Numerical age dating geology
It is important to realize that with new information about subdivision or correlation of relative time, or new measurements of absolute time, the dates applied to the time scale can and do change. ISBN 0-521-38765-5 [One of the more recent compilations of the entire geologic time scale.] Holmes, A., 1937.
Revisions to the relative time scale have occurred since the late 1700s.
In this manner, geologic time is evaluated with respect to the period it takes for elements in the rock formation to reach their current chemical state.
Parent isotopes and daughter isotopes have an inverse relationship.
The geologic time scale was originally based on relative dating methods but with the development of radioactive dating technology, numerical ages further enhanced the scale.Think of relative time as physical subdivisions of the rock found in the Earth's stratigraphy, and absolute time as the measurements taken upon those to determine the actual time which has expired. Absolute time measurements can be used to calibrate the relative time scale, producing an integrated geologic or "geochronologic" time scale. [One of the earlier attempts at an integrated geochronologic time scale.] Obradovich, J. Absolute dating relies on the properties of various elements in rocks that over time decompose and may even transform into another element.Also called the “clocks in rocks”, the radioactive isotopes of elements or “parent isotopes” are atoms that decay into new isotopes or “daughter isotopes” where the “parent isotopes” may have varying numbers of neutrons but have the same number of electrons (earthsci.org, 2008).