U.S. Geological Survey Certificate of Analysis
Sample used in the preparation of this reference material was collected in 1968 from the Braggtown Quary near Durham, North Carolina. The material is one of the Triassic-Jurassic olivine-normative dolerites indigenous to the area (Ragland, et al., 1968).
Element concentrations were determined by cooperating laboratories using a variety of analytical methods. Certificate values are based primarily on USGS results (Flanagan, 1984) and international data compilations (Gladney and Roelandts, 1987, Govindaraju, 1994). USGS studies also provide background information on the sample collection site.
|Oxide||Wt %||±||Oxide||Wt %||±|
revised March 1995
David B. Smith
Central Region Mineral Resources Team (formerly Branch of Geochemistry)
Flanagan, F.J., 1984, Three USGS Mafic Rock Reference Samples, W-2, DNC-1, and BIR-1: U.S. Geological Survey Bulletin 1623, p. 54.
Gladney, E.S., and Roelandts, I., 1988, 1987 Compilation of Elemental Concentration Data for USGS BIR-1, DNC-1, and W-2: Geostandards Newsletter, 12: 63-118
Govindaraju, K., 1994, 1994 Compilation of Working Values and Descriptions for 383 Geostandards: Geostandards Newsletter, 18:1-158
Ragland, P.C., Rogers, J.J.W., and Justus, P.S., 1968, Origin and Differentiation of Triassic Dolerite Magmans, North Carolina, USA: Contributions to Mineralogy and Petrology, vol. 20. no. 1, pp. 57-80.
|Fe2O3T||Total iron expressed as Fe2O3|
|Ctot||Total carbon concentration|
|Stot||Total sulfur concentration|
|Wt %||Percent of total element concentration|
|µg/g||Total element concentration expressed as micrograms of element per gram of solid sample|
|±||One standard deviation|
Unless otherwise indicated total element concentrations are reported for material on an as-received basis, i.e., no drying.
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