Reference List for the Younger Dryas Impact

[Carnoferox]

Here is a list of papers I've found that discuss the Younger Dryas impact hypothesis (YDIH), which was originally proposed by Firestone et al. (2007).

Supporting (20):

• Bunch, T.E. et al. (2012). Very high-temperature impact melt products as evidence for cosmic airbursts and impacts 12,900 years ago. Proceedings of the National Academy of Sciences, 109(28), 1903-1912.
• Firestone, R.B. et al. (2007). Evidence for an extraterrestrial impact 12,900 years ago that contributed to the megafaunal extinctions and the Younger Dryas cooling. Proceedings of the National Academy of Sciences, 104(41), 16016-16021.
• Firestone, R.B. (2009). The case for the Younger Dryas extraterrestrial impact event: Mammoth, megafauna, and Clovis extinction 12,900 years ago. Journal of Cosmology, 2, 256-285.
• Firestone, R.B. et al. (2010). Confirmation of the Younger Dryas boundary (YDB) data at Murray Springs, AZ. Proceedings of the National Academy of Sciences, 107(26), 105.
• Firestone, R.B. et al. (2010). Analysis of the Younger Dryas impact layer. Journal of Siberian Federal University: Engineering and Technologies, 3(1), 30-62.
• Israde-Alcántara, I. et al. (2012). Evidence from central Mexico supporting the Younger Dryas extraterrestrial impact hypothesis. Proceedings of the National Academy of Sciences, 109(13), 738-747.
• Kennett, D.J. et al. (2008). Wildfire and abrupt ecosystem disruption on California's Northern Channel Islands at the Ållerød–Younger Dryas boundary (13.0–12.9 ka). Quaternary Science Reviews, 27, 2530-2545.
• Kennett, D.J. et al. (2009). Shock-synthesized hexagonal diamonds in Younger Dryas boundary sediments. Proceedings of the National Academy of Sciences, 106(31), 12623-12628.
• Kennett, D.J. et al. (2009). Nanodiamonds in the Younger Dryas boundary sediment layer. Science, 323, 94.
• Kennett, J.P. et al. (2015). Bayesian chronological analyses consistent with synchronous age of 12,835–12,735 Cal B.P. for Younger Dryas boundary on four continents. Proceedings of the National Academy of Sciences, 112(32), 4344-4353.
• Kennett, J.P. et al. (2015). Reply to Holliday and Boslough et al.: Synchroneity of widespread Bayesian-modeled ages supports Younger Dryas impact hypothesis. Proceedings of the National Academy of Sciences, 112(49), 6723-6724.
• Kurbatov, A.V. et al. (2010). Discovery of a nanodiamond-rich layer in the Greenland ice sheet. Journal of Glaciology, 56(199), 747-757.
• LeCompte, M.A. et al. (2012). Independent evaluation of conflicting microspherule results from different investigations of the Younger Dryas impact hypothesis, Proceedings of the National Academy of Sciences, 109(44), 2960-2969.
• Mahaney, W.C. et al. (2010). Evidence for a cosmogenic origin of fired glaciofluvial beds in the northwestern Andes: Correlation with experimentally heated quartz and feldspar. Sedimentary Geology, 231, 31-40.
• Mahaney, W.C., et al. (2010). Evidence from the northwestern Venezuelan Andes for extraterrestrial impact: The black mat enigma. Geomorphology, 116, 48-57.
• Mahaney, W.C. et al. (2011). Fired glaciofluvial sediment in the northwestern Andes: Biotic aspects of the Black Mat. Sedimentary Geology, 237, 73-83.
• Moore, C.R. et al. (2017). Widespread platinum anomaly documented at the Younger Dryas onset in North American sedimentary sequences. Scientific Reports, 7: 44031. doi:10.1038/srep44031
• Petaev, M.I. et al. (2013). Large Pt anomaly in the Greenland ice core points to a cataclysm at the onset of Younger Dryas. Proceedings of the National Academy of Sciences, 110(32), 12917-12920.
• Wittke, J.H. et al. (2013). Evidence for deposition of 10 million tonnes of impact spherules across four continents 12,800 y ago. Proceedings of the National Academy of Sciences, 110(23), 2088-2097.
• Wu, Y. et al. (2013). Origin and provenance of spherules and magnetic grains at the Younger Dryas boundary. Proceedings of the National Academy of Sciences, 110(38), 3557-3566.

Dissenting (26):

• Bement, L.C. et al. (2014). Quantifying the distribution of nanodiamonds in pre-Younger Dryas to recent age deposits along Bull Creek, Oklahoma Panhandle, USA. Proceedings of the National Academy of Sciences, 111(5), 1726-1731.
• Boslough, M. et al. (2012). Arguments and evidence against a Younger Dryas impact event. Geophysical Monograph Series, 198, 13-26.
• Boslough, M. (2013). Faulty protocols yield contaminated samples, unconfirmed results. Proceedings of the National Academy of Sciences, 110(18), 1651.
• Boslough, M. et al. (2015). Incomplete Bayesian model rejects contradictory radiocarbon data for being contradictory. Proceedings of the National Academy of Sciences, 112(49), 6722.
• Daulton, T.L. et al. (2010). No evidence of nanodiamonds in Younger-Dryas sediments to support an impact event. Proceedings of the National Academy of Sciences, 107(37), 16043-16047.
• Daulton, T.L. (2012). Suspect cubic diamond "impact" proxy and a suspect lonsdaleite identification. Proceedings of the National Academy of Sciences, 109(34), 2242.
• Daulton, T.L. et al. (2017). Comprehensive analysis of nanodiamond evidence relating to the Younger Dryas Impact Hypothesis. Journal of Quaternary Science, 32(1), 7-34.
• Hardiman, M. et al. (2012). Inconsistent redefining of the carbon spherule "impact" proxy. Proceedings of the National Academy of Sciences, 109(34): 2244. 
• Harris-Parks, E. (2014). The micromorphology of Younger Dryas-aged black mats from Nevada, Arizona, Texas, and New Mexico. Master's thesis: University of Arizona.
• Haynes, C.V. Jr. et al. (2010). Reply to Firestone et al.: No confirmation of impact at the lower Younger Dryas boundary at Murray Springs, AZ. Proceedings of the National Academy of Sciences, 107(26), 106.
• Haynes, C.V. Jr. et al. (2010). The Murray Springs Clovis site, Pleistocene extinction, and the question of extraterrestrial impact. Proceedings of the National Academy of Sciences, 107(9), 4010-4015.
• Holliday, V. & Meltzer, D.J. (2010). The 12.9-ka ET impact hypothesis and North American Paleoindians. Current Anthropology, 51(5), 575-607.
• Holliday, V. et al. (2014). The Younger Dryas impact hypothesis: A cosmic catastrophe. Journal of Quaternary Science, 29(6), 515-530.
• Holliday, V. (2015). Problematic dating of claimed Younger Dryas boundary impact proxies. Proceedings of the National Academy of Sciences, 112(49), 6721.
• Holliday, V. et al. (2016). A blind test of the Younger Dryas impact hypothesis. PLoS ONE, 11(7): e0155470. doi:10.1371/journal.pone.0155470
• Meltzer, D.J. et al. (2014). Chronological evidence fails to support claim of an isochronous widespread layer of cosmic impact indicators dated to 12,800 years ago. Proceedings of the National Academy of Sciences, 111(21), 2162-2171.
• Németh, P. et al. (2015). Twinning of cubic diamond explains reported nanodiamond polymorphs. Scientific Reports, 5: 18381. doi:10.1038/srep18381
• Paquay, F.S. et al. (2009). Absence of geochemical evidence for an impact event at the Bølling–Allerød/Younger Dryas transition. Proceedings of the National Academy of Sciences, 106(51), 21505-21510.
• Pigati, J.S. et al. (2012). Accumulation of impact markers in desert wetlands and implications for the Younger Dryas impact hypothesis. Proceedings of the National Academy of Sciences, 109(19), 7208-7212.
• Pinter, N. et al. (2011). The Younger Dryas impact hypothesis: A requiem. Earth-Science Reviews, 106, 247-264.
• Scott, A.C. et al. (2010). Fungus, not comet or catastrophe, accounts for carbonaceous spherules in the Younger Dryas "impact layer". Geophysical Research Letters, 37(14): L14302. doi:10.1029/2010GL043345
• Surovell, T.A. et al. (2009). An independent evaluation of the Younger Dryas extraterrestrial impact hypothesis. Proceedings of the National Academy of Sciences, 106(43), 18155-18158.
• Tian, H. et al. (2010). Nanodiamonds do not provide unique evidence for a Younger Dryas impact. Proceedings of the National Academy of Sciences, 108(1), 40-44.
• van der Hammen, T. & van Geel, B. (2008). Charcoal in soils of the Allerød-Younger Dryas transition were the result of natural fires and not necessarily the effect of an extra-terrestrial impact. Netherlands Journal of Geosciences, 87(4), 359-361.
• van Hoesel, A. et al. (2012). Nanodiamonds and wildfire evidence in the Usselo horizon postdate the Allerød-Younger Dryas boundary. Proceedings of the National Academy of Sciences, 109(20), 7648-7653.
• van Hoesel, A. et al. (2014). The Younger Dryas impact hypothesis: A critical review. Quaternary Science Reviews, 83, 95-114.

If anyone finds more papers concerning YDIH then post a link to it with the proper citation.

Edited September 4, 2017 by Carnoferox

[bmk1245]

I find arguments against YDIH quite compelling.

BTW, kudos for list 

[Carnoferox]

14 minutes ago, bmk1245 said:

I find arguments against YDIH quite compelling.

BTW, kudos for list 

Same here. Unfortunately some give it credence without having read the relevant literature first.

[Carnoferox]

Two new papers supporting YDIH:

• Wolbach, W.S. et al. (2018a). Extraordinary biomass-burning episode and impact winter triggered by the Younger Dryas cosmic impact ∼12,800 years ago. 1. Ice cores and glaciers. Journal of Geology. doi:10.1086/695703
• Wolbach, W.S. et al. (2018b). Extraordinary biomass-burning episode and impact winter triggered by the Younger Dryas cosmic impact ∼12,800 years ago. 2. Lake, marine, and terrestrial sediments. Journal of Geology. doi:10.1086/695704

[Carnoferox]

Here are some additional papers not previously listed, all supporting YDIH.

• Andronikov, A.V., & Andronikova, I.E. (2016). Sediments from around the lower Younger Dryas boundary (SE Arizona, USA): implications from LA-ICP-MS multi-element analysis. Geografiska Annaler Series A, Physical Geography, 98, 221-236.
• Andronikov, A.V. et al. (2016a). Implications from chemical, structural and mineralogical studies of magnetic microspherules from around the Younger Dryas boundary (New Mexico, USA). Geografiska Annaler Series A, Physical Geography, 98, 39-59.
• Andronikov, A.V. et al. (2016b). Trace element distribution and implications in sediments across the Allerød–Younger Dryas boundary in the Netherlands and Belgium. Geografiska Annaler Series A, Physical Geography, 98, 325-345.
• Fayek, M. et al. (2012). Framboidal iron oxide: chondrite-like material from the black mat, Murray Springs, Arizona. Earth and Planetary Science Letters, 319-320, 251-258.
• Kinzie, C.R. et al. (2014). Nanodiamond-rich layer across three continents consistent with major cosmic impact at 12,800 cal BP. The Journal of Geology, 122(5), 475-506.
• Mahaney, W.C., & Keiser, L. (2013). Weathering rinds: unlikely host clasts for evidence of an impact-induced event. Geomorphology, 184, 74-83.
• Mahaney, W.C., & Krinsley, D. (2012). Extreme heating events and effects in the natural environment: implications for environmental geomorphology. Geomorphology, 139-140, 348-359.
• Mahaney, W.C. et al. (2011). Notes on the black mat sediment, Mucuñuque catchment, northern Mérida Andes, Venezuela. Journal of Advanced Microscopy Research, 6(3), 177-185.
• Mahaney, W.C. et al. (2013). Weathering rinds as mirror images of palaeosols: examples from the Western Alps with correlation to Antarctica and Mars. Journal of the Geological Society, London, 170, 833-847.
• Mahaney, W.C. et al. (2016). A microbial link to weathering of postglacial rocks and sediments, Mount Viso area, Western Alps, demonstrated through analysis of a soil/paleosol bio/chronosequence. The Journal of Geology, 124(2), 149-169.
• Mahaney, W.C. et al. (2017). Evidence for cosmic airburst in the Western Alps archived in Late Glacial paleosols. Quaternary International, 438, 68-80.
• Melott, A.L. et al. (2010). Cometary airbursts and atmospheric chemistry: Tunguska and a candidate Younger Dryas event. Geology, 38(4), 355-358.
• Redmond, B.G., & Tankersley, K.B. (2011). Species response to the theorized Clovis comet impact at Sheriden Cave, Ohio. Current Research in the Pleistocene, 28, 141-143

[I'mConvinced]

For me, the biggest piece of evidence against YDI has to be the extinction patterns.  There should be a massive singular decline followed by a slow recovery across all species in the effected area and this isn't seen. 

 

[Piney]

3 hours ago, I'mConvinced said:

For me, the biggest piece of evidence against YDI has to be the extinction patterns.  There should be a massive singular decline followed by a slow recovery across all species in the effected area and this isn't seen. 

 

The extinction started during the initial wet "warm up" then didn't change in the dry "cool down" which always led me to believe that diseases then starvation through drought caused the megafauna collapse in North America. There is no "mass graves" with scorched bones of these large animals. 

[Piney]

Here's a possible source of the tektites found in North America.  The Chesapeake Bay Impact. 

https://pubs.er.usgs.gov/publication/70018511

[Unusual Tournament]

I still recon that Goblekli Tepe is a recording of an Astroid/meteor strike that changed the climate. Phew... There I said it at long last.

Edited October 15, 2018 by Captain Risky

[Piney]

25 minutes ago, Captain Risky said:

I still recon that Goblekli Tepe is a recording of an Astroid/meteor strike that changed the climate. Phew... There I said it at long last.

Well, there is no evidence for it. NONE.

The most recent large meteor recorded was recorded in Estonian legend. But it was too far away to effect Goblekli Tepe.

https://en.wikipedia.org/wiki/Kaali_crater

[Orphalesion]

12 minutes ago, Piney said:

Well, there is no evidence for it. NONE.

The most recent large meteor recorded was recorded in Estonian legend. But it was too far away to effect Goblekli Tepe.

https://en.wikipedia.org/wiki/Kaali_crater

That place looks beautiful!

[jesshill]

Captain Risky,

Thanks for your comment.

As I recall, geologist and author Dr. Robert Schoch also had speculated at one time that there was a comet impact about 10,900 BCE (in keeping with Firestone’s timeline).  I think he also speculated that the Sphinx may have been built to memorialize that event. However, in his most recent book, Forgotten Civilization, he suggests that Goblekli Tepe was built around the time of the extreme warming event that brought the Younger-Drays to a close (about 9,700 BCE). Sometime along the way he changed his mind about the comet impact theory. in his most recent book, Forgotten Civilization, he writes:

“How do we explain this pattern of abrupt climatic shifts? I once hypothesized that comets were responsible. A comet hitting the land or a shallow ocean, or exploding above the land's surface, scattering dust and debris into the atmosphere, could cause global cooling. However, the evidence does not support a comet hitting Earth at this time. For more information, see Appendix 9 (“Controversies concerning the End of the Last Ice Age”) of Origins of the Sphinx. Rather, I believe it was most likely due to reduced solar activity at that time, a “solar shut-down”.

What about the warming event of circa 9700 BCE? In years past I speculated that comets hitting deep oceans were responsible. A comet might break the thin oceanic crust, releasing heat from the hot magma beneath. Vaporized and displaced water would rain down on Earth, and tsunamis would wash across coastal areas, warming the planet. But even with a comet, or a series of comets, bombarding the oceans, could the warming happen as quickly as the Greenland ice cores indicate? I think not. But if not comets, what?

Oddly, the indigenous Easter Island rongorongo script may hold the answer. But first we have to consider the concept of the fourth state of matter—plasma. Plasma consists of electrically charged particles. Familiar plasma phenomena on Earth today include lightning and auroras, the northern and southern lights, and upper atmospheric phenomena known as sprites. In the past, much more powerful plasma events sometimes took place, due to solar outbursts and coronal mass ejections (CMEs) from the Sun, or possibly emissions from other celestial objects. Powerful plasma phenomena could cause strong electrical discharges to hit Earth, burning and incinerating materials on our planet's surface. Los Alamos plasma physicist Dr. Anthony L. Peratt and his associates have established that petroglyphs found worldwide record an intense plasma event (or events) in prehistory.”

Have a great day,

Jess

[Carnoferox]

1 minute ago, jesshill said:

Captain Risky,

Thanks for your comment.

As I recall, geologist and author Dr. Robert Schoch also had speculated at one time that there was a comet impact about 10,900 BCE (in keeping with Firestone’s timeline).  I think he also speculated that the Sphinx may have been built to memorialize that event. However, in his most recent book, Forgotten Civilization, he suggests that Goblekli Tepe was built around the time of the extreme warming event that brought the Younger-Drays to a close (about 9,700 BCE). Sometime along the way he changed his mind about the comet impact theory. in his most recent book, Forgotten Civilization, he writes:

“How do we explain this pattern of abrupt climatic shifts? I once hypothesized that comets were responsible. A comet hitting the land or a shallow ocean, or exploding above the land's surface, scattering dust and debris into the atmosphere, could cause global cooling. However, the evidence does not support a comet hitting Earth at this time. For more information, see Appendix 9 (“Controversies concerning the End of the Last Ice Age”) of Origins of the Sphinx. Rather, I believe it was most likely due to reduced solar activity at that time, a “solar shut-down”.

What about the warming event of circa 9700 BCE? In years past I speculated that comets hitting deep oceans were responsible. A comet might break the thin oceanic crust, releasing heat from the hot magma beneath. Vaporized and displaced water would rain down on Earth, and tsunamis would wash across coastal areas, warming the planet. But even with a comet, or a series of comets, bombarding the oceans, could the warming happen as quickly as the Greenland ice cores indicate? I think not. But if not comets, what?

Oddly, the indigenous Easter Island rongorongo script may hold the answer. But first we have to consider the concept of the fourth state of matter—plasma. Plasma consists of electrically charged particles. Familiar plasma phenomena on Earth today include lightning and auroras, the northern and southern lights, and upper atmospheric phenomena known as sprites. In the past, much more powerful plasma events sometimes took place, due to solar outbursts and coronal mass ejections (CMEs) from the Sun, or possibly emissions from other celestial objects. Powerful plasma phenomena could cause strong electrical discharges to hit Earth, burning and incinerating materials on our planet's surface. Los Alamos plasma physicist Dr. Anthony L. Peratt and his associates have established that petroglyphs found worldwide record an intense plasma event (or events) in prehistory.”

Have a great day,

Jess

More fringe nonsense. What a surprise.

[jesshill]

Orphalesion,

Thanks for the link. I enjoyed the article very much. I wish they a bit more certain about the date.

Jess

[Piney]

4 hours ago, jesshill said:

Orphalesion,

Thanks for the link. I enjoyed the article very much. I wish they a bit more certain about the date.

Jess

It was me who put up the link....and you need a serious Geology 101 class....

[Unusual Tournament]

5 hours ago, Piney said:

It was me who put up the link....and you need a serious Geology 101 class....

are you saying that 12000 odd years there wasn’t an abrupt climate change?

[Piney]

4 hours ago, Captain Risky said:

are you saying that 12000 odd years there wasn’t an abrupt climate change?

Caused by the massive amount of moisture in the air from the glaciers melting. 

[Vrcocha]

22 hours ago, jesshill said:

Captain Risky,

Thanks for your comment.

As I recall, geologist and author Dr. Robert Schoch also had speculated at one time that there was a comet impact about 10,900 BCE (in keeping with Firestone’s timeline).  I think he also speculated that the Sphinx may have been built to memorialize that event. However, in his most recent book, Forgotten Civilization, he suggests that Goblekli Tepe was built around the time of the extreme warming event that brought the Younger-Drays to a close (about 9,700 BCE). Sometime along the way he changed his mind about the comet impact theory. in his most recent book, Forgotten Civilization, he writes:

“How do we explain this pattern of abrupt climatic shifts? I once hypothesized that comets were responsible. A comet hitting the land or a shallow ocean, or exploding above the land's surface, scattering dust and debris into the atmosphere, could cause global cooling. However, the evidence does not support a comet hitting Earth at this time. For more information, see Appendix 9 (“Controversies concerning the End of the Last Ice Age”) of Origins of the Sphinx. Rather, I believe it was most likely due to reduced solar activity at that time, a “solar shut-down”.

What about the warming event of circa 9700 BCE? In years past I speculated that comets hitting deep oceans were responsible. A comet might break the thin oceanic crust, releasing heat from the hot magma beneath. Vaporized and displaced water would rain down on Earth, and tsunamis would wash across coastal areas, warming the planet. But even with a comet, or a series of comets, bombarding the oceans, could the warming happen as quickly as the Greenland ice cores indicate? I think not. But if not comets, what?

Oddly, the indigenous Easter Island rongorongo script may hold the answer. But first we have to consider the concept of the fourth state of matter—plasma. Plasma consists of electrically charged particles. Familiar plasma phenomena on Earth today include lightning and auroras, the northern and southern lights, and upper atmospheric phenomena known as sprites. In the past, much more powerful plasma events sometimes took place, due to solar outbursts and coronal mass ejections (CMEs) from the Sun, or possibly emissions from other celestial objects. Powerful plasma phenomena could cause strong electrical discharges to hit Earth, burning and incinerating materials on our planet's surface. Los Alamos plasma physicist Dr. Anthony L. Peratt and his associates have established that petroglyphs found worldwide record an intense plasma event (or events) in prehistory.”

Have a great day,

Jess

Have you seen the signs in South America of where a plasma burst may have hit an ancient wall and melted the stone. There's also indications of it happening on Easter Island and Egypt. The problem is to put it back to the Younger Dryas days that would throw the official timeline completely out of wack.

Edited October 16, 2018 by Vrcocha

[jesshill]

Vrcocha

I had read about the suspected event in South America and just looked up the event in Egypt (gulp). It’s kind of scary when you look at it rather than just talk about it. There’s an interesting supposition posted at ancient-astronomer.com that you may want to read.

NASA classifies these types of events as “high energy astronomy’ which they describe as the study of astronomical objects that release electromagnetic radiation of highly energetic wavelengths. It includes X-ray astronomy, gamma-ray astronomy, and extreme UV astronomy, as well as studies of neutrinos and cosmic rays. The physical study of these phenomena is referred to as high-energy astrophysics.

So-called “Super Flares” appear to occur randomly and with varying intensities. The last two confirmed occurrences are listed below.

993 - 994 CE (or AD)

A large enhancement in the production of radioactive carbon (14C), as evidenced by dendrochronological (tree-ring) analysis, and a corresponding enhancement in the amount of the cosmogenic nuclide 10Be in the Anatrctic Dome Fuji ice core occurs, as reported by Miyake et al. (2013, Nature Comm., 4, 1748). The anomalous amounts of these radioactive nucleides are possibly caused by either the energetic particles from a very large solar flare, or, alternatively, the high-energy radiation from a nearby supernova, slamming into the Earth's upper atmosphere. The lack of historical records of a bright supernova at this epoch and the fact that a similar event occurred in 774 - 775 CE tend to favor the solar "super-flare" hypothesis.

774 - 775 CE (or AD)

A large enhancement in the production of radioactive carbon (14C), as evidenced by dendrochronological (tree-ring) analysis, possibly caused by either a very large solar flare and/or coronal mass ejection, or the high-energy radiation from a nearby supernova, slamming into the Earth's upper atmosphere. The lack of historical records of either a bright supernova visible in the sky or of intense aurorae make the actual cause of this eventrather puzzling. Hambaryan and Neuhauser (2013, MNRAS, 430, 32) hypothesize that the event was actually a short gamma-ray burst which occurred 1-4 kpc away within the Milky Way Galaxy: if correct, this would be the first evidence for a short GRB having occurred in our Galaxy. Have a great day, Jess

[Carnoferox]

@Vrcocha @jesshill

Mind taking this off-topic "plasma" stuff elsewhere?

[Unusual Tournament]

On 10/16/2018 at 7:23 PM, Piney said:

Caused by the massive amount of moisture in the air from the glaciers melting. 

something must have melted those glaciers quickly enough to cause a mini ice age. what do you suggest?

Edited October 17, 2018 by Captain Risky

[Piney]

1 minute ago, Captain Risky said:

some must have melted those glaciers quickly enough to cause a mini ice age.

That's about what happened. The extremely fast melting of the glaciers threw too much moisture in the air and cooled everything down again. 

[Unusual Tournament]

2 minutes ago, Piney said:

That's about what happened. The extremely fast melting of the glaciers threw too much moisture in the air and cooled everything down again. 

so what type of event cause something like that...?  Jesshill and Vrcocha suggest if not a comet strike then a plasma strike. both plausible due to their intense and sudden nature. 

[Piney]

4 minutes ago, Captain Risky said:

so what type of event cause something like that...?  Jesshill and Vrcocha suggest if not a comet strike then a plasma strike. both plausible due to their intense and sudden nature. 

It wasn't so intense or sudden. We didn't find any animal or human remains from a mass die off. Just a slow die off due to a  drop and rise in temperature. 

[Unusual Tournament]

3 minutes ago, Piney said:

It wasn't so intense or sudden. We didn't find any animal or human remains from a mass die off. Just a slow die off due to a  drop and rise in temperature. 

hold on... the temperature decreased and a mini ice age came about and then after 1200 years it was over, reverting back to global warming. sounds to me that something outta place and sudden occurred.