-Demosthenes- Posted October 6, 2005 Posted October 6, 2005 Carbon dating has been the focus of controversy since it’s discovery' date=' but is indeed valid for determining the age of ancient carbon containing substances. There are complications, however, with carbon dating which must be addressed to assure accuracy (Schell, 1967; Stuiver, 1967; Suess, 1967; Morris, 1978; Coleman, 1991; Lepper, 1992; Whitelaw, 1993; Morris, 1998). First of all, it is essential to understand that Carbon-14 (C-14) can only be used with geologically "young" specimens because of it’s relatively short half-life of 5,730 years (Coleman, 1991; Hamblin, 1992; Lepper, 1992; Whitelaw, 1993). There are other problems with cabon dating, such as a discrepancy in the atmospheric ratio of carbon-14 vs. carbon-12 (Whitelaw, 1993). The specific production rate (SPR) of carbon-14 in the Earth’s atmosphere is greater than the specific decay rate (SDR) (Stuiver, 1967; Brown, 1993; Whitelaw, 1993; Morris, 1998). This shows, barring a ‘young Earth’ scenario, that the C-14 production in the atmosphere has not been constant throughout Earth's existence and has therefore lead to variations of C-14 in organic deposits, depending upon carbon conditions at the time (Schell, 1967; Stuiver, 1967; Suess, 1967; Whitelaw, 1993). Another potential problem with carbon dating is contamination of target samples from modern carbon sources (Coleman, 1991; Lepper, 1992; Brown, 1993; Whitelaw, 1993). These complications are the primary focus of debate aimed to discredit C-14 dating, and if not taken into account during the calibration of the dating process, the validity of carbon dating is indeed unreliable (Suess, 1967; Brown, 1993; Whitelaw, 1993).[/quote'] What is this? What are it's implications towards evolution?
ecoli Posted October 6, 2005 Posted October 6, 2005 Maybe you should try asking Silicon out instead. hehe
Mokele Posted October 6, 2005 Posted October 6, 2005 Towards evolution, almost none. C14 dating would only be useful for Pleistocene and Holocene specimens (and dubiously on the fomrer), and most studies involving fossilized species are much older and span much longer times, so C14 isn't used. There are numerous methods of radiometric dating, all with various limitations. But all also overlap to some degree, and thus can be used to calibrate one another. Mokele
-Demosthenes- Posted October 7, 2005 Author Posted October 7, 2005 Ah, for some reason I was under the impression that carbon dating was the main idea used to date fossils.
swansont Posted October 7, 2005 Posted October 7, 2005 Ah, for some reason I was under the impression that carbon dating was the main idea used to date fossils. A common misconception.
jdurg Posted October 7, 2005 Posted October 7, 2005 Potassium dating, uranium dating, and rubidium dating tend to be used quite frequently as well.
-Demosthenes- Posted October 7, 2005 Author Posted October 7, 2005 So fossils have uraniums and stuff in them?
LucidDreamer Posted October 7, 2005 Posted October 7, 2005 There are numerous methods of radiometric dating' date=' all with various limitations. But all also overlap to some degree, and thus can be used to calibrate one another. [/quote'] Exactly, the reason that scientist use radiometric dating is not the reliability of any one method of radiometric dating, but rather the agreement of many separate methods of radiometric dating plus other forms of dating. Creationists pretend that its circular reasoning to use radiometric dating to date strata and then use strata to test the reliability of radiometric dating, but the truth is that its good science to use several methods to test and calibrate one another.
Mokele Posted October 7, 2005 Posted October 7, 2005 So fossils have uraniums and stuff in them? Not exactly. See, we have a long list of strata from places all over the world, and enough overlap so that we can make a total list of strata from now until almost the beginning of life. In many of these strata, we have volcanic inclusions of sorts that allow us to know that the lava was deposited at a particular boundary. The lava *does* contain uranium and such, at known initial concentrations, so we can use that the date the strata, then the strata to date the fossils. Mokele
Ophiolite Posted October 10, 2005 Posted October 10, 2005 Demosthenses, it is also worth remembering that to some extent the age, in years, of the fossils we examine is of only passing interest. I wouldn't really care if an Olenellus I was examining was 500 or 450 million years old. I am interested in which fossils are older, or younger, than the others. It was after all specific fossils and fossil assembalges that were first used to date, in a relative way, different strata. Absolute age dating by radiometric methods, followed much later.
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