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Geology topics

R. M. O’Leary

Publications and source records attributed to R. M. O’Leary.

At least 55 records · Page 3Linked to original sources
USGS1984

Determination of arsenic, antimony, bismuth, cadmium, copper, lead, molybdenum, silver and zinc in geological materials by atomic-absorption spectrometry

Arsenic, antimony, bismuth, cadmium, copper, lead, molybdenum, silver and zinc are very useful elements in geochemical exploration. In the proposed method, geological samples are fused with potassium pyrosulphate and the fusate is dissolved in a solution of hydrochloric acid, ascorbic acid and potassium iodide. When this solution is shaken with a 10% V/V Aliquat 336 - isobutyl methyl ketone organic phase, the nine elements of interest are selectively partitioned in the organic phase. All nine elements can then be determined in the organic phase using flame atomic-absorption spectrometry. The method is rapid and allows the determination of Ag and Cd at levels down to 0.1 p.p.m., Cu, Mo, and Zn down to 0.5 p.p.m., Pb, Bi and Sb down to 1 p.p.m. and As down to 5 p.p.m. in geological materials.

The Analyst↗
USGS1984

Analyses of rock samples from the Circle Quadrangle, Alaska

Suspendedsediment and reservoir sedimentation data have been analyzed to determine sediment yields and transport characteristics of Tennessee streams Data from 31 reservoirs plus suspendedsediment data from TVA sampling efforts in the 1930?s and 1960?s, and U.S. Geological Survey efforts from 1975-82 have been used. Results of the analyses show that the measured suspended-sediment is mostly silt and clay-size material even in the sand bed channels of western Tennessee. Samples of suspended sediment rarely exceed 25 percent sand. Computed unmeasured load is less than 10 percent of the total sediment load in western Tennessee. Unmeasured load has not been computed for middle and eastern Tennessee streams because the bed material is generally coarse and quite variable. However, unmeasured load in these streams is believed to be less than 5 percent of total load. Transport curves show that when flow is less than about 1 cubic foot per second per square mile, western Tennessee streams have higher concentrations than middle or eastern streams. When flow exceeds about 10 cubic feet per second per square mile, however, concentrations in middle and eastern streams can equal or exceed those in western streams. The more efficient sediment-delivery processes operating in middle and eastern Tennessee basins are responsible for the rapid increases in suspended sediment concentrations with increasing flow. Sediment yields for middle and eastern Tennessee basins generally are less than 800 tons per square mile per year, however, heavily strip-mined basins can have yields from 1,000 to 3,000 tons per square mile per year. Yields for the heavily agricultural and channelized basins of western Tennessee generally range from 700 to 1,000 tons per square mile per year.

Open-File Report↗
USGS1982

Locality map for scintillometer and analytical data collected in 1981, Ugashik and Karluk quadrangles, Alaska

Scintillometer data were collected routinely in 1981 as part of the field investigations in the Ugashik and Karluk quadrangles. The instrument used was a Geometrics Model GR-101A, mounted in the helicopter. The data, in counts per second (cps), were obtained at most of the sites by the helicopter pilot (Svec) while geologists were occupying the sample site. Scintillometer localities are indicated on the map by a dot. The sites are concentrated in the southeastern part of the map area where previous work (OF 81-253) had outlined an area with anomalously high cps. The bedrock at these sites is a Late Tertiary hornblende granodiorite instrusive dated at 9.4 my. Hornfelsed sedimentary rock overlying the batholith gave cps nearly as high as the intrusive rock. Samples routinely checked by semiquantitative spectrographic analysis for thorium failed to detect the element. In general the Ugashik and Karluk quadrangles have a low level of gamma radiation. A majority of the sites, 52 percent, gave readings of less than 35 cps, and only 10 percent had values of greater than cps. Thick alluvium or glacial deposits generally gave low values. Readings from sedimentary bedrock were extremely erratic and no generalization can be made concerning their level of gamma radiation. The hornblende granodiorite and overlying hornfelsed sedimentary rock are all greater than 30 cps, but again, the values are somewhat erratic and no definitive pattern is readily apparent. Bedrock samples are collected for analysis are on the map by a triangle.

Alaska↗