Geochronology is the scientific study of the age of the Earth and the temporal sequence of events related to the formation of the planet and the history of life on Earth. The word is derived from Geo meaning Earth, and chronology, which is the study of time, or a record of events in the order of their occurrence (timeline). It is from this field of study that fossils and artifacts are dated based on the perceived age of the geological layers in which they are located. Geologists determine the age of rocks, fossils, and sediments using a variety of methods, some of which involve relative dating and others which aspire to 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 for that process to produce the present state.
- 1 Assumptions
- 2 Absolute dating methods
- 3 Relative dating methods
- 4 Problems with dating methods
- 5 Young earth evidence
- 6 References
- 7 External links
- 8 See Also
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 evolutionary 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 fossil 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 evolutionary theoretical system. Within the creation theoretical system, different assumptions are used, producing different results.
Absolute dating methods
- Main Article: Absolute 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.
- 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 interacts with the upper atmosphere creating thermal neutrons that strike 14N (Nitrogen), converting it into 14C which decays back into 14N with a half-life of 5730 years.
- 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.
- 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.
- 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.
- 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.
Relative dating methods
- Main Article: Relative dating
- Main Article: Stratigraphy
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.
- 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.
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.
Young earth evidence
- Main article: Young earth evidence
Young earth creation scientists believe that the evolutionary geological timescale is in error. They also point to multiple lines of evidence from the field of geology showing that the earth is young. The uniformitarian assumptions are rejected, in favor of catastrophic processes related to the global flood as responsible for the vast majority of the Earth's geologic features. It should be noted that catastrophism is increasing being accepted in the field of geology.  Young earth creationists also assert that old earth uniformitarian geology has numerous anomalies. For example, William R. Corliss catalogued numerous anomalies in the old earth uniformatarian geology paradigm. 
- Geomagnetic field decay - Observations made of the strength of Earth's magnetic field over the last 150 years show that it is decaying, which puts an upper limit on the age of the Earth.
- Pleochroic halos - Scars of radioactive decay, which suggest problems with the standard uniformitarian model.
- Helium diffusion - there is a significant amount of helium still inside the zircons, showing their ages to be 6000 +/- 2000 years.
- Accelerated nuclear decay - Recent experiments commissioned by the RATE group indicate that "1.5 billion years" worth of nuclear decay has taken place, but in one or more short periods 4000 - 8000 years ago. This would shrink the alleged 4.5 billion year radioisotope age of the earth to only a few thousand years.
- 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.
- Woodmorappe, John, The Geologic Column: Does It Exist? Journal of Creation 13(2):77–82, 1999
- Morris, Henry, Geology and the Flood Impact 6, August 1973
- Geologic Time Scale - The Misconceptions (All About Creation)
- Geology Questions and Answers (Answers in Genesis)
- Geology (Creationism.org)
- Geology Links (Northwest Creation Network)
- Baumgardner, John, Genesis Flood 28 July 2003.
- The Mexico Earthquake - Some Afterthoughts by Ariel A. Roth, Origins 12(2):61-63(1985)]
- Up with Catastrophism! by Henry Morris, Ph.D. August, 1976
- The Sourcebook Project: Catalog of Anomalies by Omni Edge Science Winner, December 1996
- Polystrate Fossils and the Creation/Evolution Controversy by Joe Deweese and Bert Thompson, Ph.D. Apologetics Press :: Reason & Revelation, 20:93-95 December 2000.
- An Old Age for the Earth Is the Heart of Evolution by Jonathan Henry. Creation Research Society Quarterly, Vol. 40, No. 3. December 2003.
- Evolution Handbook, Chapter 4: The Age of the Earth
- RATE group
- Accelerated decay
- Pleochroic halos
- Helium diffusion
- Geomagnetic field decay