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522 records · Page 29Linked to original sources
USGS2009

A decade of U.S. Air Force bat strikes

From 1997 through 2007, 821 bat strikes were reported to the U.S. Air Force (USAF) Safety Center by aircraft personnel or ground crew and sent to the National Museum of Natural History, Smithsonian Institution, for identification. Many samples were identified by macroscopic and or microscopic comparisons with bat specimens housed in the museum and augmented during the last 2 years by DNA analysis. Bat remains from USAF strikes during this period were received at the museum from 40 states in the United States and from 20 countries. We confirmed that 46% of the strikes were caused by bats, but we did not identify them further; we identified 5% only to the family or genus level, and 49% to the species level. Fifty-five of the 101 bat-strike samples submitted for DNA analysis have been identified to the species level. Twenty-five bat species have been recorded striking USAF planes worldwide. The Brazilian free-tailed bat (Tadarida brasiliensis; n = 173) is the species most commonly identified in USAF strike impacts, followed by the red bat (Lasiurus borealis; n = 83). Bat strikes peak during the spring and fall, with >57% occurring from August through October; 82% of the reports that included time of strike were recorded between 2100 and 0900 hours. More than 12% of the bat strikes were reported at >300 m above ground level (AGL). Although <1% of the bat-strike reports indicated damage to USAF aircraft, cumulative damage for 1997 through 2007 totaled >$825,000 and >50% of this sum was attributable to 5 bat-strike incidents. Only 5 bats from the 10 most damaging bat strikes were identified to the species level, either because we did not receive remains with the reports or the sample was insufficient for identification.

Human-Wildlife Conflicts↗
USGS2014

Standardization of vitrinite reflectance measurements in shale petroleum systems: How accurate are my Ro data?

Vitrinite reflectance generally is considered the most robust thermal maturity parameter available for application to hydrocarbon exploration and petroleum system evaluation. However, until 2011 there was no standardized methodology available to provide guidelines for vitrinite reflectance measurements in shale. Efforts to correct this deficiency resulted in publication of ASTM D7708-11: Standard test method for microscopical determination of the reflectance of vitrinite dispersed in sedimentary rocks. In 2012-2013, an interlaboratory exercise was conducted to establish precision limits for the measurement technique. Six samples, representing a wide variety of shale, were tested in duplicate by 28 analysts in 22 laboratories from 14 countries. Samples ranged from immature to overmature (Ro 0.31-1.53%), from organic-rich to organic-lean (1-22 wt.% total organic carbon), and contained Type I (lacustrine), Type II (marine), and Type III (terrestrial) kerogens. Repeatability values (difference between repetitive results from same operator, same conditions) ranged from 0.03-0.11% absolute reflectance, whereas reproducibility values (difference between results obtained on same test material by different operators, different laboratories) ranged from 0.12-0.54% absolute reflectance. Repeatability and reproducibility degraded consistently with increasing maturity and decreasing organic content. However, samples with terrestrial kerogens (Type III) fell off this trend, showing improved levels of reproducibility due to higher vitrinite content and improved ease of identification. Operators did not consistently meet the reporting requirements of the test method, indicating that a common reporting template is required to improve data quality. The most difficult problem encountered was the petrographic distinction of solid bitumens and low-reflecting inert macerals from vitrinite when vitrinite occurred with reflectance ranges overlapping the other components. Discussion among participants suggested this problem could not be corrected via kerogen concentration or solvent extraction and is related to operator training and background. Poor reproducibility (0.54% absolute reflectance, related to increased anisotropy?) in the highest maturity sample (Ro 1.53%) suggests that vitrinite reflectance is not a highly reliable parameter in such rocks. Future work will investigate opportunities to improve reproducibility in similar high maturity, organic-lean shale varieties.

Conference Paper↗
USGS2007

Mystery solved: White deposit on streambeds proves to be diatoms

In the late winter and early spring of 2006 an unusual white deposit was observed on rocks and margins of streambeds in a number of park streams. Inquiries were made to park staff and scientists studying water resources in the park as to what the deposit was and did it pose any type of risk. A number of explanations were proposed, but it was not until samples were collected and examined with a scanning electron microscope that the identity of the deposit was definitively determined.

Virginia↗
USGS2004

Topographic mapping of Mars: From hectometer to micrometer scales

We describe USGS topomapping of Mars at resolutions from 100 m to 30 µm with data from the latest spacecraft missions. Analysis of NASA 2001 Mars Odyssey Thermal Emission Imaging System (THEMIS) data combining daytime visible reflected, daytime IR emitted, and nighttime IR emitted images allows us to isolate the physical effects of topography, albedo, and thermal inertia. To a good approximation these physical influences interact linearly so that maps showing topographic shading, albedo, and relative thermal inertia can be produced by simple algebraic manipulation of the coregistered images. The shading map resembles an airbrush shaded relief portrayal of the surface, and can be used as the input for quantitative reconstruction of topography by photoclinometry (PC) at 100-m resolution over most of the planet. The High Resolution Stereo Camera (HRSC) of the ESA Mars Express orbiter includes a 9-line scanner for color and stereo imaging and a Super-Resolution Channel (SRC). We analyze these images with a combination of USGS ISIS cartographic software and commercial photogrammetric software, providing an independent check on the stereo processing pipeline developed by the HRSC team. In particular, we are producing very high resolution digital elevation models (DEMs) from the SRC images by photoclinometry and by stereoanalysis, using Mars Orbiter Camera images to complete the stereopair. The NASA Mars Exploration Rovers (MER) carry a diverse set of cameras: two wide-angle hazard camera pairs, panoramic stereo imagers (Pancam and Navcam), and a Microscopic Imager (MI) that images a 3-cm-square area at 30 µm/pixel resolution. Our work emphasizes MI data and includes geometric calibration, bundle-adjustment, mosaicking, generation of DEMs by stereo analysis and focal sectioning, and combination of MI images with color data from Pancam. The software being developed to support these analyses can also be used to produce high-precision controlled mosaics, DEMs, and other products from the Pancam and Navcam images.

Conference Paper↗
USGS1999

Environmental models of mineral deposits- A state of the art

Although mineral deposits have been classified by their geologic and mineralogical characteristics for decades, the recognition that mineral deposits also could be classified by their environmental characteristics is relatively new. In the past 5 years, numerous advancements have been made in this subject area, building on the earlier work of economic geologists who classified geologic characteristics. Several different approaches to understanding the environmental behavior of mineral deposits and associated altered areas have been taken, ranging from wholesale assessments of large areas (millions of km 2 ) to detailed assessments of individual watersheds or individual mines. While these first attempts have succeeded in describing some of the environmental characteristics of ore deposits in a number of ways, many important “environmental variables” are not included in present descriptive models. For example, the models should be expanded in scope to include a more thorough treatment of climatic and ecoregional effects- embodying such physical environmental characteristics as precipitation, evaporation, temperature, and ground water-surface water interactions. More complete model descriptions will have applications to the determination of baselines and natural backgrounds in mined and unmined areas, as well as possible anticipated effects of new mining in a given area, and mitigation and remediation strategies. The challenge to geologists and geochemists is to incorporate a widely disparate set of physical and chemical characteristics of mineralized and altered zones at scales ranging from microscopic (sub-millimeter) to macroscopic (10’s to 100’s of kilometers). This paper presents an overview of the development of mineral deposit environmental models, the current state of the art, an evaluation of needed improvements, and expected advancements in this field.

Geologica Hungarica. Series geologica↗
USGS2002

Characterization of soils and rock at an active oil production site: Effects of brine and hydrocarbon contamination

An active oil production site (Osage-Skiatook petroleum environmental research Site B) in Osage County, Oklahoma is under study to determine the impacts on soils and rock of brine and hydrocarbon spills. The goals of the soil and rock characterization are to 1) document and identify the type, degree, and areal extent of brine and hydrocarbon releases, 2) understand controls on the movement and retention of brine and hydrocarbons, and 3) determine the role of solid phases, such as clay and iron-bearing minerals, in natural mitigation. The types and amounts of clay minerals and oxidizers (particularly iron) are important because of the capacity of clay minerals to exchange cations that are dissolved in brines and the capacity of reactive ferric iron species to oxidize hydrocarbons. Characterization of soils and rock includes visual and microscopic description, X-ray diffraction of bulk and clay fraction samples, separation of size fractions, determination of cation exchange capacity, bulk chemical composition, and selective extraction of iron species. Results suggest that much of the brine and hydrocarbon contamination occurs in the shallow subsurface (< 240 cm) where the soil profile varies from dark brown topsoil to reddish orange sand to greenish-gray clay. A layer of iron-stained colluvium that is present in the shallow subsurface consists of pebbles and coarse sand and forms an important conduit for fluid movement. Unusually high percentages (as much as 97 % of total iron) of reduced iron may record the passage of hydrocarbon-rich ground water. Clay minerals are abundant in some samples and are dominated by kaolinite, mixed layer illite-smectite, and smectite. The correlation of grain size and clay mineral content with soil leachate results will be discussed and high percentages of sodium on exchange sites in clay are expected in areas of past spills of produced water.

Oklahoma↗
USGS2020

Micrometer-scale characterization of solid mine waste aids in closure due diligence

Precious- and base-metal mining often occurs in deposits with high acid-generating potential, resulting in mine waste that contains metals in forms of varying bioavailability, and therefore toxicity. The solids that host these metals are often noncrystalline, nanometer to micrometer in size, or undetectable by readily available analytical techniques (e.g., X-ray diffraction). This analytical shortcoming can pose a challenge when attempting to characterize sources and natural attenuation of metals at a given site, which is a best practice to satisfy closure due diligence. Numerous case studies have shown that efforts to characterize mine waste at multiple scales, particularly the micrometer scale, often lead to a better understanding of metal distribution and potential contamination risks. This paper presents a case study that compares the use of both traditional and non-traditional techniques to identify and quantify metal hosts in sediments downstream of the abandoned mine waste piles at the Ely Copper Mine Superfund site in Vermont (USA). The contaminant present in the highest concentration in the sediments is copper, yet not all copper-bearing solids were detected with bulk X-ray diffraction (XRD). At the micrometer scale, a combination of synchrotron-based X-ray absorption spectroscopy (XAS) and an automated mineralogy (AM) system were used to identify the most abundant copper-bearing solids. Bulk XAS and AM also provided semi-quantitative abundances of these solids in the sediment. At the Ely Copper Mine, copper in stream sediments was found to be predominantly hosted in sulphide minerals downstream of a major mine waste pile, whereas upstream copper was predominantly hosted in secondary iron and manganese (oxyhydr)oxides. These copper-bearing hosts were consistent with the expected bioavailability of copper in the sediments based on laboratory toxicity tests with aquatic organisms. When the bulk of copper was present in sulphides, aquatic organisms experienced greater survival than when copper was mostly associated with secondary iron and manganese (oxyhydr)oxides. The information gained from probing the sediments at multiple scales can now be used to prioritize containment and remediation strategies. While synchrotron-based analytical techniques have proven to be invaluable in many studies of mine waste, access to these techniques is limited. In contrast, access to a scanning electron microscope that can perform AM is becoming more common, primarily for the application in mining design and mineral processing operations. More recently, the successful use of AM to characterize mine waste suggests that this technique can be equally as valuable for mine closure plans. The resolution of information obtained may go beyond what is required from a regulatory perspective, but given that the results have the potential to be more conclusive than many traditional techniques, this level of characterization may save time and money in the long run.

Vermont↗
USGS2021

Effectiveness of rapid 'ōhi'a death management strategies at a focal disease outbreak on Hawai'i Island

The ongoing spread of rapid ‘ōhi‘a death (ROD) in the Hawaiian Islands threatens the long-term sustainability of ‘ōhi‘a lehua (Metrosideros polymorpha) forests throughout the state. First identified in the Puna district of Hawai‘i Island in 2014, the disease caused by the novel fungi Ceratocystis lukuohia and Ceratocystis huliohia has now spread island-wide and was recently detected on Kaua‘i, O‘ahu, and Maui. The leading hypothesis for the spread of ROD is through airborne ambrosia beetle frass particles that contain viable Ceratocystis propagules, thus management efforts focus on containing this frass. At the time of this study (2017–2018), the Waipunalei site was the northernmost outbreak of ROD on Hawai‘i Island. The focal nature of the outbreak and accessibility of the location provided the opportunity to monitor the effectiveness of two types of proposed management methods to reduce the airborne spread of potentially infective ambrosia beetle frass: tree felling and insecticide treatments. We placed 23 passive environmental samplers (PES), which monitored for airborne frass and wood particles containing C. lukuohia and C. huliohia in a grid that spanned the outbreak area over 22 weeks. Cross-vane panel traps with 1:1 methanol:ethanol lures were attached to nine of the PES to document wood-boring ambrosia and cerambycid beetle populations during the latter three months of the study. Monitoring with PES began three weeks before management and continued for one month after the last infected trees were felled. Glass microscope slides from the 23 PES were examined for airborne ambrosia beetle frass and wood particles by microscopy. DNA was extracted from the slides and tested by qPCR (quantitative polymerase chain reaction) for C. lukuohia and C. huliohia. We also investigated the correlation of beetle gallery counts with tree height and tested the efficacy of Bifen I/T insecticide (active ingredient: bifenthrin 7.9%) for preventing beetle attacks on the cut surface of ‘ōhi‘a bolts (tree stem sections). Beetle trapping data revealed that the area supports a diverse community of wood-boring beetles, some of which likely attack ‘ōhi‘a and may facilitate the spread of ROD. The number of beetle galleries on felled ‘ōhi‘a trees decreased linearly as tree height increased. We also observed significantly fewer beetle attacks on Bifen I/T treated ‘ōhi‘a bolts than non-treated bolts, but gallery formation nearly ceased in both treated and control bolts by week three. Ceratocystis lukuohia DNA was detected twenty-six times and C. huliohia was detected five times in the PES throughout this study. DNA detections were correlated to frass and wood counts, and the number of felled trees were correlated to wood particle counts but not frass counts. Both the timing and distribution of detections across the sampling grid indicate that tree felling may have reduced airborne detections of Ceratocystis DNA soon after tree felling was completed. A subsequent increase in detections after tree felling ceased may indicate that incomplete removal of infected trees and the appearance of new infections in previously asymptomatic trees could have allowed airborne detections of potentially infectious fungal propagules to once again increase.

Hawaii↗
USGS2020

Book review of "Plant anatomy—A concept based approach to the structure of seed plants"

Plant Anatomy: A Concept-Based Approach to the Structure of Seed Plants by Crang, Lyons-Sobaski, and Wise is a beautifully-illustrated, 600+ page textbook highlighting the wonderful diversity of anatomical form in plants. The layout of the chapters follows many traditional plant anatomy textbooks. Plant Anatomy begins with an overview of plant morphology and proceeds through evolutionary time and across systems (Chapter 1. The Nature of Plants) before zooming into the microscopic, internal world of plant structures and their function (Chapter 2. Microscopy and Imaging through Chapter 8. Phloem). Quite fortunately, historical context is described throughout these sections, highlighting seminal studies that have shaped the plant sciences over the past 300+ years.

Plant Science Bulletin↗
USGS2022

Identification of thermal maturity-relevant organic matter in Shale Working Group Report 2021

The Identification of Thermal Maturity-Relevant Organic Matter in Shale Working Group of the ICCP was established in 2008 to provide guidelines for identifying and measuring the reflectance of the population of dispersed organic matter that is relevant to thermal maturity determination. Information products published by the working group include ASTM D7708 Standard Test Method for Microscopical Determination of the Reflectance of Vitrinite Dispersed in Sedimentary Rocks (ASTM, 2014) and two interlaboratory studies (ILS) to determine precision statistics for this ASTM test method (Hackley et al., 2015, 2020). Poor reproducibility of solid bitumen and vitrinite reflectance measurements in the second ILS (Hackley et al., 2020) suggested that further work is required to standardize the identification of thermal maturity-relevant dispersed organic matter for reproducible reflectance measurements. Thus, at the 2019 ICCP meeting in The Hague, Netherlands, the working group decided to pursue additional ILS via image-based approaches to improve reproducibility.

ICCP News↗
USGS1978

Recognition of oxidized sulfide minerals as an exploration guide for uranium

The difference in color between tan to red oxidized sandstone and gray reduced sandstone on either side of the reduction-oxidation (redox) interface, which is- the locus of uranium concentration in roll-type deposits, has been noted and used locally as an exploration guide within known uranium districts. Reduced sandstone is characterized in many deposits by the presence of iron sulflde minerals (particularly marcasite and pyrite) that occur as replacements of and overgrowths on iron-titanium oxide minerals and plant debris and as cement of detrital grains. Oxidation of the sulfldes by oxygenated ground water forms yellow to red ferric oxide and ferric hydroxide phases ("limonite") that replace the FeS 2 minerals. Processes other than the oxidation of sulfldes, however, can cause reddening of clastic sediments without the creation of a redox boundary, and so color alone is not a sufficient condition by which to judge the potential for uranium ore in frontier areas. Ferric oxides that form by the oxidation of iron sulflde minerals can be distinguished from other forms of ferric oxide by reflection microscopic examination of polished grain mounts- and polished thin sections'. Diagnostic features of oxidized sulfldes are limonite pseudomorphs of sulfldes and limonite containing internal textures that mimic characteristic textures of previously sulfldized detrital phases. Recognition of oxidized sulfides by reflection microscopy, then, can distinguish oxidized sandstones, which might have a redox boundary downdip and which would therefore be favorable hosts for uranium concentration, from those without such potential.

Journal of Research of the U.S. Geological Survey↗
USGS1977

Distribution of some biostratigraphically diagnostic ostracodes in the Pliocene and lower Pleistocene of Virginia and northern North Carolina

Ostracodes are abundant and diverse in Pliocene and lower Pleistocene deposits of Virginia and North Carolina. Many readily identified species are short ranging or have well-defined beginning and (or) end points to their stratigraphic range. These microscopic crustaceans, therefore, are very useful in zonation and correlation in the region. In this paper, 54 particularly useful species are illustrated, and their ranges are indicated graphically. The range zones, concurrent range zones, and local range zones of these forms allow the recognition of the chronozones of previously proposed ostracode assemblage zones in Virginia and North Carolina as well as in other regions.

North Carolina, Virginia↗
USGS1990

Mass-marking of otoliths of lake trout sac fry by temperature manipulation

The otoliths of 676,000 sac fry of lake trout Salvelinus namaycush in 1986, and of 1,100,000 in 1987, were marked by daily manipulation of water temperature. The fish were stocked into Lake Huron in the spring. Otolith marks consisted of groups of daily growth rings accentuated into recognizable patterns by steadily raising and lowering the temperature about IOA?C (from a base of 1-4A?C) over 14h. In 1987, groups of marked and control fish were held for 6 months. The otoliths were removed from samples of the fish, embedded in epoxy, thin-sectioned by grinding in the sagittal plane, etched, and viewed by using a combination of a compound microscope (400-1000x) and a video enhancement system. One or more readable otolith sections were obtained from 39 of a sample of 40 fish. Three independent readers examined 41 otoliths for marks and correctly classified the otoliths, with accuracies of 85, 98,and 100%, as being from marked or unmarked fish. The exact number of rings in a recognizable pattern sometimes differed from the number of temperature cycles to which the fish were exposed. Counts of daily rings within groups of six rings varied less than counts within groups of three rings.

Book chapter↗
USGS1956

Histopathologic changes of a virus-like disease of sockeye salmon

Rucker et al., (1953) described a disease of sockeye salmon ( O ncorhynchus nerka ) of possible viral etiology. First seen in Washington in 1951 with relatively minor losses, the disease recurred in 1952 killing over two million fingerling salmon with a mortality rate of 91.5 percent (Watson, 1954). In 1953, the disease was present in every sockeye salmon hatchery in the state. Rucker, Watson and their associates have demonstrated that the disease is infectious, caused by a serially-transmissible and filterable agent, and specific for one species of fish. Watson et al., (1956) have described the hematology of infected salmon. The present paper deals with the histopathology of the disease.

Transactions of the American Microscopical Society↗
USGS1967

Some oligochaetes from Lake Michigan

Twenty-six species of Tubificidae, 12 Naididae, and 1 Lumbriculidae were found in three regions of Lake Michigan- Green Bay, the southern end of the lake proper, and the harbor at Ludington, Michigan. One new naidid species is described. Methods of identification of some species are discussed and illustrated. The abundance of oligochaetes and distribution of certain species vary with depth and location. Data are presented on the effects of the environment on the distribution of certain species. The presence or absence of some species reflected the quality of the environment; some were prevalent in polluted waters whereas others were restricted or absent. Possible changes in composition and abundance of species are outlined if organic enrichment increases in Lake Michigan.

Illinois, Indiana, Michigan, Wisconsin↗