Relative chronometric dating techniques
Dating techniques are procedures used by scientists to determine the age of an object or a series of events.The two main types of dating methods are relative and absolute.
The most widely used and accepted form of absolute dating is radioactive decay dating. Radioactive decay refers to the process in which a radioactive form of an element is converted into a nonradioactive product at a regular rate.Eventually, the entire ecosystem (community of plants and animals) of the planet, including humans, is filled with a concentration of carbon-14.As long as an organism is alive, the supply of carbon-14 is replenished.Narrow rings grow in cold or dry years, and wide rings grow in warm or wet years.The rings form a distinctive pattern, which is the same for all members in a given species and geographical area.With sensitive instrumentation, this range can be extended to 70,000 years.
In addition to the radiocarbon dating technique, scientists have developed other dating methods based on the transformation of one element into another.
Since certain species of animals existed on Earth at specific times in history, the fossils or remains of such animals embedded within those successive layers of rock also help scientists determine the age of the layers.
Similarly, pollen grains released by seed-bearing plants became fossilized in rock layers.
This method is based on the assumption (which nearly always holds true) that deeper layers of rock were deposited earlier in Earth's history, and thus are older than more shallow layers.
The successive layers of rock represent successive intervals of time.
By measuring the amount of original and transformed atoms in an object, scientists can determine the age of that object.