speaking of extinction series
books - 'sixth extinction'
- The Sixth Extinction: An Unnatural History, a 2014 book by Elizabeth Kolbert about the Holocene extinction
- The Sixth Extinction, a 1996 book by Richard Leakey and Roger Lewin
- "The Sixth Extinction" (The X-Files), an episode of The X-Files
- "The Sixth Extinction II: Amor Fati", an episode of The X-Files
Comet 'wiped out highly advanced ancient civilisation after smashing into Earth nearly 13,000 years ago'
Forbidden History: Vatican’s long plot to cover up the history of the pre-flood world
Wiki - Last glacial period - c. 110,000 – c. 11,700 years ago - (Max = c. 22,000 years ago)
Wiki - also lists this period - c. 125,000 – c. 14,500 years ago - (Max = c. 26,500 years ago)
"From the point of view of human archaeology, it falls in the Paleolithic and Mesolithic periods. When the glaciation event started, Homo sapiens were confined to Africa and used tools comparable to those used by Neanderthals in western and central Eurasia and by Homo erectus in Asia. Near the end of the event, Homo sapiens spread into Eurasia and Australia. Archaeological and genetic data suggest that the source populations of Paleolithic humans survived the last glacial period in sparsely wooded areas and dispersed through areas of high primary productivity while avoiding dense forest cover. The retreat of the glaciers allowed groups of Asians to migrate to the Americas and populate them."
"In the Himalaya and the Tibetan Plateau, glaciers advanced considerably, particularly between 45,000 and 25,000 BCE, but these datings are controversial. The formation of a contiguous ice sheet on the Tibetan Plateau is controversial."
"Deglaciation commenced in the Northern Hemisphere approximately 19,000 years BP, and in Antarctica approximately 14,500 years BP which is consistent with evidence that this was the primary source for an abrupt rise in the sea level 14,500 years ago."
"Approximately 13,000 years ago, the Late Glacial Maximum began. Around 11,700 years ago marked the beginning of the Holocene geological epoch, which includes the Holocene glacial retreat."
Wiki - Pleistocene megafauna -
"There is no evidence of megafaunal extinctions at the height of the LGM, indicating that increasing cold and glaciation were not factors. Multiple events appear to also involve the rapid replacement of one species by one within the same genus, or one population by another within the same species, across a broad area."
"Modern humans then made their way across the Bering land bridge and into North America between 20,000-11,000 years ago, after the Wisconsin glaciation had retreated but before the Bering land bridge became inundated by the sea. These people then populated the Americas. In the Fertile crescent the first agriculture was developing 11,500 years ago.
"Four theories have been advanced as likely causes of these extinctions: hunting by the spreading humans, climatic change, spreading disease, and an impact from an asteroid or comet. These factors are not necessarily exclusive: two or more may have combined to cause the extinctions. Most evidence suggests that humans were responsible for these extinctions.
See also: Quaternary Extinction Event
Wiki - Younger Dryas - c. 12,900 to c. 11,700 years ago
"The Younger Dryas saw a sharp decline in temperature over most of the northern hemisphere, at the end of the Pleistocene epoch, immediately preceding the current warmer Holocene. It was the most recent and longest of several interruptions to the gradual warming of the Earth's climate since the severe Last Glacial Maximum, c. 27,000 to 24,000 calendar years BP. The change was relatively sudden, taking place in decades, and resulted in a decline of 2 to 6 degrees Celsius, advances of glaciers and drier conditions, over much of the temperate northern hemisphere. It is thought to have been caused by a decline in the strength of the Atlantic meridional overturning circulation, which transports warm water from the equator towards the North Pole, and which in turn is thought to have been caused by an influx of fresh cold water from North America into the Atlantic. The Younger Dryas was a period of climatic change, but the effects were complex and variable. In the southern hemisphere, and some areas of the north such as southeastern North America, there was a slight warming."
"Based upon solid geological evidence, consisting largely of the analysis of numerous deep cores from coral reefs, variations in rates of sea level rise have been reconstructed for the postglacial period. For the early part of deglacial sea level rise, three major periods of accelerated sea level rise, called meltwater pulses, occurred. They are commonly called meltwater pulse 1A0 between 19,000 and 19,500 calendar years ago; meltwater pulse 1A between circa 14,600 and 14,300 calendar years ago; and meltwater pulse 1B between circa 11,400 and 11,100 calendar years ago."
"A hypothesized Younger Dryas impact event, presumed to have occurred in North America around 12,900 calendar years ago, has been proposed as the mechanism to have initiated the Younger Dryas cooling. Amongst other things findings of melt-glass material in sediments in Pennsylvania, South Carolina, and Syria have been reported. These researchers argue that this material, which dates back nearly 13,000 calendar years ago, was formed at temperatures of 1,700 to 2,200 °C (3,100 to 4,000 °F) as the result of a bolide impact. They argue that these findings support the controversial Younger Dryas Boundary (YDB) hypothesis, that the bolide impact occurred at the onset of the Younger Dryas. The hypothesis has been questioned by research that stated that most of the conclusions cannot be repeated by other scientists, misinterpretation of data, and the lack of confirmatory evidence. After a review of the sediments that are found at the sites, new research found that sediments claimed, by the hypothesis proponents, to be deposits resulting from a bolide impact were, in fact, dated from much later or much earlier time periods than the proposed date of the cosmic impact. The researchers examined 29 sites that are commonly referenced to support the impact theory to determine if they can be geologically dated to around 13,000 calendar years ago. Crucially, only 3 of the sites actually date from that time.
"In a study published in the Journal of Geology in its September 2014 issue, Charles R. Kinzie (et al.) looked at the distribution of nanodiamonds produced during extraterrestrial collisions; 50 million square kilometers of Northern Hemisphere at YDB was found to have these nanodiamonds. Only two layers exist showing such nanodiamonds: the YDB 12,800 calendar years ago and the Cretaceous-Tertiary boundary 65 million years ago, which is also marked by the mass extinctions.
"“The evidence we present settles the debate about the existence of abundant YDB nanodiamonds,” Kennett said. “Our hypothesis challenges some existing paradigms within several disciplines, including impact dynamics, archaeology, paleontology, paleoceanography, and paleoclimatology, all affected by this relatively recent cosmic impact.”"
Wiki - Younger Dryas impact hypothesis - c. 12,900 years ago ("10,900 uncalibrated"), North America
"The current impact hypothesis states that the air burst(s) or impact(s) of a swarm of carbonaceous chondrites or comet fragments set areas of the North American continent on fire, causing the extinction of most of the megafauna in North America and the demise of the North American Clovis culture after the last glacial period. The Younger Dryas ice age lasted for about 1,200 years before the climate warmed again. This swarm is hypothesized to have exploded above or possibly on the Laurentide Ice Sheet in the region of the Great Lakes, though no impact crater has been yet identified and no physical model by which a such a swarm could form or explode in the air has been proposed. Nevertheless, the proponents suggest that it would be physically possible for such an air burst to have been similar to, but orders of magnitude larger, than the Tunguska event of 1908. The hypothesis proposed that animal and human life in North America not directly killed by the blast or the resulting coast-to-coast wildfires would have likely starved on the burned surface of the continent."
Wiki - Holocene - c. 11,700 years ago - present - (modern era)
"Ice melt caused world sea levels to rise about 35 m (115 ft) in the early part of the Holocene. In addition, many areas above about 40 degrees north latitude had been depressed by the weight of the Pleistocene glaciers and rose as much as 180 m (590 ft) due to post-glacial rebound over the late Pleistocene and Holocene, and are still rising today. The sea level rise and temporary land depression allowed temporary marine incursions into areas that are now far from the sea."
"A number of large animals including mammoths and mastodons, saber-toothed cats like Smilodon and Homotherium, and giant sloths disappeared in the late Pleistocene and early Holocene—especially in North America, where animals that survived elsewhere (including horses and camels) became extinct. This extinction of American megafauna has been explained as caused by the arrival of the ancestors of Amerindians; though most scientists assert that climatic change also contributed. In addition, a controversial bolide impact over North America has been hypothesized to have triggered the Younger Dryas."
Wiki - Holocene extinction - c. 11,700 years ago - present - (modern era), but extended from earlier extinctions
"The Holocene extinction, otherwise referred to as the Sixth extinction or Anthropocene extinction, is the ongoing extinction event of species during the present Holocene epoch mainly due to human activity. The large number of extinctions span numerous families of plants and animals including mammals, birds, amphibians, reptiles and arthropods. With widespread degradation of highly biodiverse habitats such as coral reefs and rainforest, as well as other areas, the vast majority are thought to be undocumented. According to the species-area theory and based on upper-bound estimating, the present rate of extinction may be up to 140,000 species per year, making it the greatest loss of biodiversity since the Cretaceous–Paleogene extinction event.
"The Holocene extinction includes the disappearance of large land animals known as megafauna, starting at the end of the last Ice Age. Megafauna outside of the African continent, which did not evolve alongside humans, proved highly sensitive to the introduction of new predation, and many died out shortly after early humans began spreading and hunting across the Earth (additionally, many African species have also gone extinct in the Holocene). These extinctions, occurring near the Pleistocene–Holocene boundary, are sometimes referred to as the Quaternary extinction event.""The Holocene extinction is also known as the "Sixth extinction", due to it being the sixth mass extinct event, after the Ordovician–Silurian extinction events, the Late Devonian extinction, the Permian–Triassic extinction event, the Triassic–Jurassic extinction event, and the Cretaceous–Paleogene extinction event. There is no general agreement on where the Holocene, or anthropogenic, extinction begins, and the Quaternary extinction event, which includes climate change resulting in the end of the last ice age, ends, or if they should be considered separate events at all. Some have suggested that anthropogenic extinctions may have begun as early as when the first modern humans spread out of Africa between 100,000 and 200,000 years ago, which is supported by rapid megafaunal extinction following recent human colonisation in Australia, New Zealand and Madagascar, in a similar way that any large, adaptable predator moving into a new ecosystem would. In many cases, it is suggested even minimal hunting pressure was enough to wipe out large fauna, particularly on geographically isolated islands. Only during the most recent parts of the extinction have plants also suffered large losses.
"In The Future of Life (2002), E.O. Wilson of Harvard calculated that, if the current rate of human disruption of the biosphere continues, one-half of Earth's higher lifeforms will be extinct by 2100.""
"The Holocene extinction is mainly caused by human activity. Extinction of animals, plants, and other organisms caused by human actions may go as far back as the late Pleistocene, over 12,000 years ago. There is a correlation between megafaunal extinction and the arrival of humans, and human population growth, most prominently in the past two centuries, is regarded as one of the underlying causes of extinction.
"Megafauna was once found on every continent of the world and large islands such as New Zealand and Madagascar, but is now almost exclusively found on the continent of Africa, with notable comparisons on Australia and the islands previously mentioned experiences population crashes and trophic cascades shortly after the earliest human settlers. It has been suggested that the African megafauna survived as they evolved alongside humans. The timing of South American megafaunal extinction does not appear to correspond to human arrival, although the possibility of whether human activity at the time may have impacted the global climate enough to cause such an extinction has been suggested."
"In South America's Amazon Basin, it is estimated that such lateral diffusion was reduced over 98% following the megafaunal extinctions that occurred roughly 12,500 years ago."
Wiki - Anthropocene - modern era, orverlaps with Holocene, late Pleistocene
"The Anthropocene has no agreed start-date, but one proposal, based on atmospheric evidence, is to fix the start with the Industrial Revolution (late eighteenth century). Other scientists link the new term to earlier events, such as the rise of agriculture and the Neolithic Revolution (around 12,000 years BP). Evidence of relative human impact - such as the growing human influence on land use, ecosystems, biodiversity, and species extinction - is substantial; scientists think that human impact has significantly changed (or halted) the growth of biodiversity. Those arguing for earlier dates posit that the proposed Anthropocene may have begun as early as 14,000 to 15,000 years before present, based on geologic evidence; this has led other scientists to suggest that "the onset of the Anthropocene should be extended back many thousand years";:1 this would be closely synchronous with the current term, Holocene."
"The concept of the Anthropocene has also been approached via humanities such as philosophy, literature and art. In the scholarly world, it has been the subject of increasing attention through special journal issues, conferences, and disciplinary reports. The Anthropocene, its attendant timescale, and ecological implications prompts questions about death and the ends of civilization, memory and archives, the scope and methods of humanistic inquiry, and emotional responses to the "end of nature". It has been also criticized as an ideological construct. Some environmentalists on the political left suggest that "Capitalocene" is a more historically appropriate term. At the same time, others suggest that the Anthropocene is overly focused on the human species, while ignoring systematic inequalities, such as imperialism and racism, that have also shaped the world."
[NOTE] - I have been focusing, approximately, around the possible date of a possible meteor/comet hit on Antarctica, around 12,700 or 12,800 years ago. However, extinctions were occurring earlier in the Pleistocene, possibly going back to when humans left Africa, 100,000-200,00 years ago. Lost megafauna, surely affected by human encroachment, also included NEADERTAL.
But, we left Africa due to CLIMATE CHANGE. So, it is probably naive to attribute all loss of megafauna upon human effects. Instead, it was a MULTIFACTORAL deal, where megafauna were also plowed down by the same climate change that made us leave Africa. Humans most probably did not cause climate change so long ago, but their burning of forests certainly added to climate change. Same deal today, but more-so.
65 million years ago, the dinosaurs were made extinct. The main hypothesis is that a violent meteor/comet/s killed them. Very possible. But, I have studied this subject for years. Prior to the quick extinction of the dinosaurs, there were OTHER increasing extinctions of other dinosaurs. AND, prior to this, as in other mass extinctions, there was already a rapidly increasing extinction of life in the oceans. This says to me that climate and atmospheric change was occurring long before the meteor hit, and wiped out the dinosaurs. It is important to understand this.
I have found that there is a provable correlation between climate change and an increase of tectonic, geo-magnetic, and volcanic events - as well as an increase of meteor and/or comet hits. That means that there are wider, galactic, changes framing these events here on Earth. A multifactoral process is what killed the dinosaurs - and this is what is also happening today.
As in the extinction of the dinosaurs, the Holocene and Younger Dryas extinctions - the SIXTH EXTINCTION was already happening long before 12,700 years ago, as much as hundreds of thousands of years ago, with climate change and human emigration. This is a long time-span. The best Wiki article on this is:
Wiki - Quaternary extinction event - c. 2.588 million years ago to present, especially LATE
Excellent discussion, facts and illustrations! I don't know why there are all these overlapping eras. There is no real order to it. The Quaternary includes both the old-time Pleistocene, and the current Holocene, (or Anthropocene). Both periods experienced mass extinctions, (especially around 12,700 years ago). I highly recommend this Wiki entry, and will not bother you about it any further.
Except, the thing to remember is this: The Sixth Mass Extinction occurred in the LATE Quaternary, in the late Pleistocene, but it seriously picked up in the Younger Dryas and in the present Holocene. We are now the inheritors of this mass extinction, which is more and more caused by humans, the winners, so far, in the game of climate change.
I believe that it is very possible that no-trace comets hit the North American ice sheet. But this was only a new, precipitating event, in the ongoing extinction of megafauna, which had to do with humans, climate change, and sea-level rise.
The dates far above in this post are not concordant. Scientists do not all agree. So, I will leave it to you, for now, to ponder whether a meteor/comet hit upon ANTARCTICA may have caused the actual rapid sea-level rise, which in turn led to extinction and migration changes, around 12,700.
The main reason why I am not posing my own hypotheses and thoughts in this here post is because I tried to to that a few weeks ago, and my entire post was lost. So, you do the thinking for now. I'll get back to this later. All I am really trying to do is to decrease the number of tabs in my Firefox Browser before it crashes and destroys everything!
The SIXTH GREAT EXTINCTION is in the Anthropocene - but also in the Holocene - but also in the Younger Dryas and the Pleistocene and the Quaternary, which is a part of the Cenozoic - agggghhhhh!! Conveniently, all of this academic dys-classification blinds us to what is really going on in the real world - of life, not ice - not rock. Unfortunately, there seems to be no entry in Wiki for, "Sixth Great Extinction," so, here is a very good, broader reference:
Wiki - Extinction event
Finally, here are some decent Wiki links -
Timeline of Glaciation
Geologic time scale
Holocene Temperature Variations