Non radiometric chronometric dating techniques

Ice cores from Greenland and Antarctica show annual layers (varves) and can be traced up to about 40,000 years before the layers become too thin due to compaction.Similarly, annual lake sediments can be used to estimate relative age and conventional interpretation for the Green River varves suggests they have been formed over some 20 million years.The earth precesses (wobbles like a spinning top) around the sun in a series of cycles.These cycles affect sunlight and hence long-term can form layers in rock.Some claim Genesis in particular, and the Bible in general looks mythical from this standpoint.A full discussion of the topic must therefore include the current scientific challenge to the OE concept.This implies the earth is at least 20 million years old.

Using radiometric techniques, the oldest dated minerals (4.0 - 4.2 billion years) are zircon crystals found in sedimentary rocks in western Australia.In other words, half of the radioactive isotope in a sample would have decayed to Nitrogen-14 (N-14) in just 5,730 years.C-14 dating of carbon-bearing materials is therefore limited to roughly 50,000 years.The time required for half the original number of parent atoms to decay is called the half life.Some half-lives are listed below: It follows that uranium-lead, potassium-argon (K-Ar), and Rubidium-Strontium (Rb-Sr) decay can be used for very long time periods, whilst radiocarbon dating can only be used up to about 70,000 years. This uses a simple exponential decay formula linking the original number, Po, of parent atoms in rocks and minerals to the P atoms now present, thereby enabling an estimate of geological age.

Leave a Reply