Essay Posted October 21, 2011 Posted October 21, 2011 "...have allowed us to interpret the 4kyr BP dust-event as the fallout of a distal impact-ejecta rather than a sudden drought. I ran across this recently, and wondered if there is any biblical or other historical/anectodal record of a global event such as is suggested by this evidence below, for an impact event. === I'm still studying soils and their (recently recognized) strong influence upon climate, but impact events affect climate too.... New Trends in Soil Micromorphology Kapur, S., Mermut, A. R., Stoops, Georges Published: 2008 LC Call Number: S593.2 /.N48 /2008 Hardcover, ISBN 978-3-540-79133-1 "...have allowed us to interpret the 4kyr BP dust-event as the fallout of a distal impact-ejecta rather than a sudden drought. ...link the fallout of the far-traveled dust with high temperature effects at the soil surface and violent deflation of surface horizons by high speed winds." "Results are based on soil data from the Eastern Khabur basin (North-East Syria), the Vera Basin (Spain), and the lower Moche Valley (West Peru) compared with a new study at the reference site of Ebeon (West France)." "In the four regions studied, the intact 4kyr BP signal is identified as a discontinuous burnt soil surface with an exotic dust assemblages assigned to the distal fallout of an impact-ejecta." "Studies showed how a high quality signal allows to discriminate the short-term severe landscape disturbances linked to the exceptional 4 kyr BP dust event from more gradual environmental changes triggered by climate shift at the same time." http://espace.librar...ase=GEN01-ERA02 The co-occurrence of a sharp dust peak, low lake levels, forest reduction, and ice retreat at ca. 4-kyr BP throughout tropical Africa and West Asia have been widely explained as the effect of an abrupt climate change. The detailed study of soils and archaeological records provided evidence to re-interpret the 4 kyr BP dust event linked rather to the fallback of an impact-ejecta, but not climate change. Here we aim to further investigate the exceptional perturbation of the soil-landscapes widely initiated by the 4 kyr BP dust event. Results are based on soil data from the eastern Khabur basin (North-East Syria), the Vera Basin (Spain), and the lower Moche Valley (West Peru) compared with a new study at the reference site of Ebeon (West France). The quality of the 4 kyr BP dust signal and the related environmental records are investigated through a micromorphological study of pedo-sedimentary micro-fabrics combined with SEM-microprobe, mineralogical, and geochemical analyses. In the four regions studied, the intact 4 kyr BP signal is identified as a discontinuous burnt soil surface with an exotic dust assemblage assigned to the distal fallout of an impact-ejecta. Its unusual two-fold micro-facies is interpreted as (1) flash heating due to pulverization of the hot ejecta cloud at the soil surface, and (2) high energy deflation caused by the impact-related air blast. Disruption of the soil surface is shown to have been rapidly followed by a major de-stabilisation of the soil cover. Local factors and regional settings have exerted a major control on the timing, duration, and magnitude of landscape disturbances. Studies showed how a high quality signal allows to discriminate the short-term severe landscape disturbances linked to the exceptional 4 kyr BP dust event from more gradual environmental changes triggered by climate shift at the same time. http://www.springer....8-3-540-79133-1 The book contains state of the art new research results in micromorphology as well as other disciplines of soil science. It provides very useful up-to-date information for researchers, educators, graduate students interested in microscopic and submicroscopic studies of soils and sediments. In the past, micromorphology has been considered almost solely as a descriptive and interpretative branch of science. Attempts are now made to obtain quantitative data. There has been much progress in applying soil micromorphology in Quaternary geology, in particular identifying and characterizing palaeosols. The new areas for soil micromorphology are soil ecology, materials sciences and archaeology. There is lots of literature about the climate shift at ~4000 BP. Googled: trend in climate "4,000 years BP" http://hol.sagepub.c.../1/117.abstract "Our results show that this aridification trend began around 8000 yr BP, and culminated around 4000 yr BP." http://www.sciencedi...033589499921087 "Age-constrained pollen data and magnetic susceptibility of an alpine peat profile from the Garhwal Higher Himalaya display a continuous record of climate and monsoon trends for the past 7800 yr." "About 7800 cal yr B.P., dominance of evergreen oak (Quercus semecarpifolia), alder (Alnus), and grasses in the pollen record reflect a cold, wet climate with moderate monsoon precipitation. From 7800 to 5000 cal yr B.P., vegetation was progressively dominated by conifers, indicating ameliorated climate with a stronger monsoon. A warm, humid climate, with highest monsoon intensity, from 6000–4500 cal yr B.P. represents the mid-Holocene climatic optimum. Between 4000 and 3500 cal yr B.P., the abundance of conifers sharply decreased, with the greatest increase in evergreen oak. This trend suggests progressive cooling, with a decrease in the monsoon to its minimum about 3500 cal yr B.P. Two relatively minor cold/dry events at ca. 3000 and 2000 cal yr B.P. marked step-wise strengthening of the monsoon until ca. 1000 cal yr B.P. After a cold/dry episode that culminated ca. 800 cal yr B.P., the monsoon again strengthened and continued until today. A sharp decrease in temperature and rainfall at 4000–3500 cal yr B.P. represents the weakest monsoon event of the Holocene record. This cold/dry event correlates with proxy data from other localities of the Indian subcontinent, Arabian Sea, and western Tibet. http://www.stanford....lyr/3000bc.html4000 BC: Global; Holocene delta development worldwide Holocene delta development worldwide transgressive sequence of deltaic deposits 4000 BC: Mesopotamia; Mesopotamia delta Stratigraphic relations by the author showing the rapid development of a rich, fertile delta in Mesopotamia ALSO: http://books.google....fs1dKneX8&hl=en# "Forest Ecosystems" By David A. Perry "In the eastern North America.... A very warm and dry period from 8000 to 4000 years BP produced major changes in vegetation patterns.... The cooling trend that began approximately 4000 years BP readjusted these boundaries to roughly those we see today. Similar changes occurred in western North America." "A major warming trend beginning around 8000 BP was accompanied by both the appearance of Douglas-fir and an increase in fire frequency. With the return to a cooler, moister climate around 4000 BP, fire frequency declined and community composition shifted to western hemlock/red cedar/Douglas-fir, a forest type that persists today." === From Peru to Syria, "...the intact 4kyr BP signal is identified as ...the distal fallout of an impact-ejecta." Wow! Anybody else heard about an impact event at 4000 BP before? ~
Ophiolite Posted October 24, 2011 Posted October 24, 2011 That is an interesting possibility that merits further study. I would approach the idea cautiously: the success of the bolide impact in explaining the KT boundary extinction has made impactors a fashionable and sexy concept - an explanation in search of problems.
questionposter Posted October 25, 2011 Posted October 25, 2011 (edited) Earth naturally has its ups and downs, it wouldn't be the end of the world. Edited October 25, 2011 by questionposter
Moontanman Posted October 25, 2011 Posted October 25, 2011 This is interesting, wasn't it Emperor Constantine who on the eve of battle saw a meteor crash to the ground and took it as a sign from god to convert to Christianity? Could a large volcanic eruption account for this dust?
JohnB Posted October 30, 2011 Posted October 30, 2011 I ran across this recently, and wondered if there is any biblical or other historical/anectodal record of a global event such as is suggested by this evidence below, for an impact event. Hmmm, 2000 BC, about the beginning of the 12th Dynasty. Nothing comes to mind from anything I've read. I would have thought that any bang big enough to leave ejecta all over the globe would be mentioned by the Egyptians. However there is some confusion as to actual dating of the Kings and this might very well help solve the problem. If the impact can be accurately dated, then so could any relevent records as they are found. While it may not be connected, around the 16th C BC (give or take a century or two) the Hyksos came out of Asia somewhere with their new fangled "chariot" thingies and conquered Egypt. Given the "confusion" it might be that they were forced to move from their homelands by the abrupt change? Like I said, I'm not aware of anything, but a full blown expert on the Middle Kingdom might.
John L Posted November 22, 2011 Posted November 22, 2011 I'm always amazed(?) at the lack of knowledge, or interest, in the importance of Impactors on the planet throughout history. In fact, if there is any one thing that has played such a profound role in history, it has to be that one thing. And there are so many that no one impact can be considered without looking at the total picture. It should be obvious that earth is moving smack dab in the middle of one huge shooting gallery, and we just dodged a bullet earlier this month in the form of 2005 YU55, which is 400 metres in diametre. All one has to do is look closely at the Lake Vostok temperature chart data, and notice all the sudden drop off of temperatures throughout the last few glaciations events. Those sudden drops are most likely not due to anything But major Impactor events, which pushed the planet off the climatic cliff. And that is why Eugene Shoemaker is one of my favorite scientists, who battled the establishment dogma, when he claimed that all the craters on the lunar landscape were not the product of vulcanization, but rather Impactor craters. And at the time he was laughed at, until we actually went to the moon and brought back evidence to back him up. Think Impactors first, when you think of major geological, or climatic, change. I'll get off my soapbox now.
Ophiolite Posted November 22, 2011 Posted November 22, 2011 I'm always amazed(?) at the lack of knowledge, or interest, in the importance of Impactors on the planet throughout historyPerhaps that's because thorughout history there has been precious little evidence for impactors. We could revisit Velikovsky, with a focus on his evidence, not his mechanisms. We could look more closely at the OP research. But I stick by my earlier comment: the success of the bolide impact in explaining the KT boundary extinction has made impactors a fashionable and sexy concept - an explanation in search of problems. In asserting that the Vostok temperature drops are the result of impactors what alternatives have you considered and why have you rejected them? How well are the Vostok data supported by other palaeoclimate data? (In other words do these data global, or regional conditions?) On a lighter note, I don't think anyone ever claimed that the lunar craters were made of rubber.
JohnB Posted November 23, 2011 Posted November 23, 2011 I'm always amazed(?) at the lack of knowledge, or interest, in the importance of Impactors on the planet throughout history. In fact, if there is any one thing that has played such a profound role in history, it has to be that one thing. And there are so many that no one impact can be considered without looking at the total picture. It should be obvious that earth is moving smack dab in the middle of one huge shooting gallery, and we just dodged a bullet earlier this month in the form of 2005 YU55, which is 400 metres in diametre. All one has to do is look closely at the Lake Vostok temperature chart data, and notice all the sudden drop off of temperatures throughout the last few glaciations events. Those sudden drops are most likely not due to anything But major Impactor events, which pushed the planet off the climatic cliff. I'm sorry, but I can't let that stand unchallenged. The ice core records do indeed show precipitous drops in temperature over the the last 400,000 years but they show just as many precipitous rises in temperature. We attribute the drops to the Milancovich cycles because those cycles explain most of both the warming and cooling that we see in the records. To introduce impactors as an explanation for even a moderate percentage of the coolings leaves the associated rises in temps unaccounted for. While it is reasonable to assume impactors, the available evidence is that they were in general small (i.e. not dinosaur killers) and that their effect was either local or if global not of a long enough duration to show up in the record. Impactors large enough to effect global climate on a long term scale would have created enough ejecta to leave evidence in the sedimentary layers and the ice. There is no ash layer, ergo there were no large impactors that caused climate change.
John L Posted November 23, 2011 Posted November 23, 2011 I'm sorry, but I can't let that stand unchallenged. The ice core records do indeed show precipitous drops in temperature over the the last 400,000 years but they show just as many precipitous rises in temperature. We attribute the drops to the Milancovich cycles because those cycles explain most of both the warming and cooling that we see in the records. To introduce impactors as an explanation for even a moderate percentage of the coolings leaves the associated rises in temps unaccounted for. Challenge it any way you wish. That's your privilege. And as for rises in temperature, perhaps a little thing called 'rebound' may be the cause. And to use all those spikes up and down as an explanation of Milankovich cycles........................... there are not that many parts to the cycles. I suppose you are going to write Younger Dryas off to the Milankovich cycles too?
JohnB Posted November 23, 2011 Posted November 23, 2011 Rebound assumes some sort of preferred state to rebound to. If there is any evidence of preferred states it is between Ice Ages and slightly warmer than today. The long term record (400,000 years) shows numerous spikes and drops now termed Dansgaard–Oeschger events. But the drop is after the rise. The records show a precipitous rise in temps followed by the precipitous drop, this wouldn't be the case if the fluctuations were caused by "rebound" of some sort. Nor am I writing off the YD either. An impact event has been put forward as the cause but the evidence is slim and the temps don't really match the profile of an impact. An impact will throw up crud and cool the planet very quickly. However it doesn't stay up there very long, best estimates are 20 years or so. This being the case, we should have seen a sharp drop followed by a steady rise back to the previous temps. Even if it took 500 years for the crud to leave, the steady increase in temps should show up. What we do see is a sharp drop followed by full blown Ice Age conditions for 1,000 years and then temps rising as fast as they dropped. Meteoric dust could only explain this if we assume it stayed in the atmosphere for 950 years and then all of it was cleaned out in a 50 year period. This simply doesn't make sense. It's not that impacts don't explain the drops, they obviously can. But most of those drops occurred just after a rapid rise in temps. It is beyond possibility that every time the planet tried to lift itself out of the Ice Age a meteor arrived at exactly the right time to smack it down again. Hence the sharp rises and falls must be due to some form of "normal" forcings and not due to random events like impacts.
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