Reading the Geologic History of Your Community
In this section you will find materials that support the implementation of EarthComm, Section 7: Reading the Geologic History of Your Community.
- To learn more about radiometric dating, visit the following web site:
Radiometric Time Scale, USGS
Describes the use of radioactivity to determine the geologic ages of rocks.
To learn more about this topic, visit the following web sites:
Interpreting Geologic History
Relative Time Scale, USGS
Describes the development of the basic geologic principles and how they are used to determine the ages of rock layers.
How Do Geologists Know How Old a Rock Is?, Utah Geological Survey
Descriptions of the basic geologic principles and how they can be used to determine the age of a group of rocks.
The Grand Age of Rocks: The Numeric Ages for Rocks Exposed within Grand Canyon, NPS
Detailed description of the geologic history of the Grand Canyon. Includes pictures of several unconformities that are seen in the Grand Canyon.
Web Geologic Time Machine, University of California Berkeley
Provides links that describe events in Earth’s history from 4.5 billion years ago to the present.