Dating methods

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Previously reported problems with dating methods were reported in Science Headlines.

Contents

Sedimentary Rock Dating Method Wrong by a Factor of Two (Jan., 2008)

Hot Springs Microbes Hold Key To Dating: Sedimentary RocksA form of sedimentary rock, calcium carbonate is the most abundant mineral precipitated on the surface of Earth, and a great recorder of life. Now scientists, studying microbial communities and the growth of sedimentary rock at Mammoth Hot Springs in Yellowstone National Park, have made a surprising discovery about the geological record of life and the environment. Their discovery could affect how certain sequences of sedimentary rock are dated, and how scientists might search for evidence of life on other planets(ScienceDaily, Jan. 22, 2008).
“We found microbes change the rate at which calcium carbonate precipitates, and that rate controls the chemistry and shape of calcium carbonate crystals,” said Bruce Fouke, a professor of geology and of molecular and cellular biology at the University of Illinois.
In fact, the precipitation rate can more than double when microbes are present, Fouke and his colleagues report in a paper accepted for publication in the Geological Society of America Bulletin.
The researchers’ findings imply changes in calcium carbonate mineralization rates in the rock record may have resulted from changes in local microbial biomass concentrations throughout geologic history. A form of sedimentary rock, calcium carbonate is the most abundant mineral precipitated on the surface of Earth, and a great recorder of life. [PhysOrg, Jan 22, 2008]


Here again, previously trusted assumptions about most common sedimentary rock were off by more than a factor of two. What other untested dating assumptions will be overturned in the future?


Ancient Precambrian suddenly became young Pleistocene (!) (January 2007)

The bulletin of the Geological Society of America started 2007 with a bang (the exclamation mark "!" is called a "bang" in computerese). Titles of scientific papers rarely contain the exclamation mark. However, the paper by Donald R. Lowe (Stanford) and Gary R. Byerly (Louisiana State) does contain the exclamation mark to convey something of the shock they must have felt when they had to reclassify a rock formation from one end of the geologic column to the other.

Until this year, the Barberton deposits in South Africa were confidently dated as among the most ancient geological formations on earth to a supposed age of 3.55 billion years (Archean), e.g.

The 3.55-3.22 Ga Barberton Greenstone Belt, South Africa and Swaziland, and surrounding coeval plutons can be divided into four tectono-stratigraphic blocks that become younger toward the northwest. Each block formed through early mafic to ultramafic volcanism (Onverwacht Group), probably in oceanic extensional, island, or plateau settings. ... Evolution of the Barberton Belt may reflect an Early Archean plate tectonic cycle that characterized a world with few or no large, stabilized blocks of sialic crust. [Donald R. Lowe, Stanford University, Department of Geological and Environmental Sciences, "Accretionary history of the Archean Barberton greenstone belt (3.55-3.22 Ga), Southern Africa", Geology, December 1994, v. 22; no. 12; p. 1099-1102)

However, the latest evidence indicates promotes the supposedly ancient Barberton layers to the most recent geological layer of the the Pleistocene epoch (putatively dated to have begun about 1.8 million years ago).

Irregular bodies of goethite and hematite, termed ironstone pods, in the Barberton greenstone belt, South Africa, have been previously interpreted as the Earth's most ancient submarine hydrothermal vent deposits and have yielded putative evidence about Archean hydrothermal systems, ocean composition and temperature, and early life. This report summarizes geologic, sedimentological, and petrographic evidence from three widely separated areas showing that the ironstone was deposited on and directly below the modern ground surface by active groundwater and spring systems, probably during periods of higher rainfall in the Pleistocene.... These deposits represent a remarkable iron oxide-depositing Quaternary hydrologic system but provide no information about conditions or life on the early Earth. [Lowe DR, and Byerly GR (2007), “Ironstone bodies of the Barberton greenstone belt, South Africa: Products of a Cenozoic hydrological system, not Archean hydrothermal vents!” GSA Bulletin, January 2007, Vol. 119, No. 1 pp. 65-87, DOI: 10.1130/B25997.1, emphasis added]

Evolutionists regularly pointed to these rocks to make up stories about the origin of primitive life forms. Now we discover that these rocks "provide no information about conditions or life on the early Earth". See, for example, Earth & Life (Struik Publishers, 2005) written by experts on the Barenton layers at the University of the Witwatersrand in South Africa. Instead of these stories about ancient layers and ancient life, the rocks could be forming today.

So that's the big bang of 2007. The most ancient layers are suddenly demoted from the ancient age of about 3.5 billion years down to no more than a supposed age of at most 1.8 million years (or about 0.6% of its previous age). That's right, the age was off by three orders of magnitude.

We Were Wrong About Isochrons, Geologists Say. Order or magnitude errors (Dec. 2005)

An isochron (a word meaning "equal time") is a statistical averaging method of several isotope measurements used in radiometric dating to supposedly eliminate some of the untested assumptions of radiometric dating such as the initial ratio of parent to daughter products at the time rocks first crystallizes from magma before any parent atoms have decayed. If daughter atoms were present but unaccounted for, the rock will have a misleading appearance of age. Isochron plots are also supposed to reveal that the system remained closed over time. If atoms migrate into the rock system there could again be a misleading impression of age. As straightforward as this method is, it can it be misleading when extrapolated millions of years into the past, when the initial and intervening conditions were not subject to observation. One assumption behind isochron dating is that the initial isotope ratios were fixed at the time the rock formed. Not so fast, say four geologists from the UK, Wisconsin and California, writing in Geology:

The determination of accurate and precise isochron ages for igneous rocks requires that the initial isotope ratios of the analyzed minerals are identical at the time of eruption or emplacement. Studies of young volcanic rocks at the mineral scale have shown this assumption to be invalid in many instances. Variations in initial isotope ratios can result in erroneous or imprecise ages. [Davidson, Charlier, Hora, and Perlroth, “Mineral isochrons and isotopic fingerprinting: Pitfalls and promises,” Geology, Vol. 33, No. 1, pp. 29–32, 2005, doi: 10.1130/G21063.1, epmpahsis added.]

This realization “questions a fundamental tenet in isochron geochronology—that the initial isotope composition of the analyzed phases is identical.” Since variations in these ratios are now known, it creates the “possibility that it may compromise geochronological interpretations.”

As reported by creation evolution headlines (Crev), Sources of variation in initial ratios include: (1) rocks forming over multiple stages instead of one, (2) crustal contamination, (3) partial assimilation of parent isotopes, and (4) magma recharge. These sources of error “can, in principle, be identified,” they claim, by examining cross-sections of the rock from core to rim, “provided that the components involved are isotopically distinct.” But unless identified via independent checks, isochron ages can be “fictitious,” they warn. They give an example of how rubidium-strontium data points “may result in a good isochron fit, even though the age obtained is meaningless.” One case produced an order-of-magnitude difference between the argon age and the rubidium-strontium age, even with a valid isochron.

To date a rock via isochrons, the geologist has to know that the rock had (1) slow diffusion and (2) rapid cooling. But then, “The cooling history will depend on the volume of magma involved and its starting temperature, which in turn is a function of its composition.” They give examples where it is evident that “open-system processes during crystallization must be invoked to impart isotopic heterogeneity to the mineral population”; i.e., to explain away differences in age between two methods by claiming the rock was open to the environment during its lifetime. They admit, though, that “if the initial variation is systematic (e.g., due to open-system mixing or contamination), then isochrons are generated that can be very good” based on their fit to the graph, “but the ages are geologically meaningless.”

Read the book by radiometric expert and evolutionists, Brent Dalrymple, Ancient Earth, Ancient Skies (Stanford University Press 2004) or The age of everything (M. Hedman, Chicago University Press, 2007). These texts tout isochrons as a fail-safe method for dating rocks, because the data points are supposed to be self-checking. These texts would have you believe that radiometric dating methods are incontrovertible!

Now, these geologists, publishing in the premiere geological journal in the world, tell us that isochrons can look perfect on paper yet give meaningless ages, by orders of magnitude, if the initial conditions are not known, or if the rocks were open systems at some time in the past. Then these geologists try to put a happy face on the situation. It’s not all bad news, they say, because if geologists can know the true age by another method, they can glean some useful information out of the errors. But if they were wrong about the isochron method, what faulty assumptions are going to turn up some day about other methods, in a future issue of Geology?

As remarked by Crev, these type of confidence assertions about what happened suppsoedly 200 million years ago is about as reassuring as the surgeon who told his patient, “I have good news and bad news. The bad news is that we removed the wrong kidney. The good news is that your other kidney is doing just fine.”

More problems with dating methods emerge

Although many rocks show millions or billions of years worth of decay products, there are some stubborn anomalies and discordances in the literature which do not have a plausible scientific explanation. Discrepancies frequently appear when different teams of geologists date the same ancient geological formation involving different dating methods. Some of the world’s top scientists held a workshop sponsored by the National Science Foundation to address some of these problems. The October 17, 2003 issue of the journal Science (Kerr, R.A. 2003. “A Call for Telling Better Time over the Eons.” Science 302, no. 5466) reported on this symposium and the rationale behind it:

At a workshop held here early this month at the National Museum of Natural History, geochronologists declared that they must do better, much better, and called for an unprecedented effort to calibrate the geologic time scale. ... "We need a major international cooperative network of geochronology centers dedicated to the goal of science-driven, integrative calibration," said Samuel Bowring of the Massachusetts Institute of Technology, a workshop organizer. Although no specific plan emerged, Bowring notes, participants agreed that "we have to make sure we’re all getting the same answer on the same rocks." That doesn't always happen.” ...

One example of this is the attempted dating of the Latemar limestone belt in northern Italy’s Dolomite Mountains. Scientists have been trying to find out how long it took microscopic carbonate skeletons to pile up on the ancient seafloor to form this 600-meter layer. Science reported (see also Science, 12 November 1999, p. 1279):

“Other crucial ages are also out of whack. ... Assuming that the distinctive layers of the Latemar matched climate cycles driven by clocklike variations in the shape of Earth’s orbit, sedimentologists estimated that it took about 8 million years to form the whole pile. Uranium-lead dating of zircons from volcanic ash beds in the Latemar, however, produced a figure of about 2 million years — too little time to form such deposits, sedimentologists say. Years of work on both ways of dating the Latemar have failed to resolve the conflict”.
"In addition to more dating, researchers want better dating. Long-recognized problems with standards, interlab calibration, and sample processing have limited both the precision and the accuracy of uranium-lead and argon-argon radiometric dating. At the moment, these two leading techniques consistently differ on the age of the same sample by 1%"

The article makes the following interesting statement: “The general sparseness of reliable ages was the primary complaint at the workshop". Given that there are tens of thousands of dates reported in the literature, one wonders why reliable dates are sparse. Do geologists know something about discordances that we laypeople do not? One wonders how many results are never reported and filed away for later study because of inconsistencies. One also wonders what double-blind testing of the radiometric dating scene would reveal?

Anomalous radicarbon dates

For an example of stubborn anomalous radiocarbon dates see see Annual Review of Earth and Planetary Sciences (Stanley-2001), which discusses problems with radiocarbon dates that are both too old and in the wrong sequence:

"ANOMALOUS RADIOCARBON DATES: In contrast with patterns of clustered radiocarbon dates at the base of Holocene sections, there is a weaker relationship between C-14 dates and core depths throughout most deltaic core sections. This poor relationship has been observed since early applications of the radiocarbon dating method to Mississippi Delta cores (Fisk & McFarlan 1955, Frazier 1967). A review of the literature indicates that most deltas for which radiocarbon dates are available, regardless of geographical and geological setting, record this inconsistent upsection stratigraphy. Radiocarbon dates, both conventional and accelerator mass spectrometric (AMS), are not— as expected — consistently younger upcore between the base and surface of deltaic sequences. In addition to age-date reversals upcore, some dates in Holocene sections are clearly too old (some to late Pleistocene in age) and, not infrequently, those near the upper core surfaces are of mid- to late Holocene age (Figure 2). In general, there is a modest to poor—and in some cases no—relationship among C-14 dates, core surface elevation, subsurface depth of sample in the Holocene sequence, material used for dating (i.e. shell, organic-rich sediment, and peat), and geographic position of core site relative to the delta coast." [page 270, emphasis added]
"These findings are both remarkable and disturbing, because they call into question the reliability of both dates and method; they raise concern regarding use of the radiocarbon method as presently applied to deltas. A literature survey indicates that deltas are by no means the only late Pleistocene to Holocene settings where dating problems are encountered. Numerous articles in the journal Radiocarbon and in other publications that focus on application of this method to Quaternary research problems have called attention to anomalous 14C date results in coastal deposits and soils (Delibrias 1989)." [page 284, emphasis added]

Reference: DATING MODERN DELTAS: Progress, Problems, and Prognostics Jean-Daniel Stanley Annual Review of Earth and Planetary Sciences, May 2001, Vol. 29, Pages 257-294.

What happens when there are stubborn disagreements between dating methods?

From Science, 12 November 1999, p. 1279: When your wristwatch and a wall clock disagree about the time, one (or both) of them is wrong. Geochronologists have a similar problem, but the potential consequences are more grave. ... Yet the uranium-lead method has its difficulties as well. "The more you dig into the method," says Olsen, "the clearer it becomes that getting dependable results is not a trivial matter." For example, rock containing zircon crystals that hold the uranium and its decay product can partially melt, millions of years after their formation in a volcanic eruption, in a new volcanic outpouring. The zircon can survive the melting and then grow a new layer of crystal over its old core. When the whole crystal is analyzed, the apparent age will be older than the age of the eruption that laid down the ash layer. Some geochronologists, including Mundil, say they address such problems in their standard methods, screening out zircons with old cores through inspection under the microscope. But others aren't so sure. They look to other techniques that can pick out chemically distinct cores that would otherwise be invisible. Telling which clock, if any, is right will obviously take more effort than dialing up the time lady. [emphasis added]
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