CHAPTER 5: THE YOUNGER DRYAS
- Mark Howitt
- Dec 19, 2025
- 39 min read
Updated: Feb 1
Written by Mark Howitt
"Archeology tries to think of itself as scientific, but its primary goal is controlling the narrative of the past"
-Graham Hancock
It is very evident that the Earth has survived numerous asteroid impact events in its past, and due to the geographic location and timeline of these impacts it seems likely that occasionally these events occur in waves and cycles. Every once in a while, our planet crosses the path of a cluster of space debris and as the evidence shows, the Earth gets hit with a series of objects in a short span of time. An important era that seems to support the evidence of this happening is known as the Younger Dryas period.
I strongly believe that something significant happened during both of the Dryas periods, at some point between 22,000 years ago and 11,000 years ago. This can be explained quite easily with the acceptance of the idea that asteroid impacts have caused a majority of the shaping of the land masses of our Earth, setting the course of the continents that can be seen today. Although many ideas have been put forth to explain what exactly happened, nothing has been agreed upon by the majority despite the mounting evidence to support that the Earth went through radical and peculiar changes during these specific periods of Earth's history.
This subject that has been the cause of widespread dispute amongst scholars within the last decade or so and is known as the "Younger Dryas Impact Hypothesis", which proposes that climate change and periods of warming and cooling was the result of an impact event which happened around the time frame of between 12,800 and 11,600 years ago. Among many of the researchers, perhaps the most prominent is the author Graham Hancock, in whose books, articles, and interviews relating to the subject are highly recommended.
The controversy and heated debates relating to the Younger Dryas has divided many researchers in regards to what happened near the ending of the last Ice Age, where on the one side of the argument are the mainstream scientists who argue that the climatic changes evidenced during this time were not the result of an asteroid impact, but due to other reasons caused by natural phenomenon.
On the other side of the coin are the researchers who continue to bring forth evidence to support that there actually was an impact event during that period in our history, whose findings are outright aggressively refuted by those who wish so bad for this theory to go away. So then, what is the truth in all of this?
MAINSTREAM NARRATIVE
Just as with any subject dealing with human history, there exists many sides and multiple opinions with what actually transpired during the Dryas periods. At this time, largely due to the debates relating to the subject, there are no confirmed and definitive answers as of yet. I will offer my own interpretation of what I believe happened, but first it is important to understand what the traditional view is so that you may decide for yourself what seems to be the correct version of events that took place during this time period in our not-so-distant past.
The Dryas periods are named after a flower known to withstand colder conditions and commonly found in Europe, known as the "Dryas Octopetala". The Dryas eras had various stages, known as the younger, older, and oldest stages. The dating and reason for focusing on this time period is based on the evidence of climatic change and anomalies found in the GISP2 ice core from Greenland. This ice core is like looking through a window into the past, and among other similar cores that have been extracted, are used to analyze the climatic changes on the Earth during specific time periods.
Because of the drastic shifts and changes noticed during the Dryas periods, we have been able to zero in on this time frame to try and piece together what caused these sudden and drastic Earth changes. The Oldest Dryas period occurred between 15,070 and 14,670 years ago, lasting around 400 years, taking place approximately 1770 years before the Younger Dryas. The Older Dryas was preceded by the Bølling Oscillation, which separated it from the Oldest Dryas. In retrospect, these events occurred within a short timeframe, with lots of activity happening quickly during these time periods.
In turn, the Younger Dryas is viewed by geologists as a textbook example of abrupt climate change within a small length of time. Following the gradual warming period after the last Glacial Maximum began receding around 20,000 years ago, a return to glacial conditions took place, seeing temperatures nearly as cold as during the peak of the Ice Age approximately 21,000 years ago. The evidence of this period of abrupt cooling is found within the ice cores extracted from Greenland, however an event similar to the Younger Dryas has also been documented in Bolivian ice cores recovered from the Sajama summit in Bolivia by L.G. Thompson in 1998.
Further evidence was found in the advancement of a mountain glacier in the Southern Alps of New Zealand by G.H. Denton and C.H. Hendy in 1994. The evidence of the consequences of this period has been found all over the globe however, spanning from North America to Europe and New Zealand. This data indicates that the Earth has seen several cycles of cooling and warming periods, a pattern we can expect to continue to occur during the lifecycle of our planet.
It is during this time, about 12,800 years ago, that the entire genus of 35 mammals is documented to have become extinct, including the woolly mammoth, saber-tooth cats, mastodons, ground sloths, giant beavers, dire wolves, horses, camels and other megafauna. But humans...we lived on. This period of time is marked not only with the extinction of several animal species, but also evidence of global flooding and intense cold periods.
The 1200-year period of time at the end of the last Ice Age which lasted until around 11,600 years ago is the time span of the Younger Dryas and was the longest lasting and most recent interruption to the continual warming evidenced since the last Glacial Maximum between 27,000 and 24,000 years ago.
The ending of the Younger Dryas is particularly abrupt, indicating something happened very quickly to cause the return to the warming period, ending the Ice Age and marking the beginning of the warmer Holocene Epoch in which we are currently living in and experiencing. This sudden change occurred within the span of just decades, showing a decline of between 2 and 6 degrees Celsius over the northern hemisphere.
When the Younger Dryas occurred, the Earth had seen a period of steady gradual warming, lasting about 10,000 years as we emerged from the Ice Age. During this Ice Age, immense ice sheets up to two miles thick formed the North American ice cap for close to 100,000 years, until the period of warming caused the ice to begin melting. This also caused a rise in sea levels and had other effects of climate change and global warming.
During this time, the melting dramatically increased between 15,000 and 11,600 years ago, not only causing a rise in sea levels but saw episodes of global flooding and natural disasters. This flood period has been dubbed by geologists as “Meltwater Pulse 1B”, describing the sequence of the melting of the remaining ice caps in North America and in Northern Europe, both of which melted simultaneously as a result of the period of global warming brought on during the Younger Dryas period.
While these climatic changes are generally agreed upon by scientists, what is not agreed upon is the cause of the abrupt Younger Dryas cold period. The prevailing hypothesis is that it was due to a significant reduction or complete shutdown of the North Atlantic thermohaline switch, also referred to as the North Atlantic Conveyor. It seems that scientists wish to avoid admitting the involvement of any cosmic activity or asteroid impacts.
Due to the meltdown of deglaciation, it caused the warm tropical waters which flowed northward to receive a sudden influx in water from the meltwaters coming in from the north. This change caused a significant increase in sea levels all around the world, as floods occurred resulting in the climatic changes and cataclysms observed in the historical record of the Greenland ice cores. This caused a recession of the warming temperatures, resulting in the sudden deep freeze of the Younger Dryas that lasted about 1200 years. Or so their story goes...
With the amount of evidence depicting these obvious and sudden changes on the Earth, it is almost comical that it is explained away as being the result of a flow of water, and the shutdown of the North Atlantic thermohaline switch. There is a good reason for the debate regarding the Younger Dryas, as the peer approved ideas put forth to describe the event just doesn't make a lot of sense in comparison to the mounting evidence and new discoveries relating to the Younger Dryas Impact Hypothesis.
Now that we have reviewed the basic elements of the Younger Dryas period, let's investigate the evidence of an extraterrestrial impact event that has been opposed by so many mainstream scientists and scholars.
IMPACT PROPONENTS
The Younger Dryas Impact Hypothesis (YDIH) was first proposed in 2007 by a research group composed of many scientists from various disciplines known as the Comet Research Group (CRG). The investigators that compose the groups structural basis believe that the cause of the dramatic Earth changes during the Younger Dryas including the evidence of flooding and extinction of megafauna was due to a comet that struck the planet, hitting the North American ice cap and causing the devastation evidenced in the ice cores.
The proponents of the YDIH have been "disproven" in publications, however continue to put forth evidence to disprove the disprovers, all the while adding weight to the mounting evidence that supports their case of an asteroid impact. In most cases, when we witness such opposition to these type of theories, it means they are hiding something and will fight tooth and nail to have the ideals opposed by the mainstream. This is done in part to help maintain the agenda they are following.
Among some of the CRG's leading researchers includes the work and efforts of the famous oceanographer Jim Kennett from the University of California, Albert Goodyear, the Professor of Archaeology at the University of South Carolina, Wendy Wollbach, Professor of Inorganic Chemistry and Geochemistry at DePaul University, nuclear chemist Richard Firestone from Lawrence Berkeley National Laboratory, astrophysicist Malcolm Le Compte, geophysicist Allan West, and geologists Ted Bunch and James Teller. Their work has been invaluable in an effort to piece together the past of our great planet Earth.
The growing number of scientists that compose the Comet Research Group span over 16 countries, and currently includes 63 scientists from 55 universities, but these numbers keep growing as new evidence is brought forth to paint a more accurate picture. You would think that if such a theory was so controversial it would see dwindling numbers as evidence proving it wrong came to light, but we see the opposite happening in regard to the independent and voluntary work of the researchers that make up the Comet Research Group.
The work of this group has been quite profound in the interest of getting to the bottom of what really happened and providing evidence to support their findings. Because its membership includes such a vast array of disciplines, many angles of interest are covered in the overall analysis of the Younger Dryas. Many of these scholars have also been targeted in an attempt to discredit their research and proposals.
Despite the efforts of these researchers, there exists heavy opposition to the notion of an impact by critics such as physicist Mark Boslough from Sandia National Laboratories, Nicholas Pinter, Professor of Geology at Southern Illinois University, and Tyrone Daulton, a research physicist at Washington University, to name a few of the more publicly vocal opponents. There is clearly a divide among scientists in regard to the Younger Dryas, which is a sign of the times, as more and more people are discovering that scientists and scholars of the past got it wrong, and we have based much of what we know off of misconceptions caused by misinformation.
Although not all cases dealing with history have intentional falsities put forth as truth, as revealed in this book, it has happened quite often, and therefore one naturally must eventually ask the question, is this merely a coincidence, or is there something more to this pattern of scientists and historians "getting it wrong". Why does there exist so much opposition for those who believe in the idea of the Younger Dryas Impact Hypothesis?
In so many cases of historic opposition to newly presented theories, we see a clear pattern of these theories become proven as fact later on, causing the revision of our history books. At least it's supposed to, but rarely do we see such upgrades. Discoveries such as the Chicxulub impact event put forth by father and son Luis and Walter Alvarez, the work of Alfred Wegener regarding plate tectonics and continental drift, J. Harlen Bretz and his Scablands flood research, and let's not forget Galileo and his astronomical observations.
All of these people put forth profound new ideas to explain things in a more rational manner and were outright opposed until the end of their lives. Despite the opposition however, eventually their research aided in the proof of the originally proposed theories. It is because of this reason that science and history are constantly being rewritten. It seems as though it is extremely difficult to get rid of old habits, as they die hard as the mainstream holds on to these falsities for dear life.
I for one, am proud to see this new surge of independent researchers taking the stage and redefining what was likely intentionally covered up and known all along.
MULTIPLE IMPACT EVENTS
If the map of our current planet is a testament to the shaping of continents due to massive impact events, then there can be no doubt that during this period of time the Earth survived a cosmic cataclysm. One in which the global effects that occurred as a result and are evidenced will reveal much more insight into our own human history on this planet as well as define a more accurate description of our palaeogeographical history.
It is my belief, as well as that of many other researchers, that there was not only one impact during this time but perhaps several over a specific period of time, as we entered the orbit path of a debris field or asteroid cluster. The Earth was then bombarded with multiple impacts, shaping some of the geographical features now seen on the Earth and causing large scale devastation and planetary changes. I believe that events like this have occurred several times in the past and will happen again at some point in the future.
According to calculations from the Comet Research Group, there may have been as many as four impacts within the timeframe of the Younger Dryas, describing a massive asteroid breaking up into several smaller, yet still large fragments and causing multiple impacts during this time. Therefore the source for the climatic cooling could not have come from the North Atlantic thermohaline switch, but from the atmospheric changes after the impact events. During the 1700's and 1800's, the word saw record cold spells that have often been referred to as mini ice ages. Although not as severe, this shows that the Earth sees shifts and anomalies in weather patterns from time to time.
The search for evidence to support the Younger Dryas Impact has resulted in a wide range of various theories to explain what happened. Because these events took place so long ago, no one on Earth knows exactly how everything enveloped but the evidence that was left behind has been used to form several new theoretical conclusions. As the saying goes, often it is the simplest and most obvious answer that is the correct one.
Astrophysicist's and authors Victor Clube and Bill Napier have helped us understand more about comets and impact events. Along with the work and contributions of Sir Fred Hoyle and Professor Chandra Wiskramasinghe, who modernly defined our understanding of panspermia, and the work on celestial mechanics by mathematician Emilio Spedicato, the realization that just outside of this planet is quite a busy and active place has come to the surface and discussed more openly especially in more recent years.
We are continuing to see new revelations come to light the deeper we probe into these concepts. New considerations of our view of space and the objects in it has reached a renewed level of importance and interest, receiving more attention in recent years thanks in part to the efforts of these pioneer researchers, whose ideas were often initially opposed or ignored but eventually they become recognized for their work.
Many people firmly believe that the Younger Dryas was a multiple impact event which took place in North America, with the first cataclysm happening around 12,800 years ago. This event caused a drop in global temperatures and massive flooding on the Earth, and the second impact event occurred around 11,600 years ago, which saw global warming and additional periods of flooding.
These dual periods of natural disasters were the cause of our planet interacting with a debris field known as the Taurid Stream, the largest stream of matter in our solar system and associated with the comet Encke. This comet was named after the German astronomer who calculated its orbit, Johann Franz Encke, a member of the Royal Society. Interestingly enough, the Sumerian legend of Enki plays a part in the story later on in this book.
The original comet had a diameter of around 50 to 100 kilometers and broke apart about 20,000 years ago. After disintegrating, smaller pieces which ranged from 1 to 5 kilometers in size collided with the Earth, causing what has been referred to as an "impact winter". The remaining portions of this asteroid still exist in our solar system, forming the Taurid Complex, returning to the Earth on occasion. The pieces that hit the Earth collided with high velocities, liquidizing the ice, damaging the continent and causing great floods.
It is theorized that the largest pieces of the bolide landed on the Laurentide Ice Sheet near the region of the Great Lakes, although no impact crater has currently been verified. It is due to this first intersection with Earth that several of these still deadly fragments caused the Paleolithic extinctions about 12,900 years ago. It could very well be that if the Great Lakes are impact craters themselves, then the Taurid bombardment may have been the cause of their formation.
Then, a second interaction occurred, however it has been proposed that this time the brunt of the impacts hit the ocean instead of the frozen ice cap. This is said to be the reason that the first event saw a period of cooling and the second experienced warming effects. Because the impacts were on water, vapor plumed into the stratosphere creating a greenhouse effect, causing an increase in humidity and global temperatures around the planet.
Astronomer Sir Fred Hoyle described this scenario by saying "The difference between a warm ocean and a cold one amounts to a 10-year supply of sunlight. Thus, the warm conditions produced by a strong water vapor greenhouse must be maintained for at least a decade in order to produce the required transformation of the ocean, and this is just about the time for which water, suddenly thrown into the stratosphere, might be expected to persist there. The needed amount of water is so vast, 100 million-million tons, that only one kind of causative event seems possible, the infall of a comet-sized object into a major ocean."
It is commonly believed that the epicenter that these impacts is located in North America, with the first series of impacts hitting the ice cap and the second hitting the ocean. Because the first impacts connected with ice, this caused the ejecta to be thrust upward, which consisted largely of ice as the cap was still over a mile thick at the time of 12,800 years ago.
In a paper that appeared in the publication Geomorphology which was written by Antonio Zamora, he points out that it was not simply the shock waves and blast caused by the impacts themselves that caused the damage, but it was also the rocks, dust and debris known as ejecta that was thrown into the upper atmosphere. This ejecta travelled at high speeds at distances of up to thousands of kilometers before landing back to the surface of the Earth, covering it with a blanket.
LAYERS OF EVIDENCE
Isochron dating has been used at many proposed YD sites, and is a commonly used radiometric dating technique that is applied to date specific events. These events include processes like shock events, crystallization, metamorphism, and using the history of rocks to find the differentiation of precursor melts.
There is literally layers of evidence to support the YDIH which have been used time and time again to support the hypothesis. Despite those who seek to disprove the theory and put it to rest by nitpicking certain aspects of the evidence, further evidence continues to surface which adds to the overall credibility of the theory itself. Much of this evidence can be found within what is known as the "ejecta blanket" that has been found spanning much of the Earth as evidenced in various ice cores.
Materials found in these blankets offer a literal window into the past. These layers contain elements that are quite rare on Earth but abundantly found in space. Furthermore, some of these materials only appear as a result of a cosmic impact. Because ejecta blankets have been found on multiple continents, perhaps the continents themselves broke apart at a much more recent date than has been proposed by the paleogeographic map of the world.
At one point, when the land masses were joined, a massive impact could have separated the continents which is why a similar ejecta blanket has been found on multiple continents. After all, since the same materials found on different continents are from the same period in time, it only makes sense that these land masses were originally connected, and the ejecta evidence could be used to determine a date of this occurrence.
Found underneath as many as fifty Clovis sites across the continent of North America is soil that has been charred, rich in carbon that contains some rare materials that could have only been transported here from an impact event in the past. Some of these materials include glass-like carbon containing nanodiamonds, carbon spherules, fullerenes containing helium-3 (which is found in abundance on our Moon), iridium, metallic micro spherules, magnetic spherules, iridium, platinum, and other rare materials to Earth. This blanket of materials can be found at the bottom of organic material called black mats and are found at the beginning of the Younger Dryas period.
Evidence of these findings were published in a 2010 article entitled "Discovery of a Nanodiamond-Rich Layer in the Greenland Ice Sheet", which was published in the Journal of Glaciology, Sedimentary Geology, and the Monthly Notices of the Royal Astronomical Society. A portion of the article reads "The presence of rounded nanodiamonds and lonsdaleite in Greenland ice suggests that a large cosmic impact occurred...The existence of this layer...appears consistent with the occurrence of a major impact event that correlates with the nanodiamond-rich YDB in North America at 12,900 years ago". One thing is for certain, and that is that Ionsdaleite Diamonds are worth a small fortune.
The Journal of Geology published another article about the subject four years later, which supports the fact that the Younger Dryas boundary layer had been discovered on four different continents, and not just exclusive to North America. The article outlines "A major cosmic-impact event has been proposed at the onset of the Younger Dryas cooling episode at 12,800 years (plus or minus 150 years) before the present, forming the Younger Dryas Boundary (YDB) Layer distributed across up to 50 million square kilometers on four continents”.
The article also noted that “In 24 dated stratigraphic sections in 10 countries of the Northern Hemisphere, the YDB layer contains a clearly-defined abundance peak in nanodiamonds (NDs), a major cosmic impact proxy...The site in Venezuela, along with one in Peru, are the two southernmost sites currently known to display evidence for the YDB impact event, and these sites represent the first evidence that the effects of the impact event extended into South America, even into the Southern Hemisphere."
In the September 2014 article published by the Journal of Geology, chemist Charles R. Kinzie investigated the traces of nanodiamonds distributed across 50 million square miles of the Northern Hemisphere and concluded that only two layers were found to contain these nanodiamonds. The layers, not surprisingly, were the Younger Dryas Boundary from 12,800 years ago, and the Cretaceous-Tertiary Boundary going back to 65 million years ago, to the time of the great dinosaur extinction. Nanodiamonds were discovered within the black mat at various Clovis sites, which were located at levels within the 200 feet range.
Although the Cretaceous-Tertiary event has been accepted as a mass extinction event, the YDB event has yet to be accepted as a more recent extinction level event. The K-T boundary is the layer that was found that separates the Cretaceous period from the Tertiary period. The letter K stands for “kreide” in the German language, which means “chalk”, because the K-T layer is very chalk like in relation to its texture.
In a previous article published in 2009 by the Proceedings of the National Academy of Sciences, and authored by 26 diligent scientists, it reads "We propose that the YD event resulted from multiple ET airbursts along with surface impacts. We further suggest that the catastrophic effects of this ET event and associated biomass burning led to abrupt YD cooling, contributed to the late Pleistocene megafaunal extinction, promoted human cultural changes, and led to immediate decline in some post-Clovis human populations”.
The scientists also discussed the scale of the event in the report, stating that "this layer also extends throughout at least 15 Carolina Bays, which are unique, elliptical depressions, oriented to the northwest across the Atlantic Coastal Plain. We propose that one or more large, low-density ET objects exploded over northern North America, partially destabilizing the Laurentide Ice Sheet and triggering YD cooling". The more scientists continue to investigate these details, the closer we are to finding out the truth about what really happened during the YD timeline.
In the central Mexican state of Guanajuato, research has been conducted at Lake Cuitzeo which supports and modifies the Younger Dryas impact theory, as hexagonal nanodiamonds called lonsdaleite have been found in lakebed cores dating back to 12,900 years ago. Also found in the cores were carbon and magnetic spherules, common indicators of an extraterrestrial impact. Ionsdaleite is found in cosmic dust and occurs naturally in asteroids, adding strong evidence to support that the lake was likely formed during the time of the Younger Dryas multiple impact event.
An important impact paper written by 28 scientists and researchers with the lengthy title of "Evidence for Deposition of 10 million Tonnes of Impact Spherules Across Four Continents 12,800 y ago", holds significant evidence supporting the Younger Dryas impact theory. The report provides evidence through a "detailed geochemical and morphological analyses of nearly 700 spherules from 18 sites in support of a major cosmic impact at the onset of the Younger Dryas episode (12.8 ka). The impact distributed ∼10 million tonnes of melted spherules over 50 million square kilometers on four continents."
The paper not only provides detailed evidence disproving the currently held “industry standard” belief, but it boldly defies it by stating that the "Origins of the spherules by volcanism, anthropogenesis, authigenesis, lightning, and meteoritic ablation are rejected on geochemical and morphological grounds. The spherules closely resemble known impact materials derived from surficial sediments melted at temperatures >2,200 °C. The spherules correlate with abundances of associated melt-glass, nanodiamonds, carbon spherules, aciniform carbon, charcoal, and iridium."
GOING PLATINUM
Nanodiamonds and various spherules are not the only anomalous items discovered in peak amounts at the 12,800-year time frame. A 100-fold spike in platinum has been observed in multiple Greenland ice cores that have been dated within a five-year accuracy to 12,890 years ago. The evidence seems to show that indeed there was multiple cosmic impacts during an extended period of time. There has also been a recent political interest in these rare earth materials located in Greenland.
These events likely did not occur over a couple of days, but several hundreds of years, indicating that when our Earth enters these orbit paths, the periods of bombardment likely lasts for hundreds of years. This is a shocking and devastating truth to swallow, which could be why the Younger Dryas hypothesis is opposed so intently by certain scientists. To avoid causing a panic, it is refuted despite the mounting of evidence over the last decade. The platinum anomaly adds hard evidence to support an elongated time of alignment with the debris field.
Archaeologists have discovered high traces of platinum at eleven Clovis sites in the United States, indicating that these impacts could have been the cause of the end of their culture, and their mysterious disappearance from the historical record. The anomaly of platinum being found in high concentrations across North America is unique because it is often associated with extraterrestrial materials.
Christopher Moore, an archaeologist and lead author of a study on the platinum anomaly stated that "Platinum is very rare in the Earth’s crust, but it is common in asteroids and comets.” Regarding an earlier study of the GISP2 ice-core, which was done by Michail Pataev, Moore said “Previously a large platinum (Pt) anomaly was reported in the Greenland ice sheet at the Younger Dryas boundary (YDB) (12,800 Cal B.P.)".
He also explained the detailed methods in which they used to confirm the platinum discovered by Pataev by saying "In order to evaluate its geographic extent, re-assay and inductively coupled plasma mass spectrometry (FA and ICP-MS) elemental analyses were performed on 11 widely separated archaeological bulk sedimentary sequences. We document discovery of a distinct Pt anomaly spread widely across North America and dating to the Younger Dryas (YD) onset."
Moore goes on to conclude with confidence that "the apparent synchroneity of this widespread YDB Pt anomaly is consistent with Greenland Ice Sheet Project 2 (GISP2...This study finds no evidence to contradict the conclusions of Petaev et al. that the Greenland Pt enrichment most likely resulted from an extraterrestrial source." Indeed, it appears that the cataclysmic event deposited large concentrations of platinum that spans over much of the northern hemisphere, as well as the main areas of the impact sites.
Dr. Martin Sweatman from the University of Edinburgh's School of Engineering led the research team in these platinum studies, and believes the evidence speaks for itself. He stated that “I think this research, along with the recent finding of a widespread platinum anomaly across the North American continent, virtually seal the case in favour of (a Younger Dryas comet impact). 'Our work serves to reinforce that physical evidence. What is happening here is the process of paradigm change.”
FIRESTORMS AND BLACK MATS
Indeed, it seems a paradigm change has taken place in regard to these matters and the platinum discoveries is but the tip of the iceberg in a mountain of evidence supporting the Younger Dryas impact scenario. There is evidence of periods of vast wildfires that occurred in the past, similar to what we are currently witnessing on our planet today.
Air bursts and impacts from the swarm of carbonaceous chondrites, as well as the fragments of comets set several areas ablaze, roaring with massive fires that would have made the recent Alberta fires pale in comparison. These air bursts would have been similar to, but much larger in scale, to the Tunguska impact event which occurred in 1908. Essentially, what we are looking at here is of a more similar magnitude to the big one that killed off the dinosaurs.
It is believed that these fires were a direct factor which led to the extinction of most of the megafauna that were found in North America after the last glacial period. This would have caused the destruction of plants and food sources of herbivores and carnivores, disrupting the food chain on many levels. This is also believed to be one of the main contributing causes to the finality of the Clovis culture that existed in the area around the same time frame.
The evidence to support this notion is contained within the Younger Dryas layers and include high dust concentrations with a noticeable peak of ammonium, an aerosol that is created from the burning of biomass materials. In what appears to be one of the largest biomass burning periods within a 120,000-year timeframe, sudden peaks of a similar increase of combustion aerosols have been noted from four separate ice-core samples taken from Greenland, Antarctica and Russia.
These peaks include traces of nitrate, acetate, formate and oxalate. According to CO2 records taken in Antarctica from the Taylor Glacier, this burning episode scorched up to 10% of the Earth's biomass, or 10 million square miles. The evidence supports that these wildfires were the result of an impact event which caused the sudden triggering of an "impact winter", resulting in climatic changes which have been shown in the records of various ice-core samples and have been studied meticulously. The record clearly shows that there were some serious changes happening to the Earth around this time.
Melt-glass materials have also been discovered and analysed by a team of 18 international researchers and scientists, contained within a thin layer of sedimentary rock found continents apart. These materials were discovered in many locations including Pennsylvania, South Carolina and as far away as Syria. Samples taken have been dated back to nearly 13,000 years ago, and were formed by extreme temperatures ranging between 1700 to 2200 degrees celsius, or 3100 to 3600 degrees fahrenheit. This can only be explained as the result of a cosmic impact during this time period.
The results of the teams research were published in a Proceedings of the National Academy of Sciences article. In the report, H. Richard Lane, the program director of the National Science Foundation's Division of Earth Sciences said that "These scientists have identified three contemporaneous levels more than 12,000 years ago, on two continents yielding siliceous scoria-like objects (SLO's)...SLO's are indicative of high-energy cosmic airbursts/impacts, bolstering the contention that these events induced the beginning of the Younger Dryas. That time was a major departure in biotic, human and climate history."
Among those on the team was the professor of earth sciences at UC Santa Barbara and oceanographer James Kennett. Kennett claims that the melt-glass material found at Abu Hureyra, the archaeological location in Syria in the Euphrates Valley is a unique site, as it records a transition from nomadic-hunter gatherers to farmer-hunters who settled at permanent villages. Perhaps this change took place because of a scarcity of food due to the effects caused by these impact events.
According to Kennett, "Archeologists and anthropologists consider this area the 'birthplace of agriculture,' which occurred close to 12,900 years ago...The presence of a thick charcoal layer in the ancient village in Syria indicates a major fire associated with the melt-glass and impact spherules 12,900 years ago...Evidence suggests that the effects on that settlement and its inhabitants would have been severe."
Kennett also described the distances between impact sites, supporting a multiple impact event with great range over the surface of the Earth. "Because these three sites in North America and the Middle East are separated by 1,000 to 10,000 kilometers, there were most likely three or more major impact/airburst epicenters for the YDB impact event, likely caused by a swarm of cosmic objects that were fragments of either a meteorite or comet.” If this is the case, then it is likely that we can expect to experience similar events again at some point in the future.
Superheated ejecta is proposed to have caused some of the wildfires outside of the impact zones, which destroyed several terrains including forested areas, plains, and grasslands, creating toxic fumes, soot, charcoal, and ash. This resulted in the destruction of vegetation used as a food source by many animals and people in the affected areas. As mentioned, the aftermath of these fires left the landscape devastated, making it hard to survive in these post-apocalyptic conditions.
Therefore, we can assume that ejecta must have spread over vast amounts of the Earth's surface. Evidence of wildfires and abrupt ecosystem disruption were reported in a 2008 Quaternary Science Reviews article. This article reported findings on the Northern Channel Islands of California, dating to the period of 13,000 to 12,900 years ago, and concluded that the evidence found on these offshore islands was consistent with an Allerod-Younger Dryas boundary cosmic impact event. For a black mat to exist on these islands indicates the ejecta blanket spread out over large distances.
In a comprehensive study that was published in February of 2018, several researchers have concluded that approximately one tenth of the Earth's surface became engulfed in flames in the time frame of 12,800 years ago as a result of comet fragments that measured up to 100 kilometers across. Heated ejecta the size of stadiums lifted out from the impact zones, traveling great distances and spreading fires across the Earth's surface wherever they landed. This caused a period of cooling for around 1000 years, whereas prior to this the Earth was covered in glaciers for 100,000 years.
According to the international team of scientists, after these fires eventually fizzled out, life was able to continue again. It is perhaps during this time, or shortly after, that modern man first arrived to re-colonize the planet, after conditions were right to reseed the human population for our continued survival on the Earth. It is to my belief that we have had to do this several times, whenever conditions on the planet became uninhabitable to support human life, and we currently have the technology to do it again. If this is the case, then indeed we are the alien species.
An American physicist and one of the authors of the report, Adrian Melott, from the University of Kansas, is one of the pioneers in using large computers to search the dark matter in the universe to investigate the formation of large structures. Melott states that "a number of different chemical signatures – carbon dioxide, nitrate, ammonia and others – all seem to indicate that an astonishing 10 percent of the Earth's land surface, or about 10 million square kilometres (3.86 million square miles), was consumed by fires...Computations suggest that the impact would have depleted the ozone layer, causing increases in skin cancer and other negative health effects." Melott was part of a team of 24 scientists who measured geochemical and isotopic markers from more than 170 sites found around the world.
Additional evidence can be found in a black mat site located in the Andes, in Northwestern Venezuela, where there exists fired glaciofluvial beds which correlates with experimentally heated quartz and feldspar. This black mat was likely formed from the fallout of the cosmic airburst above the Laurentide ice sheet, an interhemispheric event which spread ejecta across large portions of North America as well as Europe.
The microstructural texturing of the spherules found in Venezuela provides evidence of melting and are identical to spherules discovered at other sites in North America, Europe and Asia. Curiously, Venezuela has also been a key area of political and military interest recently, as there has been much discussion regarding the natural resources and rare earth materials that are located there. It seems that wherever they find evidence of this kind, there is an interest in excavating and taking control of these cosmic materials.
Found in the carbonaceous coating and considered a part of the incoming ejecta is the presence of large amounts of monazite, a mineral not common in the local lithology of some black mat sites. The resulting patina, with a thickness of between 100-400 nm, contains thermally disrupted quartz and feldspar. This could only have occurred if there were temperatures reaching over 900 degrees centigrade. These discoveries add further evidence supporting a cosmogenic origin.
One can only imagine the destruction these impacts would have caused after analyzing the evidence found continents apart. According to Kennett, "The entire continent (North America) was on fire". Author Antonio Zamora described the event in great detail in his book "Killer Comet". He believes that the entire extinction event took place in less than ten minutes, claiming “All living things within 100 kilometers of the impact died instantly. They were either burned by the heat blast or killed by the shock wave."
Human and animal life that was not killed instantly upon impact were killed off from the coast to coast infernos which spread across the land, burning up vital food sources on the continent. Researchers believe that the glaciers that were once retreating were then able to advance again, and that any survivors of the cataclysm had to develop new techniques to adapt and cope with the harsher conditions of living. This resulted in drastic population decline and migrations to more habitable areas.
EARTH PLASMA
As discussed in previous chapters, the effects of the sun on the Earth takes many forms, having the ability to cause drastic changes to nearly all aspects of life. We are at the mercy of this star as we live out our daily lives on this orbiting planet, and there are those who believe that the phenomenon surrounding the Younger Dryas event were actually caused by solar activities.
The most common state of matter found in the universe is plasma. This abundant substance has a profound effect on the Earth, causing the plasmasphere to rotate when the particles travel along the magnetic field lines of the planet. This cold donut-shaped cloud of ionized gas and charged particles rotates with the Earth within the magnetosphere, expanding during calm solar periods and shrinking when solar storms and space weather events take place.
Robert Schoch, a professor at Boston University, agreed that the Younger Dryas event was suddenly abrupt, and that "given our inability to resolve the finest details of something that happened so long ago, it may literally have happened overnight." Schoch believes the flooding and abrupt warming marking the end of the Younger Dryas to be more around the time frame of between 9700 to 11,700 years ago, however, and offers a different outlook on what took place during that time.
According to Schoch, he believes that it was not a comet-sized object that caused the sudden changes in climate, but rather the result of irregular solar activity in the form of strong plasma phenomena. "In the past, much more powerful plasma events sometimes took place, due to solar outbursts and coronal mass ejections (CME’s) from the Sun, or possibly emissions from other celestial objects."
In describing the effect this would have had on the planet, Schoch said that "Powerful plasma phenomena…hitting the surface of Earth could heat and fuse rock, incinerate flammable materials, melt ice caps, vaporize shallow bodies of water, creating an extended deluge of rain, and send the climate into a warming spell." He also pointed out that "the release of pressure that follows the melting of thousands-of-meters-thick ice sheets can induce earthquakes and even cause hot rock under pressure to melt and erupt to the surface as volcanoes."
Schoch also claims that the plasma event he believes to have occurred around 9700 BC destroyed the advanced civilizations of the time, going further by proposing "This could be the basis for the nearly universal myth of a Golden Age… The 9700 BC event may be the original basis for the Atlantis legends; the timeframe fits well with Plato’s account." We will expand upon this notion furthermore in the chapter on Atlantis.
What is interesting to note here is that in more recent years, we have not only seen an increase in record temperatures and weather anomalies, but we have also witnessed an increase in intense solar activity. A multitude of earthquakes and natural disasters occurred in 2025, along with irregular solar behavior, and new evidence seems to show that these phenomena are very likely connected. The increase of chaotic solar anomalies parallels in synchronicity with the earthquakes and extreme weather changes we have been seeing on the Earth.
It seems clear that these events are not happening largely because of global warming and human activities, but something far beyond our control. I believe these are warning signs, letting us know that we have a long bumpy road ahead of us.
GEOMAGNETIC EXCURSION
The Earth's magnetic field is an important element and not only is there evidence of impacts and irregular solar activity during the time of the Younger Dryas, but there is also evidence of polar shifts, often described as geomagnetic excursions or geomagnetic reversals.
This field is a protective magnetic bubble which surrounds the Earth in the outer core and is generated by swirling molten iron that shields us from harmful solar radiation which causes auroras near the poles of the planet. This bubble is tilted at -11 degrees in relation to Earth's axis and acts like a bar magnet which extends into space. It is used to guide compasses, and the strongest points of this magnetic field are located at the north and south poles, with the weakest areas being located at the equator.
A geomagnetic excursion happens when the earth's magnetic field wanders, resulting in a temporary but significant weakening of the layer which can last for centuries up to tens of thousands of years. The magnetic poles dramatically shift without fully reversing, often returning to the original polarity over time. Periodically these poles shift, causing changes that have been documented in the geological history of the Earth and the evidence seems to show that this has occurred during the timeframe of the Younger Dryas period.
Perhaps the best example of this has been documented at the Fjärås Stadial, which is located in areas of Southern Scandinavia. This anomaly is known as the Gothenburg Magnetic Excursion, which begins around 13,750 years ago and ends with the Gothenburg Magnetic Flip between 12,400 and 12,350 years ago, having a Central Pacific equatorial VGP position.
The magnetic flip was documented within five different cores sampled in Sweden, all in which showed a completely reversed inclination found in the layer that represented the Fjärås Stadial, dating to the time of the flip between 12,400 and 12,350 years before the present. Both marine and lacustrine environments were tested, with the cores being taken from different locations 160 km apart.
The Gothenburg Magnetic Flip is a unique event as it represents the most rapid polar change currently documented and is the best-dated paleomagnetic event. Both the events of the Gothenburg Excursion and Flip are both proposed to be a single standard magnetostratigraphic unit. The time frame of the excursion and flip sits within the 12,000-year era making it likely another result of an increase in impact events and orbital energy alignment witnessed on the Earth during this time in history.
LOCATING THE IMPACT ZONES
In Volume 194 of the New Scientist Magazine, an article was published in 2007 which contained some key points supporting the Younger Dryas period of climatic shifting and sudden extinctions due to a cosmic impact event. There has yet to be any agreed and confirmed locations by scientists as to where the impact craters are that caused the Younger Dryas, but generally, as we have discussed it is thought to have occurred over the North American ice cap around 12,900 years ago.
The article published by New Scientist held a statement from geophysicist Allan West which I found especially intriguing. In part it read: "Levels of the apparent extraterrestrial debris, for example, are highest at the Gainey archaeological site in Michigan, just beyond the southern reach of North America’s primary ice sheet 12,900 years ago. Moreover, levels decrease the further you go from Gainey, suggesting that the comet blew up largely over Canada..."
This means that logically we should be able to locate these impact sites fairly easily by simply taking samples of the impact debris on the continents it has been found on. If higher traces are found in a certain location, it must then indicate that the imact zone is closer to the area with the highest concentrations. The impact sites can therefore be located once we have found the areas with the highest traces of this charred black mat material and impact debris.
Researchers involved in the studies of the YDIH have often been met with clear opposition. When asked about the reasons why no crater has yet to be identified supporting the impact which occurred around 12,900 years ago, West responded by suggesting the smaller parts of the comet with low density exploded in the atmosphere, with the larger portions crashing into the North American ice cap which would have been around a mile deep at the time. “Such craters would have been ice-walled and basically melted away at the end of the last ice age.” Due to this meltdown, it would have left few visible traces. With all of the other supporting evidence, it seems a likely probability.
Further evidence to support this method might prove to be successful can be found in the more recent impact at Tunguska. Evidence of drastic temperature drops at greater distances from the impact site were recorded, and as would be expected the direct location of the impact site showed the highest recording of temperature. Therefore, if we follow the highest concentrations of this material we should, by logic, be able to locate where the impact zones are specifically. However, although this method can be used to find the impact sites on land, it is much harder to do if the cosmic bodies landed into the ocean.
Also, as we have discussed, if an impact did occur on land, it would have since filled up with water and formed a lake or body of water. What we instead see is it being explained away as being formed from glacial melts and erosion. I believe that in time, though all the debates and continued research efforts, we will eventually come to agree and accept that something significant transpired during this very specific timeframe in our geological history.
Another probable scenario is that if the impact were to have occurred near a shoreline, then it likely broke off a portion of the land mass, as evidenced and discussed in the previous chapter in relation to the Mariana's trench and the formation of the Indonesian Islands. Therefore, if an island has high traces of this material, it could have been originally part of the main continent, and it is actually an island now due to the cosmic impact and fragmentation that occurred.
After all, if a massive comet slammed down into a small island like Cuba or even the UK, it would obliterate it entirely, and there would be no land mass left visible above the ocean surface and erasing the visible evidence.
THE GREAT LAKES
Many researchers believe that the Great Lakes are a key location relating to the Younger Dryas impact hypothesis, perhaps even being the epicenter of the impact itself. The traditional view of how these lakes formed however differs greatly, and so there exists a divide in opinion from scientists and researchers probing the subject.
According to the Proceedings for the National Academy of Sciences paper relating to the Younger Dryas impact, "Lasting evidence may have been limited to enigmatic depressions or disturbances in the Canadian Shield, e.g. under the Great Lakes, or Hudson Bay." The Great Lakes are a unique feature on the planet, and because of this factor have been the focus point of related research efforts. The location of these lakes is in a very specific region of the globe and may hold the key to unlocking some of these mysteries.
The Great Lakes contain one fifth of the worlds freshwater supply and is the largest group of freshwater lakes found on Earth. About a quarter of Canada's population live around the Great Lakes, as well as around 10% of all Americans, so basically around 40 million people rely on the freshwater of these lakes. The Great Lakes also contain lake sturgeon, which are the largest freshwater fish found in the world. Lake sturgeons are considered to be living fossils because they have survived for over 100 million years, nearly unchanged.
It is traditionally taught that the Great Lakes started their formation around 14,000 years ago, near the end of the last glacial period. It is believed that the basins were carved out by retreating ice sheets, which due to the weight of the 2-mile-thick ice, gouged out the surface of the Earth creating basins, which after melting filled in with the meltwater. Therefore, the Great Lakes are considered to be glacial lakes, since it has been proposed that they were formed by these glacial melts.
It is to my belief that the Great Lakes are craters and were in fact formed as a result of impact activity, but perhaps not the epicenter of this. It could very well be that the actual location of the impact is located more northward, in the Hudson Bay area and that the Great Lakes were formed as a result of the ejecta and debris from the initial collision. If an object hits a point of solid resistance, it bounces and needs to return to the ground again due to gravity, but it would still leave traces of impact.
Some objects bounce multiple times, while others less, similar to a throwing a tennis ball. It travels further with more bounces on a harder surface, while on grass it bounces much less due to the shock absorption. Heavier objects, after bouncing off the surface after an initial impact often land again, but drag across the ground before coming to a halt. This could be an explanation to the unique shapes that the Great Lakes have. It may even be possible that the famous site of Niagara Falls was also carved out as a result of the impact.
As we've discussed, the current held theory is that the glaciation melted and receded, which caused the formation of the Great Lakes. I believe that they were possibly formed in the opposition direction. Meaning, they were not formed from the ice cap melting and filling a basin as the cap got smaller, but from a flood that came from the Northeast travelling downward into the Great Lakes region.
The basins of the Great Lakes were likely formed by impacts prior to this, causing the depressions that were later filled in when the ice melted, or they were formed during the same time as the impact event about 13,000 years ago, as a result of the ejecta. It is also possible that the debris from the impact near Greenland and Hudson Bay caused this flooding and merged the Great Lakes with Lake Agassiz and Hudson Bay at one point in time.
There are many who believe the Great Lakes region to either be the epicenter of an impact event or at least created as a result of an impact event and subsequent flooding. It is said that the Great Lakes were not lakes during the time frame of the Younger Dryas impact but were depressions that were buried underneath the icecap 12,800 years ago. It could very well be that if an incoming object did explode in the upper atmosphere, it fragmented and the lakes were formed due to the pieces landing on the Earth which caused these depressions initially.
This would mean that the depressions were in fact caused by the impact or ejecta and then filled in with water over time after the flooding that occurred as a result of the quick icecap melt. Reanalysis of the dating of these North American sites would need to be done to prove this, however it is entirely possible. After all, our dating methods have advanced and are more accurate now as compared to when the original dating happened, leading us to reach the traditionally believed current dates.
Two researchers who believe the site of the impact to be over the Saginaw Bay area of Lake Michigan are expert in geospatial big data, algorithms and data mining Michael E. Davias of Cintos Research, and Thomas H.S. Harris from Comsat Orbit Operations, and orbit analyst for the Lockheed Martin Corporation, a company that builds space shuttles.
These researchers provided evidence using ballistics and triangulation to show that the impact likely occurred over the inlet of Saginaw Bay in Michigan. They believe that this would have created ejecta and secondary impacts which appear in a "butterfly-wing" pattern over the Carolina Bays to the Southeast and to the Southwest, and the Nebraska Rainwater Basins. This scenario was also described by Zamora and fits precisely with our key impact and ejecta angles of 23.5% and 144%.
Both Davias and Harris claim that Saginaw Bay is the result of a “a unique singular event that cuts through the central bedrock”. In describing the current held view regarding the formation of Saginaw Bay, they state that it has been “commonly attributed to erosion by the Saginaw glacial lobe penetrating through the Mississippian and Pennsylvanian Cuestas." This area was not a bay at the time but was rather solid land covered by ice of up to a mile or more thick 12,800 years ago.
Regarding Saginaw Bay, the researchers have noted that the characteristics seem to show us what would be expected to be seen if a large oblique impact occurred onto this thick sheet of glacial ice, which caused shock effects to pass through the icecap which would have been absorbed into the bedrock below. Supporting these finds, in the geomorphology paper presented by Zamora in 2017 regarding the glacial ice impact hypothesis, Zamora believes that Saginaw Bay was formed 12,800 years ago and is an impact structure caused by one of the fragments of a Younger Dryas comet.
According to Zamora, the Laurentide Ice Sheet spanned the convergence point that was previously determined by Davias and Harris in 2015 and said that the thickness of the ice at Saginaw Bay would have been approximately 1500 to 2000 meters thick during the Pleistocene. He goes on to say, "An impact by a meteorite at this location would have ejected chunks of ice in ballistic trajectories, and the heat of the impact would have melted some ice to produce water and steam."
Four processes were described by Zamora that were likely to have occurred in a sequential order leading to the formation of the Carolina Bays. Those processes were the extraterrestrial impact itself, which would have produced ejecta in the form of glacier boulders and ballistic trajectories, the secondary impacts which would have liquified unconsolidated soil, the oblique impacts on the liquified soil which caused the conical cavities present, as well as the viscous relaxation converts cavities into the shallow elliptical bays.
Zamora reported that “Experiments of high-speed impacts on ice sheets using NASA’s Ames Vertical Gun demonstrate that ice shatters when a projectile hits it. Pieces of ice are ejected radiating from the impact site in ballistic trajectories and the icy layer reduces the extent of subsurface damage." As research efforts continue into these matters, we seem to be getting closer to the truth of what really happened.
CONCLUSIONS
What remains clear is that no matter which side of the fence you are on, something very significant took place during the time of the Younger Dryas. As we have discussed, it seems that a multitude or series of events transpired in a sort of domino effect, leading to important geological changes on the Earth that continue to be debated even to this day.
As we have discovered, the physical evidence supporting the opposed hypothesis of a YD cosmic impact event spans much of the Earth, which has been documented in North and South America, Europe, Russia, and the Middle East, among other regions. In time, more sites and evidence are likely to surface and enter the history books as accepted fact, and once the opposition to this information has been nullified we may finally know the truth of what really happened during this time.
I believe in the very near future we will discover that for a duration of time between 12,900 years ago and 11,900 years ago, our Earth entered the orbit path of a debris field and was bombarded with multiple impact events. This also occurred approximately 66 million years ago, forming the KT boundary. This is why there are two specific and visible blankets found in ice-core samples supporting impact events during these specific time periods, and it is because of these events that our Earth took its shape as we see it today.
It is highly likely that our Earth will once again enter the path of a debris field, in which we would witness again a fierce and devastating multiple impact event spanning a certain period of time, until our Earth exited the path of these incoming extraterrestrial objects. This process seems cyclical, and with the increase of weather intensity and cosmic anomalies, we may be inevitably getting closer to this point.
According to authors Clube and Napier, we can expect to see further encounters with the remaining fragments at some point in the future. They warned us that "This unique complex of debris is undoubtedly the greatest collision hazard facing the Earth at the present time."
SOURCES
Paper: Proceedings for the National Academy of Sciences - http://www.pnas.org/content/104/41/16016
Podcast: Joe Rogan Podcast #2051 – Graham Hancock Interview
Article: New Scientist, 22 May 2007: http://www.newscientist.com/article/dn11909-did-a-comet-wipe-out-prehistoric-americans.html
Article: R.B. Firestone, A. West, J.P. Kennett, et al, ‘Evidence for an extraterrestrial impact 12,900 years ago that contributed to the megafaunal extinctions and the Younger Dryas cooling’, PNAS, Vol. 104, No. 41, 9 October 2007
Article: Antonio Zamora, “A model for the geomorphology of the Carolina Bays”, Geomorphology, Vol 282, 1 April 2017, op.cit., p.215
Book: Antonio Zamora - Killer Comet (2016)
Article: Andrew Curry, “Coming to America,” Nature, Vol 485, 3 May 2012, pp. 30-32
Article: "Young Americans”, Nature, Vol 485, 3 May 2012, page 6
Book: Victor Clube and Bill Napier - The Cosmic Winter, p. 153.
Book: Sir Fred Hoyle, The Origin of the Universe and the Origin of Religion, op. cit., p. 29.
Document: LG Thompson (1998) - A 25,000-Year Tropical Climate History from Bolivian Ice Cores https://www.ncbi.nlm.nih.gov/pubmed/9836630
Document: G.H. Denton, C.H. Hendy - Younger Dryas age advance of Franz Josef Glacier in the Southern Alps of New Zealand https://www.ncbi.nlm.nih.gov/pubmed/17838426
Document: Michail I. Petaev https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3740870/
Document: Evidence for deposition of 10 million tonnes of impact spherules across four continents 12,800 y ago - https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3677428/
Magazine: Quarternary Research - Volume 7, Issue 3 May 1977 , pp. 413-427
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