Geologic Time and Dating
The geologic time scale and geologic age dating.
The 2004 Geologic Time Scale
Start here with the eons and eras and zoom in on the period you want. Numbers and names come from the International Commission on Stratigraphy.
Start here with the eons and eras and zoom in on the period you want. Numbers and names come from the International Commission on Stratigraphy.
Introducing the Anthropocene
A brand-new name for the current time period, the Anthropocene Epoch, might get some currency.
A brand-new name for the current time period, the Anthropocene Epoch, might get some currency.
The Quaternary Refuses to Die
The time period encompassing the most recent past was (temporarily) erased by a bureacratic bulldozer.
The time period encompassing the most recent past was (temporarily) erased by a bureacratic bulldozer.
Mapping Deep Time
How we learned to keep track of geologic time without using clocks or numbers.
How we learned to keep track of geologic time without using clocks or numbers.
About Isotopic Dating: Measuring Deep Time
Explaining the isotopic dating method in terms of your backyard barbecue.
Explaining the isotopic dating method in terms of your backyard barbecue.
Uranium-Lead Dating
Uranium-lead method is the oldest and, when done carefully, the most reliable isotopic dating method.
Uranium-lead method is the oldest and, when done carefully, the most reliable isotopic dating method.
Potassium-Argon Dating Methods
Potassium-argon isotopic dating is especially useful for determining the age of lavas.
Potassium-argon isotopic dating is especially useful for determining the age of lavas.
Radioisotopes from Space
Closing in on radiocarbon discrepancies through the space program pays off in knowledge about the Earth.
Closing in on radiocarbon discrepancies through the space program pays off in knowledge about the Earth.
Geo-Quiz Number 23: Geologic Time
Who wants to be a geo-whiz? The trivia game: GEOLOGIC TIME
Who wants to be a geo-whiz? The trivia game: GEOLOGIC TIME
Geologic Time: The Story of a Changing Earth
This online exhibit lets you zoom in and out of the billions of years of Earth history and includes some good supporting material.
This online exhibit lets you zoom in and out of the billions of years of Earth history and includes some good supporting material.
"How Old Is the Earth? Why Should We Care?"
A commentary by Marli Miller of the University of Oregon gives the answer to the question, and the reasons, in a lucid and commonsense way.
A commentary by Marli Miller of the University of Oregon gives the answer to the question, and the reasons, in a lucid and commonsense way.
Geological Time Machine
Click on any of the geologic ages, eras, and epochs to learn more about that part of ancient time, from the University of California Berkeley.
Click on any of the geologic ages, eras, and epochs to learn more about that part of ancient time, from the University of California Berkeley.
Dr. Bob's Geologic Time Page
Geo-time mnemonics, or handy ways to keep all the geologic time units straight, from Eastern Illinois University.
Geo-time mnemonics, or handy ways to keep all the geologic time units straight, from Eastern Illinois University.
1999 North American Geologic Time Scale
This Geological Society of America time scale is still relevant for some uses; click through for the PDF.
This Geological Society of America time scale is still relevant for some uses; click through for the PDF.
Earth-Time
This cooperative effort to intercalibrate and improve the world's age dating methods is the cutting edge of geochronology.
This cooperative effort to intercalibrate and improve the world's age dating methods is the cutting edge of geochronology.
Pseudonumerology
Geologist Allan Krill has been teaching this memorization technique for many years. This page shows you how to memorize all the geologic time units and their ages!
Geologist Allan Krill has been teaching this memorization technique for many years. This page shows you how to memorize all the geologic time units and their ages!
Dendrochronology
From your About Forestry Guide, more links centered around the study of tree rings and what they tell us about the past.
From your About Forestry Guide, more links centered around the study of tree rings and what they tell us about the past.
The Ancient Bristlecone Pine
A lovely site by Leonard Miller about the oldest trees on Earth, including a section on dendrochronology.
A lovely site by Leonard Miller about the oldest trees on Earth, including a section on dendrochronology.
Accelerator Mass Spectrometry
An introduction from the Purdue Rare Isotope Measurement (PRIME) Lab.
An introduction from the Purdue Rare Isotope Measurement (PRIME) Lab.
Luminescence Dating
An introductory page from the Research Laboratory for Archaeology and the History of Art, Oxford University.
An introductory page from the Research Laboratory for Archaeology and the History of Art, Oxford University.
Radiocarbon
The flagship journal of carbon-14 studies (and other cosmogenic isotopes) has contents, abstracts, and some sample articles online for nonsubscribers.
The flagship journal of carbon-14 studies (and other cosmogenic isotopes) has contents, abstracts, and some sample articles online for nonsubscribers.
Radiometric Dating: A Christian Perspective
Roger Wiens, an Earth scientist who is a Christian, wrote this article to combat common misunderstandings among creationists about the tools of geologic dating.
Roger Wiens, an Earth scientist who is a Christian, wrote this article to combat common misunderstandings among creationists about the tools of geologic dating.
Radiogenic Isotopes and the Eastern Mineral Resources Program
Robert Ayuso of the U.S. Geological Survey describes exactly how radiometric dating studies are being used on real practical problems.
Robert Ayuso of the U.S. Geological Survey describes exactly how radiometric dating studies are being used on real practical problems.
Radiometric Dating
A brief version from Pamela Gore's Geology 102 course notes at Georgia Geoscience Online.
A brief version from Pamela Gore's Geology 102 course notes at Georgia Geoscience Online.
Radiometric Dating
A lucid, thorough treatment of the subject from Jonathon Woolf's superb Woolf's Den that emphasizes why creationist criticisms of this technique are mistaken at best.
A lucid, thorough treatment of the subject from Jonathon Woolf's superb Woolf's Den that emphasizes why creationist criticisms of this technique are mistaken at best.
Radiometric Time Scale
From the U.S. Geological Survey's pamphlet "Geologic Time" comes this basic explanation of isotope geochronology.
From the U.S. Geological Survey's pamphlet "Geologic Time" comes this basic explanation of isotope geochronology.
The Sclerosponge Home Page
It's a bit sketchy, but it's the best place to learn about these hard white "corals" that I think of as the bristlecone pines of the sea.
It's a bit sketchy, but it's the best place to learn about these hard white "corals" that I think of as the bristlecone pines of the sea.
Stable Carbon Isotopes in Paleoceanography
Ellen Thomas, at Wesleyan University, posted this in-depth look at carbon isotopics and their use in studying ancient climate.
Ellen Thomas, at Wesleyan University, posted this in-depth look at carbon isotopics and their use in studying ancient climate.
Table of the Nuclides
Every isotope known to science is displayed here. Click on any one for a bunch of basic physical data.
Every isotope known to science is displayed here. Click on any one for a bunch of basic physical data.
TIMS Sample Loading Tour
Cornell University's geology lab hosts this trip through its Thermal Ionization Mass Spectrometer. See exactly how radiometric dating is done!
Cornell University's geology lab hosts this trip through its Thermal Ionization Mass Spectrometer. See exactly how radiometric dating is done!