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PETROS - Worldwide Databank of Major Element Chemical Analyses of Igneous Rocks

Published by NOAA National Centers for Environmental Information | National Oceanic and Atmospheric Administration, Department of Commerce | Metadata Last Checked: January 27, 2026 | Last Modified: 1981-05-15T00:00:00.000+00:00
PETROS is a worldwide data bank of major element chemical analyses of igneous rocks compiled for research and teaching purposes by Dr. Felix Mutschler and Staff at Eastern Washington University. PETROS version 6.1 includes 37,300 major element chemical analyses divided into 307 major groups representing geographic areas or petrologic provinces. The data are for 4,512 cores, grabs and dredges. Also included are 468 average igneous rock compositions calculated by various authors, a bibliography of information sources, and complete format/operating instructions for PETROS. In compiling PETROS, as few analyses as possible were rejected, allowing data bank users to exercise their own judgment on data values. Sources include published works, theses, and in a few cases, unpublished analytical data, all of which are referenced in the bibliography. Generally, only those analyses which included determinations of at least eight major oxides were accepted. Some quality control was exercised, and duplicate analyses, where possible were eliminated. Latitude/longitude information for samples is to the nearest one degree. An accompanying program listing in FORTRAN for searching PETROS is included with the data file, along with complete format documentation.

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