Absolute and relative rock dating
Keyed to the relative time scale are examples of index fossils, the forms of life which existed during limited periods of geologic time and thus are used as guides to the age of the rocks in which they are preserved.William "Strata" Smith, a civil engineer and surveyor, was well acquainted with areas in southern England where "limestone and shales are layered like slices of bread and butter." His hobby of collecting and cataloging fossil shells from these rocks led to the discovery that certain layers contained fossils unlike those in other layers.
Direct Dating of Wood Cross-dating determines the age of undated wood by directly matching ring patterns with trees of known age.Overview of Methods Superposition Stratigraphy Dendrochronology Radiocarbon C14 Radiometric Dating Methods Obsidian Hydration Dating Paleomagnetic/Archaeomagnetic Luminescence Dating Methods Amino Acid Racemization Fission-track Dating Ice Cores Varves Pollens Corals Cation Ratio Fluorine Dating Patination Oxidizable Carbon Ratio Electron Spin Resonance Cosmic-ray Exposure Dating This is an excellent overview of dating methodologies, and is a chapter in a textbook on Archaeology.You may find it useful for the clear definitions, and for excellent links on a variety of topic.Because of the distortions and lies spread by fundamentalists about scientific dating there is a need for a centralized source of information on the topic.A few examples of such lies are presented at the very bottom of this page.Many of these links also appear where appropriate below.
James Hutton and William Smith advanced the concept of geologic time and strengthened the belief in an ancient world.
Radiocarbon Dating Founded on a false belief that levels of carbon isotopes never vary, initial radiocarbon dates were commonly off by hundreds of years.
Because wood can be dated directly and by radiocarbon, scientists used bristlecone pines to calculate a new calibration curve, and convert radiocarbon results into accurate calendar dates.
Further, he proposed that wherever uncontorted layers were exposed, the bottom layer was deposited first and was, therefore, the oldest layer exposed; each succeeding layer, up to the topmost one, was progressively younger.
The Major Divisions of Geologic Time are shown here, arranged in chronological order with the oldest division at the bottom, the youngest at the top. Specifically, stratigraphy refers to the application of the Law of Superposition to soil and geological strata containing archaeological materials in order to determine the relative ages of layers.
Bristlecones grow so slowly that a century of tree rings adds less than an inch of girth.