Tracing sediment provenance from source to sink: Isotope records in the Bay of Bengal and Indonesia

Annika Johansson, Lamont-Doherty Earth Observatory of Columbia University and Jeff Ryan, University of South Florida


In this exercise students examine data from a geochemical database to understand the link between source rocks and sedimentary deposits in the ocean, focusing on the Bay of Bengal in the context of the MARGINS Source-to-Sink initiative and contrasting these data with those offshore of Indonesia. This activity utilizes the online geochemical database SedDB, GeoMapAPP, and Excel.

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Context for Use

This exercise is at an introductory geoscience class level. It is best suited as a laboratory activity as it requires hands-on use of computers and discussion time. During the exercise both instructor and students should have access to the web and individual computers to work on. Students should have a basic understanding of general geology and isotope geochemistry.

Students should perform the task on Mac or PC computers loaded with the following software: a web browser, Excel, and GeoMapApp.

The exercise can be modified into an advanced level undergraduate or graduate level course with expanded data mining and combination of this data with that from other geochemical databases such as PetDB and GEOROC accessible through Earthchem. The geographical area queried within SedDB can also be expanded to include a global dataset of Sr and Nd isotope chemistry.

Students should be familiar with basic plate tectonics, and sedimentary processes such as weathering, transport and deposition.

Description and Teaching Materials

Included in this activity is an assignment sheet, along with an Excel spreadsheet containing Bay of Bengal datasets if there are difficulties with website connections.
Assignment sheet (Microsoft Word 2.8MB Oct15 08) 
Indian Ocean-Indonesia Excel Spreadsheet

Teaching Notes and Tips

The instructor should be familiar with the SedDB database and how to complete the query, as well as visualizing the data in GeoMappApp.

Note: GeoMapApp will only show the core site, not how many underlying data points there are in each core, it also does not allow down hole plotting. The instructor may wish to discuss the significance of down hole variations in Sr and Nd isotopes in the context of climate changes and monsoonal variations.

References and Resources

Integrated Datamanagement for Sediment Geochemistry (SedDB)