Keyah Math > Activities > Geochronology in the San Juan Mountains (Advanced)

# Geochronology in the San Juan Mountains (Advanced)

This activity was selected for the On the Cutting Edge Reviewed Teaching Collection

This activity has received positive reviews in a peer review process involving five review categories. The five categories included in the process are

• Scientific Accuracy
• Alignment of Learning Goals, Activities, and Assessments
• Pedagogic Effectiveness
• Robustness (usability and dependability of all components)
• Completeness of the ActivitySheet web page

#### Summary

This is a mathematically more advanced version of the Ages of Rocks and the Earth activity that introduces students to the mathematics of radiometric dating. Students derive the decay equation for the rubidium-strontium isotopic system, then apply it to date rock samples from the San Juan Mountains of southwest Colorado and a meteorite assumed to be approximately coeval with the Earth.

Click here to view the full activity on the Kéyah Math Project website.

## Learning Goals

Objectives
• Review the use of radioactive decay as a "natural clock" for dating rocks.
• Derive the decay equation for the rubidium-strontium isotope system.
• Apply this decay equation to obtain ages for rock samples from the San Juan Mountains in southwest Colorado.
• Apply this equation to data from a meteorite to estimate the age of the Earth

Mathematical Skills
• Use basic algebra.
• Solve exponential equations.
• Use logarithms.
• Perform linear regression analysis.
• ## Context for Use

This activity consists of a set of quantitative problem-solving exercises that can be used as an in-class activity or an assignment in any introductory course with a unit on geologic time or geochronology, such as:
-Physical geology or physical geography
-Historical geology or Earth history
-Earth materials, mineralogy, or petrology

## Teaching Notes and Tips

An Instructor's Guide to all Kéyah Math activities is available online from the Instructor Resources page on the Kéyah Math website.

## Assessment

Students record their work and answers in a word-processor document or a notebook, which can be submitted to the instructor for assessment. Solutions to these problems are available online from the Instructor Resources page on the Kéyah Math website.

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