Radiometric Dating

Notes

1. Rhodes, 2012, p. 103: “The rocks of the Earth’s crust vary greatly in age.  Several thousand rocks from many parts of the Earth have now been measured, and the oldest–the so-called Acasta Gneiss near Great Slave Lake in northwest Canada–prove to be some 4.03 billion years old (Ga).  Slightly younger rocks are known from west Greenland (3.7-3.8 Ga), northern Michigan (3.5-3.7 Ga), and western Australia (3.4-3.6 Ga). Zircon crystals found as detrital fragments in sedimentary rocks in western Australia have been dated at 4.04 billion years, implying the existence of an even older parent rock.” ↩
2. Sarfati, 1999, p. 110: “There are many examples where the dating methods give ‘dates’ that are wrong for rocks of known historical age.  One example is rock from a dacite lava dome at Mount St. Helens volcano.  Although we know the rock was formed in 1986, the rock was ‘dated’ by the potassium-argon (K-Ar) method as 0.35 +/- 0.05 million years old.  Another example is K-Ar ‘dating’ of five andesite lava flows from Mr. Ngauruhoe in New Zealand.  The ‘dates’ ranged from < 0.27 to 3.5 million years — but one lava flow occurred in 1949, three in 1954, and one in 1975!
   What happened was that excess radiogenic argon ((40)Ar*) from the magma (molten rock) was retained in the rock when it solidified.  The secular scientific literature also lists many examples of excess (40)Ar* causing ‘dates’ of millions of years in rocks of known historical age.  This excess appears to have come from the upper mantle, below the earth’s crust.  This is consistent with a young world — the argon has had too little time to escape.” ↩
3. http://www.answersingenesis.org/articles/nab/does-radiometric-dating-prove ↩
4. http://www.answersingenesis.org/articles/2005/06/01/evidence-for-young-world  ↩
5. Rhodes, 2012, p. 103: “Different methods of dating these ancient rocks, using several different radioactive mineral clocks, give remarkably consistent results.  Only a few localities have proved to have such ancient rocks.  Most of Earth’s older rocks have been reworked and re-formed under the forces that continually shape the crust.” ↩
6. Palmer, 2011, p. 22: “In 2008, geologists Jonathan O’Neill and Don Francis from Montreal’s McGill University, together with Richard Carlson of Washington’s Carnegie Institution, used a new radiometric dating technique based on isotopes of the rare earth elements samarium (¹⁴⁶Sm) and neodymium (¹⁴²Nd), found in metamorphic rocks known as amphibolites, to estimate the age of the rocks with renewed accuracy.  Their results pointed to an astonishing age of between 3.8 and 4.28 billion years old, making Nuvvuagittuq the most ancient large rock mass known.  However, other experts such as Stephen J. Mojzsis of the University of Colorado, disagree and argue that the Nuvvuagittuq rocks are no more than 3.8 billion years old, and therefore similar in age to Greenland rocks.” ↩
7. Sarfati, 1999, p. 111: “Another problem is the conflicting dates between different methods.  If two methods disagree, then at least one of them must be wrong.  For example, in Australia, some wood was buried by a basalt lava flow, as can be seen from the charring.  The wood was ‘dated’ by radiocarbon ((14)C) analysis at about 45,000 years old, but the basalt was ‘dated’ by the K-Ar method at c. 45 million years old!  Other fossil wood from Upper Permian rock layers has been found with (14)C still present.  Detectable (14)C would have all disintegrated if the wood were really older than 50,000 years, let alone the 250 million years that evolutionists assign to these Upper Permian rock layers.” ↩
8. Rhodes, 2012, p. 102: “In contrast, a handful of elements–uranium, thorium, rubidium, and potassium among them–are unstable under any conditions, breaking down spontaneously into more stable daughter elements at a rate that is both measurable and constant, whatever the external conditions.  Uranium, for example, breaks down to produce lead at a constant, measurable rate, and it can be demonstrated that, whatever the changes in temperature, pressure, or chemical conditions, the rate remains constant.” ↩
9. Palmer, 2011, p. 123: “One particular problem with reliance on chemical fossils is the danger that source rocks have been cantiminated by more recent hydrocarbons — organic compounds that are notoriously mobile within Earth’s crustal rocks.  Since the Pilbara rocks are known to have suffered some metamorphism around 2.2 billion years ago, it is certainly possible that the biomarkers were introduced at this time.  Nevertheless, supporters of Pilbara’s importance have argued that the abundance of the biomarkers and their distribution indicates that they are indigenous to the rock.  However, there is also another chemical clue that all may not be quite right — the ratios of carbon isotopes (atoms of the same element with different weights) in the biomarkers do not match those fro mother (non-biological) carbon residues called kerogens found in the surrounding sedimentary rocks.  This suggests that the biomarkers could indeed be younger contaminants.” ↩
10. Palmer, 2011, p. 23: “Unfortunately, like most very ancient rocks, the Nuvvuagittuq greenstones have been metamorphosed by a later phase of burial or ‘subduction’ deep within the crust, accompanied by heating to around 500°C (930°F) that has erased many signs of their formation.  Luckily, however, they were never heated above their melting point, so their ‘radiometric clock’ has not been reset.  Despite this, their age may still be somewhat exaggerated–the magma from which their ‘greenstone’ lavas formed originated as melting rock many kilometres below the surface, and it is possible that the date obtained from the isotopes is actually that of the magma’s subterranian formation, rather than its eruption to the surface as lava, which could have been several million years later.” ↩
11. Palmer, 2011, p. 123: “If there is one lesson to be learned from these various controversies surrounding the earliest traces of life on Earth [including disparity between the ‘background’ kerogen hydrocarbons and the extracted biomarkers of Pilbara’s chemical fossils], it is that scientific investigations pushing the boundaries of knowledge — especially those in areas of research where far-reaching conclusions are drawn from limited samples of scientific data — always ned to be regarded sceptically, and ideally reassessed when there are contradictions in the results.” ↩
12. Cotner and Moore, 2011, p. 32: “Conversely, the K-Ar method is not well suited for estimating the ages of sedimentary and metamorphic rocks because these rocks have sometimes been heated and are composed of other rocks (or debris from older rocks).” ↩
13. Rhodes, 2012, p. 99: “Earth’s earliest rocks have long ago been resorbed and recycled within the Earth.  Earth must be older, appreciably older, than its oldest observable rocks.” ↩
14. Rhodes, 2012, p. 103: “Is this figure–the age of the oldest discovered rocks–also the age of the Earth?  That seems unlikely … the most ancient rocks must surely have been metamorphosed, resorbed, and reworked as Earth developed. We can, however, use the same radioactive clocks to explore the ages of two other groups of rocks: those of the Moon and the meteorites that have fallen on Earth’s surface, which are generally regarded as part of the debris from which Earth itself formed.

    That assumes, of course, that the Earth and all the other solid bodies in the solar system formed at the same time, which seems a reasonable proposition.” ↩

15. Rhodes, 2012, p. 103: “Few lunar rocks have yet been returned to Earth and those that have differ in age.  The oldest have ages between 3.1 and 4.6 billion years, however, and thus seem to confirm the minimum age calculated for Earth.” ↩
16. Rhodes, 2012: “More than seventy different meteorites, representing various types, have now been dated by radiometric analyses and all give ages between 4.53 and 4.58 billion years.  These ages are remarkably consistent with those of the oldest rocks of the Earth and Moon.  By analyzing Earth’s oldest lead ores, and comparing these with the lead 207-lead 206 (²⁰⁷Pb-²⁰⁶Pb) ratio in uranium-free phases of meteorites, we can also calculate the time of their origin.  This gives an age of 4.54 billion years for the time at which these elements, uranium and lead, were swept up into meteorites and the Earth.” ↩
17. Cotner and Moore, 2011, p. 32:”The most direct method for estimating Earth’s age is a lead/lead isochron method using meteorites and ancient sediments.” ↩