List of time periods - Wikipedia
This is a list of such named time periods as defined in various fields of study. These can be divided broadly into prehistorical periods and historical periods (when written records began to be kept).
Geologic time scale - Wikipedia
The geologic time scale is a way of representing deep time based on events that have occurred throughout Earth's history, a time span of about 4.54 ± 0.05 Ga (4.54 billion years). [3] It chronologically organises strata, and subsequently time, by observing fundamental changes in stratigraphy that correspond to major geological or ...
Geologic time | Periods, Time Scale, & Facts | Britannica
2024年11月19日 · The geologic time scale is the “calendar” for events in Earth history. It subdivides all time into named units of abstract time called—in descending order of duration— eons , eras , periods , epochs , and ages.
Geologic Time Scale: A List of Eons, Eras, and Periods - ThoughtCo
2020年2月28日 · The geologic time scale is a system used by scientists to describe Earth's history in terms of major geological or paleontological events (such as the formation of a new rock layer or the appearance or demise of certain lifeforms).
Geologic Time Scale : Divisions, Periods and Eons - Geology Science
2023年12月6日 · The Geologic Time Scale is divided into several large units of time, including eons, eras, periods, and epochs, and it provides a framework for understanding the relationships between events in Earth’s history.
Geologic Time Scale - Geology (U.S. National Park Service)
2021年10月5日 · Geologic time scale showing the geologic eons, eras, periods, epochs, and associated dates in millions of years ago (MYA).
Geologic Time Scale - Major Divisions of Geologic Time Chart
A geologic time scale is composed of standard stratigraphic divisions based on rock sequences and is calibrated in years (Harland and others, 1982). Over the years, the development of new dating methods and the refinement of previous methods have stimulated revisions to …
Geologic Time Scale - Geological Time Line
In the time scale above you can see that the Phanerozoic is divided into three eras: Cenozoic, Mesozoic and Paleozoic. Very significant events in Earth's history are used to determine the boundaries of the eras. Eras are subdivided into periods.
11.6: Geologic Time Scale - Geosciences LibreTexts
Scientists have put together the geologic time scale to describe the order and duration of major events on Earth for the last 4 1 ⁄ 2 billion years. Some examples of events listed on the geologic time scale include the first appearance of plant life on Earth, the first appearance of animals on Earth, the formation of Earth’s mountains, and ...
When geologic time is compressed to the scale of a calendar year, 1 second equals about 146 years. At this scale, World War II began about 0.4 second before midnight on December 31; because of rounding, this is shown as midnight of the new year.