Chemical and Isotope Data

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Background information on the chemical and isotope data

The request water data web site makes available the chemical and isotope data accumulated by two USGS Projects (I. Barnes and R. Mariner) over a time period of about 40 years. This is principally data collected as part of various studies carried out by members of the Barnes or Mariner projects supplemented by samples submitted to us for analysis by other researchers of similar interests. The data are primarily chemical and isotopic analyses of waters (thermal, mineral, or fresh) and associated gas (free and/or dissolved) collected from hot springs, mineral springs, cold springs, geothermal wells, fumaroles, and gas seeps. Data are also presented for a few streams, lakes, and oil wells.

Explanation of headings and symbols used in the table

Site names If a spring or well is named on a U. S. Geological Survey topographic map (scale 1:24,000 or 1:62,500) then that name is used in the file. In some cases where a spring is unnamed or not shown on the appropriate topographic map, a "local" name or a name based on some nearby feature was used. For example, "Rye Grass Hot Springs" in Malheur County, Oregon, is not a recognized spring name; it does not appear on USGS topographic maps of the area, nor is it present in the GeoRef data base. This hot spring issues on the left bank of the Owyhee River near where Ryegrass Creek "flows" into the Owyhee River.

Location data Sites with longitudes and latitudes in degrees, minutes, and seconds (or decimal minutes) are exact locations but sites with longitudes and latitudes only in decimal degrees are approximate locations. Letters (such as ADB) following the section number indicate the ¼ section (160-acre tract), ¼ - ¼ section (40-acre tract), and the ¼ - ¼ - ¼ section (10-acre tract). The letters A, B, C, and D in this system are arranged in counter clockwise order from the northeast quarter of the section (640-acre block). Forty-acre tracts in 160-acre blocks and ten-acre tracts in 40-acre blocks are lettered in the same manner. Letters such as NE, NW, SW, and SE in the ¼ section block of the table preceding the section number designate the ¼ - ¼ - ¼ section, ¼ - ¼ section, and ¼ section in which the spring or well is located. Divisions in this system are arranged from smallest to largest, thus ADB of the previous system becomes NW ¼ - SW ¼ - NE ¼ and is abbreviated to NWSWNE in the file.

°C Degrees Celsius To convert °C to °F multiply by 9/5 and add 32.

C-14 (% mdn.) Carbon-14 in percent modern carbon

mg/L Concentration of the solute given in milligrams (mg) of the constituent per liter (L) of water - equivalent to parts per million (ppm) in dilute waters.

ppm In waters: concentration reported in a weight-per-weight ratio. In dilute waters, one ppm is equivalent to 1 mg of solute per kilogram of solution. In gases: 1 ppm is equal to 0.0001% by volume.

TU Tritium units — One TU corresponds to an atom ratio of tritium to hydrogen of 10-18, or to an activity of 3.2 picocuries per liter.

% free gas Percent by volume of constituent free gas relative to total free gas.

μm-gas/kg-water Micromoles of dissolved gas per kilogram of water.

μS/cm Microsiemens per centimeter, a measure of the electrical conductivity of a block of water one centimeter long and one centimeter squared in cross section. Numerically equivalent to micromhos.

δ-values Parts per thousand (permil, ‰). For example, δ18O = -5‰, indicates that the sample has 5‰ (0.5%) less 18O than the standard.

Terms and headings used in the tables

Filter size - Pore size of filter in microns. Virtually all samples were filtered in the field (at collection) through 0.1 or 0.45 μ (micron) pore size membrane filters with either compressed air or compressed nitrogen as the pressure source. Absence of a number in this field usually indicates that the pore size of the filter was not recorded.

LDMW - Locally derived meteoric water.

Monomeric Al - The aluminum monomer (Al(OH)4-) extracted into MIBK (methyl isobutyl ketone) in the field whereas Al represents total dissolved aluminum (monomers and polymers).

NH4(N) - Ammonia concentration determined in the lab and reported as N (nitrogen).

NH4(N) field - Ammonia concentration determined in the field and reported as N.

NO3(N) - Nitrate concentration reported as N.

NO2(N) - Nitrite concentration reported as N.

PO4(P) - Phosphate concentration reported as P (Phosphorus).

δD = [{(D/H) sample — (D/H) SMOW}/(D/H) SMOW] x 103‰, where SMOW is Standard Mean Ocean Water. Positive values indicate enrichment in deuterium relative to the standard and negative values indicate depletion in deuterium relative to the standard.

δ18O = [{(18O/16O) sample — (18O/16O) SMOW}/(18O/16O) SMOW] x 103‰, where SMOW is Standard Mean Ocean Water.

δ15N = [{(15N/14N) sample — (15N/14N) air}/(15N/14N) air] x 103‰.

δ13C = [{(13C/12C) sample — (13C/12C) PDB}/(13C/12C) PDB] x 103‰, where PDB is the PDB standard of the University of Chicago (Belemnitella Americana, Peedee Formation, Cretaceous, South Carolina).

3He/4He R/Ra Ratio of 3He/4He in the sample to the same ratio in air (R/Ra); the 3He/4He value of air is 1.4 x 10-6.

Water Collection Methods

Water samples were generally collected in a 1 gallon stainless steel pressure vessel, and filtered on-site using a 142 mm diameter stainless steel filter housing. Pressure drive was provided by using a tank of compressed nitrogen. Membrane filters of 0.45μ or 0.1μ pore-size were preferred. The finer pore-size filter was used when aluminum or other trace metals were of interest. Alternately, a stainless steel cylinder fitted with a membrane filter (usually 0.45μ), and compressed air (provided by a bicycle pump) was used to filter the water on-site. Samples for cation analysis were acidified to pH 2 with high purity concentrated nitric acid, or less commonly with high purity concentrated hydrochloric acid. Acidified sample pH values were checked with pH paper. Samples for anions were collected identically, but not acidified. Unstable constituents - pH, hydrogen sulfide (H2S), sulfate (SO4) if H2S was present, total alkalinity as bicarbonate (HCO3), and ammonia (NH3) - were determined on site. Sample pH was measured in the spring or as near the wellhead temperature as possible using a pH meter calibrated to two buffers. Sample pH was corrected for the temperature dependent changes in buffer values. Total alkalinity was determined by titration with 0.05N H2SO4 to the endpoint of the titration. Hot samples were permitted to cool to 35°C or less before the titration was begun. Sulfide was determined by thiosulfate titration whenever the rotten-egg smell of H2S was noticed by the field crew. Sulfate was determined in the field using a portable spectrophotometer whenever high sulfide was present. Ammonia was determined by specific ion electrode. For hot waters where silica concentration was expected to be above 100 mg/L, an aliquot of the filtered sample was diluted with distilled deionized water in the field to prevent polymerization and gelation of dissolved silica.

Not all samples in this compilation were collected using the above procedures. We occasionally received single samples or a few samples for major constituent analyses that were not filtered, or acidified for cations, and were collected in everything from beer bottles to plastic shampoo containers. In general, above procedures were rigorously followed by persons that were part of the project (Ivan Barnes, Bob Mariner, Bill Evans, John Rapp, Theresa Presser, or Larry Wiley), were in other projects at the USGS Menlo Park Center (Manuel Nathenson, Mike Thompson, Ed Sammel, and Mike Sorey) or were in the USGS State Water Resources Division Offices (Bill Young in Idaho, Alan Welch or Mike Lico in Nevada, Bob Leonard in Montana, and Frank Trainer in New Mexico).

Analytical techniques and methods

Alkalinity as bicarbonate (HCO3) Titration was carried out at the collection site with 0.05 N H2SO4 to the bicarbonate inflection point on the titration curve. In some cases where titration at the collection site was not practical, total alkalinity as bicarbonate was determined by automatic titration in the laboratory. Field titrations are preferred because the concentrations of other titratable species (H3SiO4-, H2SiO4-2, S-2, HS-, NH3, B(OH)4-, and OH-) are known or can be calculated and their effect on the titration corrected.

Aluminum (monomeric Al) Monomeric aluminum was complexed with 8-hydroxyquinoline, buffered at a pH of 8.3, and extraction into MIBK in the field. Extracted samples were run on an atomic absorption spectrophotometer in the laboratory.

Cations Aluminum total (Al), Antimony (Sb), Arsenic (As), Barium (Ba), Beryllium (Be), Cadmiun (Cd), Calcium (Ca), Cesium (Cs), Chromium (Cr), Cobalt (Co), Copper (Cu), Gold (Au), Iron (Fe), Lead (Pb), Lithium (Li), Magnesium (Mg), Manganese (Mn), Nickel (Ni), Potassium (K), Rubidium (Rb), Silver (Ag), Sodium (Na), Strontium (Sr), Zinc (Zn) were run on an atomic absorption spectrophotometer in the laboratory.

Ammonia (NH3 as N) Specific ion electrode.

Boron (B) Colorimetric.

Bromide (Br) Hypochlorite oxidation until approximately 1980, Dionex in more recent samples.

Chloride (Cl) Specific-ion electrode or Mohr titration until approximately 1980, Dionex in more recent samples.

Fluoride (F) Specific ion electrode until approximately 1980, Dionex in more recent samples.

Hydrogen (H) Calculated from field pH, rarely from base titration.

Hydroxide (OH) Calculated from field pH, rarely from acid titration.

Iodide (I) Hypochlorite oxidation.

Mercury (Hg) Samples for mercury analysis were stabilized in the field by adding 2:1 H2SO4:HNO3, 5% KMnO4 (W/V), and 5% K2S2O8 (W/V). Stabilized samples were analyzed by a flameless atomic absorption technique in the laboratory.

Nitrate (NO3) and nitrite (NO2) Spectrophotometer using brucine or diazotization until approximately 1980, Dionex in more recent samples.

Orthophosphate (as P) Spectrophotometer using phosphomolybdate until approximately 1980, Dionex in more recent samples.

Selenium (Se) Diaminobenzidine until approximately 1980, hydride generation in more recent samples.

Silica (SiO2) Atomic absorption spectrophotometer was used for silica concentrations greater than 10 mg/L. Colorimetric (molybdate blue) was used for silica concentrations between 0.1 and 10 mg/L.

Sulfate (SO4) Barium chloride titration (with thorin) until approximately 1980, field spectrophotometer in high sulfide waters, Dionex in more recent samples.

Sulfide (as H2S) Iodine-thiosulfate titration.

Uranium (U) Fluorophotometric.

δ13Cmineral Carbonate mineral is converted to CO2 with 100% phosphoric acid at 25°C.

δ13Ctotal diss. Dissolved carbon precipitated by addition of ammoniacial SrCl2, followed by conversion of SrCO3 to CO2; or acidification of sample in gas tight bottles in the field followed by CO2 extraction and analysis.

δ13CCO2 and δ18OCO2 gas purified and analyzed on mass spectrometer.

δ13CCH4 CH4 oxidized to CO2 for analysis.

14C Dissolved carbon precipitated by addition of ammoniacial SrCl2, followed by conversion of SrCO3 to CO2; or acidification of the sample in gas tight bottles in the field followed by CO2 extraction and analysis.

δDwater Uranium technique, zinc technique, or H2-H2O equilibration with platinum catalyst.

3He/4He purified from gas or water sample and analyzed on mass spectrometer.

δ15NN2 purified from gas sample and analyzed on mass spectrometer.

δ18Owater CO2- H2O equilibration technique.

δ18Odiss. sulfate Filtered sample treated with formaldehyde to prevent sulfide conversion to sulfate by bacteria, sulfate precipitated as BaSO4, CO2 for analysis is produced by carbon reduction of the BaSO4.

δ18Osulfate mineral Mineral dissolved, sulfate precipitated as BaSO4, and SO4 converted to CO2 by carbon reduction.

208Pb/204Pb, 207Pb/204Pb, 206Pb/204Pb, 87Sr/86Sr Lead or strontium from water samples was caught on selective resin, eluted off, and run on the mass spectrometer; rock samples were partially dissolved in weak acid, the remaining residue dissolved in strong acid and then both fractions were run separately on the mass spectrometer.

Tritium (T) Tritium was concentrated by distillation and counted by scintillation.


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Last Modification: Wednesday, 03-Jan-2018 11:59:25 (dyv)