Teaching about absolute dating
Before starting this activity, students should have at least a good understanding of relative age dating, and preferably have completed Principles of Biostratigraphy.
As this lab is designed for students to work in small groups, it can be used for a large range of class sizes.
With absolute age dating, you get a real age in actual years.
It’s based either on fossils which are recognized to represent a particular interval of time, or on radioactive decay of specific isotopes. Based on the Rule of Superposition, certain organisms clearly lived before others, during certain geologic times.
This 5-12-grade activity introduces students to the idea of sequencing information in overlapping data sets and the Principle of Superposition, which is a core concept in relative dating. Offers history of age dating, stratigraphic principles, rock correlation, fossil correlations, radiometric dating, and the geologic time scale. Short discussion of radioactive dating and stratigraphic principles.
Radiometric Dating and the Geologic Time Scale, The Talk Origins Archive. Provides brief overview of (1) relative dating and stratigraphic methods, (2) absolute dating and radiometric dating, including a table with parent to daughter isotopes and half lives of those isotopes commonly used in radiometric dating, (3) paleomagnetics and (4) geologic time. Includes tables of common radioactive parent isotopes and their stable daughter products, and half lives of common radioactive isotopes.
In a way this field, called geochronology, is some of the purest detective work earth scientists do.
Absolute age dating is like saying you are 15 years old and your grandfather is 77 years old.
To determine the relative age of different rocks, geologists start with the assumption that unless something has happened, in a sequence of sedimentary rock layers, the newer rock layers will be on top of older ones. This rule is common sense, but it serves as a powerful reference point.
Upon completion of this exercise students will be able to: 1.
Model the statistics used to date rocks with the decay of radioactive isotopes. Distinguish which decay schemes are most effective for dating different kinds of materials. Correlate relative time boundaries established by the fossil record with absolute dates.