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Geochronology

From CreationWiki, the encyclopedia of creation science

Image came from a single remote-sensing device-NASA’s Moderate Resolution Imaging Spectroradiometer, or (MODIS)

Chronology is the study of time, or a record of events in the order of their occurrence (timeline). Geochronology, as a scientific endeavor, is an attempt to determine the temporal sequence of events related to the formation of the planet and the history of life on Earth. It is from this field of study that artifacts are dated based on the age of the geological formations in which they are located. Geologists determine the age of rocks, fossils, and sediments using a variety of methods including relative and absolute dating.

In dating any object, geologists:

Observe the present state of the system.
Measure a process rate within the system.
Assume certain things about the past.
Calculate the time necessary from that process to produce the present state.

1 Assumptions
2 Dating methods
3 Problems with dating methods
4 References
- 4.1 Creationist References
- 4.2 Secular References
5 See Also

Assumptions

When dating an object, a geologist measures some physical property of the object, which is believed to provide evidence regarding its age. All dating methods rely upon assumptions about the past. These assumptions are based on the axioms or worldview the scientist is operating within. This worldview is the basis for an entire system of theories. Creation science is one theoretical system and Evolution is another. Thus even when creationists and evolutionists use the same dating methods, they will more often than not achieve radically different results.

In using these dating methods, evolutionists assume that there was no global flood as told in the Bible or Qur'an. Therefore, at their outset these methods are used by investigators who seek to prove their interpretation of the data. The methods are all ultimately calibrated to relative dates of the geologic column, such that data that conflicts with a fossil's or rock's placement in the geologic column is explained away by the Evolution theoretical system. For example Carbon-14 would decay to nothing in well under 1 million years, so if Carbon-14 is found in a dinosaur it is interpreted as resulting from contamination. The result is that the geologic column is the ultimate filter for other dating methods. This not only makes the other dating methods look more consistent than they actually are, but it also renders the very existence of the geologic column untestable.

The result is that these dating methods only produce old ages for the Earth within the Evolution theoretical system, thus the results are meaningless within the Creation theoretical system.

Dating methods

Radiometric Dating

Main Article: Radiometric dating

Radiometric dating utilizes the decay rates of certain radioactive atoms to date rocks or artifacts. Uniformitarian geologists consider this form of dating strong evidence that the Earth is billions of years old. However, research by creationists has revealed a large number of problems with radiometric dating. In some cases such as Carbon-14 dating, radioactive dating actually gives strong evidence for a young Earth, while other methods such as K-Ar dating and Isochron dating are based on faulty assumptions and are so unreliable as to be useless.

Carbon-14 dating

Main Article: Carbon-14 dating

Carbon-14 dating is a radiometric dating technique used to deduce the approximate age of organic remains by measuring the quantity of the isotope ¹⁴C in the sample and comparing it with the current atmospheric level. The usual isotope of carbon found in living organisms, ¹²C, is stable, while ¹⁴C is not stable. It is formed when cosmic radiation strikes ¹⁴N (Nitrogen), converting it into ¹⁴C, and it decays back into ¹⁴N, with a half-life of 5730 years.

Isochron dating

Main Article: Isochron dating

Scientists have realized that there are difficulties in dealing with the assumptions of radiometric dating. Isochron dating has been developed in an attempt to solve such problems. According to theory, the sample starts out with daughter isotopes present at constant ratios in relation to one another, but with the parent isotope, the ratio is arbitrary. As a result it forms a straight horizontal line on a graph. As the parent decays to daughter, the ratios change and the straight line remains but becomes angled. The slope of the line equals the number of half-lives the parent isotope has passed since solidification.

Ice cores

Main Article: Ice cores

Ice cores are obtained by drilling core samples of ice in glaciated regions, such as near the poles. Visible light and dark rings can be found in such cores that are then analyzed to determine the age of the ice. These layers are presumed to be the result of annual fluctuations in climate, and using this method, uniformitarians purport to document ages of over 100,000 years. Creationists, such as Michael Oard, contend that these laminations are from subannual events, including layering due to dust to be found in a post-flood ice age. He discusses this theory briefly here. Subannual formation is supported by observations that several such layers of snow and ice can result from the storms within a single winter season.

Dendrochronology

Main Article: Dendrochronology

Dendrochronology is a technique of dating past climatic changes through a study of tree ring growth. Each year a tree adds a layer of wood to its trunk and branches thus creating the annual rings we see when viewing a cross section. Wide rings are produced during wet years and narrow rings during dry seasons. This technique has posed a different problem for creationists, as this dating method does not make use directly of accelerated decay. By using dendrochronology scientists have dated certain living trees to having ages of around 4600 years. This finding showed the current model for carbon-14 dating to be incorrect, so scientists recalibrated their ¹⁴C model based on this tree.

Concordia dating

Main Article: Concordia dating

Concordia dating is a form of uranium/lead dating that uses a concordia diagram. The theory is that when zircons crystallize they lose all of their lead and as long as the crystal remains closed its lead/uranium ratios should follow a predictable trend. It is further theorized that since all isotopes of the same element are chemically identical, they should be removed in proportional amounts, forming a straight line on the concordia diagram, that crosses the concordia curve at both the crystallization and the contamination date. Loss of uranium moves the point up and to the right, while a loss of lead moves the point down and to the left.

Fission-track dating

Main Article: Fission-track dating

Fission-track dating involves counting the damage tracks left by fragments of the spontaneous fission of uranium-238. The spontaneous fission of ²³⁸U has a known rate, and as such the number of tracks is theoretically related to the age of the sample. Because fission-track dating requires a manual count of the fission tracks, the process is more prone to human error and bias than other radiometric dating methods. This problem is made worse because other types of crystal defects can easily be counted as fission tracks.

Relative dating

Main Article: Relative dating

Relative dating is a technique that uses the "relative" positions of layers and fossils to assign estimated dates to strata. Uniformitarian geologists began using the principles of stratigraphy to assign dates to the layers of the geological column fossils back in the late 1700s. Relative dating uses a combination of fossil studies and structural interpretation to draw conclusions about the geological history of an area.

Problems with dating methods

Any dating method depends on a fixed standard, or else it produces arbitrary dates. Uniformitarian geologists prefer to believe, and claim, that each of their methods uses such a fixed standard. But a careful examination of the so-called "standards" of dating reveals that each of their methods depends on an a priori assumption about the history of the earth. By continuing to use such methods, uniformitarians make their own chief assertion, that the earth is billions of years old, untestable. In so doing, they commit the logical fallacies of proof by assertion and circular reasoning.

Beyond this, each dating method has problems with the method itself and problems with the interpretation of its results. Some of the "adjustments" that uniformitarians make to the dates that their procedures produce are akin to the detestable practice of "dry-labbing" wherein a dishonest investigator constructs observations out of his own imagination. The adjustments of carbon-14 dates to make them concordant with other dating methods is a case in point.

Many sites get labeled a certain age based on evolutionary bias, but later get redated at much younger dates. A good example of this is the Barberton deposits. It was thought to be the product of a Archean hydrothermal vent, but supposedly it's now from a Cenozoic hydrological system.(Lowe and Byerly; 2007)

References

Creationist References

An Old Age for the Earth Is the Heart of Evolution by Jonathan Henry. Creation Research Society Quarterly, Vol. 40, No. 3. December 2003.

Secular References

Geochronology by Wikipedia
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.