USGS Science⌕ Search

SEARCH · USGS Science

Results for “Elements”

Search indexed USGS publications on groundwater, aquifers, geologic maps, mineral resources and earthquakes. Explore source records by subject and place.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,369 records · Page 76Linked to original sources
USGS1984

Rehabilitation materials from surface- coal mines in western U.S.A. III. Relations between elements in mine soil and uptake by plants.

Plant uptake of Cd, Co, Cu, Fe, Mn, Ni, Pb and Zn from mine soils was assessed using alfalfa Medicago sativa, sainfoin Onobrychis viciaefolia, smooth brome Bromus inermis, crested wheatgrass Agropyron cristatum, slender wheatgrass A. trachycaulum and intermediate wheatgrass A. intermedium; mine soil (cover-soil and spoil material) samples were collected from rehabilitated areas of 11 western US surface-coal mines in North Dakota, Montana, Wyoming and Colorado. Correlations between metals in plants and DTPA-extractable metals from mine soils were generally not statistically significant and showed no consistent patterns for a single metal or for a single plant species. Metal uptake by plants, relative to amounts in DTPA extracts of mine soil, was positively related to mine soil organic matter content or negatively related to mine soil pH. DTPA-extractable metal levels were significantly correlated with mine soil pH and organic-matter content.-from Authors

Reclamation and Revegetation Research↗
USGS2006

Mineralogical anomalies and their influences on elemental geochemistry of the main workable coal beds from the Dafang Coalfield, Guizhou, China

Mineralogy and geochemistry of the No. 11 Coal bed were investigated by using inductively-coupled plasma mass spectrometry (ICP-MS), X-ray fluorescence (XRF), scanning electron microscopy equipped with energy-dispersive X-ray (SEM-EDX), sequential chemical extraction procedure (SCEP), and optical microscopy. The results show that the No. 11 Coal bed has very high contents of veined quartz (Vol. 11.4%) and veined ankerite (Vol. 10.2 %). The veined ankerite was generally coated by goethite and the veined quartz embraced chalcopyrite, sphalerite, and selenio-galena. In addition, a trace amount of kaolinite was filled in the veins. These seven minerals often occur in the same veins. The formation temperatures of the veined ankerite and quartz are 85??C and 180??C respectively, indicating their origins of iron-rich calcic and siliceous low-temperature hydrothermal fluids in different epigenetic periods. Studies have also found that the veined quartz probably formed earlier than the veined ankerite, and at least three distinct ankerite formation stages were observed by the ration of Ca/Sr and Fe/Mn of ankerite. The mineral formation from the early to late stage is in order of sulfide, quartz, kaolinite, ankerite, and goethite. The veined ankerite is the dominant source of Mn, Cu, Ni, Pb, and Zn, which are as high as 0.09%, 74.0 ??g/g, 33.6 ??g/g, 185 ??g/g, and 289 ??g/g in this coal seam, respectively. However, the veined quartz is the main carrier of Pd, Pt, and Ir, which are 1.57 ??g/g, 0.15 ??g/g, and 0.007 ??g/g in this coal seam, respectively. In addition, chalcopyrite, sphalerite, and selenio-galena of hydrothermal origin were determined in the veined quartz, and these three sulfide minerals are also important carriers of Cu, Zn and Pb in the No. 11 Coal bed.

Acta Geologica Sinica↗
USGS2015

Contaminants in sea ducks: metals, trace elements, petroleum, organic pollutants, and radiation: Chapter 6

Exposure to lead and petroleum has caused deaths of sea ducks, but relatively few contaminants have been shown to cause mortality or be associated with population level effects. This chapter focuses primarily on field reports of contaminant concentrations in tissues of sea ducks in North America and Europe and results of some pertinent experimental studies. Much of the available interpretive data for contaminants in waterfowl come from studies of freshwater species. Limits of available data present a challenge for managers interested in sea ducks because field reports have shown that marine birds may carry greater burdens of some pollutants than freshwater species, particularly metals. It is important, then, to distinguish poisoning due to a particular contaminant as a cause of death in sea ducks versus simple exposure based solely on tissue residues. A comprehensive approach that incorporates information on field circumstances, any observed clinical signs and lesions, and tissues residues is recommended when evaluating contaminant concentrations in sea ducks.

Book chapter↗
USGS1977

Rare earths, thorium, and other minor elements in sphene from some plutonic rocks in west-central Alaska

Sphene is an abundant accessory mineral in some abnormally radioactive plutonic rocks in west-central Alaska. Seven samples of sphene from four different areas in west-central Alaska contained from 20350 to 39180 parts per million total rare earths and 390 to 2000 ppm thorium. The lanthanide content in six of the seven sphenes is chiefly the light rare earths and is similar to that of crustal abundance; a seventh sphene from the Darby Mountains, however, contains above average amounts of the heavy rare earths. A comparison of the lanthanide distribution in sphene from several areas indicates that the structure of sphene will accommodate whatever lanthanides are available when the mineral crystallizes. The amount of thorium and rare earths in sphene is also affected by the presence of other accessory minerals. Sphene in rocks containing either allanite or zircon has a lower thorium content than in rocks that do not contain allanite or zircon. Sphene, because of its abundance, may contain the greater part of the rare earths and thorium in some of the plutonic rocks of west-central Alaska.

Alaska↗
USGS1998

Results from the hydrodynamic element of the 1994 entrapment zone study in Suisun Bay

The entrapment zo as long been considered an important region of the San Francisco estuary. It has been the subject of several previous studies, and its location has been suggested as an index of condition of the estuarine ecosystem.A close correlate of this location, X2 1, is now used as a management objective on the basis that X2 is correlated with the abundance or survival of several estuarine-dependent species. X2 is a crude tool to use for this purpose, but it can be refined only through improved understanding of the various mechanisms underlying these correlations. These mechanisms probably differ among species, but for species resident in and near the entrapment zone, the correlation with X2 may be due to variations in intenSity oftrapping mechanisms with pOSition of the entrapment zone. Therefore, it is worthwhile to investigate these trapping mechanisms, the nature of the entrapment zone as habitat, and the responses of the entrapment zone to changes in X2 or outflow from the Sacramento-San Joaquin Delta. Studies ofthe entrapment zone ofthe San Francisco estuary have been conducted in springs of 1994, 1995, and 1996. These studies have been funded by the Interagency Ecological Program and conducted by scientists from IEP member agencies, the Romberg Tiburon Center for Environmental Studies, Bodega Marine Laboratory, and the University of California at Santa Cruz. This report presents results from 1994, a low-flow year. Subsequent reports will describe results from 1995 and 1996 and highlight differences among years. This report is organized in chapters that comprise more-or-Iess independent papers, with an introductory chapter for the entire study. This Executive Summary presents highlights of the overall study plan and summarizes the major findings.

California↗
USGS1995

Preliminary results from the hydrodynamic element of the 1994 entrapment zone study

This article discusses preliminary results from analyses of USGS hydrodynamic data collected as part of the 1994 Interagency Ecological Program entrapment zone study. The USGS took part in three 30-hour cruises and deployed instruments for measuring currents and salinity from April to June. This article primarily focuses on the analysis of data from five Acoustic Doppler Current ProUers (ADCPs) deployed in Carquinez Strait, Suisun Bay, and the Western Delta. From these analyses a revised conceptual model of the hydrodynamics of the entrapment/null zone has evolved. The ideas discussed in this newsletter article are essentially working hypotheses, which are presented here to stimulate discussion and further analyses. In this article we discuss the currently-held conceptual model of entrapment and present data that are inconsistent with this conceptual model. Finally, we suggest a revised conceptual model that is consistent with all of the hydrodynamic data collected to date and describe how the 1995 study incorporates our revised conceptual model into its design.

California↗
USGS1984

Finite element solution methods for circulation in estuaries

In this paper, the shallow water equations are used to approximate the depth-mean circulation in estuaries. The time scales of the motions can be conveniently divided into three ranges: 1) low-frequency (residual) variations with periods of two days or longer, 2) tidal-frequency variations, and 3) high-frequency variations with periods of an hour or shorter. The emphasis here will be on the tidal-period variations that are characterized by line spectra and thus allow a harmonic decomposition of the governing equations.

Book chapter↗