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USGS2020

Foreward: Geology Field Trips in and around the U.S. Capital

The first annual meeting of the Geological Society of America (GSA) was held in 1888 in Ithaca, New York (Fairchild, 1932), but official Sections of GSA formed much later. During the spring of 1949, a symposium in Knoxville, Tennessee, on mineral resources of the southeastern United States became the catalyst for the creation of the Southeastern Section of the Geological Society of America (King, 1964), and the first annual meeting of the Southeastern Section was held in 1952 in Roanoke, Virginia (Wilson, 1954). The Northeastern Section formed much later, and its first annual meeting was held in 1966 in Philadelphia, Pennsylvania (Socolow, 1968). At all of these section meetings, field trips have been important venues for geologists and especially students to gather together, examine rocks in the field, and discuss ideas. These field trips have been especially important at combined section meetings because they provide settings for geologists who are experienced in one geographic region to examine and compare the geology of other regions. The first combined meeting of the Southeastern and Northeastern sections occurred in 1976 in Arlington, Virginia. Since then, the Southeastern and Northeastern sections have met together on numerous occasions, including 1982 in Washington, DC; 1991 in Baltimore, Maryland; 2004 in Tysons Corner, Virginia; and 2010 in Baltimore, Maryland. Since the first combined section meeting in 1976, there has been a gradual increase in the role of technology in geology field studies. In fact, during the past several decades there has been an increase in emphasis in our society on the instrumental component of science, the goal of which is operational techniques to do or control things, and a corresponding decrease in emphasis on the natural philosophy component of science, the goal of which is a greater understanding of the natural world (Dear, 2006). The modern education acronym STEM (Science, Technology, Engineering, and Mathematics), for example, is often used as a catch-all term that implies that science and technology are relatively synonymous, and implies that greater technology leads automatically to greater understanding of the natural world. This assumption, however, is not always valid (Dear, 2006), and technology should not be promoted as a substitute for field experiences. Technology can be a tool that leads to greater understanding of the natural world, but not all Science uses technology as a means of providing greater understanding. The benefits of new technologies include: (1) data of greater resolution; and (2) greater efficiency of capturing, storing, and visualizing data. The risks of new technologies include: (1) an overabundance of data, some of which may be of little value; (2) less time available for analysis of data, if geologists become occupied primarily with capturing and storing data; and (3) errors that arise from complacency and the perception that field-checking may not be necessary. In other words, there is a risk that a glut of data and vast amounts of time devoted to the capturing and storing of data may result in a reduced interest and (or) willingness to field-check data. In the spirit of the early GSA section meetings, we feel that there are still enormous advantages to conducting geology field trips in conjunction with traditional meeting presentations and posters. In 2020, with this current combined Southeastern and Northeastern section meeting in Reston, Virginia, we have assembled eight different field trips that cover a wide range of territory in and around the Nation’s capital. These field trip localities include the immediate vicinity of Washington, DC, as well as various locations in nearby areas of Virginia, Maryland, and West Virginia. The physiographic provinces include Mesozoic Rift Basins, the Piedmont, the Blue Ridge, the Valley and Ridge, and the Allegheny Plateau of the Appalachian Basin. The field trip sites exhibit a wide range of igneous, metamorphic, and sedimentary rocks, as well as rocks with a wide range of geologic ages from the Mesoproterozoic to the Holocene. We hope that this guidebook provides new motivation for geologists to examine rocks in the field, to discuss ideas with colleagues in the field, and to avoid becoming complacent. The editors of this volume would like to thank the authors of the different field trip guides, the field trip leaders, and all of the reviewers who made suggestions for improving the field trip manuscripts. The editors would also like to thank Elle Derwent of GSA for her logistical help and guidance regarding the field trips, and April Leo and the staff of the GSA Publications Department for seeing this book through to publication.

Maryland, Virginia, West Virginia↗

USGS2008

Linking landscapes and habitat suitability scores for diadromous fish restoration in the susquehanna river basin

Dams within the Susquehanna River drainage, Pennsylvania, are potential barriers to migration of diadromous fishes, and many are under consideration for removal to facilitate fish passage. To provide useful input for prioritizing dam removal, we examined relations between landscape-scale factors and habitat suitability indices (HSIs) for native diadromous species of the Susquehanna River. We used two different methods (U.S. Fish and Wildlife Service method: Stier and Crance [1985], Ross et al. [1993a, 1993b, 1997], and Pardue [1983]; Pennsylvania State University method: Carline et al. [1994]) to calculate HSIs for several life stages of American shad Alosa sapidissima, alewives Alosa pseudoharengus, and blueback herring Alosa aestivalis and a single HSI for American eels Anguilla rostrata based on habitat variables measured at transects spaced every 5 km on six major Susquehanna River tributaries. Using geographical information systems, we calculated land use and geologic variables upstream from each transect and associated those data with HSIs calculated at each transect. We then performed canonical correlation analysis to determine how HSIs were linked to geologic and land use factors. Canonical correlation analysis identified the proportion of watershed underlain by carbonate rock as a positive correlate of HSIs for all species and life stages except American eels and juvenile blueback herring. We hypothesize that potential mechanisms linking carbonate rock to habitat suitability include increased productivity and buffering capacity. No other consistent patterns of positive or negative correlation between landscape-scale factors and HSIs were evident. This analysis will be useful for prioritizing removal of dams in the Susquehanna River drainage, because it provides a broad perspective on relationships between habitat suitability for diadromous fishes and easily measured landscape factors. This approach can be applied elsewhere to elucidate relationships between fine- and coarse-scale variables and suitability of habitat for fishes. ?? Copyright by the American Fisheries Society 2008.

North American Journal of Fisheries Management↗

USGS1980

Organochlorine and heavy metal residues in black duck eggs from the Atlantic Flyway, 1978

Black duck ( Anas rubripes ) eggs were collected during 1978 in the Atlantic Flyway. One egg from each of 49 clutches was analyzed for organochlorine compounds and mercury. DDE was detected in 39 eggs, ranging from 0.09 ppm to 3.4 ppm, wet weight. DDE residues were highest in eggs from Delaware, where the mean DDE level was 2.0 ppm. DDT and TDE were present at Iow levels in only five and four eggs, respectively. PCBs resembling Aroclor 1260 were detected in 24 eggs and ranged from 0.43 ppm to 2.9 ppm. Eggs from Massachusetts and Rhode Island contained an average of >1.0 ppm PCBs, but eggs from Nova Scotia, Pennsylvania, Maryland, and Virginia contained no detectable PCBs. Dieldrin, oxychlordane, and heptachlor epoxide were present in a few samples at low levels. Mercury was detected in 31 eggs, ranging from 0.07 ppm to 0.34 ppm, wet weight. Twenty eggs analyzed for chromium, copper, and arsenic contained averages of 0.64 ppm, 1.7 ppm, and 0.18 ppm, respectively. No geographic pattern was observed in these metal residue levels. Eggshell thickness (0.347 mm) was identical to the pre-1946 norm.

Delaware, Maine, Maryland, Massachusetts, New Brun↗

USGS2001

Digital data used to relate nutrient input to water quality in the Chesapeake Bay watershed

Digital data sets compiled by the U.S. Geological Survey were used as input for a collection of Spatially Referenced Regressions On Watershed (SPARROW) attributes for the Chesapeake Bay region including parts of Delaware, Maryland, New York, Pennsylvania, Virginia, West Virginia, and the District of Columbia. These regressions use a nonlinear statistical approach to relate nutrient sources and land-surface characteristics to nutrient loads of streams throughout the Chesapeake Bay watershed. A digital segmented-watershed network serves as the primary framework for spatially referencing nutrient-source and land-surface characteristic data within a geographic information system. Flow direction and flow accumulation generated from a 30-meter cell-size Digital Elevation Model and attributes from 1:500,000-scale stream data were used to generate stream and watershed networks. Spatial data sets representing nutrient inputs of total nitrogen and total phosphorus from the early 1990's were created and compiled from numerous sources. Data include atmospheric deposition, septic systems, point-source locations, land use, land cover, and agricultural sources such as commercial fertilizer and manure. Some land-surface characteristic data sets representing factors that affect the transport of nutrients also were compiled. Data sets include land use, land cover, average-annual precipitation and temperature, slope, hydrogeomorphic regions, and soil permeability. Nutrient-input and land-surface characteristic data sets merged with the segmented-watershed network provide the spatial detail by watershed segment required by SPARROW. Stream-nutrient load estimates for 132 sampling sites representing the early 1990's (103 for total nitrogen and 121 for total phosphorus) serve as the dependent variables for the regressions. These estimates were used to calibrate models of total nitrogen and total phosphorus depicting 1992 land-surface conditions. Examples of model predictions consist of stream-nutrient load and source percentages contributed locally to each stream reach, as well as percentages of the load that reach Chesapeake Bay.

Open-File Report↗

USGS2004

Distribution of Holocene Sediment in Chesapeake Bay as Interpreted from Submarine Geomorphology of the Submerged Landforms, Selected Core Holes, Bridge Borings and Seismic Profiles

Overview -- We have interpreted the geomorphology of the submerged landforms to show thick Holocene sediment that accumulated from three different sources during on-going sea level rise that began 10,000 - 12,000 years ago at the end of Pleistocene. We used a variety of subsurface data from the literature and unpublished information to document thicknesses, materials, dates and duration of processes. Although the details of the true extent and thicknesses are unknown, the deposits of different sources have affinity for particular geographic and submerged geomorphic regions of the Chesapeake Bay and its tidal tributaries. During the last Pleistocene glacial event (Wisconsian), the area now occupied by the Chesapeake Bay was exposed, sea level being about 100 m lower than present. The Susquehanna River valley extended beyond the Bay well out on the exposed Atlantic Shelf. The Susquehanna transported glacial outwash from northern Pennsylvania and New York; the glacio-fluvial deposits were graded to the edge of the continental shelf (Colman et al., 1990; Hack, 1957). Other Piedmont and Appalachian Rivers including the Potomac and James Rivers transported large volumes of sediment to confluence with the Susquehanna channel. Locally, across the encompasing coastal plain landscape, intensive headward erosion, gullies, and slope failure, generated extensive debris flows, sheet wash, and terraces of braided alluvial channel deposits. Large volumes of sediment were moved through the river system to the continental shelf. This was accomplished by a cold, wet climate that included much freezing and thawing; steep eroding slopes resulted from the lowering of sea level from the previous high stand (Stage 5e) between glacial events. Across the Delmarva peninsula extensive wind-blown deposits of sand and loess were recycled onto low terraces and uplands from the unvegetated glacio-fluvial sediments moving through the system (Denny et al., 1979). The volume and distribution of sediment eroded and transported from the watershed surrounding the area of the Bay was several orders of magnitude greater than generally observed in transport and storage on the present day landscape.

Open-File Report↗

USGS1993

Genetic variability and glacial origins of yellow perch ( Perca flavescens ) in North America

Starch–gel electrophoresis was used to analyze muscle and liver tissue for variation in 13 enzymes representing 31 presumptive loci in yellow perch ( Perca flavescens ) from 13 localities scattered throughout the natural geographic range of the species in North America. Ten loci were polymorphic, but only three, alcohol dehydrogenase ( ADH-1 *), glucose-6-phosphate isomerase ( GPI-1 *), and phosphoglucomutase ( PGM-2 *), exhibited polymorphisms at relatively high frequencies across localities. Western populations were fixed for one allele at ADH-1 *, eastern populations were fixed for another allele, and populations from intermediate locations in Lake Ontario and Pennsylvania had both alleles. The distributions of alleles at GPI-1 * and PGM-2 *were similar to that of ADH-1 *, exhibiting strong differences between eastern and western populations, although the delineation was not as clear. Western populations were much less variable than eastern populations, and the distribution of alleles indicated that the two groups were derived from Mississippi and Atlantic glacial refugia. Populations near the physiographic discontinuity between the Mississippi and Atlantic drainages in western New York and Pennsylvania exhibited an admixture of typically western and eastern alleles. Such observations are consistent with the mixed faunal history of the region and limited postglacial dispersal of western and eastern populations across the boundary.

Canadian Journal of Fisheries and Aquatic Sciences↗

USGS2019

Ordovician Point Pleasant/Utica-Lower Paleozoic Total Petroleum System—Revisions to the Utica-Lower Paleozoic Total Petroleum System in the Appalachian Basin Province

Hydrocarbon reserves and technically recoverable undiscovered resources in continuous accumulations are present in Upper Ordovician strata in the Appalachian Basin Province. The province includes parts of New York, Pennsylvania, Ohio, Maryland, West Virginia, Virginia, Kentucky, Tennessee, Georgia, and Alabama. The Upper Ordovician strata are part of the previously defined Utica-Lower Paleozoic Total Petroleum System (TPS) that extends from New York and southern Canada to Tennessee. This publication presents a revision to the hydrocarbon source rocks in the TPS, a change to the name of the TPS, and changes to the geographic extent of the Utica-Lower Paleozoic TPS. The revision to the TPS recognizes the Upper Ordovician Point Pleasant Formation as a major hydrocarbon source rock in this TPS. Consequently, the name of the TPS is changed to Ordovician Point Pleasant/Utica-Lower Paleozoic TPS. The most significant modification to the boundary of the newly defined Ordovician Point Pleasant/Utica-Lower Paleozoic TPS is a westward extension in the southwesterly portion of the TPS, adding areas in Ohio, Indiana, Kentucky, and Tennessee in order to include Ordovician strata, including potential petroleum source rocks, from the subsurface to their near-surface exposure. Also, portions of the former Utica-Lower Paleozoic TPS are now excluded from the newly defined TPS in a portion of northwestern Ohio and adjacent States to eliminate overlap with the Ordovician to Devonian Composite TPS in the Michigan basin.

Appalachian Basin Province↗

USGS2014

Coal and petroleum resources in the Appalachian basin: index maps of included studies

This chapter B.1 of U.S. Geological Survey (USGS) Professional Paper 1708 provides index maps for many of the studies described in other chapters of the report. Scientists of the USGS and State geological surveys studied coal and petroleum resources in the central and southern Appalachian structural basins. In the southern Appalachian basin, studies focused on the coal-bearing parts of the Black Warrior basin in Alabama. The scientists used new and existing geologic data sets to create a common spatial geologic framework for the fossil-fuel-bearing strata of the central Appalachian basin and the Black Warrior basin in Alabama. Digital data have been compiled into a geographic information system (GIS) that is included in chapter I.1 (Trippi and others, this volume). Shape files and related metadata for features shown in the index maps of this chapter can be downloaded from chapter I.1. The study area for the Appalachian basin resource framework study includes the fossil-fuel-bearing strata of the following States (listed alphabetically): Alabama, Kentucky, Maryland, New York, Ohio, Pennsylvania, Tennessee, Virginia, and West Virginia. The outline of the study area is shown in figure 1; it differs from the boundary of the Appalachian Basin Province (Province 67) defined for the 1995 National Oil and Gas Assessment (NOGA) by the U.S. Geological Survey (1996a). The difference is that the study area includes regions where the Pennsylvanian coal-bearing strata crop out but does not include all of the oil- and gas-bearing strata of the Black Warrior basin, Alabama. The reasons for providing the index maps in this chapter are to show the locations of different studies, to give an overview of topics covered, and to help the user choose which chapter to read. Figures 1 and 2 show the study area outline and county names. Figure 3 shows oil and gas production in 1995 and 2005. Figure 4 shows locations of Upper Devonian sandstone oil and gas fields. Figure 5 shows major coal regions and coal fields. Figure 6 shows coal production by county. Figure 7 shows the locations of 10 cross sections of regional extent through the subsurface of the Appalachian basin. Figure 8 shows conodont alteration index sample locations and interpreted isograds for Ordovician rocks. Figure 9 shows vitrinite-reflectance data for Pennsylvanian coal in the Appalachian basin. Figure 10 shows the locations of coalbed-methane (CBM) assessment units in the study area, and figure 12 shows counties producing CBM. Figure 12 shows sulfur content of coal delivered to powerplants from coal-producing counties in the Appalachian basin and Black Warrior basin. Figure 13 shows locations of wells in Ohio and Pennsylvania where oil and gas were sampled in Lower Silurian reservoirs. Figure 14 shows the Conasauga-Rome/Conasauga Total Petroleum System and selected wells in the Rome trough in Kentucky and West Virginia having oil and gas production and shows. Figure 15 shows the locations of samples from Silurian reservoirs in Kentucky, New York, Ohio, Pennsylvania, and West Virginia; the samples yielded total organic carbon data. Figure 16 shows the locations of the Ben Hur and Rose Hill oil fields, Virginia, and the Swan Creek oil field, Tennessee. The one index map that is not shown is the areal extent of the shale gas plays in the basin. The extents of the plays can be found in Coleman and others (this volume, chap. G.13).

Appalachian basin↗

USGS2014

Decreased atmospheric sulfur deposition across the southeastern U.S.: When will watersheds release stored sulfate?

Emissions of sulfur dioxide (SO 2 ) to the atmosphere lead to atmospheric deposition of sulfate (SO 4 2- ), which is the dominant strong acid anion causing acidification of surface waters and soils in the eastern United States (U.S.). Since passage of the Clean Air Act and its Amendments, atmospheric deposition of SO 2 in this region has declined by over 80%, but few corresponding decreases in stream-water SO 4 2- concentrations have been observed in unglaciated watersheds. We calculated SO 4 2- mass balances for 27 forested, unglaciated watersheds from Pennsylvania to Georgia, by using total atmospheric deposition (wet plus dry) as input. Many of these watersheds still retain SO 4 2- , unlike their counterparts in the northeastern U.S. and southern Canada. Our analysis showed that many of these watersheds should convert from retaining to releasing SO 4 2- over the next two decades. The specific years when the watersheds crossover from retaining to releasing SO 4 2- correspond to a general geographical pattern of later net watershed release from north to south. The single most important variable that explained the crossover year was the runoff ratio, defined as the ratio of annual mean stream discharge to precipitation. Percent clay content and mean soil depth were secondary factors in predicting crossover year. The conversion of watersheds from net SO 4 2- retention to release anticipates more widespread reductions in stream-water SO 4 2- concentrations in this region.

Environmental Science & Technology↗

USGS1995

Canada geese in the Atlantic Flyway

Large changes have occurred in the geographic wintering distribution and subspecies composition of the Atlantic Flyway population of Canada geese ( Branta canadensis ) over the last 40 years. The Atlantic Flyway can be thought of as being partitioned into four regions: South, Chesapeake, mid-Atlantic, and New England. Wintering numbers have declined in the southern states (North Carolina, South Carolina, Georgia, Florida), increased then decreased in the Chesapeake region (Delaware, Maryland, Virginia), and increased markedly in the mid-Atlantic region (New York, New Jersey, Pennsylvania, West Virginia) (Serie 1993; Fig. 1). In the New England region (Maine, New Hampshire, Vermont, Massachusetts, Rhode Island, Connecticut), wintering numbers increased from around 6,000 during 1948-50 to between 20,000 and 30,000 today (Serie 1993). Overall, the total number of wintering geese reaching a peak of 955,000 in 1981 and has since declined 40% to 569,000 in 1993. Compounding these distributional changes in wintering numbers, the subspecies composition has also changed. The Canada goose population is composed of migrant geese (primarily B.c. canadensis and B.c. interior ) that breed in the subarctic regions of Canada and resident geese (primarily B.c. maxima and B.c. moffitti ) that breed in southern Canada and the United States (Stotts 1983). The number of resident geese in Maine to Virginia has increased considerable from maybe 50,000 to 100,000 in 1981 (Conover and Chasko 1985) to an average of 560,000 in 1992-93 (H. Heusman, Massachusetts Division of Fisheries and Wildlife, personal communication). This rapid increase in resident geese suggests that the migrant population has declined more than the 40% decline observed in total wintering geese from 1981 to 1993.

Atlantic Flyway↗

USGS2022

Broad-scale geographic and temporal assessment of northern long-eared bat (Myotis septentrionalis) maternity colony-landscape association

As the federally threatened northern long-eared bat Myotis septentrionalis continues to decline due to white-nose syndrome (WNS) impacts, the application of effective conservation measures is needed but often hindered by the lack of ecological data. To date, recommended management practices have been adopted in part from other federally listed sympatric species such as the endangered Indiana bat M. sodalis . During the maternity season, these measures have largely focused on conservation of known day-roost habitat, often with little consideration for foraging habitat, particularly riparian areas. We examined acoustic activity of northern long-eared bats relative to day-roost and capture data at coastal and interior sites in the District of Columbia, New York, Pennsylvania, Virginia, and West Virginia, USA, over the course of 6 summers (2015-2020), where maternity activity was still documented after the initial arrival and spread of WNS. Acoustic activity of northern long-eared bats relative to forest cover decreased at the acoustic site level (fine scale) but increased at the sampling region level (coarse scale). We observed a positive association of northern long-eared bat acoustic activity with riparian areas. Additionally, we observed higher levels of activity during pregnancy through early lactation period of the reproductive cycle prior to juvenile volancy. Our findings suggest the need for more explicit inclusion of forested riparian habitats in northern long-eared bat conservation planning. Acoustic sampling in spring and early summer rather than mid- to late summer and in forested riparian areas is the most effective strategy for identifying potential active northern long-eared bat maternity colonies on the local landscape.

Maryland, New York, Pennsylvania, Virginia, and We↗

USGS2008

Spatial Distribution of Ground-Water Recharge Estimated with a Water-Budget Method for the Jordan Creek Watershed, Lehigh County, Pennsylvania

This report presents the results of a study by the U.S. Geological Survey, in cooperation with the Pennsylvania Geological Survey, to illustrate a water-budget method for mapping the spatial distribution of ground-water recharge for a 76-square-mile part of the Jordan Creek watershed, northwest of Allentown, in Lehigh County, Pennsylvania. Recharge was estimated by using the Hydrological Evaluation of Landfill Performance (HELP) water-budget model for 577 landscape units in Jordan Creek watershed, delineated on the basis of their soils, land use/land cover, and mean annual precipitation during 1951-2000. The water-budget model routes precipitation falling on each landscape unit to components of evapotranspiration, surface runoff, storage, and vertical percolation (recharge) for a five-layer soil column on a daily basis. The spatial distribution of mean annual recharge during 1951-2000 for each landscape unit was mapped by the use of a geographic information system. Recharge simulated by the water-budget model in Jordan Creek watershed during 1951-2000 averaged 12.3 inches per year and ranged by landscape unit from 0.11 to 17.05 inches per year. Mean annual recharge during 1951-2000 simulated by the water-budget model was most sensitive to changes to input values for precipitation and runoff-curve number. Mean annual recharge values for the crop, forest, pasture, and low-density urban land-use/land-cover classes were similar (11.2 to 12.2 inches per year) but were substantially less for high-density urban (6.8 inches per year), herbaceous wetlands (2.5 inches per year), and forested wetlands (1.3 inches per year). Recharge rates simulated for the crop, forest, pasture, and low-density urban land-cover classes were similar because those land-use/land-cover classes are represented in the model with parameter values that either did not significantly affect simulated recharge or tended to have offsetting effects on recharge. For example, for landscapes with forest land cover, values of runoff-curve number assigned to the model were smaller than for other land-use/land-cover classes (causing more recharge and less runoff), but the maximum depth of evapotranspiration was larger than for other land-use/ land-cover classes because of deeper root penetration in forests (causing more evapotranspiration and less recharge). The smaller simulated recharge for high-density urban and wetland land-use/land-cover classes was caused by the large values of runoff-curve number (greater than 90) assigned to those classes. The large runoff-curve number, however, certainly is not realistic for all wetlands; some wetlands act as areas of ground-water discharge and some as areas of recharge. Simulated mean annual recharge computed by the water-budget model for the 53-square-mile part of the watershed upstream from the streamflow-gaging station near Schnecksville was compared to estimates of recharge and base flow determined by analysis of streamflow records from 1967 to 2000. The mean annual recharge of 12.4 inches per year simulated by the water-budget method for 1967-2000 was less than estimates of mean annual recharge of 19.3 inches per year computed from the RORA computer program and base flow computed by the PART computer program (15.1 inches per year). In theory, the water-budget method provides a practical tool for estimating differences in recharge at local scales of interest, and the watershed- average recharge rate of 12.4 inches per year computed by the method is reasonable. However, the mean annual surface runoff of 4.5 inches per year simulated by the model is unrealistically small. The sum of surface runoff and recharge simulated by the water-budget model (16.9 inches per year) is 7 inches per year less than the streamflow measured at the gaging station near Schnecksville (23.9 inches per year) during 1967-2000, indicating that evapotranspiration is overestimated by the water-budget model by that amount. This discrepancy ca

Scientific Investigations Report↗

USGS2001

A geostatistical approach to predicting sulfur content in the Pittsburgh coal bed

The US Geological Survey (USGS) is completing a national assessment of coal resources in the five top coal-producing regions in the US. Point-located data provide measurements on coal thickness and sulfur content. The sample data and their geologic interpretation represent the most regionally complete and up-to-date assessment of what is known about top-producing US coal beds. The sample data are analyzed using a combination of geologic and Geographic Information System (GIS) models to estimate tonnages and qualities of the coal beds. Traditionally, GIS practitioners use contouring to represent geographical patterns of "similar" data values. The tonnage and grade of coal resources are then assessed by using the contour lines as references for interpolation. An assessment taken to this point is only indicative of resource quantity and quality. Data users may benefit from a statistical approach that would allow them to better understand the uncertainty and limitations of the sample data. To develop a quantitative approach, geostatistics were applied to the data on coal sulfur content from samples taken in the Pittsburgh coal bed (located in the eastern US, in the southwestern part of the state of Pennsylvania, and in adjoining areas in the states of Ohio and West Virginia). Geostatistical methods that account for regional and local trends were applied to blocks 2.7 mi (4.3 km) on a side. The data and geostatistics support conclusions concerning the average sulfur content and its degree of reliability at regional- and economic-block scale over the large, contiguous part of the Pittsburgh outcrop, but not to a mine scale. To validate the method, a comparison was made with the sulfur contents in sample data taken from 53 coal mines located in the study area. The comparison showed a high degree of similarity between the sulfur content in the mine samples and the sulfur content represented by the geostatistically derived contours. Published by Elsevier Science B.V.

International Journal of Coal Geology↗

USGS2009

Bathymetry and Sediment-Storage Capacity Change in Three Reservoirs on the Lower Susquehanna River, 1996-2008

The Susquehanna River transports a substantial amount of the sediment and nutrient load to the Chesapeake Bay. Upstream of the bay, three large dams and their associated reservoirs trap a large amount of the transported sediment and associated nutrients. During the fall of 2008, the U.S. Geological Survey in cooperation with the Pennsylvania Department of Environmental Protection completed bathymetric surveys of three reservoirs on the lower Susquehanna River to provide an estimate of the remaining sediment-storage capacity. Previous studies indicated the upper two reservoirs were in equilibrium with long-term sediment storage; only the most downstream reservoir retained capacity to trap sediments. A differential global positioning system (DGPS) instrument was used to provide the corresponding coordinate position. Bathymetry data were collected using a single beam 210 kHz (kilohertz) echo sounder at pre-defined transects that matched previous surveys. Final horizontal (X and Y) and vertical (Z) coordinates of the geographic positions and depth to bottom were used to create bathymetric maps of the reservoirs. Results indicated that from 1996 to 2008 about 14,700,000 tons of sediment were deposited in the three reservoirs with the majority (12,000,000 tons) being deposited in Conowingo Reservoir. Approximately 20,000 acre-feet or 30,000,000 tons of remaining storage capacity is available in Conowingo Reservoir. At current transport (3,000,000 tons per year) and deposition (2,000,000 tons per year) rates and with no occurrence of major scour events due to floods, the remaining capacity may be filled in 15 to 20 years. Once the remaining sediment-storage capacity in the reservoirs is filled, sediment and associated phosphorus loads entering the Chesapeake Bay are expected to increase.

Scientific Investigations Report↗

USGS2006

Organic Compounds and Trace Elements in Fish Tissue and Bed Sediment in the Delaware River Basin, New Jersey, Pennsylvania, New York, and Delaware, 1998-2000

As part of the National Water-Quality Assessment (NAWQA) program activities in the Delaware River Basin (DELR), samples of fish tissue from 21 sites and samples of bed sediment from 35 sites were analyzed for a suite of organic compounds and trace elements. The sampling sites, within subbasins ranging in size from 11 to 600 square miles, were selected to represent 5 main land-use categories in the DELR -forest, low-agricultural, agricultural, urban, and mixed use. Samples of both fish tissue and bed sediment were also collected from 4 'large-river' sites that represented drainage areas ranging from 1,300 to 6,800 square miles, areas in which the land is used for a variety of purposes. One or more of the organochlorine compounds-DDT and chlordane metabolites, polychlorinated biphenyls (total PCBs), and dieldrin- were detected frequently in samples collected over a wide geographic area. One or more of these compounds were detected in fish-tissue samples from 92 percent of the sites and in bed-sediment samples from 82 percent of the sites. Concentrations of total DDT, total chlordanes, total PCBs, and dieldrin in whole white suckers and in bed sediment were significantly related to urban/industrial basin characteristics, such as percentage of urban land use and population density. Semi-volatile organic compounds (SVOCs)-total polycyclic aromatic hydrocarbons (PAHs), total phthalates, and phenols- were detected frequently in bed-sediment samples. All three types of SVOCs were detected in samples from at least one site in each land-use category. The highest detection rates and concentrations typically were in samples from sites in the urban and mixed land-use categories, as well as from the large-river sites. Concentrations of total PAHs and total phthalates in bed-sediment samples were found to be statistically related to percentages of urban land use and to population density in the drainage areas represented by the sampling sites. The samples of fish tissue and bed sediment collected throughout the DELR were analyzed for a large suite of trace elements, but results of the analyses for eight elements-arsenic, cadmium, chromium, copper, lead, nickel, mercury, and zinc- that are considered contaminants of concern are described in this report. One or more of the eight trace elements were detected in samples from every fish tissue and bed-sediment sampling site, and all of the trace elements were detected in samples from 97 percent of the bed-sediment sites. The concentrations of organic compounds and trace elements in the DELR samples were compared to applicable guidelines for the protection of wildlife and other biological organisms. Concentrations of total DDT, total chlordanes, total PCBs, and dieldrin in fish-tissue samples from 14 sites exceeded one or more of the Wildlife Protective Guidelines established by the New York State Department of Environmental Conservation. Concentrations of one or more organic compounds in samples from 16 bed-sediment sites exceeded the Threshold Effects Concentrations (TEC) of the Canadian Sediment Quality Guidelines, and concentrations of one or more of the eight trace elements in samples from 38 bed-sediment sites exceeded the TEC. (The TEC is the concentration below which adverse biological effects in freshwater ecosystems are expected to be rare.) Concentrations of organic compounds in samples from some bed-sediment sites exceeded the Canadian Probable Effects Concentrations (PEC), and concentrations of trace elements in samples from 18 sites exceeded the PEC. (The PEC is the concentration above which adverse effects to biological organisms are expected to occur frequently). Concentrations of organic compounds and trace elements in samples from the DELR were compared to similar data from other NAWQA study units in the northeastern United States and also data from the Mobile River (Alabama) Basin and the Northern Rockies Intermontane Basin study units. Median concentrations of to

Scientific Investigations Report↗

USGS2015

Modeling the present and future geographic distribution of the Lone star tick, Amblyomma americanum (Ixodida: Ixodidae ), in the continental United States

The Lone star tick ( Amblyomma americanum L.) is the primary vector for pathogens of significant public health importance in North America, yet relatively little is known about its current and potential future distribution. Building on a published summary of tick collection records, we used an ensemble modeling approach to predict the present-day and future distribution of climatically suitable habitat for establishment of the Lone star tick within the continental United States. Of the nine climatic predictor variables included in our five present-day models, average vapor pressure in July was by far the most important determinant of suitable habitat. The present-day ensemble model predicted an essentially contiguous distribution of suitable habitat extending to the Atlantic coast east of the 100th western meridian and south of the 40th northern parallel, but excluding a high elevation region associated with the Appalachian Mountains. Future ensemble predictions for 2061–2080 forecasted a stable western range limit, northward expansion of suitable habitat into the Upper Midwest and western Pennsylvania, and range contraction along portions of the Gulf coast and the lower Mississippi river valley. These findings are informative for raising awareness of A. americanum -transmitted pathogens in areas where the Lone Star tick has recently or may become established.

American Journal of Tropical Medicine and Hygiene↗

USGS1877

Geology of the Henry Mountains

If these pages fail to give a correct account of the structure of the Henry Mountains the fault is mine and I have no excuse. In all the earlier exploration of the Rocky Mountain Region, as well as in much of the more recent survey, the geologist has merely accompanied the geographer and has had no voice in the determination of either the route or the rate of travel. When the structure of a mountain was in doubt he was rarely able to visit the points which should resolve the doubt, but was compelled to turn regretfully away. Not so in the survey of the Henry Mountains. Geological exploration had shown that they were well disposed for examination, and that they promised to give the key to a type of structure which was at best obscurely known; and I was sent by Professor Powell to make a study of them, without restriction as to my order or method. I was limited only in time, the snow stopping my work two months after it was begun. Two months would be far too short a period in which to survey a thousand square miles in Pennsylvania or Illinois, but among the Colorado Plateaus it proved sufficient. A few comprehensive views from mountain tops gave the general distribution of the formations, and the remainder of the time was spent in the examination of the localities which best displayed the peculiar features of the structure. So thorough was the display and so satisfactory the examination, that in preparing my report I have felt less than ever before the desire to revisit the field and prove my conclusions by more extended observation.

Utah↗

USGS2005

Development and analysis of regional curves for streams in the non-urban valley and ridge physiographic province, Maryland, Virginia, and West Virginia

Regression relations for bankfull stream characteristics based on drainage area (often called 'regional curves') are used in natural stream channel design to verify field determinations of bankfull discharge and stream channel characteristics. Bankfull stream characteristics were assessed for stream reaches at 41 streamflow-gaging stations in the Valley and Ridge Physiographic Province in Maryland, Virginia, and West Virginia. Data collected included bankfull cross-sectional geometry, flood plain geometry, and longitudinal profile data. In addition, particle-size distributions of streambed material were determined and data on basin characteristics were compiled for each reach. Regional curves were developed for bankfull cross-sectional area, width, and discharge with R2 values of 0.95, 0.89, 0.87, and 0.91, respectively. Examination of the regional curves residuals indicates that there is more variability in bankfull cross-sectional area, width, and discharge for smaller streams than for larger streams. In contrast, there is more variability for bankfull mean depth for larger streams than for smaller streams. Geographic analysis of regional curve residuals indicated that there were no further subdivisions within the Valley and Ridge Physiographic Province in the three-state study area for which individual sets of regional curves should be developed. In addition, two separate sets of regional curves were developed with data from the 41 sites to examine potential differences in the relations between the southern (n = 9) and central (n = 32) sections of the province. There were differences in slope and intercept between the two bankfull discharge test relations and a difference in intercept for the width test relations at the 95-percent confidence level. However, the results of this analysis were inconclusive and therefore one set of regional curves for the study area is presented in this report. The regional curves were compared to regression models developed from similar data collected in the Pennsylvania and Maryland portions of the province. No statistical difference in the slope or intercept of regression lines of the three data sets was detected for any of the four bankfull parameters at the 95-percent confidence level. Basin characteristics such as percentage of basin forested (percent forested) and percentage of basin underlain by carbonate bedrock (percent carbonate) were analyzed to evaluate variability among regression points. Multivariate regression relations including explanatory terms for percent carbonate and drainage area produced higher R2 values than the regional curves for bankfull cross-sectional area (R2 = 0.95), bankfull width (R2 = 0.92), and bankfull discharge (R2 = 0.93). There was no improvement for the bankfull mean depth relation from adding the additional term. Inclusion of the other basin characteristics in multivariate relations did not improve the regression models. Regression models developed for the 1.5-year discharge for all streamflow-gaging stations with peak discharge data throughout Virginia (n = 486) and throughout the Valley and Ridge Physiographic Province in Virginia (n = 147) were compared to the regional curve relating bankfull discharge to drainage area. A similar trend in decreasing variability with increasing drainage area was observed for the 1.5-year discharge for all stations in Virginia . This indicates that the change in variability observed in the discharge regional curve likely would exist with a larger data set. There was no statistical difference at the 95-percent confidence level between regression relations for the southern section of the province (n = 40) and the central section (n = 107). This finding supports maintaining only one set of regional curves for the study area. Not all of the variability in the regional curves is explained by drainage area alone. Causes of the remaining variability likely vary among study sites. Users of the regional curves developed in this study are cautioned that, because of inherent variability in hydrologic data, a thorough analysis of the fluvial system and the drainage basin is necessary when evaluating the bankfull characteristics of a stream.

Maryland, Virginia, West Virginia↗