Sedimentation Rates from Pb-210 data

Steven Petsch, University of Massachusetts Amherst

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In this exercise, students use a data table of depth, porosity, Pb-210 activity, CaCO3 concentration, 14C age and d13C values to calculate mass accumulation rates, linear sedimentation rates, CaCO3 dissolution and contributions of terrestrial vs aquatic organic matter in a hypothetical coastal sediment core.

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upper-level elective sedimentary geochemistry course

Skills and concepts that students must have mastered

radioactive decay equations
isotope mixing models
dimensional analysis and unit conversions

How the activity is situated in the course

This is the first in a sequence of problem sets in the course.


Content/concepts goals for this activity

Using radio-isotope data to calculate mass accumulation and sedimentation rates in sediments.
Using concentration data to estimate rates of change in mineral abundance in sediments.
Using stable isotope data to construct mixing models.
Interpreting sedimentation rates and sources in the context of possible environmental change.

Higher order thinking skills goals for this activity

Other skills goals for this activity

Description and Teaching Materials

This is a one-page stand-alone problem set. Students complete the calculations and return their answers. I typically give students 1-2 weeks to complete this problem set.

Problem Set: Sedimentation Rates, Reactions and Sources (Microsoft Word 2007 (.docx) 176kB Apr15 13)

Teaching Notes and Tips


This assignment is assessed based on simply grading of the answers. Typically, students have not encountered this type of quantitative problem set prior to my class, and many have challenges completing the assignment. I spend class time going through the solutions to the problems.

References and Resources