Over the years, USGS scientists recognized several problems with the database. The two primary issues were location coordinates (either incorrect or lacking) and sample media (not precisely identified). This dataset represents a re-processing of the original RASS data to make the data accessible in digital format and more user friendly. This re-processing consisted of checking the information on sample media and location against the original sample submittal forms, the original analytical reports, and published reports. As necessary, fields were added to the original data to more fully describe the sample preparation methods used and sample medium analyzed. The actual analytical data were not checked in great detail, but obvious errors were corrected.
N = the element was not detected at concentrations above the lower limit of determination for the method. The value of the lower limit of determination is often given in the accompanying data field
L = the element was detected by the technique but at a level below the lowest reportable lower limit of determination for the method. The value is of the lower limit of determination is often given in the accompanying data field
G = the element was measured at a concentration greater than the upper limit of determination for the method
H = an analytical value could not be determined due to physical, chemical, or spectral interference
B = an analytical value was not determined
These qualifying values appear in this dataset as a separate field preceding each element. The attribute, or field name, for the qualifying values field always ends with a Q. For example S_FE_Q would be the name of the field containing and N, L, G, H, or B qualifiers for iron analyzed by optical emission spectroscopy.
Emission spectrography: Grimes and Marranzino, 1968; Fe, Mg, Ca, Ti, Mn, Ag, As, Au, B, Ba, Be, Bi, Cd, Co, Cr, Cu, La, Mo, Nb, Ni, Pb, Sb, Sc, Sn, Sr, V, W, Y, Zn, Zr, Th, Ga, Ge, Pd, and Pt
Atomic absorption spectrometry, partial extraction: O'Leary and Meier, 1986; O'Leary and Viets, 1986; Viets, 1978; Viets, Clark, and Campbell, 1984; Viets, O'Leary, and Clark, 1984; Ward and others, 1969: Ag, Bi, Cd, Cu, Mo, Pb, Sb, and Zn
The complete references for most of the analytical methods used are given below. It was not possible to determine the exact technique used or find a reference for a small number of the analytical data fields.
Adrian, B.A., and Carlson, R.R., personal communication, Platinum-group elements and gold by nickel-sulfide fire assay separation and optical emission spectroscopy.
Alminas, H., and Mosier, E.L., 1976, Oxalic-acid leaching of rock, soil, and stream-sediment samples as an anomaly-accentuation technique: U.S. Geological Survey Open-File Report 76-275, 26 p. (oxalic acid leachates derived from rock, soil, or steam-sediment samples analyzed for 30 elements by the emission spectrographic method of Grimes and Marranzino, 1968)
Chao, T.T., Sanzolone, R.F., and Hubert, A.E., 1978, Flame and flameless atomic absorption determination of tellurium in geologic materials: Analytica Chimica Acta, v. 96, p. 251-257.
Church, S.E., 1981, Multi-element analysis of fifty-four geochemical reference samples using inductively coupled plasma-atomic emission spectrometry: Geostandards Newsletter, v. 5, p. 133-160.
Cooley, E.F., Curry, K.J., and Carlson, R.R., 1976, Analysis for the platinum-group metals and gold by fire-assay emission spectroscopy: Applied Spectroscopy, v. 30 p. 52-56.
Ficklin, W.H., 1970, A rapid method for the determination of fluoride in rocks and soils, using an ion-selective electrode: U.S. Geological Survey Professional Paper 700-C, p. C186-C188.
Fishman, M.J., and Pyen, G., 1979, Determination of selected anions in water by ion chromatography: U.S. Geological Survey Water Resources Investigations 79-101, 30 p.
Grimes, D.J., and Marranzino, A.P., 1968, Direct-current arc and alternating-current spark emission spectrographic field methods for the semiquantitative analysis of geologic materials: U.S. Geological Survey Circular 591, 6 p.
Hubert, A.E., and Chao, T.T., 1985, Determination of gold, indium, tellurium and thallium in the same sample digest of geological materials by atomic-absorption spectroscopy and two-step solvent extraction: Talanta, v. 32, no. 7, p. 568-570.
McKown, D.M., and Knight, R.J., 1990, Determination of uranium and thorium in geologic materials by delayed neutron counting, in Arbogast, B.F., editor, Quality assurance manual for the Branch of Geochemistry, U.S. Geological Survey: U.S. Geological Survey Open-File Report 90-668, p. 146-150.
Mosier, E.L., 1972, A method for semiquantitative spectrographic analysis of plant ash for use in biogeochemical and environmental studies: Applied Spectroscopy, v. 26, no. 6, p. 636-641.
Mosier, E.L., 1975, Use of emission spectroscopy for the semiquantitative analysis of trace elements in silver and native gold, in Ward, F.N., editor, New and refined methods of trace analysis useful in geochemical exploration: U.S. Geological Survey Bulletin 1408, p. 97-105. (used for a special study on gold particles collected from several placer gold operations throughout Alaska)
Mosier, E.L., and Motooka, J.M., 1984, Induction coupled plasma-atomic emission spectrometry-Analysis of subsurface Cambrian carbonate rocks for major, minor, and trace elements, in Proceedings volume of international conference on Mississippi Valley-type lead-zinc deposits, Oct. 11-14: Rolla, MO, University of Missouri-Rolla, p. 155-165.
Motooka, J.M., and Sutley, S.J., 1982, Analysis of oxalic acid leachates of geologic materials by inductively coupled plasma-atomic emission spectroscopy: Applied Spectroscopy, v. 36, no.5, p. 524-533.
Myers, A.T., Havens, R.G., and Dunton, P.J., 1961, A spectrochemical method for the semiquantitative analysis of rocks, minerals, and ores: U.S. Geological Survey Bulletin 1084-I, p. I207-I229.
O'Leary, R.M., 1990, Determination of sulfur in geologic materials by iodometric titration, in Arbogast, B.F., editor, Quality assurance manual for the Branch of Geochemistry, U.S. Geological Survey: U.S. Geological Survey Open-File Report 90-668, p. 136-138.
O'Leary, R.M., and Meier, A.L., 1986a, Analytical methods used in geochemical exploration in 1984: U.S. Geological Survey Circular 948, 48 p.
O'Leary, R.M., and Meier, A.L., 1986b, Bismuth, cadmium, copper, lead, silver, and zinc, organic extraction method, in Analytical methods used in geochemical exploration, 1984: U.S. Geological Survey Circular 948, p. 11-13.
O'Leary, R.M., and Viets, J.G., 1986, Determination of antimony, bismuth, cadmium, copper, lead, molybdenum, silver, and zinc in geologic materials by atomic absorption spectrometry using a hydrochloric acid-hydrogen peroxide digestion: Atomic Spectroscopy, v. 7, no. 1, p. 4-8.
Orion Research, Inc., 1975, Orion Research Analytical Methods Guide, 7th edition: Cambridge, MA, 20 p.
Perkin-Elmer Corporation, 1976, Analytical methods for atomic absorption spectrophotometry: Norwalk, CT, Perkin-Elmer Corp., 586 p.
Perkin-Elmer Corporation, 1977, Analytical methods for atomic absorption spectrophotometry, using the HGA graphite furnace: Norwalk, CT, Perkin-Elmer Corp., 286 p.
Skougstad, M.W., Fishman, M.J., Friedman, L.C., Erdman, D.E., and Duncan, S.S., eds., 1979, Methods for the determination of inorganic substances in water and fluvial sediments: Techniques of Water-Resources Investigations of the U.S. Geological Survey, Book 5, Chap. A1, 626 p.
Smee, B.W., and Hall, G.E.M., 1978, Analysis of fluoride, chloride, nitrate, and sulphate in natural waters, using ion chromatography: Journal of Geochemical Exploration, v. 10, no. 3, p. 245-258.
Sutley, S.J., and Mosier, E.L., personal communication, Rb, Cs, Li, Tl by modification of emission spectrography method of Grimes and Marranzino, 1968.
Thompson, C.E., Nakagawa, H.M., and VanSickle, G.H., 1968, Rapid analysis for gold in geologic materials: U.S. Geological Survey Professional Paper 600-B, p. B130-B132.
Vaughn, W.W., and McCarthy, J.H., Jr., 1964, An instrumental technique for the determination of submicrogram concentrations of mercury in soils, rocks, and gas: U.S. Geological Survey Professional Paper 501-D, p. D123-D127.
Viets, J.G., 1978, Determination of silver, bismuth, cadmium, copper, lead, and zinc in geologic materials by atomic absorption spectrometry with tricaprylyl methyl ammonium chloride: Analytical Chemistry, v. 50, no. 8, p. 1097-1101.
Viets, J.G., Clark, J.R., and Campbell, W.L., 1984, A rapid, partial leach and organic separation for the sensitive determination of Ag, Bi, Cd, Cu, Mo, Pb, Sb, and Zn in surface geologic materials by flame atomic absorption: Journal of Geochemical Exploration, v. 20, p. 355-366.
Viets, J.G., O'Leary, R.M., and Clark, J.R., 1984, Determination of arsenic, antimony, bismuth, cadmium, copper, lead, molybdenum, silver and zinc in geological materials by atomic-absorption spectrometry: The Analyst, v. 109, p. 1589-1592.
Ward, F.N., Lakin, H.W., Canney, F.C., and others, 1963, Analytical methods used in geochemical exploration by the U.S. Geological Survey: U.S. Geological Survey Bulletin 1152, 100 p.
Ward, F.N., Nakagawa, H.M., VanSickle, G.H., and Harms, T.F., 1969, Atomic absorption methods useful in geochemical exploration: U.S. Geological Survey Bulletin 1289, 45 p.
Watterson, J.R., 1976, Determination of tellurium and gold in rocks to 1 part per billion: U.S. Geological Survey Open-File Report 76-531, 3 p.
Sample Preparation Methods:
Various sample preparation methods were used depending on the sample media. Stream-sediment and soil samples were generally sieved to minus-80 mesh before pulverizing but other sieve sizes may have been used depending on the requirements of the submitter and the nature of investigation for which the samples were collected. Heavy-mineral-concentrate samples were usually sieved to minus-35 mesh prior to further separation but again other sieve sizes may have been used. Most of the heavy-mineral-concentrate samples were panned in the field and subjected to heavy liquid and magnetic separation in the laboratory prior to analysis. However there are some samples that were only panned in the field and then analyzed in the laboratory. Occasionally there are heavy-mineral-concentrate samples that were field panned, subjected to heavy liquid and magnetic separation, and then 2 or more of the magnetic separation fractions were combined for analysis. Each sample in the database has been coded in the DESCRIPT1, DESCRIPT2, and MESH_SIZE fields to describe the sample media and preparation methods used as accurately as possible. Sample preparation methods used and references are given below:
Stream-sediment and soil samples are thoroughly dried, generally at less than 50 degrees C. The dried samples are disaggregated by hand as necessary and as much organic material as possible is removed. The samples are then sieved to the required particle size using stainless steel sieves. The sieved fraction is generally ground using a vertical pulverizer with ceramic plates, placed in a 3-ounce cardboard sample container, and mixed to ensure homogeneity.
Heavy-mineral-concentrate samples are generally sieved through a minus-10 mesh (2 mm) screen into a 14-16 inch stainless-steel gold pan and then further reduced by panning. In the laboratory, the remaining sample is sieved through a minus-35 mesh screen. The minus-35 mesh fraction is separated into heavy and light fractions using bromoform with a specific gravity of 2.8. The heavy fraction, the sample material with specific gravity >2.8, is further separated magnetically using a Frantz Isodynamic Separator, into a highly magnetic (ferromagnetic, C1) fraction, a weakly magnetic (paramagnetic, C2) fraction, and a nonmagnetic (C3) fraction. Depending on the amount of material available, the heavy, nonmagnetic (C3) fraction is divided into an analytical split and a split used for mineralogical identification by the submitter. The analytical split is pulverized using an agate mortar and pestle.
References for sample preparation methods:
Peacock, T.R., and Taylor, C.D., 1990, Physical preparation of stream-sediment and soil samples, in Arbogast, B.F., editor, Quality assurance manual for the Branch of Geochemistry, U.S. Geological Survey: U.S. Geological Survey Open-File Report 90-668, p. 26-32.
Taylor, C.D., 1990, Physical preparation of heavy-mineral concentrates by heavy liquid and magnetic separation, in Arbogast, B.F., editor, Quality assurance manual for the Branch of Geochemistry, U.S. Geological Survey: U.S. Geological Survey Open-File Report 90-668, p. 33-37.