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The Geologic Time Scale
This site contains a large, easy to read, detailed geologic time scale for the Phanerozoic Eon (544 million years ago - Present). This is the period of time, also known as an eon, between the end of the Precambrian and today. The Phanerozoic begins with the start of the Cambrian period, 544 million years ago. It encompasses the period of abundant, complex life on Earth. The chart includes the Era, Period or System, and the Epoch or Series and features a brief description of each.
Intended for grade levels:
  • Intermediate (3-5)
  • Middle (6-8)
  • High (9-12)
Type of resource:
  • Text:
    • Ref. material
Subject:
  • Geological Sciences:
    • Geologic time
    • Geology
    • Paleontology
Technical requirements:
No specific technical requirements, just a browser required
Cost / Copyright:
No cost
Information presented on this website is considered public information (unless otherwise noted) and may be distributed or copied. Use of appropriate byline/photo/image credit is requested. We strongly recommend that USGS data be acquired directly from a USGS server and not through other sources that may change the data in some way. While USGS makes every effort to provide accurate and complete information, various data such as names, telephone numbers, etc. may change prior to updating. USGS welcomes suggestions on how to improve our home page and correct errors. USGS provides no warranty, expressed or implied, as to the accuracy, reliability or completeness of furnished data. Some of the documents on this server may contain live references (or pointers) to information created and maintained by other organizations. Please note that USGS does not control and cannot guarantee the relevance, timeliness, or accuracy of these outside materials.
DLESE Catalog ID: DLESE-000-000-005-430
Educational standards:
  • National Science Education Standards (NSES):
    • K-4:
      • Unifying concepts and processes:
        • Systems, order, and organization
    • 5-8:
      • Unifying concepts and processes:
        • Systems, order, and organization
      • D - Earth and space science:
        • Earth's history
    • 9-12:
      • Unifying concepts and processes:
        • Systems, order, and organization
      • D - Earth and space science:
        • Origin and evolution of the earth system
Resource contact / Creator / Publisher:
Publisher: United States Geological Survey, Cascades Volcano Observatory