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USGS2014

Powder X-ray diffraction laboratory, Reston, Virginia

The powder x-ray diffraction (XRD) laboratory is managed jointly by the Eastern Mineral and Environmental Resources and Eastern Energy Resources Science Centers. Laboratory scientists collaborate on a wide variety of research problems involving other U.S. Geological Survey (USGS) science centers and government agencies, universities, and industry. Capabilities include identification and quantification of crystalline and amorphous phases, and crystallographic and atomic structure analysis for a wide variety of sample media. Customized laboratory procedures and analyses commonly are used to characterize non-routine samples including, but not limited to, organic and inorganic components in petroleum source rocks, ore and mine waste, clay minerals, and glassy phases. Procedures can be adapted to meet a variety of research objectives.

Virginia↗

USGS2014

Controls on sediment production in two U.S. deserts

Much of the world’s airborne sediment originates from dryland regions. Soil surface disturbances in these regions are ever-increasing due to human activities such as energy and mineral exploration and development, recreation, suburbanization, livestock grazing and cropping. Sediment production can have significant impacts to human health with particles potentially carrying viruses such as Valley Fever or causing asthma or other respiratory diseases. Dust storms can cause decreased visibility at the ground level, resulting in highway accidents, and reduced visual quality in park and wildland airsheds. Sediment production and deposition is also detrimental to ecosystem health, as production reduces soil fertility at its source and can bury plants and other organisms where it is deposited. Therefore, it is important to understand how we can predict what areas are prone to producing sediment emissions both before and after soil surface disturbance. We visited 87 sites in two deserts of the western U.S. that represented a range of soil texture and surface cover types. We used a portable wind tunnel to estimate the threshold friction velocity (TFV) required to initiate sediment transport and the amount of sediment produced by the tunnel at a set wind speed. Wind tunnel runs were done before and after soil surface disturbance with a four-wheel drive vehicle. Results show that most undisturbed desert soils are very stable, especially if covered by rocks or well-developed biological soil crusts, which make them virtually wind-erosion proof. Particles at disturbed sites, in contrast, moved at relatively low wind speeds and produced high amounts of sediment. Silt was an important predictor of TFV and sediment production across all sites, whereas the influence of rock cover and biological soil crusts was site-dependent. Understanding the vulnerability of a site after disturbance is important information for land managers as they plan land use activities and attempt to mitigate the harmful effects that sediment production can have on both human and ecosystem health.

Aeolian Research↗

USGS2012

Modeling prey consumption by native and non-native piscivorous fishes: implications for competition and impacts on shared prey in an ultraoligotrophic lake in Patagonia

We examined trophic interactions of the nonnative salmonids Rainbow Trout Oncorhynchus mykiss, Brown Trout Salmo trutta, and Brook Trout Salvelinus fontinalisand the main native predator Creole Perch Percichthys trucha in Lake Nahuel Huapi (Patagonia, Argentina) to determine the relative impact of each predator on their forage base and to evaluate the potential vulnerability of each predator to competitive impacts by the others. Using bioenergetics simulations, we demonstrated the overall importance of galaxiids and decapods to the energy budgets of nonnative salmonids and Creole Perch. Introduced salmonids, especially Rainbow Trout, exerted considerably heavier predatory demands on shared resources than did the native Creole Perch on both a per capita basis and in terms of relative population impacts. Rainbow Trout consumed higher quantities and a wider size range of Small Puyen (also known as Inanga) Galaxias maculatus than the other predators, including early pelagic life stages of that prey; as such, this represents an additional source of mortality for the vulnerable early life stages of Small Puyen before and during their transition from pelagic to benthic habitats. All predators were generally feeding at high feeding rates (above 40% of their maximum physiological rates), suggesting that competition for prey does not currently limit either Creole Perch or the salmonids in this lake. This study highlights the importance of keystone prey for the coexistence of native species with nonnative top predators. It provides new quantitative and qualitative evidence of the high predation pressure exerted on Small Puyen, the keystone prey species, during the larval to juvenile transition from pelagic to littoral-benthic habitat in Patagonian lakes. This study also emphasizes the importance of monitoring salmonid and Creole Perch population dynamics in order to detect signs of potential impacts through competition and shows the need to carefully consider the rationale behind any additional trout stocking.

Transactions of the American Fisheries Society↗

USGS2023

Evidence for density-dependent effects on body composition of a large omnivore in a changing Greater Yellowstone Ecosystem

Understanding the density-dependent processes that drive population demography in a changing world is critical in ecology, yet measuring performance–density relationships in long-lived mammalian species demands long-term data, limiting scientists' ability to observe such mechanisms. We tested performance–density relationships for an opportunistic omnivore, grizzly bears ( Ursus arctos , Linnaeus, 1758) in the Greater Yellowstone Ecosystem, with estimates of body composition (lean body mass and percent body fat) serving as indicators of individual performance over two decades (2000–2020) during which time pronounced environmental changes have occurred. Several high-calorie foods for grizzly bears have mostly declined in recent decades (e.g., whitebark pine [ Pinus albicaulis , Engelm, 1863]), while increasing human impacts from recreation, development, and long-term shifts in temperatures and precipitation are altering the ecosystem. We hypothesized that individual lean body mass declines as population density increases (H1), and that this effect would be more pronounced among growing individuals (H2). We also hypothesized that omnivory helps grizzly bears buffer energy intake from changing foods, with body fat levels being independent from population density and environmental changes (H3). Our analyses showed that individual lean body mass was negatively related to population density, particularly among growing-age females, supporting H1 and partially H2. In contrast, population density or sex had little effect on body fat levels and rate of accumulation, indicating that sufficient food resources were available on the landscape to accommodate successful use of shifting food sources, supporting H3. Our results offer important insights into ecological feedback mechanisms driving individual performances within a population undergoing demographic and ecosystem-level changes. However, synergistic effects of continued climate change and increased human impacts could lead to more extreme changes in food availability and affect observed population resilience mechanisms. Our findings underscore the importance of long-term studies in protected areas when investigating complex ecological relationships in an increasingly anthropogenic world.

Idaho, Montana, Wyoming↗

USGS1990

Iron sulfide minerals at Cement oil field, Oklahoma: Implications for magnetic detection of oil fields

Aeromagnetic anomalies at Cement oil field (Anadarko basin, Oklahoma) have been attributed to authigenic magnetite. The following characteristics of the magnetite, however, indicate that it is contamination introduced by drilling: (1) occurrence as sharp angular blades and as spheres, commonly with metallographic textures typical of industrial alloys and with associated steel and wustite (FeO); (2) presence only in well cuttings and absence from core and quarry samples; and (3) lack of association with detrital framework grains or with authigenic carbonate and sulfide minerals. Ferrimagnetic pyrrhotite occurs in well cuttings, cores, and quarry samples at Cement and is a possible natural source of the magnetic anomalies. Pyrrhotite, which is intergrown with more abundant FeS 2 minerals, formed as a result of hydrocarbon seepage. Pyrrhotite is confined to beds above oil and gas reservoirs. These beds, which lack detrital organic matter, contain higher mineral sulfide and lower mineral sulfate sulfur (1.7 and 0.1 wt %, respectively) than do correlative beds off the field (0.2 and 1.1 wt %, respectively). In the field, isotopic values of sulfide S show a systematic decrease upward through the Permian section from positive values (maximum, +12 per mil at ∼610-760 m depth) to negative values (-1 to -11 per mil between 32 and 230 m; -26 to -30 per mil at the surface). Geochemical results, together with time-temperature data derived from burial curves, limit the major sources of the sulfide in the Fe-S minerals to two possibilities. Isotopically heavy sulfide was generated either inorganically at temperatures >∼90 °C in beds beneath Permian beds, or by bacterial sulfate reduction at temperatures <∼60 °C in Permian strata. If the latter, microbial sulfate reduction occurred under sulfate-limited conditions. The isotopically light sulfide occurring in minerals near the present surface is attributed to bacterial reduction of sulfate. Sulfate-reducing bacteria derived metabolic energy from leaking hydrocarbons and associated organic compounds.

Oklahoma↗

USGS2011

Linking habitat quality with trophic performance of steelhead along forest gradients in the South Fork Trinity River Watershed, California

We examined invertebrate prey, fish diet, and energy assimilation in relation to habitat variation for steelhead Oncorhynchus mykiss (anadromous rainbow trout) and rainbow trout in nine low-order tributaries of the South Fork Trinity River, northern California. These streams spanned a range of environmental conditions, which allowed us to use bioenergetics modeling to determine the relative effects of forest cover, stream temperature, season, and fish age on food consumption and growth efficiency. Evidence of seasonal shifts in reliance on aquatic versus terrestrial food sources was detected among forest cover categories and fish ages, although these categories were not robust indicators of O. mykiss condition and growth efficiency. Consumption estimates were generally less than 20% of maximum consumption, and fish lost weight in some streams during summer low-flow conditions when stream temperatures exceeded 15°C. Current 100-year climate change projections for California threaten to exacerbate negative growth patterns and may undermine the productivity of this steelhead population, which is currently not listed as endangered or threatened. To demonstrate the potential effect of global warming on fish growth, we ran three climate change scenarios in two representative streams. Simulated temperature increases ranging from 1.4°C to 5.5°C during the summer and from 1.5°C to 2.9C during the winter amplified the weight loss; estimated average growth for age-1 fish was 0.4–4.5 times lower than normal (low to high estimated temperature increase) in the warm stream and 0.05–0.8 times lower in the cool stream. We conclude that feeding rate and temperature during the summer currently limit the growth and productivity of steelhead and rainbow trout in low-order streams in the South Fork Trinity River basin and predict that climate change will have detrimental effects on steelhead growth as well as on macroinvertebrate communities and stream ecosystems in general.

Transactions of the American Fisheries Society↗

USGS2023

Evaluation of hydrologic processes in the eastern Snake River Plain aquifer using uranium and strontium isotopes, Idaho National Laboratory, eastern Idaho

Waste constituents discharged to the eastern Snake River Plain aquifer at the U.S. Department of Energy (DOE) Idaho National Laboratory (INL) pose risks to the water quality of the aquifer. To understand these risks, the U.S. Geological Survey, in cooperation with the DOE, is conducting geochemical studies to better understand the hydrologic processes at the INL that affect the movement of groundwater and waste constituents. In this study, we used natural uranium ( 234 U/ 238 U) and strontium ( 87 Sr/ 86 Sr) isotope ratios of surface water and groundwater to identify the sources of water, the mixing of different source waters, and the flow directions in the shallow part (upper 250 feet) of the aquifer at the INL. Samples were collected from 17 sites at and near the INL that represent the source-water contributions to the aquifer. These source-water sites included surface water, regional groundwater, and springs. Groundwater samples from 63 sites were collected at and near the INL. For all sites, sample collection dates ranged from 1979 to 2019, but groundwater samples collected at the INL are representative of wet climate cycles when the Big Lost River (BLR) was flowing onto the INL. The 234 U/ 238 U activity ratios and 87 Sr/ 86 Sr from groundwater at the INL were plotted on graphs within ternary mixing webs in which the three end members of the mixing web represented specific sources of recharge. The large number of sources of recharge required numerous mixing webs, representing various geographic locations at the INL, so that each mixing web represented an area with just three sources of recharge. Considerations for determining the sources of recharge to groundwater sites included chemical signatures in addition to 234 U/ 238 U and 87 Sr/ 86 Sr, hydrologic context, and geographic location. The mixing webs were used to estimate the percentage of recharge from specific sources to groundwater at wells. The results of this study identified groundwater from the Lemhi Range as a source of recharge to the INL, which was a previously unsuspected source of recharge. The estimated spatial distribution of recharge from the BLR and groundwater from the Lost River Range also decreased and increased, respectively, relative to the spatial distribution estimated from an earlier study. Upwelling geothermal water was identified at only one well, which indicates that the upward movement of deep groundwater to the shallow part of the aquifer is largely nonexistent. Mixing between surface water and groundwater, different groundwater recharge sources, or both is ubiquitous at the INL. Mixing of water fully explains the distribution of 234 U/ 238 U and 87 Sr/ 86 Sr in groundwater at the INL and thus renders unnecessary the hypothesis that fast and slow flow zones at the INL are required to explain the distribution of 234 U/ 238 U and 87 Sr/ 86 Sr.

Idaho↗

USGS1977

Reconnaissance of ground-water resources in the Mountain Home plateau area, southwest Idaho

The Mountain Home plateau area occupies approximately 1,220 square miles of the western Snake River Plain in southwestern Idaho. About 40,000 acres are presently (1977) irrigated with ground water, about 30,000 acres with surface water. An estimated 450,000 acres are potentially irrigable, if water is available. Development of ground-water re- sources has caused water-level declines in several places. Largest declines are south of Mountain Home, where water levels dropped more than 20 feet in the last 9 years. Ground water in the area occurs primarily under water-table conditions. Perched-water zones are present in several locations. The most productive aquifer in the eastern part of the plateau is basalt of the Bureau Formation of the Idaho Group. In the western part, the most productive aquifers are sand and gravel of the older terrace gravel lithologic unit and the Idaho Group. Recharge to the ground-water system is water from the Boise River drainage basin, precipitation on the plateau and adjacent mountains, and leakage from irrigation structures. Ground-water movement is generally south or southwest. Natural ground-water discharge from the plateau is about 18,000 acre-feet annually. The chemical composition of the ground water generally reflects water characteristics in the area of the source of recharge and, for the most part, is good. Deuterium and oxygen-18 isotope analyses suggest that the water at the lower end of the ground-water flow system underlying the plateau was recharged a long time ago, although climatic conditions then were similar to current conditions in the Boise River basin. Additional large-scale ground-water development will probably result in economically prohibitive pumping lifts, which also would consume excessive amounts of energy. Therefore, large-scale new agricultural development would depend heavily on the availability of surface water. However, one or several deep test holes, in selected places, could help answer some questions about the occurrence of ground water and perhaps encourage further exploration for untapped deep artesian aquifers. The occurrence of perched-water zones beneath lands irrigated by surface water suggests that more zones of this type could develop if water is imported into the area to irrigate additional lands, and if the efficiency of the present distribution systems remains unchanged.

Idaho↗

USGS2007

Influence of Cougar Reservoir Drawdown on Sediment and DDT Transport and Deposition in the McKenzie River Basin, Oregon, Water Years 2002-04

Construction of a selective withdrawal tower at Cougar Reservoir in the South Fork McKenzie River, Oregon, during 2002-05 resulted in a prolonged release of sediment and high-turbidity water to downstream reaches throughout the summer of 2002, with additional episodic releases during storms in the following winters. Suspended-sediment concentrations and loads at five continuously monitored turbidity and discharge gaging stations were estimated using regression methods. Deposition in salmonid spawning beds was measured using infiltration bags. Stations were located upstream and downstream of Cougar Reservoir in the South Fork McKenzie River, in the mainstem of the McKenzie River upstream of the South Fork and downstream of Blue River, and in Blue River downstream of Blue River Reservoir. During 2002, Cougar Reservoir released approximately 17,000 tons of suspended sediment into the South Fork McKenzie River, or more than twice the incoming load from the South Fork upstream of the reservoir. In 2003 and 2004, the release of sediment from Cougar Reservoir decreased to 10,900 and 4,100 tons, respectively. Although Cougar Reservoir likely was a substantial source of sediment to the lower reaches during water years 2002 and 2003, the lack of continuous turbidity monitoring at stations other than the South Fork McKenzie River prior to January 2003 prevents quantification of the actual contribution to the mainstem. During water year 2004, the only year with complete records at all sites, Cougar Reservoir released about 24 percent (4,100 tons) of the sediment load estimated on the mainstem near Vida (16,900 tons); however, the relative contribution of Cougar Reservoir is expected to have been substantially larger during 2002 and 2003 when the newly exposed river channel in the upper reaches of the reservoir was actively eroding and migrating. Deposition of fine (less than 0.063-millimeter diameter) sediment into spawning beds, measured with the use of deployed infiltration bags, was greatest downstream of Cougar and Blue River Reservoirs (1.0 and 1.2 percent of total sediments, respectively). Deposition was least in the high-energy, unregulated environments (about 0.25 percent) of the South Fork McKenzie River above Cougar Reservoir and in the mainstem above the South Fork, and intermediate near Vida, the most downstream site on the mainstem. DDT, applied throughout much of the upper McKenzie River drainage basin to control spruce budworm during the 1950s, was detected in the South Fork near Rainbow in the form of its metabolites DDD and DDE in fine sediment captured in the infiltration bags. DDE also was detected in infiltration bags deployed in the McKenzie River near Vida, downstream of the South Fork. All concentrations of DDD and DDE were less than the aquatic-life criterion for bed sediment. DDT species were not detected in water samples, including samples collected during large storms. The reservoir apparently acted as a trap for sediment and DDT throughout the course of its existence, facilitating degradation of the trapped DDT, and may have been a source for both during the construction period in 2002-05, but the lack of detections during storms indicates that DDT transport was small. Transport of detectable amounts of DDT likely was limited to periods of high suspended-sediment concentrations (greater than 75-100 milligrams per liter). Infiltration bags were deployed during August 2003-July 2004 and were a useful device for measuring fine-sediment deposition and for chemical analysis of the deposited material. Deposition of fine-grained sediment downstream of the flood-control dams may be reduced if bed-moving events can be periodically reintroduced to those reaches.

Scientific Investigations Report↗

USGS2004

Ecoregions and ecoregionalization: geographical and ecological perspectives

Ecoregions, i.e., areas exhibiting relative homogeneity of ecosystems, are units of analysis that are increasingly important in environmental assessment and management. Ecoregions provide a holistic framework for flexible, comparative analysis of complex environmental problems. Ecoregions mapping has intellectual foundations in both geography and ecology. However, a hallmark of ecoregions mapping is that it is a truly interdisciplinary endeavor that demands the integration of knowledge from a multitude of sciences. Geographers emphasize the role of place, scale, and both natural and social elements when delineating and characterizing regions. Ecologists tend to focus on environmental processes with special attention given to energy flows and nutrient cycling. Integration of disparate knowledge from the many key sciences has been one of the great challenges of ecoregions mapping, and may lie at the heart of the lack of consensus on the “optimal” approach and methods to use in such work. Through a review of the principal existing US ecoregion maps, issues that should be addressed in order to advance the state of the art are identified. Research related to needs, methods, data sources, data delivery, and validation is needed. It is also important that the academic system foster education so that there is an infusion of new expertise in ecoregion mapping and use.

Environmental Management↗

USGS1999

Climatic impact of glacial cycle polar motion: Coupled oscillations of ice sheet mass and rotation pole position

Precessional motion of Earth's rotation axis relative to its orbit is a well-known source of long-period climatic variation. It is less well appreciated that growth and decay of polar ice sheets perturb the symmetry of the global mass distribution enough that the geographic location of the rotation axis will change by at least 15 km and possibly as much as 100 km during a single glacial cycle. This motion of the pole will change the seasonal and latitudinal pattern of temperatures. We present calculations, based on a diurnal average energy balance, which compare the summer and winter temperature anomalies due to a 1° decrease in obliquity with those due to a 1° motion of the rotation pole toward Hudson Bay. Both effects result in peak temperature perturbations of about 1° Celsius. The obliquity change primarily influences the amplitude of the seasonal cycle, while the polar motion primarily changes the annual mean temperatures. The polar motion induced temperature anomaly is such that it will act as a powerful negative feedback on ice sheet growth. We also explore the evolution of the coupled system composed of ice sheet mass and pole position. Oscillatory solutions result from the conflicting constraints of rotational and thermal stability. A positive mass anomaly on an otherwise featureless Earth is in rotational equilibrium only at the poles or the equator. The two polar equilibria are rotationally unstable, and the equatorial equilibrium, though rotationally stable, is thermally unstable. We find that with a plausible choice for the strength of coupling between the thermal and rotational systems, relatively modest external forcing can produce significant response at periods of 10 4 –10 6 years, but it strongly attenuates polar motion at longer periods. We suggest that these coupled oscillations may contribute to the observed dominance of 100 kyr glacial cycles since the mid-Pleistocene and will tend to stabilize geographic patterns that are suitable to glaciations.

Journal of Geophysical Research B: Solid Earth↗

USGS1953

Airborne radioactivity survey of parts of Atlantic Ocean beach, Virginia to Florida

The accompanying maps show the results of an airborne radioactivity survey along the Atlantic Ocean beach from Cape Henry, Virginia to Cape Fear, North Carolina and from Savannah Bach Georgia to Miami Beach, Florida. The survey was made March 23-24, 1953, as part of a cooperative program with the U.S. Atomic Energy Commission. The survey was made with scintillation detection equipment mounted in a Douglas DC-3 aircraft and consisted of one flight line, at a 500-foot altitude, parallel to the beach. The vertical projection of the flight line coincided approximately with the landward limit of the modern beach. The width of the zone on the ground from which anomalous radiation is measured at the normal 500 foot flight altitude varies with the areal extent radioactivity of the source. For strong sources of radioactivity the width of the zone would be as much as 1,400 feet. The location of the flight lines is shown on the index map below. No abnormal radioactivity was detected along the northern flight line between Cape Henry, Virginia and Cape Fear, North Carolina. Along the southern flight line fourteen areas of abnormal radioactivity were detected between Savannah Beach, Georgia and Anastasia Island, Florida as shown on the map on the left. The abnormal radioactivity is apparently due to radioactive minerals associated with "black sand" deposits with occur locally along the beach in this region. The present technique of airborne radioactivity measurement does not permit distinguishing between activity sue to thorium and that due to uranium. An anomaly, therefore, may represent radioactivity due entirely to one or to a combination of these elements. It is not possible to determine the extent or radioactive content of the materials responsible for the abnormal radioactivity. The information given on the accompanying map indicates only those localities of greater-than-average radioactivity and, therefore suggest areas in which uranium and thorium deposits are more likely to occur.

Florida;Georgia;North Carolina;South Carolina;Virg↗

USGS1989

Hydrological, morphometrical, and biological characteristics of the connecting rivers of the International Great Lakes: a review

The connecting channels of the Great Lakes are large rivers (1, 200-9, 900 m3 • s-1) with limited tributary drainage systems and relatively stable hydrology (about 2:1 ration of maximum to minimum flow). The rivers, from headwaters to outlet, are the St. Marys, St. Clair, Detroit, Niagara, and St. Lawrence. They share several characteristics with certain other large rivers: the fish stocks that historically congregated for spawning or feeding have been overfished, extensive channel modification have been made, and they have been used as a repository for domestic and industrial wastes and for hydroelectric energy generation. Levels of phosphorus, chlorophyll a, and particulate organic matter increase 3- to 5-fold from the St. Marys River to the St. Lawrence River. Biological communities dependent on nutrients in the water column, such as phytoplankton, periphyton, and zooplankton similarly increase progressively downstream through the system. The standing crop of emergent macrophytes is similar in all of the rivers, reflecting the relatively large nutrient pools in the sediments and atmosphere. Consequently, emergent macrophytes are an important source of organic matter (67% of total primary production) in the nutrient poor waters of the St. Marys River, whereas phytoplankton production dominates (76%) in the enriched St. Lawrence River. Submersed and emergent macrophytes and the associated periphyton are major producers of organic matter in the connecting channels. Another major source of organic matter (measured as ash free dry weight, AFDW) in the Detroit River is sewage, introduced at a rate of 26, 000 t per year. The production of benthos ranges from a low 5.4 g AFDW•m-2 in the Detroit River to a high of 15.5 g AFDW•m-2 in the St. Marys River. The rivers lack the organic transport from riparian sources upstream but receive large amounts of high quality phytoplankton and zooplankton from the Great Lakes.

Canadian Special Publication of Fisheries and Aqua↗

USGS2002

How many kilojoules does a Black-billed Magpie nest cost?

Energetic costs of nest construction are difficult to estimate for birds, and currently estimates are available for only a handful of species. In this paper, I estimate the minimum cost of nest construction by a pair of Black-billed Magpies ( Pica hudsonia ). Data on the number of sticks and mud pellets comprising a nest were used to determine the minimum number of trips required to construct the nest, and were combined with information on distances to the nearest sources of nesting materials, data on flight speeds, and bird morphometric measures to estimate costs of transporting nesting materials. For the Black-billed Magpie pair I observed, nest construction required a minimum of 2564 trips for nesting materials, 276.2 km of commuting, 8.4 h of flight, and cost 209.1 kJ. Spreading this cost over the 40 d required to build the nest yields an estimate of 2.61 kJ/adult/day. I compared this value to published estimates of daily metabolizable energy intake for Black-billed Magpies, and calculated that breeding adults would need to increase their daily intake between 0.7% and 1.0% to cover the energetic costs of nest construction. In contrast, egg laying is estimated to require a full 23% of the daily energy expenditure of female magpies. These values suggest the energetic cost of nest building in Black-billed Magpies is relatively insignificant.

Journal of Field Ornithology↗

USGS2003

Location of long-period events below Kilauea Volcano using seismic amplitudes and accurate relative relocation

We present methods for improving the location of long-period (LP) events, deep and shallow, recorded below Kilauea Volcano by the permanent seismic network. LP events might be of particular interest to understanding eruptive processes as their source mechanism is assumed to directly involve fluid transport. However, it is usually difficult or impossible to locate their source using traditional arrival time methods because of emergent wave arrivals. At Kilauea, similar LP waveform signatures suggest the existence of LP multiplets. The waveform similarity suggests spatially close sources, while catalog solutions using arrival time estimates are widely scattered beneath Kilauea's summit caldera. In order to improve estimates of absolute LP location, we use the distribution of seismic amplitudes corrected for station site effects. The decay of the amplitude as a function of hypocentral distance is used for inferring LP location. In a second stage, we use the similarity of the events to calculate their relative positions. The analysis of the entire LP seismicity recorded between January 1997 and December 1999 suggests that a very large part of the LP event population, both deep and shallow, is generated by a small number of compact sources. Deep events are systematically composed of a weak high-frequency onset followed by a low-frequency wave train. Aligning the low-frequency wave trains does not lead to aligning the onsets indicating the two parts of the signal are dissociated. This observation favors an interpretation in terms of triggering and resonance of a magmatic conduit. Instead of defining fault planes, the precise relocation of similar LP events, based on the alignment of the high-energy low-frequency wave trains, defines limited size volumes. Copyright 2003 by the American Geophysical Union.

Journal of Geophysical Research B: Solid Earth↗

USGS1953

Airborne radioactivity survey of parts of the Atlantic Ocean beach, North and South Carolina

The accompanying map shows the results of an airborne radioactivity survey along the Atlantic Ocean beach between Edisto Island, South Carolina and Cape Fear, North Carolina. The survey was made May 20, 1953, as part of a cooperative program with the U.S. Atomic Energy Commission. The survey was made with scintillation detection equipment mounted in a Douglas DC-3 aircraft and consisted of one flight line, at a 500-foot altitude, parallel to the beach. The vertical projection of the flight line coincided approximately with the landward limit of the modern beach. The width of the zone on the ground from which anomalous radiation is measured at the nominal 500 foot flight altitude varies with areal extent and intensity of radioactivity of the source. For strong sources of radioactivity the width of the zone may be as much as 1400 feet. The accompanying maps show the approximate locations of the areas of greater-than-average radioactivity (at left) and the location of the traverse flown (at right). The abnormal radioactivity is apparently caused by radioactive minerals associated with "black sand" deposits which occur locally along the beach in this region. The present technique of airborne radioactivity measurement does not permit distinguishing between activity due to thorium and that due to uranium. An anomaly, therefore, may represent radioactivity due entirely to one or a combination of these elements. It is not possible to determine the extent or radioactive content of the materials responsible for the abnormal radioactivity. The information given in the accompanying map showing the localities of greater-than-average radioactivity therefore, suggests areas in which uranium and thorium deposits are more likely to occur.

North Carolina;South Carolina↗

USGS1993

Characterizing the hydrogeologic framework of the Death Valley region, Southern Nevada and California

Three-dimensional (3-D) hydrogeologic modeling of the complex geology of the Death Valley region requires the application of a number of Geoscientific Information System (GSIS) techniques. This study, funded by United States Department of Energy as a part of the Yucca Mountain Project, focuses on an area of approximately 100,000 square kilometers (three degrees of latitude by three degrees of longitude) and extends up to ten kilometers in depth. The geologic conditions are typical of the Basin and Range province; a variety of sedimentary and igneous intrusive and extrusive rocks have been subjected to both compressional and extensional deformation. GSIS techniques allow the synthesis of geologic, hydrologic and climatic information gathered from many sources, including satellite imagery and published maps and cross-sections. Construction of a 3-D hydrogeological model is possible with the combined use of software products available from several vendors, including traditional GIS products and sophisticated contouring, interpolation, visualization, and numerical modeling packages.

Conference Paper↗

USGS2008

Mineralogical and compositional characteristics of Late Permian coals from an area of high lung cancer rate in Xuan Wei, Yunnan, China: Occurrence and origin of quartz and chamosite

Some townships in Xuan Wei County, Yunnan Province, have one of the highest lung cancer mortality rates in China and the epidemic disease in the area has generally been attributed to the polycyclic aromatic hydrocarbons (PAHs) released from domestic coal burning. However, the cancer-causing culprit is not settled as Tian [Tian, L., 2005. Coal Combustion Emissions and Lung Cancer in Xuan Wei, China. Ph.D. thesis, University of California, Berkeley.] found nanometer quartz in these coals, soot emissions, and lung cancer tissues. We have conducted mineralogical and geochemical studies of the coals from Xuan Wei for the purpose of shedding light on the minerals which may be related to the epidemic lung cancer. In this paper, abundances, modes of occurrence, and origins of minerals and elements in the coals from two mines in Xuan Wei have been studied using optical microscope, low-temperature ashing, X-ray diffraction analysis, scanning electron microscope equipped with energy-dispersive X-ray spectrometer, and inductively-coupled plasma mass spectrometry. The minerals in the coals are mainly composed of quartz, chamosite, kaolinite, and calcite. The particle size of quartz is rather small, mostly less than 20????m and it is of authigenic origin. Chamosite occurs mainly as cell-fillings. The occurrence of quartz and chamosite indicates that they were derived from the hydrothermal fluids. Epigenetic calcite is derived from calcic fluids. Kaolinite is derived mainly from sediment source region of Kangdian Oldland to the west of coal basin. The composition of Xuan Wei coal is high in SiO2, Fe2O3, TiO2, CaO, MnO, V, Co, Ni, Cu, and Zn. The high SiO2 content is attributed to quartz, and the Fe2O3 content to chamosite. The high Mn and low Mg contents in the coal indicate the inputs of hydrothermal fluids. CaO occurs mainly in epigenetic calcite. Elements Ti, Co, Ni, Cu, Zn, and rare earth elements were derived from the basaltic rocks at sediment source region. ?? 2008 Elsevier B.V. All rights reserved.

International Journal of Coal Geology↗