See also:

• Reference: Time  (89)
• Science: Earth Sciences: Geology: Rocks and Minerals: Sedimentary Petrology: Sedimentology and Stratigraphy: Sequence Stratigraphy  (2)
• Science: Earth Sciences: Paleontology  (1,379)

• Berkeley Geochronology Center - Non-profit scientific research institution dedicated to establishing the history of the Earth, its various inhabitants, and its interactions with the rest of our Solar System, throughout the 4.6 billion years of our Planet's existence.
• Geologic Time - USGS on-line publication about the relative and radiometric geologic time scales, age of the earth, index fossils, and related topics.
• Geological Time - Lecture notes on different methods of measuring geologic time.
• Strontium Isotope Stratigraphy - Describes this method, used primarily to date marine sediments, and provides access to the global seawater strontium curve and a user-friendly table for converting 87Sr/86Sr values to numerical ages.
• Web Time Machine - Geologic time scale with links for each time interval.