Dating methods

thumb|The growth rings of a tree at Bristol Zoo, [[England. Each ring represents one year; the outside rings, near the bark, are the youngest]] thumb|A "tree cookie" cross-section of a Pseudotsuga menziesii var. menziesii|Coast Douglas-fir tree displayed in the [[Royal Ontario Museum. The tree was over 500 years old when it was cut down in British Columbia in the 1890s. The markings indicating historical events were added in the 1920s.]] Dendrochronology (or tree-ring dating) is the scientific method of dating tree rings (also called growth rings) to the exact year they were formed in a tree.

process of determining an age on a specified chronology in archaeology and geology

method mostly used in identification of various fossils which are about millions and billions years old

determining the relative order of past events

law stating that newer strata stack above older ones

alternating warm and cool periods in the Earth's paleoclimate, deduced from oxygen isotope data

radiometric tool for geochronology

powerful burst of cosmic rays

fossils succeed each other vertically in a specific, reliable order that can be identified over wide horizontal distances

type of dating

earliest date possible for something

Nucleocosmochronology, or nuclear cosmochronology, is a technique used to determine timescales for astrophysical objects and events based on observed ratios of radioactive heavy elements and their decay products. It is similar in many respects to radiometric dating, in which trace radioactive impurities were selectively incorporated into materials when they were formed.

Method of determining the age of events or artifacts