Accepted wisdom says that rocks can take millions of years to form and have existed in the strata beneath our feet for billions of years. For example, geology teaches that the Carboniferous period, during which the coal in the UK formed, occurred roughly 354-290 million years ago.
To the lay person it seems that such figures have never been significantly questioned by the scientific community. However, in his book How Old is the Earth?, Dr. Monty White has gathered together a body of information that contradicts the mainstream view.
Dating Rocks by Potassium Argon Testing
Geochronologists – scientists who focus on dating rocks and understanding the way the Earth was put together - use radiometric dating to establish the age of rocks. The underlying premise is that certain elements found in rocks decay and become transformed into other elements. The tests most often used include Potassium – Argon (K-Ar), Rubidium – Strontium and Uranium-Thorium-Lead.
The theory is that Potassium-40 spontaneously "decays", becoming Argon-40. This process proceeds very slowly at a known rate, having a half-life for potassium-40 of 1.25 billion years. The amount of potassium-40 and argon-40 in a rock sample is measured and the results are used to calculate how old the rock is. When this is done, the age is usually very great.
Reasons to Question K-Ar Radiometric Dating Method
- Radiometric dating assumes a constant rate of decay from one element to another. Dr White asserts that this assumption may not be correct as we have no way of knowing that this rate of decay is a constant over millions of years.
- It also assumes that we can know the amounts of parent and daughter elements (Potassium and Argon, in this case) in the rock when it formed (ie when it solidified) – even though we can never be sure of this. This will affect the result obtained for the age of the rock. In the case of Potassium-Argon dating, if Argon was present in rock as it was formed, this would significantly compromise the results obtained.
- Finally, radiometric dating assumes a "closed system". However, rocks are subjected to many outside influences that can change the overall chemical composition of the rock. For example, in the case of Potassium-Argon dating, pressure can cause the Argon to migrate
He points to the great variation in results that are obtained using radiometric dating exemplified by samples taken by Dr Steve Austin from the volcanic plug that formed in the crater at Mount St Helens after it erupted in the early 1980s. K-Ar testing gave various results of between 350,000 and 2.8 million years for rocks that were less than a decade old!
Other Evidence Used in Dating Rocks
Dr White goes on to list other criteria and tests that are used to date materials, rocks and the earth itself, such as Radiocarbon dating, fossils, and the measurements of the earth's decaying magnetic field. This scholarly book is packed full of useful information that fuels the debate about how old the earth really is.
Reference:
How Old is the Earth, Dr Monty White, Evangelical Press, July 2004 ISBN 0-87552-982-8
