Absolute dating methods determine how much time has passed since rocks formed by measuring the radioactive decay of isotopes or the effects of radiation on the crystal structure of minerals.*

Mainstream science organizations usually present radiometric dating methods as infallible. But are the so-called "absolute" dating methods free of assumptions? Are they absolute?

Absolute dating is the process of determining an age on a specified chronology in archaeology and geology. Some scientists prefer the terms chronometric or calendar dating, as use of the word "absolute" implies an unwarranted certainty of accuracy. Absolute dating provides a numerical age or range, in contrast with relative dating, which places events in order without any measure of the age between events.*

In the definition there is already doubt about these methods being "absolute". Let's check the most widely used dating method called potassium–argon dating...

K–Ar dating

The K–Ar method and its derivative, the 40Ar/39Ar method, are based on the radioactive decay of 40K to the noble gas 40Ar (sometimes symbolically indicated as 40Ar, or radiogenic Ar). Potassium (K) is a major element in the Earth’s crust and is abundant in many rocks and minerals. It possesses two stable isotopes: 39K (93 %) and 41K (7 %).

As with all isotopic dating methods, there are a number of assumptions that must be fulfilled for a K–Ar age to relate to events in the geological history of the region being studied.

Dating methods are based on certain assumptions. One of those assumptions...

The radiogenic argon measured in a sample was produced by in situ decay of ⁴⁰K in the interval since the rock crystallized or was recrystallized. Violations of this assumption are not uncommon. The sample must have remained a closed system since the event being dated. Thus, there should have been no loss or gain of ⁴⁰K or ⁴⁰Ar, other than by radioactive decay of ⁴⁰K. ... departures from this assumption are quite common, particularly in areas of complex geological history.*

Excess Argon...

If excess Argon is present in the rock then the date will be too old. For example rocks from a volcanic eruption of Mt. Erebus in 1984 gave an age of 700,000 years due to excess argon in melt inclusions.*

Since Ar is a noble gas, it can escape from a magma or liquid easily, and it is thus assumed that no 40Ar is present initially. Note that this is not always true. If a magma cools quickly on the surface of the Earth, some of the Ar may be trapped. If this happens, then the date obtained will be older than the date at which the magma erupted. For example lavas dated by K-Ar that are historic in age, usually show 1 to 2 million year old ages due to trapped Ar. Such trapped Ar is not problematical when the age of the rock is in hundreds of millions of years.*

But if, according to the assumptions, the rocks are assumed to be closed systems then such trapped Ar is problematic because the dating results will show older dates. And if decades old rocks show dates of 1 to 2 million years then how old would those rocks, that are dated to hundreds of millions of years, really be?

The simple assumption often made in order to calculate K–Ar and some Ar–Ar dates is that the samples initially contained no radiogenic argon. Argon escaping from minerals above their closure temperature is assumed to enter an ‘infinite reservoir’, leaving minerals free of radiogenic argon. The dilemma in this scenario is that studies of ground waters, fluid inclusions and many natural volcanic glasses demonstrate that hydrous fluids and magmas at all depths in the crust contain argon. Moreover, most if not all of these fluids and magmas contain argon enriched in the radiogenic isotope 40Ar, in other words they contain excess argon.*

One of the most important problems in K–Ar geochronology is the identification of excess argon. The presence of excess 40Ar in measurements of argon isotopes from both whole rock and mineral samples causes the samples to yield apparently old ages.*

Evolutionist Brent Dalrymple wrote in 1994...

Like all radiometric methods, the K–Ar method does not work on all rocks and minerals under all geologic conditions. By many experiments over the past three decades, geologists have learned which rocks and minerals act as closed systems and under what conditions they do so.
Some cases of initial 40Ar remaining in rocks have been documented but they are uncommon, as noted by Dalrymple and Lanphere, who also described studies of historic lava flows showing ‘excess’ argon is rare in these rocks.

But as we've already seen, researchers now state...

Excess argon is a common problem in high-pressure metamorphic rocks.*

So it seems that people like Dalrymple, who were key in developing these dating methods, have underestimated or downplayed the problem of excess Argon in volcanic rocks that were dated to hundreds of millions of years, based on "studies of historic lava flows" which are now possibly shown to be wrong more or less.

Catastrophic Argon...

The solid Earth is widely believed to have lost its original gases through a combination of early catastrophic release and regulated output over geologic time. In principle, the abundance of ⁴⁰Ar in the atmosphere represents the time-integrated loss of gases from the interior, thought to occur through partial melting in the mantle followed by melt ascent to the surface and gas exsolution. Here we present data that reveal two major difficulties with this simple magmatic degassing scenario—argon seems to be compatible in the major phases of the terrestrial planets, and argon diffusion in these phases is slow at upper-mantle conditions. These results challenge the common belief that the upper mantle is nearly degassed of ⁴⁰Ar, and they call into question the suitability of ⁴⁰Ar as a monitor of planetary degassing.

Our data suggest that argon does indeed stay trapped in the mantle even at extremely high temperatures, making it difficult for the Earth to continuously purge itself of argon produced by radioactive decay of potassium.*

Understanding the growth rate of the continental crust through time is a fundamental issue in Earth sciences. The isotopic signatures of noble gases in the silicate Earth (mantle, crust) and in the atmosphere afford exceptional insight into the evolution through time of these geochemical reservoirs. However, no data for the compositions of these reservoirs exists for the distant past...*

First of all, the assumption about Argon being absent of early rocks is wrong and to assume it disappeared from rocks which are assumed to be closed systems invalidates the method more or less.
Secondly, science is limited when it comes to the unobservable past and scientists are forced to make use of assumptions. The major philosophical assumption on which all of the earth's unobservable history is based is uniformitarianism. But, ironically, scientists make use of catastrophic events to try to explain a lot of phenomena which are believed to have happened. Often earlier assumptions turn out to be wrong, but the paradigm is never questioned. A lot of theories contradict each other and a lot of theories are formed to fit with the paradigm.

The sample, whether mineral or whole rock, must have remained a closed system since the event being dated. This includes gain or loss of either argon or potassium. This assumption is sometimes invalid, particularly in systems with complex geological and thermal histories. However, Ar-Ar stepwise heating and laser spot techniques can often be used to extract thermal history information from partially opened systems, taking advantage of the manner and extent of argon loss.

To compensate for the excess Argon the Ar-Ar method is used in stepwise heating and laser technique...

This new technique combines the use of laser-induced plasma spectroscopy for the determination of potassium, with noble gas mass spectrometry for the determination of argon, both extracted simultaneously by laser ablation.*

Calibration...

In order for an age to be calculated by the 40Ar/39Ar technique, the J parameter must be known. For the J to be determined, a standard of known age must be irradiated with the samples of unknown age. Because this (primary) standard ultimately cannot be determined by 40Ar/39Ar, it must be first determined by another isotopic dating method. The method most commonly used to date the primary standard is the conventional K/Ar technique. The primary standard must be a mineral that is homogeneous, abundant and easily dated by the K/Ar and 40Ar/39Ar methods. Traditionally, this primary standard has been a hornblende from the McClure Mountains, Colorado (a.k.a. MMhb-1). Once an accurate and precise age is determined for the primary standard, other minerals can be dated relative to it by the 40Ar/39Ar method. These secondary minerals are often more convenient to date by the 40Ar/39Ar technique (e.g. sanidine). However, while it is often easy to determine the age of the primary standard by the K/Ar method, it is difficult for different dating laboratories to agree on the final age. Likewise, because of heterogeneity problems with the MMhb-1 sample, the K/Ar ages are not always reproducible.*

This Ar-Ar method is also not an absolute dating method, it must be calibrated relative to a "standard of known age" before it can be used to date materials relative to the K-Ar method that needs to be verified. And "The method most commonly used to date the primary standard is the conventional K/Ar technique". So the K-Ar method is ultimately used to verify the K-Ar method and that is based on the "standard of known age". But how was that "standard of known age" calibrated in the past?

Fission track dating is calibrated (the "zeta calibration") using rocks of "known" ages. However, if these "known" ages are incorrect, then fission track dating that is based on these ages is also incorrect. Thus fission track dating is not an independent test that helps to verify the accuracy of other tests. The result is that radiometric dating in general is in danger of being based on circular reasoning.

So all these dating methods are based on assumptions and all needed to be calibrated in order to have meaningful results. But were those dating methods reliable when they were introduced and what were they calibrated with?

Evolution website Talk Origins states...

If one of these assumptions has been violated, the simple computation above yields an incorrect age. ... In many cases, there are independent cues (such as geologic setting or the chemistry of the specimen) which can suggest that such assumptions are entirely reasonable.*

The dating of rocks by using radioactive elements depends on very basic assumptions. The significance and relevance of these assumptions have not been demonstrated. In fact, the first radiochronology assumptions were adapted to fit the stratigraphic scale used by geochronologists of the end of the 19th century.*

Early radiometric dating methods are of course calibrated against the geologic column which is a relative timescale. Naturalists based this timescale on Darwin's very slow and gradual evolution theory and on the unprovable philosophies naturalism and uniformitarianism.

Another crucial assumption is that the radioactive decay rates must be constant. But have radioactive decay rates always been constant throughout the unobservable past?

"It doesn't make sense according to conventional ideas," Fischbach said. Jenkins whimsically added, "What we're suggesting is that something that doesn't really interact with anything is changing something that can't be changed." "It's an effect that no one yet understands," agreed Sturrock. "Theorists are starting to say, 'What's going on?' But that's what the evidence points to. It's a challenge for the physicists and a challenge for the solar people too." If the mystery particle is not a neutrino, "It would have to be something we don't know about, an unknown particle that is also emitted by the sun and has this effect, and that would be even more remarkable," Sturrock said.*

Radioactive decay rates, thought to be unique physical constants and counted on in such fields as medicine and anthropology, may be more variable than once thought.*

Additional experimental evidence is presented in support of the recent hypothesis that a possible solar influence could explain fluctuations observed in the measured decay rates of some isotopes.

The so-called decay constant* may not be very constant after all. It might just as well have been dramatically different from what is assumed today given the catastrophic events in the unobservable past.

If an inconsistent data point is found, geologists ask the question: "Is this date wrong, or is it saying the current geological time scale is wrong?" In general, the former is more likely, because there is such a vast amount of data behind the current understanding of the time scale... However, this statistical likelihood is not assumed, it is tested, usually by using other methods (e.g., other radiometric dating methods or other types of fossils), by re-examining the inconsistent data in more detail, recollecting better quality samples, or running them in the lab again.*

The geologic column is a relative time scale and the current explanation of the geological time scale within mainstream science is the result of more than two centuries of evolutionary paradigm paralysis, circular reasoning based on the unprovable philosophies uniformitarianism and naturalism within the world of mainstream science run by naturalists. It is one huge circular theory based on faith. Pro-evolution website Talk Origins, trying to talk its way out of this, confirms it nicely for us.