Teaching with GEOROC
The Data Set
GEOROC (Geochemistry of Rocks of the Oceans and Continents) is a database that provides chemical and isotopic data for rocks, minerals, and inclusions. Users can search for data from multiple geological settings including convergent margins, ocean islands, seamounts, oceanic plateaus, submarine ridges, ocean-basin flood basalts, continental flood basalts, and archean cratons (including greenstone belts). The site contains analyses for over 150,000 samples.
Use and Relevance
Use in Teaching
This data can be used to teach the following:
1) Volcanic and plutonic igneous rocks
2) Mantle xenoliths
3) Volcanic glasses
4) Metamorphic rocks
5) Inclusions (glass, minerals, and fluid)
1) Generating graphs from raw data (using programs such as Excel)
2) Interpreting petrological data (including chemical composition of rocks in % weight and ppm)
3) Examining the function of plate tectonics in the formation of igneous rocks
Igneous Rock Compositions and Plate Tectonics
4) Generating "Harker" diagrams to analyze compositional changes and make petrologic interpretations
CompositionalDiversity in Volcanic Suites
Crystallization-Differentiation of Basaltic Magma
About the data
Collection methods vary greatly. For some data sets, the collection method (such as dredging or drilling) is indicated, but this information is not provided for all data sets. References associated with data sets are given and users could search through primary literature for details regarding collection methods and analyses.
Limitations and sources of error
Age data is not consistently given in all data sets (which is particularly problamatic for users who are interested in isotopic compositional changes). Sources of error are not directly given in the datasets, and therefore the references given should be examined by users who would like information regarding data limitions and sources of error.
Data type and presentation
Data is presented as tables in HTML format and can be downloaded as an Excel compatible (comma delimited text) format.
Accessing the data
Users can query data by bibliography, tectonic settings, geography, chemistry, or petrography (including volcanic rocks, plutonic rocks, and mantle xenoliths). Once a query path is chosen, data sets can be further refined by a variety of selection criteria, including rock type (e.g., volcanic), rock name (e.g., alkali basalt), and chemical composition.
Data manipulation tools
Raw data can be be used to generate graphs and diagrams (using programs such as Exel).
References and resources
About the data
Abstracts from AGU meetings:
GEOROC - Current and Upcoming Activities
Progress in the GEOROC Database - Fast and Simple Access to Analytical Data by Precompilation
GEOROC provides a reference list (associated with datasets) that can be downloaded in Excel and a list of papers that refer to GEOROC data.
Insights on WWW-based geoscience teaching: Climbing the first year learning cliff : Discusses use of databases in teaching petrology.
1) Resources for Teaching Petrology
2) PETDB (Petrologic Database of the Ocean Floor)