[meteorite-list] Re: Last Word (from me) on the Crackpot Theory, I Think...
From: Paul <bristolia_at_meteoritecentral.com>
Date: Tue Nov 1 12:05:20 2005 Message-ID: <20051101170513.75000.qmail_at_web36208.mail.mud.yahoo.com> Sterling Webb wrote: " The clustering I mentioned came from a complete list of dated carcases. Most dates were single and isolated times, but there were several dates clustered around the two time periods Firestone found (elsewhere) anomalies for. It was a very weak association and I probably shouldn't have even suggested it supported even vaguely the isotopic timetable. And it was the one from the "talkorigins" website you recommended, Paul." The fundamental problem. as I pointed out in my last post in detail, is not that the clustering is "weak". This problem is that given few number of dates available, it is impossible to know at this time if it exists at all. A few data points selected from a larger population of data points can be and usually is quite misleading. In case of the 30,000 to 35,000 BP period is absolutely no clustering of dates in that time period. Sterling Webb wrote: "When I referred to the megafauna extinction at 13,000 to 11,000 years ago, I was referring SOLELY to North America and said so. I specifically mentioned that the extinctions took place at other times on other continents. What Paul called this "old misstatement of the facts, which has been endlessly recycled on various catastrophist web sites despite having been long known to be quite false" was mostly taken from the web site of the American Museum of Natural History in New York, New York..." One problem is that just because something is posted on a web page does not make it true. Unfortunately, even the web pages of reputable museums are often **not** peer-reviewed and sometimes prepared by publicists and other non-scientists, who repeat what they learned years ago in school and not what is now known about the subject. As a result, old, outdated material is recycled with the best of intentions, regardless of whether the information in it is still supported by the current research. Apparently, whoever wrote the Natural Museum of Natural History web page, like the catastrophists and other people, who also repeat this claim their web pages, mindlessly repeated Paul S. Martin and H. E. Wright in their 1967 book "Pleistocene Extinctions " when they stated: "A sudden wave of large animal extinction, involving at least 200 genera, most of them lost without phyletie replacement, characterized the late Pleistocene." Unfortunately for whoever prepared the Museum of Natural History web pages, they, like various catastrophists, failed to research what they were writing. Had the done this, they would have found that in the 38 years since book "Pleistocene Extinctions " was published, research has conclusively proved that Paul S. Martin and H. E. Wright were totally wrong about there being a single and sudden wave of extinctions. They occurred at different times in different places over a period of tens of thousands of years as demonstrated by the articles, which I cited in my previous papers. The disproved nature of Martin and Wright's "200 genera" statement is important because, the fact there was **not** a single wave of extinction greatly contradicts the idea of using a supernova to explain such extinctions. (Also, it reflects badly one a person's scholarship to use antiquated and long discarded and disproved ideas to support a person's hypothesis.) The multiple waves of extinction, which occurred on different continents at different times over a period of tens of thousands of years is **not** the pattern of extinction that would be expected from a supernova, which would have caused a single synchronous extinctions event of global extent. An extinction event associated with a supernova would have more resembled the Cretaceous-Tertiary boundary because of the amount of irradiation proposed by Firestone and his colleagues based on his chert data and many other nasty aftereffects of a supernova. It is impressive that 15 genera of mostly megafauna became extinct at the end of the Pleistocene in North America. However, this is far too localized to have been caused by a supernova. Also, as noted in papers discussed in my previous post, i,e, Stafford et al (2005) paper in the same conference, which found that it actually consisted of two waves of extinction, which is inconsistent with a supernova or any other instantaneous event. A supernova or similar cosmic event also cannot explain why horses in Alaska were being subject increasing environmental stress before they became extinct in Alaska before elsewhere and why remnant populations of mammoths survived on St Paul island a couple of thousand years past 10,000 BP. Sterling wrote: "Here is the problem with my attempting to deal with the data (the isotopic anomalies). People seem to consider me instead a supporter of various theories, whacky or not, Firestone's or any other's, about extinctions. I have no brief for these theories. I am interested only in what exterior astronomical events created these isotopic anomalies. They require an explanation." There is nothing wrong with this. However, a person needs to carefully vet what they find on web pages to separate fact from either fiction; antiquated and disproved conclusions; and misstated and mangled facts. Basing your conclusions on ideas, i.e. Martin and Wright's "200 genera" statement, which have been disproved is not the way to this. ...text deleted... Sterling wrote: "Marco mentions the vagaries of radiocarbon dating and so forth. It's obvious nobody is reading the reference I gave for Firestone's earlier paper on them: <http://www.centerfirstamericans.com/mt.html?a=36 > It derives, among other things, from trying to calibrate those vagaries. As a geochronologist, he was (apparently) called in to examine material from a group of paleoindian sites that, in varying degrees, yielded anomalous dates. Below a strata well-known to date geologically to 10,000 BP (before present) are artifacts with thermoluminescent dates of 12,400 BP but with radiocarbon dates that are almost recent, 2880 BP. There are a number of these sites, including one where there is an area with an archaic cultural items whose radiocarbon date is 160 years old!" Sterling wrote: One signifcant problem here is that thermoluminescent dating presumes a steady level of radiation damage over time by the decay of radioactive elements trapped in either quartz or feldspar comprising the sand. Irradiation significant enough to have altered the isotopic composition of uranium in chert would have also caused extensive radiation damage to the quartz and feldspar in the sand surrounding. Therefore, had what Firestone and his colleagues claimed to have occurred, actually happened, any thermoluminescent dates from the effected site should have also been altered to the point of providing apparent dates considerably older than the associated Paleo-Indian artifacts. The fact, that the thermoluminescent dates are only slightly older, which is common due to incomplete bleaching of the sand, than age of the culture affiliated with the Paleo-Indian artifacts, strongly refutes the idea that these sites were irradiated at all. Had these sites been irradiated as much as proposed by Firestone, then the ages given by the thermoluminescent dates would have given apparent dates significantly older than the artifacts actually are,which was not the case. Sterling wrote: "This indicates an large excess of radiocarbon, which is normally formed in the upper atmosphere by the solar wind (protons) and cosmic rays (also protons) at a relatively constant rate, but in fact is produced in variable qualtities. But these excesses are far beyond mere variation, much larger." The fundamental problem here is that Firestone and his colleagues, although they cite texts on geomorphology and pedology, failed to understand that although Paleo-Indian archaeological deposits may occur at depth in Wisconsinan deposits that predate Holocene sediment buildup that it does not mean that these deposits are undisturbed by pedogenesis, weathering, and other processes. In case of the Paleo-Indian sites, which they mentioned, they have greatly misjudged, as did the archaeologists, who originally dug the sites, by greatly underestimating the degree to which these sites have been modified by pedogenesis, including bioturbation. The fact of matter is that it is quite possible, in fact probable, that the charcoal and other organic matter, which gave the anomalous dates was mixed into the Paleo-Indian levels by bioturbation. The claim that the archaeological sites, form which he cited C14 data have **not** been altered in any way by pedogenesis, specifically bioturbation, is simply false. It is impossible for them to claim that the C14 dated material could not have been introduced by bioturbation. Sterling Webb wrote: "Firestone finds other isotopic anomalies. The soil itself is radioactively enhanced. The uranium content of the flint implements is very abnormal. This whole area of the upper Midwest US has been, more than once, irradiated on a massive scale. Go to the link; read the details. Everything indicates a massive radiation exposure. This is not a minor occurrence. The dose is "comparable to being irradiated in a 5-megawatt reactor more than 100 seconds," in other words, instantly lethal." This paragraph states a fundamental problem with the supernova idea. Such an event would have obliterated entire ecosystems in an area, if not the entire world. In case of a supernova, the irradiation would have lasted more than 100 seconds. The initial burst of gamma rays would have destroyed Earth's ozone layer by creating massive amounts of nitrous oxide and other chemicals. As a result, the sky would have turned brown with the entire Earth shrouded in a brown toxic smog and ultraviolet radiation, 50 times above normal, powerful enough to killed exposed life, would have bathed the Earth. Even if the initial burst of gamma rays was by some mysterious process localized, such a supernova would cause a global disruption of ecosystems. More than just mammoths and mastodons would have become extinct. Not just the Midwest would have been effected. Just in the Midwest, there are more than a couple dozen cores from lakes and ponds, which have yielded pollen records recording environmental changes back into the last glacial and, in a couple case, the last interglacial. In none of these records is there indication of the type of catastrophic ecological disruptions, which such an event would have caused, for the past 14,000 years, and in a couple of cases, more than the past 100,000 years. Although Firestone and his colleagues talk about random anomalies in Be and other elements as evidence of their having been a supernova, this proposal makes absolutely no sense in the fact that the buildup of cosmogenic nuclides, i.e. Be10, Al26, and Cl36, within the upper one meter of the land's surface has been and is being used to date various types of landforms, i.e. glacial moraines, river terraces, and alluvial fans, which are hundreds of thousands of years old. The fact that cosmogenic dating works as well as it does, is strong evidence that the steady accumulation of these isotopes in the ground's surface, including dates form the Midwest, have not been disturbed by being irradiated by a supernova event. For details, look at "Cosmogenic Exposure Dating and the Age of the Earth" at http://www.geocities.com/earthhistory/tcn.htm The fact that Cosmogenic Exposure Dating works as well as it does indicates to me that the isolated and quite random isotope anomalies, from which Firestone and his colleagues base their ideas have a far different cause than they have so far proposed. The reason nobody really pays an serious attention to Firestone is that he has done an extremely poor job of understanding the consequences of what he proposed and of explaining why none of the obvious consequences of his hypothesis can be found in the enormous amount of paleoenvironmental data that has been published in the scientific literature. Best Regards, Paul __________________________________ Yahoo! FareChase: Search multiple travel sites in one click. http://farechase.yahoo.com Received on Tue 01 Nov 2005 12:05:13 PM PST |
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