man to animal ratio would have been great enough to start population declines. After YDB, that’s another story. Humans were able to change and adapt and the mega aniamls couldn’t fast enough. Qevin: Are there any songs, stories, or legends from the paleoindians telling how life was before YDB? Was there ample food and game or was there a decline in availability? This might give a hint of trouble before YDB.

  • Cevin Q

    Jim,
    Whether times were good or not depends on the tribe and story.
    The two stories which really stand out and make associate them with the YDB event, are the
    Legend of To tau ka nu’ la and Tis sa ack, a some what romantic tale of love and loss framed by a series of spectacular events. The temporal arrangements of the events may not in the right order.
    From the story
    “Here they found food in abundance for all. The rivers gave them plenty of la-pe’-si (trout). They found in the meadows sweet ha’-ker (clover), and sour yu-yu’-yu-mah (oxalis) for spring medicine, and sweet toon’-gy and other edible roots in abundance. The trees and bushes yielded acorns, pine nuts, fruits and berries. In the forests were herds of he’-ker (deer) and other animals, which gave meat for food and skins for clothing and beds. And here they lived and multiplied, and, as instructed by their medicine men, worshipped the Great Spirit which gave them life, and the sun which warmed and made them happy.”
    So it seems in the beginning life was good.

    The later we have the catastrophic part.
    “This was’ the beginning of a series of calamities which nearly destroyed the great tribe of Ah-wah-nee’-chees. First a great drouth prevailed, and the crops failed, and the streams of water dried up. The deer went wild and wandered away. Then a dark cloud of smoke arose in the East and obscured the sun, so that it gave no heat,

    p. 86

    and many of the people perished from cold and hunger. Then the earth shook terribly and groaned with great pain, and enormous rocks fell from the walls around Ah-wah’-nee. The great dome called Tis-sa’-ack was burst asunder, and half of it fell into the Valley. A fire burst out of the earth in the East, and the ca’-lah (snow) on the sky mountains was changed to water, which flowed down and formed the Lake Ah-wei’-yah. 1 And all the streams were filled to overflowing, and still the waters rose, and there was a great flood, so that a large part of the Valley became a lake, and many persons were drowned.”

    There are so many stories, across a host of languages about , the world on fire, a great flood, all of the first people dying, then the new people emerging from the ground or cave, that they have to grounded in a historical recollections

  • Trent Telenko

    >>I agree with you that human predation did play a role in the mega fauna,
    >>but I think it was the last nail in the coffin. Before YDB I don’t think the
    >>man to animal ratio would have been great enough to start population declines.
    >>After YDB, that’s another story.

    I would rate ecological destruction and competitive pressure from smaller herbivore species in the post-YDB recovery, like the evolving American bison, as far more important to the wipe out of the mega-fauna than human predation.

    Faster breeding, smaller critters had room to fill the massively changed and relatively vacant ecological room.

    The massive bison herds that evolved then definitely kept large forested areas from reappearing in the center of North America.

    The small, isolated, populations of mega-fauna just could not reconnect into long term viable breeding populations in the face of that competitive pressure.

  • Tom Holsinger

    Thanks, Kevin, that is a neat story.

    Trent, there are also issues about the YDB event and post-event humans creating the Great Plains environment which favored the immense herds of American bison, and so helped create them from the previous less gregarious species of bison. As an example of my uninformed speculation here, the YDB blasted away the forests and the rapidly springing back human population might have kept the forests from growing back in the Great Plains area by deliberately spreading wildfires.

    The immense environmental effects of prehistoric human populations in altering and fostering environments more favored to them is little understood, and sometimes denied for politically correct reasons. I recommend Tim Flannery’s _The Eternal Frontier – an Ecological History of North America and its Peoples_, Steven Pyn’es _The Burning Bush – a Fire History of Australia_, and Marlene Zuk’s _Paleofantasy – What Evolution Tells Us about Sex, Diet and How We Live_.

  • Tom Holsinger

    And here’s a new study in _Popular Archaeology_ alleging that “anatomically modern humans may have been in eastern Asia as much as 100,000 years ago”.

    http://popular-archaeology.com/issue/09012013/article/modern-humans-were-in-china-much-earlier-than-previously-thought

  • Trent Telenko

    Tom,

    There is no doubt that paleo-indians used wild fire to hunt big game. The forested meadows of New England were not “natural” when the Puritans arrived, they were an artifact of Indian land management practices.

    Natural populations of humans expand to the limits of their ecology, technology and organization.

    The impact on ecology over time depends on things like human territoriality. I have zero idea of how that would play out post-YDB, post-clovis era in North America. I do know that in Eurasia that human migrations tended to be east-west because the nomads were better adapted to a specific latitude band than going north south.

    The adaptation of American Indians to horse based north-south migration with the Bison seems relatively unique in history and involved the American Indian horse nomads overwhelming their un-horsed American Indian competitors.

  • One of the things you find with hunting wildlife is that the game animals get educated about hunting tactics. They don’t need an evolutionary response. The wildlife learns over time. Females teach the young what they know at some level.

    One example comes from a yearly deer hunt on the grounds of the AF Academy in Colorado Springs in the 1980s and 1990s. There was an area open for hunting, but the deer roamed free across the entire grounds. Very, very soon after the first shots are fired, most of the deer show up on the closed side where they can’t be shot.

    We’ve seen a similar thing up here in AK with brown bears. Decades ago, you would see few if any griz in town as they were shot on sight. These days it is not uncommon to see them as they are not actively hunted in town.

    Final story comes out of fly fishing for very large rainbow trout in SW Alaska. The majority of these fish are very old and experienced. Most have been caught more than a few times before, making it difficult to catch for the inexperienced.

    The animals learn and can do so much quicker than an evolutionary change would take. Cheers –

  • Hermann Burchard

    At the Paleocene/ Eocene transition (55.8 Ma), there may have been an event or events stunningly similar to the YDB (HSIE) comet impact. Unexplained so far is one aspect of the events, which is now revealed as having been essentially instantaneous:

    http://www.pnas.org/content/early/2013/09/13/1309188110

    Quoting (slightly edited) from the article:

    Deep sea carbon isotope and CaCO3 records across the Paleocene/ Eocene thermal maximum (PETM) and associated carbon isotope excursion (CIE) require a A massive addition of 13C- depleted carbon to the ocean–atmosphere system. Proposed mechanisms include the destabilization of the global methane reservoir by a thermal trigger or physical disturbance, production of thermogenic CH4 and CO2 during the emplacement of a large igneous province (LIP), wildfires burning peat-lands, desiccation of a large epi- continental sea, decomposition of terrestrial permafrost, and bolide impact.

    Notice bolide impact is mentioned last as cause. But several of the other possible triggers are known from YDB to be allied to a comet impacting.
    IMHO, an LIP is result of impact volcanism, that occurs primarily for large oceanic impacts because of the thinner crust.

  • Trent Telenko

    agimarc,

    I doubt paleo-indians would be “politially correct in their hunting practices. 😉

  • Steve Garcia

    Trent –

    The term “noble savage” was coined in the 1700s (maybe earlier) to reflect the idealization of the native Americans as being somehow more true to their humanity than the then “modern men.” For all intents and purposes the idea of the noble savage has never gone out of favor. Those who think that living that close to nature is the true and only place for humans in the ecology of the world are more or less delusional. For several reasons.

    The first is that the idea the the native Americans didn’t terraform the landscape for their own ends is not correct. The farmed and they started wildfires to assist them in farming. In the Amazon they created something fabulous that is only recently coming to light – terra preta – which is a manufactured soil that includes charcoal, humus, and broken pottery shards by the billions. Terra preta appears to need NO fertilizer. EVER. People are trying to copy it, but so far to no avail. Terra preta confounds almost everything we thought we knew about the Amazon. Google it and see what the native South American pre-Columbian peoples did to their environment. That it was something good as opposed to the idea that everything modern man does is evil doesn’t negate the reality: Human beings modified their environment, making the environment of the Americans not the pristine system that is continually asserted by the back-to-natural-man crowd. Many modern people put value judgments on what was done in the pre-Industrial-Age and also on the modern age, and to some sizable degree they don’t know what they are talking about.

    So, basically, modern tree huggers consider anything we do to this world to be sinister and they give a pass to anything from before 1492 (or even pre-1800, really). The paleo-Americans being politically correct? Only because modern man creates an artificial value system, one in which modern man can’t win. Politically correct? Bull. Of COURSE back then the value system was different. We can’t judge past humans based on our current mores, morals and delusions – but some do, anyway.

  • Cevin Q

    Herman,
    Since you brought up LIP’s here is am oldie but goodie

    “Antipodal Hotspots on the Earth: Vestiges of Major Oceanic Bolide Impacts?:

    Abstract

    The distribution of hotspots on the Earth has a distinct antipodal character, which has previously been shown to be statistically significant (p100 Myr) and could have drifted quite far from antipodality with their opposite hotspots. The remaining 9 primary hotspots have antipodes in the Pacific Ocean where submerged hotspots or impact structures could yet be identified. All hotspots antipodal to those associated with flood basalt provinces or formed in continental crust are, or were, in oceanic crust suggesting links between major deep-ocean impacts, greater impact/seismic efficiency, and the creation of antipodal hotspot pairs. In general, `spotless’ areas [5] occur opposite to continental masses, and no hotspot volcanism is found at or antipodal to known continental impact structures. [1] Rampino and Caldeira, GRL (1992) 2011; [2] Schultz and Gault, The Moon (1975) 159; [3] Boslough et al., GSA Spec. Pap. 307 (1996) 541; [4] Roddy et al., Int. J. Impact Eng. (1987) 525; [5] Vogt, JGR (1981) 950.”
    http://adsabs.harvard.edu/abs/2003AGUFM.V12B0577H

    I read that paper when it first came out and was fascinated by the implications.
    LIP’s are marker for larger oceanic impacts. Like you mentioned oceanic crust is thinner allowing the mantle to absorb most of the energy, while strikes on continental crust reflect most of the energy back into space.
    One also has to wonder if even small impacts on ocean floors ,in regions of strong volcanism. can impart enough energy into the area to cause localized volcanism. In many areas and eras where there has been suspected impacts, there ate also eruptions with the same time frame, such as krakatoa in 536, and the purported encounter with Enke at the same time.

  • E.P. Grondine

    Hi Cevin –

    Briefly

    1)It’s the Holocene Start Impact Event.

    2) The mega-fauanal extinctions were GLOBAL, caused by an instantaneous GLOBAL climate collapse

    3) The impact changed the temperature of the North Pacific Current, which led to the melting of the ice sheets.

    4) The YD drainage of the melt water occurs 1,000 years after the melt begins.

    5) If you use tribal memories, identify the nation, the speaker, and when and who recorded it. Otherwise the mention is useless.

  • Cevin Q

    E.P.G.
    1)Question, how could the younger dryas boundy impact event , be called the holocene start impact event, when the holocene doesnt start for nearly another thousand years after the well dated layer at the boundary.

    2) The mega faunal extinctions were not complete in north america, as several species survived for several thousand more years in assorted refugium areas. In austrailia some species didn’t dissapear till the arrival of dogs, well into the Holocene.

    3) That may very well be , but the warming and melt had been going on for several thousand years before the ydb event.

    4) In terms of the story I related, the flood was a localised event, from the melting of the glaciers of the southern sierra glacial anomoly. The southern sierra were still heavily glaciated, even as other more northly ice sheets retreated.
    5) The story I related was from the Yosemite, an ethnically mixed band of yokuts, miwok and mono.
    I don’t know who related the story but it was published in 1904 by Galen Clark, one of the first whites to live in Yosemite. Clark lived among the people of Yosemite for many years starting in the 1850’s. I’m not sure who related the tales to Clark l, but who ever it was they learned the stories precontact.

  • Dennis Cox

    “Yosemite” is a place name. And it is not what the people who lived there before white folks came called the place. They called it “Ahwahnee”, their word for ‘deep grassy valley . They called themselves the Ahwahneechee, or deep grassey valley people.

  • Also, since the California archeological record shows a 700 year gap in human occupation beginning 12,900 YA then any memories the Ahwahneechee have of the Earth shaking, and giant catastrophic fire events to the east can’t have anything to do with the YD impact event. Both glacial valleys in Yosemite were full of ice at the time of the YD impact, and were no people there for centuries afterwards. So the story the native folks tell is more likely related to a volcanic eruption somewhere in the Long Valley caldera, or Mammoth Lakes region.

  • Cevin Q

    Dennis,

    From Clark(1904),

    “chief, left the Mo’nos, where he had been born and brought up, and, gathering some of his father’s old tribe around him, visited the Valley and claimed it as the birthright of his people. He then became the founder of a new tribe or band, which received the name “Yo-sem’-i-te.” This word signifies a full-grown grizzly bear, and Teneiya said that the name had been given to his band because they occupied the mountains and valleys which were the favorite resort of the grizzly bears, and his people were expert in killing them; that his tribe had adopted the name because those who had bestowed it were afraid of the grizzlies, and also feared his band.”

  • And finally, at the time of that story’s inception the Ahwahneechee were devided between those two valleys. The names that white settlers gave them were Hetch Hetchy Valley, and Yosemite Valley.

    Hetch Hetchy was the grassy one. In Yosemite, the terminal moraine running between El Capitan, and Cathedral rocks held the water table so high that most of it was marshes, and swamps. So one valley had a grassy, park like floor. And the other was a swamp, but with spactacular waterfalls flowing from hanging valleys. When the corps of engineers dammed up Hetch Hetchy for a resevoir for San Francisco they also blasted out the terminal moraine in Yosemite. That gave one valley the best characteristics of both.

  • I grew up in those mountains. And I went to grammer school on the Mono indian reservation. Clark’s 1904 notes are not the last word. He had many misunderstanongs about the Ahwahneechee. And there have been many more accurate, and archeologically significant works done on the region since then.
    P.S. The correct spelling of the chief’s name is Tenaya. And before his story was through he considered Clark an enemy, and cursed him.

  • Cevin Q

    Dennis,
    I agree with you that there is a prolonged hiatus of occupation at KNOWN sites in California, but that doesn’t mean everyone died.
    Some traditions clearly state that people survived, usually in a cave or under ground.
    And certain central sierra traditions there were seven bands of survivors, from seven different caves,to which, interestingly enough, you find parallels to in Aztec origins lore, a reference to the seven caves of their origin.

    Also there has been no events in the western continental US, within the time humans have been here, of a sufficient scale to affect the oral traditions of so many widely dispersed groups. From California to Utah and down into Mexico you have a set of stories that share a broadly related set of themes.
    There are stories of the world being set aflame,a great rain or in the case of Mexico a resinous rain, ( which by the way fits with survivor accounts how the ash and soot rained out after the bombings at Hiroshima and Nagasaki), a great flood, a great death, and a period of darkness and cold.
    Masse and masse (2007?) have shown that two things get remembered in the collective mythology of a region, ultra plinian eruptions and extra terrestrial impacts.
    An eruption at either June or mammoth could fill the bill, as far as the people in the immediate vicinity, but it wouldnt affect the stories of people living 400 miles to the north west or those living in the deserts of the Colorado basin.
    And again there hasn’t been an eruption of that scale within the time frame required.

  • I remain suspicious that any oral traditions contain acurate memories that are 12,000 years old.
    But back then the valleys of Yosemite were stiil filled with ice. And besides the oral traditions of the Ahwahneechee of their arrival there indicate that not only was the ice gone, but there had been time for a thriving ecology to develope.

  • E.P. Grondine

    Hi Cevin –

    Just saw your earlier note.

    First off, thanks for identifying where and when the tradition was shared.
    You have to be very careful not to conflate impact accounts and memories, as there have been many impacts.

    If you look at the normal glacial cycles, you will note that the lat one did not reach the normal minima. This missing minima is called the “Grondine Minima”, and it is when the melt started. That is what the phytolith record shows as well. That is normalluy referred to as the start of the Holocene.

    The drainage of the glacial melt waters starts about 1,000 years later. In Europe, this period of decreased temperatures is known as the Younger Dryas, and it has been known that way for a long long time. I can understand your intense immediate interest, but you will hve to excuse me from not providing you with all of this personally on an ephemeral web site, as the information has to be madde available to many others as well.

    There are also problems of site and artifact and geofact protection to deal with as well.

  • Dennis Cox

    Stop it Ed. Your childish, discouraging, and insulting behavior has gone on for far too long. Regarding my work, or the field work I’ve been doing for the past couple of months, you have not the remotest clue. But while you sit at home as a full time armchair theorist, some of us are actually turning over some rocks, sending them into a lab, and doing some real science.

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