Radioactive Dating Is Reliable

I. Contamination and Assumptions The large majority of isochron dating results are in accordance with the mainstream age and history of the Earth. If the results were essentially random numbers, that would not be the expected distribution of results. "Counter-intuitive" ages -- for example results which indicate an event earlier than the time of crystallization of the sampled object - are usually produced by inappropriate selection of samples, and can be avoided in most cases. The processes which could produce incorrect isochron ages require special circumstances, and are not universally applicable across the wide range of rock and mineral types on which isochron dating (by several different radioactive isotopes) has been successfully performed. Basically, most isochron dating has a built-in check for contamination, and pleas to contamination do not address the fact that radiometric results are nearly always in agreement with old-Earth expectations. If the methods were producing completely "haywire" results essentially at random, such a pattern of concordant results would not be expected. [1][2]Overall, only data that falls into a "straight line" is considered to be admissible. Incoherent results are not used. So in conclusion, while contamination is possible, in all published cases, there is a coherent line that is uncontaminated. II. InconsistenciesThe chart which my opponent provides showing the various dating attempts of the Allende meteorite is actually evidence of radioactive dating's reliability. While there is a difference of about 100 million years between the two extremes, on the scale of 4.5 billion years, that's a total error of only 2%, which is pretty good for the dating of such old objects. Consider the Mundrabrilla meteorite. There were four successive dating attempts: 4.50 +/- 0.06 by 4.57 +/- 0.06 by 4.54 +/- 0.04 by 4.50 +/- 0.04 by[2] Using the margins of error, one can reasonably assume that this meteorite is 4.51-4.52 billion years old, which all four data points agree with. Or take the meteorite Y-75011: 4.50 +/- 0.05 by 4.52 +/- 0.16 by 4.46 +/- 0.06 by 4.52 +/- 0.33 by[2] Again using the margins of error, one can reasonably assume that this meteorite is 4.50-4.52 billion years old, which all four data points agree with. Finally, here is a visual representation of several dating methods on one sample: [5]The ages of the Fen Complex (A,B) are on two separate dikes within the Fen Complex. Not only are their ages similar, but the direction of magnetization in the rocks is also identical and indicates that Oslo, Norway was located at about 30 degrees south at the time. This is an important consideration. In order to refute the ages, ye-creationists must not only explain how three different isotopic systems (with different decay constants and chemical behavior) all gave the same age and the same magnetic direction. It is also not trivial that the magnetic direction in these rocks indicates that Norway has moved northward following the emplacement of these rocks. [5][6]In the first point, I mentioned that "straight line" plots prove consistencies in dating. This is a graph showing the age of rocks as distance from a specific volcano increases (the closer to a volcano a rock is, the younger it is because it was thrown out in a recent eruption) using the dating of the formation of the Hawaiian Islands based upon radiometric dating of lava flows: [3]It shows a clear linear slope, a strong, direct correlation between the tectonic motion of the Pacific Plate over the Hawaiian hotspot, and the age of the Hawaiian Island chain. It was shown that as samples get further away from a volcano, they get older, and that the line is relatively straight (although some timeframes may have erupted more or less material, showing the small errors). [4]Overall, radioactive dating has produced very reliable, consistent results. However, my opponent does cite one sample which a large discrepancy. However, that study has a potential problem. While most layers of the ground are sorted by age, there is a possibility for overturning. There could have been overturning by faulting or folding, or lava intrusions. There are many examples of this too. [7]In addition, and more importantly, an instance where a method fails to work does not imply that it does not ever work. The question is not whether there are "undatable" objects, but rather whether or not all objects cannot be dated by a given method. The fact that one wristwatch has failed to keep time properly cannot be used as a justification for discarding all watches. These arguments also fail to address the fact that radiometric dating produces results in line with "evolutionary" expectations about 95% of the time (Dalrymple 1992, personal correspondence). The claim that the methods produce bad results essentially at random does not explain why these "bad results" are so consistently in line with mainstream science. Why is it that five radiometric dating methods agree on the age of one of the Earth's oldest rock formations? [2][8]Overall, one or two problems in dating should not discredit the whole process. Sources [1]: . http://www.talkorigins.org...[2]: . http://www.talkorigins.org...[3]: . http://www.soest.hawaii.edu...[4]: . http://www.tim-thompson.com...[5]: . http://gondwanaresearch.com...[6]: McDougall, I. and Harrison, T. M. , 1999, Geogchronology and thermochronology by the 40Ar/39Ar method, Oxford University Press, Oxford, pp. 269[7]: . http://www.examiner.com...[8]: Dalrymple, G. Brent, 1986. Radiometric Dating, Geologic Time, and the Age of the Earth: A Reply to "Scientific" Creationism. U. S. Geological Survey Open-File Report 86-110. pp. 76