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P. J. Lamothe

Publications and source records attributed to P. J. Lamothe.

28 records · Page 2Linked to original sources
USGS1999

Metal emissions from Kilauea, and a suggested revision of the estimated worldwide metal output by quiescent degassing of volcanoes

Measurements of a large suite of metals (Pb, Cd, Cu, Zn and several others) and sulfur at Kilauea volcano over an extended period of time has yielded a detailed record of the atmospheric injection of ordinarily-rare metals from this quiescently degassing volcano, representative of an important type. We have combined the Kilauea data with data of recent studies by others (emissions from volcanoes in the Indonesian arc; the large Laki eruption of two centuries ago; Etna: estimates of total volcanic emissions of sulfur) to form the basis for a new working estimate of the rate of worldwide injection of metals to the atmosphere by volcanoes. The new estimate is that volcanoes inject a substantially smaller mass of ordinarily-rare metals into the atmosphere than was stated in a widely cited previous estimate [J.O. Nriagu, A global assessment of natural sources of atmospheric trace metals, Nature 338 (1989) 47-49]. Our estimate, which is an upper limit, is an annual injection mass of about 10,000 tons of the metals considered, versus the earlier estimate of about 23,000 tons. Also, the proportions of the metals are substantially different in our new estimate.

Earth and Planetary Science Letters↗
USGS1999

Elemental analyses of modern dust in southern Nevada and California

Selected samples of modern dust collected in marble traps at sites in southern Nevada and California (Reheis and Kihl, 1995; Reheis, 1997) have been analyzed for elemental composition using instrumental neutron activation analysis (INAA) and inductively coupled plasma atomic emission spectroscopy (ICP-AES) and inductively coupled plasma mass spectroscopy (ICP-MS). For information on these analytical techniques and their levels of precision and accuracy, refer to Baedecker and McKown (1987) for INAA, to Briggs (1996) for ICP-AES, and to Briggs and Meier (1999) for ICP-MS. This report presents the elemental compositions obtained using these techniques on dust samples collected from 1991 through 1997. The dust-trap sites were established at varying times; some have been maintained since 1984, others since 1991. For details on site location, dust-trap construction, and collection techniques, see Reheis and Kihl (1995) and Reheis (1997). Briefly, the trap consists of a coated angel-food cake pan painted black on the outside and mounted on a post about 2 m above the ground. Glass marbles rest on a circular piece of galvanized hardware cloth (now replaced by stainless-steel mesh), which is fitted into the pan so that it rests 3-4 cm below the rim. The 2-m height eliminates most saltating sand-sized particles. The marbles simulate the effect of a gravelly fan surface and prevent dust that has filtered or washed into the bottom of the pan from being blown back out. The dust traps are fitted with two metal straps looped in an inverted basket shape; the top surfaces of the straps are coated with a sticky material that effectively discourages birds from roosting.

California, Nevada↗
USGS1993

Heavy metal anomalies in the Tinto and Odiel River and estuary system, Spain

The Tinto and Odiel rivers drain 100 km from the Rio Tinto sulphide mining district, and join at a 20-km long estuary entering the Atlantic Ocean. A reconnaissance study of heavy metal anomalies in channel sand and overbank mud of the river and estuary by semi-quantitative emission dc-arc spectrographic analysis shows the following upstream to downstream ranges in ppm (??g g-1): As 3,000 to <200, Cd 30 to <0.1, Cu 1,500 to 10, Pb 2,000 to <10, Sb 3000 to <150, and Zn 3,000 to <200. Organic-rich (1.3-2.6% total organic carbon, TOC), sandysilty overbank clay has been analyzed to represent suspended load materials. The high content of heavy metals in the overbank clay throughout the river and estuary systems indicates the importance of suspended sediment transport for dispersing heavy metals from natural erosion and anthropogenic mining activities of the sulfide deposit. The organic-poor (0.21-0.37% TOC) river bed sand has been analyzed to represent bedload transport of naturally-occurring sulfide minerals. The sand has high concentrations of metals upstream but these decrease an order of magnitude in the lower estuary. Although heavy metal contamination of estuary mouth beach sand has been diluted to background levels estuary mud exhibits increased contamination apparently related to finer grain size, higher organic carbon content, precipitation of river-borne dissolved solids, and input of anthropogenic heavy metals from industrial sources. The contaminated estuary mud disperses to the inner shelf mud belt and offshore suspended sediment, which exhibit metal anomalies from natural erosion and mining of upstream Rio Tinto sulphide lode sources (Pb, Cu, Zn) and industrial activities within the estuary (Fe, Cr, Ti). Because heavy metal contamination of Tinto-Odiel river sediment reaches or exceeds the highest levels encountered in other river sediments of Spain and Europe, a detailed analysis of metals in water and suspended sediment throughout the system, and epidemiological analysis of heavy metal effects in humans is appropriate. ?? 1993 Estuarine Research Federation.

Estuaries↗
USGS1987

Geochemistry of metal-rich brines from central Mississippi Salt Dome basin, U.S.A.

Oil-field brines are the most favored ore-forming solutions for the sediment-hosted Mississippi Valley-type ore deposits. Detailed inorganic and organic chemical and isotope analyses of water and gas samples from six oil fields in central Mississippi, one of the very few areas with high metal brines, were conducted to study the inorganic and organic complexes responsible for the high concentrations of these metals. The samples were obtained from production zones consisting of sandstone and limestone that range in depth from 1900 to 4000 m (70–120°C) and in age from Late Cretaceous to Late Jurassic. Results show that the waters are dominantly bittern brines related to the Louann Salt. The brines have extremely high salinities that range from 160,000 to 320,000 mg/l total dissolved solids and are Na Ca Cl-type waters with very high concentrations of Ca (up to 48,000 mg/l) and other alkaline-earth metals, but with low concentrations of aliphatic acid anions. The concentrations of metals in many water samples are very high, reaching values of 70 mg/l for Pb, 245 mg/l for Zn, 465 mg/l for Fe and 210 mg/l for Mn. The samples with high metal contents have extremely low concentrations (<0.02 mg/l) of H 2 S. Samples obtained from the Smackover Formation (limestone) have low metal contents that are more typical of oil-field waters, but have very high concentrations (up to 85 mg/l) of H 2 S. Computations with the geochemical code SOLMINEQ.87 give the following results: (1) both Pb and Zn are present predominantly as aqueous chloride complexes (mainly as PbCl 4 2− and ZnCl 4 2− , respectively); (2) the concentrations of metals complexed with short-chained aliphatic acid anions and reduced S species are minor; (3) organic acid anions are important in controlling the concentrations of metals because they affect the pH and buffer capacity of the waters at subsurface conditions; and (4) galena and sphalerite solubilities control the concentrations of Pb and Zn in these waters.

Applied Geochemistry↗
USGS1986

Determination of ammonium in a buddingtonite sample by ion-chromatography

An ion-chromatographic method for the direct determination of ammonium, potassium, and sodium in geologic materials is described. Samples are decomposed with a mixture of hydrofluoric and hydrochloric acids in a sealed polycarbonate bottle heated in a microwave oven. The ion-chromatograph separates the cations and determines them by conductivity measurement. The ammonium concentrations thus determined have been verified by use of an ammonia-specific electrode. A total of 32 analyses of ammonium salts by both techniques showed an average error of −4%, with a relative standard deviation (RSD) of 6%. The ammonium concentrations found in a buddingtonite sample had an RSD of 2.2% and their mean agreed with that obtained by the Kjeldahl method. By use of the prescribed dilution of the sample, detection limits of 0.1% can be achieved for all three cations.

Talanta↗