ref no stratigraphic age subdivision type age symbol* keyboard position for "fgdcgeoage" font* *For more information, see general guidelines on pages A-i to A-v. 32.25

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 …

Geologists from the U.S. Geological Survey (USGS), State geological surveys, academia, and other organizations require a consistent time scale to be used in communicating ages of geo …

Oct 5, 2021 · Geologic time scale showing the geologic eons, eras, periods, epochs, and associated dates in millions of years ago (MYA).

What symbols and features are included on geologic maps? Below are summarized some of the important data and interpretations to look for on a map. Many of these should be familiar from …

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 …

Likewise, in geology, there are some common symbols that are used to convey a message. In the case of geologic maps, symbols tell a history story. The image here shows what is called a …

The Geologic Time Scale (GTS) is an arbitrary chronological arrangement or sequence of geologic events, used as a measure of the relative or absolute duration or age of any part of …

The left half shows a timeline of Earth’s geologic history which is split into Eons, Eras, Periods, and Epochs and how many millions of years ago (MYA) these occurred. The right half labels …

This page contains the latest version of the International Chronostratigraphic Chart (v2024-12) which visually presents the time periods and hierarchy of stratigraphic names of Earth's …