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At least 415 records · Page 23Linked to original sources
USGS2019

It is raining plastic

Atmospheric deposition samples were collected using the National Atmospheric Deposition Program / National Trends Network (NADP/NTN) at 6 sites in the Denver-Boulder urban corridor and 2 adjacent sites in the Colorado Front Range. Weekly wet-only atmospheric deposition samples collected at these sites during winter-summer of 2017 were filtered (0.45 micrometers, polyethersulfone) to obtain particulates washed from the atmosphere (washout). Plastics were identified on over 90 percent of the filters. The plastic materials are mostly fibers that are only visible with magnification (~40X). Fibers were present in a variety of colors; the most frequently observed color was blue followed by red > silver > purple > green > yellow > other colors. Plastic particles such as beads and shards were also observed with magnification. More plastic fibers were observed in samples from urban sites than from isolated, montane sites. However, frequent observation of plastic fibers in washout samples from the isolated Loch Vale site in Rocky Mountain National Park (elevation 3,159 meters) suggests that wet-deposition of plastic is ubiquitous and not just an urban condition. The mass of plastic in even the most concentrated samples was not large enough to weigh or reliably estimate. Developing a routine capability to calculate plastic wet-deposition loads is not possible with current technology. Counting plastic fibers under a microscope and multiplying the counts by a mean mass per fiber might be possible, but it is tedious, expensive, and has large inherent error. A means to estimate the recovery of the plastic materials from the NADP samples is needed. However, saving the NADP filters for subsequent analysis would make a washout deposition network possible with very little added expense, and methods could be developed to more accurately estimate plastic loads using the NTN. It is unclear how these plastic materials are accumulating and being assimilated in the environment and biota. Moreover, the potential effects of these materials on biota is not understood.

Colorado↗
USGS2022

Compilation and evaluation of data used to identify groundwater sources under the direct influence of surface water in Pennsylvania

A study was conducted to compile and evaluate data used to identify groundwater sources that are under the direct influence of surface water (GUDI) in Pennsylvania. In the early 1990s, the Pennsylvania Department of Environmental Protection (PADEP) implemented the Surface Water Identification Protocol (SWIP) for the identification of GUDI sources. Since the establishment of the SWIP, PADEP has classified more than 500 individual sources across Pennsylvania as GUDI, but Pennsylvania’s complex geology and physiography provide a challenge for a uniform method of GUDI determination. Components used in this study to compile and evaluate data associated with GUDI determination include: (1) a preliminary review of file information for 43 public water-supply wells, (2) quality control and addition of data to PADEP’s database for public water-supply systems to prepare data for analysis, and (3) exploratory evaluation of existing GUDI sources in the database with respect to hydrogeologic and source-construction characteristics that are currently utilized in the assessment methodology. Case files for 43 wells from PADEP’s Northcentral and Southcentral regions were reviewed to: (1) provide a better understanding of how the SWIP was applied in practice, (2) verify and compile missing data, and (3) find additional attributes not previously available that might explain a well’s categorization as GUDI. Review of file information showed that the SWIP outlined in PADEP technical guidance was usually followed, but for some sources, the GUDI determination was more complex and could not be easily summarized. Data compiled for study analyses provided by PADEP include source data derived from public water-supply system case files, a source-information database for public water-supply systems, and Microscopic Particulate Analysis (MPA) results and associated water-quality data for public water-supply system groundwater sources. Data from the Pennsylvania Drinking Water Information System (PADWIS) , which is PADEP’s database for public water-supply systems, were also used for this study. The PADWIS database originally included data for 12,147 groundwater sources (11,812 groundwater sources not under the direct influence of surface water (non-GUDI) wells and 335 GUDI wells). A subset (4,018 wells consisting of 3,842 non-GUDI wells and 175 GUDI wells) of the PADWIS database was created for an analysis and includes only community wells evaluated in accordance with the SWIP. MPA results for 631 community and noncommunity wells were compiled, along with associated water-quality data (alkalinity, chloride, Escherichia coli , fecal coliform, nitrate, pH, sodium, specific conductance, sulfate, total coliform, total dissolved solids, total residue, and turbidity) populated from the PADEP Bureau of Laboratories Sample Information System. Data compiled from sources other than PADEP include spatial data, both naturogenic (for example, average precipitation or distance to closest hydrologic feature) and anthropogenic (for example, percentage of developed or agricultural land cover within a specific vicinity of a public water-supply system well) data representing spatially derived variables. Comparison among wells in the PADWIS dataset subset using the nonparametric Kruskal-Wallis test showed that GUDI wells had significantly older median construction years, shallower depths, and static water levels closer to the land surface than non-GUDI wells and that carbonate aquifers had the highest percentages of wells designated as GUDI (12 percent; 57 wells). Further comparison of wells in the PADWIS database subset using the Spearman’s rho monotonic correlation test illustrated that public water-supply wells designated as GUDI largely occur in unconfined aquifers and have high average yield and shallow static water levels. Assessment of the MPA database subset using the Kruskal-Wallis test showed wells with MPA total risk-factor scores that exceeded zero had older median construction years and shallower casing depths than wells with MPA total risk-factor scores of zero and that carbonate aquifers had the highest percentages of wells with MPA total risk-factor scores exceeding zero (30 percent; 63 wells). Spearman’s rho correlations showed that wells completed in aquifers with depths to major water-bearing zones closer to the land-surface had higher total risk-factor scores resulting from MPA samples. Based on the results of the analyses described in this report, broad conclusions can be drawn regarding site-specific well characteristics as well as anthropogenic and naturogenic factors that could be responsible for a well being designated as GUDI, but the accuracy of these results is dependent on the quality of the data being analyzed. Ultimately, study results serve as an added resource for initial desktop screening of wells to determine if additional site-specific investigation is warranted and underscore the need for field evaluation.

Pennsylvania↗
USGS2025

Characterizing Meteor Crater impact melts through geochemistry and textural analysis

The U.S. Geological Survey Astrogeology Science Center houses the Meteor Crater sample collection, an assemblage of over 2,500 meters of cuttings from 161 drill holes into Meteor Crater’s rim, flanks, and ejecta blanket. We have utilized this unique collection to study the composition and spatial distribution of impact-generated materials from within the ejecta blanket. Meteor Crater has historically been known to have generated only a relatively small amount of impact melt compared to other terrestrial craters of similar size. A detailed compositional and textural dataset of impact-derived melts from this impact can therefore be a useful asset in improving our understanding of crater formation, and in particular impact melt formation. We have characterized 42 impact-melt particles from Meteor Crater using a scanning electron microscope and an electron microprobe for textural and compositional analysis. We analyzed samples from six drill holes in the ejecta blanket, situated to the northwest, southeast, south, and southwest of the crater (ejecta northeast of the crater is devoid of impact melts). Impact melts were collected from drill cuttings at various depths within the ejecta blanket, ranging from a few centimeters below the surface down to ~6.5 meters. Backscattered electron (BSE) images were acquired for each analyzed impact-melt particle. To characterize the various textures and phases present in each impact melt, we also took many detailed BSE images. Our geochemical analyses include full spectral profiles using energy dispersive X-ray spectrometry and well-calibrated wavelength dispersive spectrometry for a number of phases, including minerals (olivine, pyroxene, and so on), pristine glass, and metallic inclusions. The full dataset is available in ScienceBase as a data release (Gullikson and others, 2024), accessible at https://doi.org/10.5066/P9OGAJ8P . Our goal for this Open-File Report is to provide a summary of this immense dataset, details on data collection, descriptions of the different phases observed within impact-melt particles (both geochemically and texturally), and observable trends.

Arizona↗
USGS1953

Descriptive logs of exploratory holes drilled during 1952 by the U.S. Geological Survey in Dubuque County, Iowa

The exploratory holes were drilled as part of a larger geologic investigation, the objective of which is to determine in the Dubuque, Iowa, area the probable occurrence of zinc and lead ore stratigraphically lower than that which has been mined. The primary purpose of the drilling was to supply information required for geologic mapping in upland areas where bedrock exposures are sparse or absent. Where possible, the doles were located also on the extension of known mineralized trends. Seven holes aggregating 1,687 feet were drilled with cable tools. Descriptive logs, prepared by A. E. Flint and C. E. Brown frog binocular microscope study of cuttings that were recovered from the drilling, are accompanied by assay values of significant mineralized samples. Index maps show hole locations.

Iowa↗
USGS1956

Drilling data in the Montfort, Rewey, Mifflin, Belmont, and Calamine quadrangles, Wisconsin

Sixty-six churn drill holes aggregating 10,351 feet were drilled in the fall of 1955 in the zinc-lead district of southwestern Wisconsin (fig. 1). This drilling was part of a cooperative program of geologic mapping by the U. S. Geological Survey and the Wisconsin Geologic and Natural History Survey. The holes penetrate the Maquoketa, Galena, Decorah, and Platteville formations of Late and Middle Ordovician age in areas of sparse outcrop and subsurface information. They provide basic data for stratigraphic study and for the projection of geologic structures in these areas. Exact location of the holes is shown in figs. 2, 3, 4, 5, and 6. Generalized descriptive logs of the 66 holes were prepared mainly from driller's logs, and from a field study of the drill cuttings by J. E. Carlson. Where delineation of the formations drilled was difficult in the field, the cuttings were examined by binocular microscope.

Wisconsin↗
USGS1958

The geology of the Bishop 15-minute quadrangle, California

The purpose of the study of the Bishop 15-minute quadrangle in east-central California was to appraise the mineral resources and to delineate and interpret the stratigraphic and structural history of the area. A report on the mineral resources has been published and the emphasis here is on stratigraphy and structure. About 8 months were spent in field study, and several months were spent in the office and laboratory compiling and analyzing data and in microscopic study.

Open-File Report↗
USGS1958

Origin of manganese deposits of Busuanga Island, Philippines

The manganese deposits of Busuanga Island, Palawan, are tabular and broadly lenticular bodies which lie conformably within a thick sequence of deformed abort beds. The purpose of this study is to determine the probable mode of origin of the deposits. Similar deposits in other parts of the world have been described by others as products of several different genetic processes. Field and laboratory methods of research were employed in the course of the investigation. Detailed geologic mapping was done on the surface and underground, and many samples of rocks and ores were obtained. Later, intensive study of samples from four typical deposits and from the rooks in the surrounding areas was undertaken, using a variety of laboratory techniques. Microscopic study of thin sections and polished surfaces was supplemented by X-ray and chemical work. More than one hundred X-ray diffraction powder photographs were made to identify minerals, and qualitative chemical studies were made of a number of aamples by use of the X-ray spectrograph. In addition, quantitative chemical analyses were made of certain samples. Finally, published accounts of the occurrence and geological behavior of manganese and silica were consulted to aid in interpretation of the data at hand. Oherty layers in the manganese deposits are lithologically similar to the chart wallrooks and country rook beds. Radiolarian fossils are common in the chart and are also found in some ore specimens. Manganese content of the wallrocks and the country rock beds, however, in essentially nil. The manganese deposits contain mostly psilomelane-type oxides in their near-surface parts, and in the deepest mines this ore grades downward into siliceous protore. In three of the deposits studied, the protore consists mainly of braanite and quartz; in the fourth deposit, hausmannite and the silicate alleghatvite make up the milk of the protore. Some of the protoro is massive, but cherty stones are commonly well layered parallel to the wall rock structure. Grain size is very small, but, like the silica in the chert beds, becomes relatively coarse where the rocks are much deformed. No evidence of large-scale replacement or cross-cutting veins is found in the protores. It is concluded that the original manganiferous deposits were largely non-clastic or oolloidal marine sediments laid down in a reducing environment. The protorea were developed from these beds by processes of diagenesis and low-grade regional metamorphism. The protores were in turn altered to black oxide ore by near-surface agencies during the present erosion cycle. Particular interest is attached to the occurrence of alleghanyite and traces of pyroxmangite and hubnerite(?) in the protorea.

Busuanga Island↗
USGS1971

Geology of the Stroudsburg quadrangle and Adjacent areas, Pennsylvania--New Jersey

The Stroudsburg area is within the Valley and Ridge and Great Valley physiographic provinces, Northampton and Monroe Counties, Pennsylvania, and Warren County, New Jersey. The northeast-trending subparallel valleys and ridges resulted from erosion of folded heterogeneous sedimentary rocks. These are Middle Ordovician to Middle Devonian in age and are more than 17,000 feet thick. Deposition of a thick flysch sequence (Martinsburg Formation of Ordovician age) accompanied onset of Taconic orogenesis. It was followed by deposition of a thick molasse sequence of Silurian and Early Devonian age (continental and marginal-marine clastics--Shawangunk Formation and Bloomsburg Red Beds--overlain by predominantly marginal-marine and subtidal limestone, dolomite, shale, and sandstone--Poxono Island Formation through Oriskany Group). Basin deepening and gradual shallowing occurred during Esopus through Mahantango deposition, heralding the Acadian clastic wedge exposed north of the Stroudsburg area. Interpretation of sedimentary structures and regional stratigraphic relations suggest that the Silurian and Devonian rocks were deposited in the following environments: A1luviated coastal plain (meandering and braided streams), tidal flats (supratidal and intertidal), barrier zone, and neritic zone (upper and lower). The rock stratigraphic units have been grouped into four lithotectonic units, each having a different style of deformation. Folds produced in these rocks are disharmonic, and it is believed that each rock sequence is set off from units above and below by decollements, or zones of detachment. Movement was northwest into the Appalachian basin, primarily by gravitational sliding. The contact between the Shawangunk Formation of Silurian age and Martinsburg Formation of Ordovician age, is one zone of detachment as well as an angular unconformity. Deformational effects of the Middle to Late Ordovician Taconic orogeny are elusive, but it appears that the folds and most minor structures, including the prominent regional cleavage, were produced during the late Paleozoic Appalachian orogeny and are superimposed upon larger Taconic folds and faults. Field relations and microscopic study suggest that the regional cleavage in the Stroudsburg area is due to laminar flow of pelitic material along cleavage folia accompanied by mechanical reorientation of platy and elongate minerals and neocrystallization of mica, quartz, chlorite, and probably albite. Numerous lines of evidence point to the conclusion that cleavage developed after the rock was indurated and formed at, and Just below, conditions of low-grade metamorphism. Intensity of cleavage development increases to the southeast across the area. Second-generation slip cleavage, also believed to be Appalachian in age, formed by mechanical reorientation of minerals as well as by limited new mineral growth. The topography had a profound effect on the direction of movement of the Wisconsin glacier, as well as the manner of its retreat and the deposits that were formed. Till and stratified drift of Wisconsin age and till of Illinoian(?) age are common in the area. Wisconsin deglaciation occurred by northeastward retreat and by stagnation. A conspicuous terminal moraine marks the limit of Wisconsin ice movement. Lake Sciota was dammed between the retreating ice, the moraine, and the surrounding ridges north of Godfrey Ridge. Several deltas mark ice stand positions during the retreat of the ice. Lake-bottom and kame deposits are locally common in Cherry Valley. South of Kittatinny Mountain, on the other hand, melt water was freely discharged to the south. The wind and water gaps in the Stroudsburg area (including Delaware Water Gap and Wind Gap) are structurally controlled; specifically they are located where folds die out in short distances, where folding is locally more intense, or where resistant rocks dip steeply and have a narrow width of outcrop. This conclusion is contrary to

Open-File Report↗
USGS1977

Image analysis as a method for determining grain-size distributions in sandstones

A Quantimet 720 image analyzing computer is useful for A Quantimet 720 image analyzing computer is useful for determination of grain-size distributions of sand-size material. Results including histograms and statistical measures of size can be produced in approximately 5 to 10 minutes per sample. Comparison with sieve results shows only small differences in the mean grain-sizes obtained. Research into operating methods for the image analyzing computer and into mathematical methods for combining data is continuing so that material coarser and finer than sand can be measured. The instrument, which is attached to a microscope via a black and white television scanner, uses the gray shades of features in the field of view as the means of detecting those features. The image analyzing computer can then measure the features including area, perimeter, and several types of diameters. These data are then analyzed by a computer and the results are plotted. Sample preparation for this technique is conventional. Samples can be run as loose disaggregated grains, grain mounts, or thin sections.

Open-File Report↗
USGS1979

Mineral resources of the Citico Creek Wilderness Study Area, Monroe County, Tennessee

The proposed Citico Creek Wilderness comprises about 5,670 hectares (56.7 km2) in the Cherokee National Forest south of the Little Tennessee River in easternmost Monroe County, Tennessee. Principal drainages are Citico Creek and Doublecamp Creek. Rocks of the study area include greenschist-facies arkosic metasandstone, metagraywacke, slate, and metaconglomerate of the Great Smoky Group of late Precambrian age. Minor deposits of unconsolidated Quaternary alluvium locally mantle the bedrock. Deformation is shown by asymmetric and overturned folds and by several major faults. More than 500 sample s of soil, rock, and stream sediment were collected and analyzed for 31 major, minor, and trace elements by semiquantitative spectrographic, atomic absorption, and fire assay methods No significant metal anomalies were detected. Concentrations of Cu, Co, As, Pb, and Zn slightly higher than background are found within sulfidic parts of a distinctive stratigraphic unit composed of graphitic slate and metagraywacke. Pyrite and pyrrhotite are the chief sulfide minerals, with traces o f accessory sphalerite, chalcopyrite, galena, and arsenopyrite occurring as microscopic intergrowths. A reconnaissance ground radiometric survey and subsequent neutron activation analyses of selected radioactive rock samples show that the sulfidic parts of the graphitic slate unit have a relatively high content of Th and U, but are not potentially economic. No metallic mineral resources appear to exist within the Citico Creek Wilderness Study Area. Resources of slate, silica, and stone are present, but they display no special qualities to differentiate them from other such material throughout the region. Ceramic evaluation tests on selected samples of slate indicate that the slate would have only marginal use for structural clay products such as brick and tile. Minor sand and gravel deposits occur along a few streams but are present in larger quantities and are more easily recovered in other areas.

Tennessee↗
USGS1979

Metals in Devonian kerogenous marine strata at Gibellini and Bisoni properties in southern Fish Creek Range, Eureka County, Nevada

A kerogen-rich sequence of siliceous mudstone, siltstone, and chert as much as 60 m thick on ridge 7129 in the southern Fish Creek Range, referred to as Gibellini facies of the Woodruff Formation, has been evaluated on the surface and in drill holes principally for its potential resources of vanadium, zinc, selenium, molybdenum, and syncrude oil content. The strata are part of a strongly deformed allochthonous mass of eugeosynclinal Devonian marine rocks that overlie deformed allochthonous Mississippian siliceous rocks and relatively undeformed autochthonous Mississippian Antler flysch at this locality. The vanadium in fresh black rocks obtained from drill holes and fresh exposures in trenches and roadcuts occurs chiefly in organic matter. Concentrations of vanadium oxide (V2O5) in unoxidized samples range from 3,000 to 7,000 ppm. In oxidized and bleached rock that is prevalent at the surface, concentrations of vanadium oxide range from 6,000 to 8,000 ppm, suggesting a tendency toward enrichment due to surficial weathering and ground-water movement. Zinc occurs in sphalerite, and selenium occurs in organic matter; molybdenum appears to occur both in molybdenite and in organic matter. Concentrations of zinc in unoxidized rock range from 4,000 to 18,000 ppm, whereas in oxidized rock they range from 30 to 100 ppm, showing strong depletion due to weathering. Concentrations of selenium in unoxidized rock range from 30 to 200 ppm, whereas in oxidized rock they range from 200 to 400 ppm, indicating some enrichment upon weathering. Concentrations of molybdenum in unoxidized rock range from 70 to 960 ppm, whereas in oxidized rock they range from 30 to 80 ppm, indicating strong depletion upon weathering. Most fresh black rock is low-grade oil shale, and yields as much as 12 gallons/short ton of syncrude oil. Metahewettite is the principal vanadium mineral in the oxidized zone, but it also occurs sparsely as small nodules and fillings of microfractures in unweathered strata. In fresh rock, bluish-white opaline-like silica (chalcedonic quartz) fills microfractures, and is believed to have originated by diagenetic mobilization of opaline silica from radiolarian tests and sponge spicules. As revealed by microscopic study, the Gibellini facies originally consisted of siliceous muds, slimes, and oozes high in organic constituents. The organic matter is amorphous flaky and stringy sapropel, and probably includes remains of bacteria, phytoplankton, zooplankton, and minor higher plants. Recognizable organic remnants include radiolarian tests, sponge spicules, conodonts, brachiopod shells, algae, and humic debris. Diagnostic radiolarians indicate a Late Devonian age for the Gibellini facies of the Woodruff Formation. Some pyrite is disseminated through the rock and may be primary (syngenetic) but significant pyrite and marcasite occur in chalcedonic quartz veinlets and appear to be diagenetic. In fresh rock, black solid bitumen and liquid oil fill voids and microfractures. These early phase hydrocarbons probably were released during diagenesis from complex nonhydrocarbon molecular structures originating from living organisms, and formed without any major thermal degradation of the kerogen. Gas chromatographic analysis of the saturated hydrocarbon fraction indicates a very complex mixture dominated by branched and cyclic compounds. Conodont and palynomorph color alteration, vitrinite reflectance, and other organic geochemical data suggest that the organic matter in the rock is thermally immature and has not been subjected to temperatures greater than 60?C since deposition in Devonian time. All of these characteristics are consistent with the interpretation of a relatively low temperature and a shallow-burial history for the Gibellini facies on ridge 7129.

Open-File Report↗
USGS1980

Lithologic log of drill cuttings for DOGAMI heat flow hole CR-SB, Mount Hood, Oregon

CR-SB is one of three shallow (-82.0 m) heat flow holes drilled in 1976 at Mount Hood, Oregon by the Oregon Department of Geology and Mineral Industries (DOGAMI). Drill hole CR-SB was located on the southern flank of the mountain near the Snow Bunny ski lodge at an elevation of 1167.7 m (T 3 S, R 8.5 E, Sec. 25 AA) (Fig. 1). Temperatures, measured at 5.0 m intervals, and geothermal gradient data for the drill hole are given in Hull, Blackwell, and Black (1978) and are reproduced in Table 1 and Figures 2 and 3 in this report. Blackwell and Steele (1979) give an average thermal conductivity, based upon 6 samples of drill cuttings, of 4.53 (standard error =0.26) but indicated that the data obtained from the drill hole are unsuitable for heat flow calculations. Splits of the drill cuttings were obtained courtesy of J. F. Riccio (DOGAMI). The drill cuttings were wet sieved through a 200 mesh (0.074 mm) screen and both fractions were air dried and saved. Representative rock types and alteration material were hand-picked from the coarse fraction using a binocular microscope. Slurry slides of finely-ground cuttings were routinely run at 1/2°/min. from 3° to 37° 20 using unfiltered CuK radiation on a Norelco 1/ X-ray diffractometer equipped with a focusing monochrometer.

Oregon↗
USGS1982

Leaching characteristics of ash from the May 18, 1980, eruption of Mount St. Helens Volcano, Washington

Leaching of freshly erupted air-fall ash, unaffected by rain, from the May 18, 1.980,eruption of Mount St. Helens volcano, Washington, shows that Ca 2+, Na+, Mg+, SO4 2-, and Cl- are the predominant chemical species released on first exposure of the ash to water. Extremely high correlation of Ca with SO4 and Na with Cl in water leachates suggests the presence of CaSO4 and NaCl salts on the ash. The amount of water soluble material on ash increases with distance from source and with the weight fraction of small (less than 63 micrometers) ash particles of high-surface area. This suggests that surface reactions such as adsorption are responsible for concentrating the soluble material. CaSO4, NaCl, and other salts are probably formed as microscopic crystals in the high-temperature core of the eruption column and are then adsorbed by silicate ash particles. The environmentally important elements Zn, Cu, Cd, F, Pb, and Ba are released by a water leach in concentrations which could pose short-term hazards to some forms of aquatic life. However, calculated concentrations are based on a water-to-ash ratio of 4:1 or less, which is probably an underestimation of the regionally operative ratio. A subsequent leach of ash by warm alkaline solution shows dramatic increases in the amount of dissolved SiO2, U, and V, which are probably caused by increased dissolution of the glassy component of ash. Glass dissolution by alkaline ground water is a mechanism for providing these three elements to sedimentary traps where they may co-accumulate as uraniferous silica or U-V minerals. Leaching characteristics of ash from Mount St. Helens are comparable to characteristics of ash of similar composition from volcanoes in Guatemala. Ashes from each locality show similar ions predominating for a given leachate and similar fractions of a particular element in the ash removed on contact with the leach solution.

Open-File Report↗
USGS1989

XAP, a program for deconvolution and analysis of complex X-ray spectra

The X-ray analysis program (XAP) is a spectral-deconvolution program written in BASIC and specifically designed to analyze complex spectra produced by energy-dispersive X-ray analytical systems (EDS). XAP compensates for spectrometer drift, utilizes digital filtering to remove background from spectra, and solves for element abundances by least-squares, multiple-regression analysis. Rather than base analyses on only a few channels, broad spectral regions of a sample are reconstructed from standard reference spectra. The effects of this approach are (1) elimination of tedious spectrometer adjustments, (2) removal of background independent of sample composition, and (3) automatic correction for peak overlaps. Although the program was written specifically to operate a KEVEX 7000 X-ray fluorescence analytical system, it could be adapted (with minor modifications) to analyze spectra produced by scanning electron microscopes, electron microprobes, and probes, and X-ray defractometer patterns obtained from whole-rock powders.

Open-File Report↗
USGS1995

Origin of water that discharges from Calf Creek Spring, Garfield County, Utah

Calf Creek Spring provides drinking water to users of Calf Creek Campground, which is operated by the Bureau of Land Management in southcentral Utah. Use of all methods and tools available indicates that surface water from Calf Creek does not contribute to the discharge of Calf Creek Spring. Microscopic Particulate Analysis of spring water indicates that the spring has a low risk of surface-water contamination, which is substantiated by a bacterial test of water from the point of discharge of Calf Creek Spring, the Calf Creek Spring collection box, a tap from the water distribution system, and Calf Creek near the picnic area. Bacteria colonies were found in Calf Creek near the picnic area. Calf Creek Spring discharges from fractured Navajo Sandstone where the potential for contamination by animal or human microbes is slight. Calf Creek probably gains water along its entire length from the aquifer in the Navajo Sandstone. Once at the surface, water in Calf Creek is exposed to animal- and human-borne microbes. If the water level in the Navajo aquifer at the spring remains higher than the water level of the creek, mixing is unlikely to occur and contamination is unlikely. The water level of Calf Creek Spring in June 1994 was at least 4 feet above the water level of Calf Creek. Water from Calf Creek Spring is a mixed type composed of magnesium, calcium, sodium, bicarbonate, and sulfate ions, and water from Calf Creek is a mixed type composed of calcium, magnesium, bicarbonate, sulfate, and chloride ions. Compositional similarity is not unusual if both water sources are derived from the Navajo aquifer. Discharge and temperature measurements at the spring and in the creek in May and June 1994 vary independently and do not indicate a hydraulic connection. Turbidity measurements, though not conclusive, indicate that no direct hydraulic connection exists between Calf Creek and Calf Creek Spring. Hydrologic characteristics of Calf Creek provide evidence that the probable long-term, sustainable source of water is the Navajo aquifer and not precipitation-derived runoff. Ground-water leakage from adjacent drainages could contribute to perennial flow in Calf Creek. Fractures modify the movement of ground water to discharge areas, such as Calf Creek Spring.

Utah↗
USGS1998

MORPH-I (Ver 1.0) a software package for the analysis of scanning electron micrograph (binary formatted) images for the assessment of the fractal dimension of enclosed pore surfaces

MORPH-I is a set of C-language computer programs for the IBM PC and compatible minicomputers. The programs in MORPH-I are used for the fractal analysis of scanning electron microscope and electron microprobe images of pore profiles exposed in cross-section. The program isolates and traces the cross-sectional profiles of exposed pores and computes the Richardson fractal dimension for each pore. Other programs in the set provide for image calibration, display, and statistical analysis of the computed dimensions for highly complex porous materials. Requirements: IBM PC or compatible; minimum 640 K RAM; mathcoprocessor; SVGA graphics board providing mode 103 display.

Open-File Report↗
USGS1977

Paleozoic-Mesozoic boundary in the Berry Creek Quadrangle, northwestern Sierra Nevada, California

Structural and petrologic studies in the Berry Creek quadrangle at the north end of the western metamorphic belt of the Sierra Nevada have yielded new information that helps in distinguishing between the chemically similar Paleozoic and Mesozoic rocks. The distinguishing features are structural and textural and result from different degrees of deformation. Most Paleozoic rocks are strongly deformed and thoroughly recrystallized. Phenocrysts in meta volcanic rocks are granulated and drawn out into lenses that have sutured outlines. In contrast, the phenocrysts in the Mesozoic metavolcanic rocks show well-preserved straight crystal faces, are only slightly or not at all granulated, and contain fewer mineral inclusions than do those in the Paleozoic rocks. The groundmass in the Paleozoic rocks is recrystallized to a fairly coarse grained albite-epidote-amphibole-chlorite rock, whereas in the Mesozoic rocks the groundmass is a very fine grained feltlike mesh with only spotty occurrence of well-recrystallized finegrained albite-epidote-chlorite-actinolite rock. Primary minerals, such as augite, are locally preserved in the Mesozoic rocks but are altered to a mixture of amphibole, chlorite, and epidote in the Paleozoic rocks. In the contact aureoles of the plutons, and within the Big Bend fault zone, which crosses the area parallel to the structural trends, all rocks are thoroughly recrystallized and strongly deformed. Identification of the Paleozoic and Mesozoic rocks in these parts of the area was based on the continuity of the rock units in the field and on gradual changes in microscopic textures toward the plutons.

Professional Paper↗