.... all the fountains of the great deep broken up, and the windows of heaven were opened.
Genesis 7:11
"One of the (many) assumptions in radiometric dating, and specifically for U-Pb dating, is that most of the three lead (Pb) isotopes we see on earth (206Pb, 207Pb and 208Pb)—which today are produced by radiometric decay of Uranium (U), Thorium (Th), Actinium (Ac) and several other elements with radioactive
isotopes—were derived in the past only from radiometric decay of these elements.
This is a completely arbitrary and unprovable assumption presupposing a naturalistic evolutionary history for the universe. However, in the biblical creation worldview, God would have created all the isotopes of Pb, including both non-radiogenic Pb isotopes and the Pb isotopes, which today result from radioactive decay of U, Th, Ac, and other elements. 204Pb is the main non-radiogenic isotope of lead and is often referred to as common or initial Pb, but common or initial lead can also contain all the other stable isotopes of Pb, including 206Pb, 207Pb, and 208Pb.
Accurate radioisotope age determinations require that the decay constants (half-lives) of the parent radionuclides be precisely known and constant. However, as Dr. Snelling has written about in other articles, Uranium decay constants aren’t accurately known due to wide decay differences in the U isotope ratio in minerals and rocks which had been assumed to be constant by conventional geologists.
Additionally, the 1997–2005 RATE (Radioisotopes and the Age of The Earth) project successfully pointed out some of the pitfalls in the radioisotope dating methods, and especially in demonstrating that radioisotope decay rates have not always been constant at today’s measured rates, but have had a period of accelerated nuclear decay (during the global flood of Noah’s day).
Accurate determinations, however, depend not only on accurate determinations of the decay constants of the respective parent radioisotopes but on the reliability of the other two assumptions these supposed absolute dating methods rely on. Those are the “parent element atoms only” or “known amount of daughter element atoms” starting conditions and the a priori assumption of no contamination of closed systems.
Both assumptions are unprovable because no observers were there in the past to observe the starting conditions and that there was no subsequent contamination.
Yet secular geochronologists claim they can be circumvented via the isochron technique because it is claimed to be independent of the starting conditions and sensitive to revealing any contamination. However, even the secular publications show that any data points which fall outside the isochron are discarded as “contamination” without proving that they really are due to contamination.
Lead (Pb) is widely distributed throughout the earth, occurring not only as the radiometric decay daughter of U and Th, but also forming its own minerals apart from any U and Th. Therefore, the isotopic composition of Pb varies between wide limits, from highly “radiogenic Pb” in supposedly old U- or Th-bearing minerals to the “common Pb” in galena (PbS) and other minerals.
Zircon (ZrSiO4 ) is a common mineral, especially in granites and sandstones. It is usually claimed that such zircon grains make excellent U-Pb geochronometers. This is because it is claimed that when they crystallize, they do not incorporate Pb atoms into their crystal lattice structure. Pb2+ is regarded as being excluded from being admitted into zircon crystals because of its large ionic radius (1.32 Å) and its low charge (2+). Therefore, zircons are supposed to contain very little initial Pb at their time of formation and have high U/Pb ratios. Thus, it is presumed that all the Pb measured in them today has been added by radio decay of parent U and Th atoms since the grains crystallized.
It is acknowledged in the secular literature that for isotope dilution thermal ionization mass spectrometer (ID-TIMS) analyses common or initial Pb can be an issue with age determination of zircons, but that there are several methods to minimize or account for such initial Pb. Common lead in zircons is claimed to be primarily in inclusions, present as surface contamination, or introduced during chemical processing. To address these problems, minimization (reducing contamination) of laboratory blanks has remained the single most important requirement for high-precision U-Pb analyses. Most laboratories now claim to have reduced analytical blanks to below 5 picograms (a picogram is defined as one-trillionth of a gram, or 10-12 grams), and some to less than 1 picogram, of Pb.
So, most laboratories have incorporated into their procedures a realistically large uncertainty “error margin” for their blanks. It is often claimed that in an ID-TIMS zircon U-Pb analysis, the most crucial parameter is the ratio of radiogenic to common Pb, often indirectly expressed by the measured 206Pb/204Pb ratio.
The most direct method is by measuring non-radiogenic 204Pb that is unique to common Pb. Then once the other Pb isotopes are determined, they can be subtracted from the analysis. Then assuming the ratio of total (204Pb/206Pb) has always been a constant throughout time, you can calculate the 206Pb isotopic composition of the common Pb. Although 204Pb provides the most direct measure of common Pb, researchers realized that the low relative abundance of 204Pb can make that correction procedure imprecise, so they suggested a more precise estimate of the isotopic composition of the common Pb can sometimes be made from the 208Pb/206Pb and the measured Th/U (Thorium/Uranium) ratios. But this measurement relies on the unprovable assumptions that neither the Th/U nor radiogenic 208Pb/206Pb ratio has changed throughout the zircon’s history, except by decay, and that the zircon’s age is known.
Laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) to date zircon is claimed not to usually require large common Pb corrections. But in many cases, they selectively integrate only the most isotopically concordant data points, thereby hugely (and artificially) reducing the incidence of analyses they believed were affected by common Pb and Pb loss.
However, it could be argued that when such selections are made with the predetermined assumption that the isotopically concordant portions of the signals must yield the “correct” age of the sample being analyzed, that this is not good science, but rather is agenda-driven dogma.
Additionally, mass spectrometers are designed to primarily
measure isotopic ratios, not absolute quantities of individual isotopes. And while this is usually not made evident in secular literature, sometimes that fact creeps out. McLean, Bowring, and Gehrels (2016) admitted: that researchers are “interested in the relative abundances of isotopes present, usually expressed as ratios, and rarely require or have information on their absolute abundance to the same precision.”
As Dr. Snelling then explained, the absolute quantity of 204Pb in samples cannot be measured with certainty. Plus, to directly measure the absolute quantity of 204Pb with sufficient accuracy is muddied by isobaric interference from the 204Hg (Mercury) signal, particularly in LA-ICP-MS procedures.
-----The only way to determine an absolute amount of 204Pb from them is to make assumptions about the past history of the Pb isotopes in the samples, especially a deep time history for the earth and its origin, as well as for a deep time history for the samples being dated (for example, the Pb-evolution models). Yet the U-Pb radioisotope ages derived using those assumptions are then used to construct that deep time history. So, the outcome is model dependent, and the model chosen will be dependent on one’s worldview.
----Furthermore, the formation of igneous and metamorphosed rocks involves melting, crystallization, and/or recrystallization of minerals, which could cause the distributions of the various elements and their isotopes to be altered. So, there is no guarantee that all the atoms of U, Th, and Pb isotopes in the source rocks will be transferred into the new rocks that form (or are metamorphosed) and their constituent minerals. It is basically impossible to quantify the amount of isotopic mixing, extraction, and fractionation in mantle and crustal isotopic reservoirs at each stage, which then impacts the assumed Pb isotopic evolution in the next stage.
The Biblical creation model has several entirely scientifically reasonable postulations, which would then have significant effects on radiometrically-derived dates.
Dr. Snelling then bluntly brought out the point in his conclusion. The earth’s deep time evolutionary history has only been assumed, not proven."
AIG
Genesis 7:11
"One of the (many) assumptions in radiometric dating, and specifically for U-Pb dating, is that most of the three lead (Pb) isotopes we see on earth (206Pb, 207Pb and 208Pb)—which today are produced by radiometric decay of Uranium (U), Thorium (Th), Actinium (Ac) and several other elements with radioactive
This is a completely arbitrary and unprovable assumption presupposing a naturalistic evolutionary history for the universe. However, in the biblical creation worldview, God would have created all the isotopes of Pb, including both non-radiogenic Pb isotopes and the Pb isotopes, which today result from radioactive decay of U, Th, Ac, and other elements. 204Pb is the main non-radiogenic isotope of lead and is often referred to as common or initial Pb, but common or initial lead can also contain all the other stable isotopes of Pb, including 206Pb, 207Pb, and 208Pb.
Accurate radioisotope age determinations require that the decay constants (half-lives) of the parent radionuclides be precisely known and constant. However, as Dr. Snelling has written about in other articles, Uranium decay constants aren’t accurately known due to wide decay differences in the U isotope ratio in minerals and rocks which had been assumed to be constant by conventional geologists.
Additionally, the 1997–2005 RATE (Radioisotopes and the Age of The Earth) project successfully pointed out some of the pitfalls in the radioisotope dating methods, and especially in demonstrating that radioisotope decay rates have not always been constant at today’s measured rates, but have had a period of accelerated nuclear decay (during the global flood of Noah’s day).
Accurate determinations, however, depend not only on accurate determinations of the decay constants of the respective parent radioisotopes but on the reliability of the other two assumptions these supposed absolute dating methods rely on. Those are the “parent element atoms only” or “known amount of daughter element atoms” starting conditions and the a priori assumption of no contamination of closed systems.
Both assumptions are unprovable because no observers were there in the past to observe the starting conditions and that there was no subsequent contamination.
Yet secular geochronologists claim they can be circumvented via the isochron technique because it is claimed to be independent of the starting conditions and sensitive to revealing any contamination. However, even the secular publications show that any data points which fall outside the isochron are discarded as “contamination” without proving that they really are due to contamination.
Lead (Pb) is widely distributed throughout the earth, occurring not only as the radiometric decay daughter of U and Th, but also forming its own minerals apart from any U and Th. Therefore, the isotopic composition of Pb varies between wide limits, from highly “radiogenic Pb” in supposedly old U- or Th-bearing minerals to the “common Pb” in galena (PbS) and other minerals.
Zircon (ZrSiO
It is acknowledged in the secular literature that for isotope dilution thermal ionization mass spectrometer (ID-TIMS) analyses common or initial Pb can be an issue with age determination of zircons, but that there are several methods to minimize or account for such initial Pb. Common lead in zircons is claimed to be primarily in inclusions, present as surface contamination, or introduced during chemical processing. To address these problems, minimization (reducing contamination) of laboratory blanks has remained the single most important requirement for high-precision U-Pb analyses. Most laboratories now claim to have reduced analytical blanks to below 5 picograms (a picogram is defined as one-trillionth of a gram, or 10-12 grams), and some to less than 1 picogram, of Pb.
So, most laboratories have incorporated into their procedures a realistically large uncertainty “error margin” for their blanks. It is often claimed that in an ID-TIMS zircon U-Pb analysis, the most crucial parameter is the ratio of radiogenic to common Pb, often indirectly expressed by the measured 206Pb/204Pb ratio.
The most direct method is by measuring non-radiogenic 204Pb that is unique to common Pb. Then once the other Pb isotopes are determined, they can be subtracted from the analysis. Then assuming the ratio of total (204Pb/206Pb) has always been a constant throughout time, you can calculate the 206Pb isotopic composition of the common Pb. Although 204Pb provides the most direct measure of common Pb, researchers realized that the low relative abundance of 204Pb can make that correction procedure imprecise, so they suggested a more precise estimate of the isotopic composition of the common Pb can sometimes be made from the 208Pb/206Pb and the measured Th/U (Thorium/Uranium) ratios. But this measurement relies on the unprovable assumptions that neither the Th/U nor radiogenic 208Pb/206Pb ratio has changed throughout the zircon’s history, except by decay, and that the zircon’s age is known.
Laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) to date zircon is claimed not to usually require large common Pb corrections. But in many cases, they selectively integrate only the most isotopically concordant data points, thereby hugely (and artificially) reducing the incidence of analyses they believed were affected by common Pb and Pb loss.
However, it could be argued that when such selections are made with the predetermined assumption that the isotopically concordant portions of the signals must yield the “correct” age of the sample being analyzed, that this is not good science, but rather is agenda-driven dogma.
Additionally, mass spectrometers are designed to primarily
As Dr. Snelling then explained, the absolute quantity of 204Pb in samples cannot be measured with certainty. Plus, to directly measure the absolute quantity of 204Pb with sufficient accuracy is muddied by isobaric interference from the 204Hg (Mercury) signal, particularly in LA-ICP-MS procedures.
-----The only way to determine an absolute amount of 204Pb from them is to make assumptions about the past history of the Pb isotopes in the samples, especially a deep time history for the earth and its origin, as well as for a deep time history for the samples being dated (for example, the Pb-evolution models). Yet the U-Pb radioisotope ages derived using those assumptions are then used to construct that deep time history. So, the outcome is model dependent, and the model chosen will be dependent on one’s worldview.
----Furthermore, the formation of igneous and metamorphosed rocks involves melting, crystallization, and/or recrystallization of minerals, which could cause the distributions of the various elements and their isotopes to be altered. So, there is no guarantee that all the atoms of U, Th, and Pb isotopes in the source rocks will be transferred into the new rocks that form (or are metamorphosed) and their constituent minerals. It is basically impossible to quantify the amount of isotopic mixing, extraction, and fractionation in mantle and crustal isotopic reservoirs at each stage, which then impacts the assumed Pb isotopic evolution in the next stage.
The Biblical creation model has several entirely scientifically reasonable postulations, which would then have significant effects on radiometrically-derived dates.
- It is scientifically reasonable for Biblical Christians to believe that when God brought the earth into existence at the beginning by supernatural creation, he gave the earth an initial Pb isotopic composition, which included all four stable Pb isotopes.
- Of those four stable Pb isotopes, none of those Pb atoms had been derived by radioactive decay from U or Th (and other element’s) isotopes.
- Since that initial or primordial Pb isotopic endowment was not that of the Canyon Diablo iron meteorite’s troilite, the starting point in Pb isotopic evolution models on the divinely created earth could be very different to that assumed by evolutionists.
- Some mixing and redistribution of Pb isotopes may have occurred during Day 3 of creation week in the “Great Upheaval” where the dry land was formed from under the waters.
- The crust and the mantle underwent major melting and isotopic mixing at the time of the Flood, and there quite probably was a period of accelerated nuclear decay during this time.
- If accelerated nuclear decay did occur, then ~600 million years’ worth of daughter Pb isotopes and portions thereof were sequentially added to crustal minerals and rocks during the Flood year, which would greatly skew Pb isotopic compositions leading to secular interpretations of vastly inflated apparent ages.
Dr. Snelling then bluntly brought out the point in his conclusion. The earth’s deep time evolutionary history has only been assumed, not proven."
AIG