Geologic Time Clock

The Clock of Eras is a graphic aid to help us visualize geologic time. It is nearly impossible for the human mind to comprehend the amount of time that it has taken for the Earth to develop to its present state, yet we try to imagine each stage of its unfolding and the time that passed during each phase of development.

The geologic time scale is the quotcalendarquot for events in Earth history. It subdivides all time into named units of abstract time calledin descending order of duration eons, eras, periods, epochs, and ages.

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This clock representation shows some of the major units of geological time and definitive events of Earth history. The geologic time scale is used by geologists and other scientists to map the timing and relationships between events that have occurred during the history of the Earth.

This page discusses Earth's 4.5 billion-year history through the geologic time scale, which categorizes significant events and organisms into eons, eras, and periods based on fossil evidence.

The geologic time scale, proportionally represented as a log-spiral with some major events in Earth's history. A megaannus Ma represents one million 10 6 years. The geologic time scale or geological time scale GTS is a representation of time based on the rock record of Earth. It is a system of chronological dating that uses chronostratigraphy the process of relating strata to time and

The Geologic Timescale Figure 7 was first constructed by geologists in the 1800s before the discovery of radioactive decay that provides the clock used in many numeric dating techniques.

An exercise assembled by Dr. Stephen Greb, Kentucky Geological Survey to demonstrate changes in the Earth through time, and the length of time it took to make many of the changes.

By determining the relative amounts of parent and daughter isotopes, the age of these rocks can be calculated. Thus, the results of studies of rock layers stratigraphy, and of fossils paleontology, coupled with the ages of certain rocks as measured by atomic clocks geochronology, attest to a very old Earth!

Geologic Time Scale Humans subdivide time into useable units such as our calendar year, months, weeks, and days geologists also subdivide time. They have created a tool for measuring geologic time, breaking it into useable, understandable segments. For the purposes of geology, the quotcalendarquot is the geologic time scale.