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At least 703 records · Page 39Linked to original sources
USGS1992

Distribution and characteristics of a Middle Ordovician oolitic ironstone in northeastern Kansas based on petrographic and petrophysical properties: A Laurasian ironstone case study

The margins of Gondwana are generally considered to be the major sites of oolitic ironstone production during the Ordovician, and appear to be linked with global eustatic sea-level rise. Occurrences of oolitic ironstones within the North American craton are less well documented, but provide important supplementary data. The low latitude of Laurasia contrasted with Gondwana allows useful comparisons of climatic and temporal patterns of Ordovician ironstone formation. Middle Ordovician ironstones occur in siliciclastic sequences in the American mid-continent and appear to become progressively younger as the epicontinental sea advanced from the southwest across a predominantly carbonate terrain. In northeastern Kansas, the regional distribution pattern of primary, syndiagenetic goethite iron oolites within the St. Peter Sandstone indicate deposition peripheral to a north-northeast-trending chain of islands underlain by predominantly granitic rocks, located along an ancestral Nemaha uplift. Detailed compositional mapping in the subsurface was made possible by the distinctive petrophysical properties of the goethite zone and the extensive regional control of wireline-logged exploration wells. Petrographic data from ironstone core- and drill-cuttings both validate log analysis and give insights on possible modes of genesis. We propose that eustatic changes in sea level were the primary factor governing the formation and observed distribution patterns of the oolite bed(s). The relationship of the observed occurrence patterns to major rift-related faults of the Central North American Rift system suggests that synsedimentary tectonism also influenced this process. The most likely source of iron appears to be by derivation from intensive, humid weathering of granite exposed extensively on the ancestral Nemaha uplift archipelago.

Kansas↗
USGS2014

The need for a nation‐wide program of observation‐wells

During the severe droughts of recent years almost the only water‐supplies available throughout large areas of the United States have been those obtained from underground sources. Consequently, a great interest has developed in the ground‐water resources of the country and there has been much concern lest the declining water‐levels in wells and the diminished flow of springs may be warnings of the ultimate exhaustion of our ground‐water supplies. As is well known, the United States Geological Survey has for half a century conducted investigations of the ground‐water of the country and numerous investigations have been made by State geological surveys and other agencies. However, the time is now ripe for a coordinated, continuing program to obtain systematic records of water‐levels in observation ‐ wells and correlative records of natural discharge and artificial withdrawals of ground‐water.

Eos, Transactions, American Geophysical Union↗
USGS2014

Report of Committee on Glaciers, 1942–43

The personnel of the Committee at present is as follows: Harry Fielding Reid, Professor Emeritus of Geology, Johns Hopkins University, 608 Cathedral Street, Baltimore, Maryland William H. Hobbs, Professor Emeritus of Geology, University of Michigan, Ann Arbor, Michigan Colonel Lawrence Martin, Chief, Division of Maps, Library of Congress, Washington, D.C. James E. Church, Professor of Meteorology and President, International Commission of Snow and Glaciers, Agricultural Experiment Station, University of Nevada, Reno, Nevada First Lieutenant William Osgood Field, Jr., home address, 18 West Twelfth Street, New York City Oliver Kehrlein, Chairman, Committee on Glacier Studies, Sierra Club, 1050 Mills Tower, San Francisco, California Kenneth N. Phillips, Associate Hydraulic Engineer, Water Resources Branch, Geological Survey, Chairman, Research Committee of the Masamas, 606 Post‐Office Building, Portland, Oregon William S. Cooper, Professor of Botany, University of Minnesota, Minneapolis, Minnesota Lieutenant Colonel Gerald FitzGerald, Army Air Corps, Washington, D.C. Laurence M. Gould, Professor of Geology, Carleton College, Northfield, Minnesota Arthur Johnson, Hydraulic Engineer, Conservation Branch, Geological Survey, 1105 Washington Building, Tacoma, Washington François E. Matthes (Chairman), Senior Geologist, Section of Glacial Geology, Geological Survey, Washington, D.C. The Committee is fortunate in having its membership reinforced by the addition of ARTHUR JOHNSON, who for several years has had charge of the repetitive plane‐table surveys of the lower Nisqually Glacier, on Mount Rainier—a project which the Geological Survey is carrying on in cooperation with the city of Tacoma, Washington. To him the Committee is indebted for data concerning the losses in volume of ice which the Nisqually Glacier is sustaining from year to year.

Eos, Transactions, American Geophysical Union↗
USGS2014

Water‐level fluctuations caused by Montana earthquake

The major earthquake of August 17, 1959, near the Montana‐Wyoming border had marked effects on water levels and artesian pressures in wells throughout the United States. Preliminary reports from field offices of the U. S. Geological Survey in 21 states show that water‐level fluctuations were automatically recorded in 136 observation wells. These wells for which records are available, and the maximum double amplitude of the fluctuations, are listed in Table 1.

Eos, Transactions, American Geophysical Union↗
USGS2006

Cadmium risks to freshwater life: derivation and validation of low-effect criteria values using laboratory and field studies

In 2001, the U.S. Environmental Protection Agency (EPA) released updated aquatic life criteria for cadmium. Since then, additional data on the effects of cadmium to aquatic life have become available from studies supported by the EPA, Idaho Department of Environmental Quality (IDEQ), and the U.S. Geological Survey, among other sources. Updated data on the effects of cadmium to aquatic life were compiled and reviewed and low-effect concentrations were estimated. Low-effect values were calculated using EPA's guidelines for deriving numerical national water-quality criteria for the protection of aquatic organisms and their uses. Data on the short-term (acute) effects of cadmium on North American freshwater species that were suitable for criteria derivation were located for 69 species representing 57 genera and 33 families. For longer-term (chronic) effects of cadmium on North American freshwater species, suitable data were located for 28 species representing 21 genera and 17 families. Both the acute and chronic toxicity of cadmium were dependent on the hardness of the test water. Hardness-toxicity regressions were developed for both acute and chronic datasets so that effects data from different tests could be adjusted to a common water hardness. Hardness-adjusted effects values were pooled to obtain species and genus mean acute and chronic values, which then were ranked by their sensitivity to cadmium. The four most sensitive genera to acute exposures were, in order of increasing cadmium resistance, Oncorhynchus (Pacific trout and salmon), Salvelinus ('char' trout), Salmo (Atlantic trout and salmon), and Cottus (sculpin). The four most sensitive genera to chronic exposures were Hyalella (amphipod), Cottus, Gammarus (amphipod), and Salvelinus. Using the updated datasets, hardness dependent criteria equations were calculated for acute and chronic exposures to cadmium. At a hardness of 50 mg/L as calcium carbonate, the criterion maximum concentration (CMC, or 'acute' criterion) was calculated as 0.75 mug/L cadmium using the hardness-dependent equation CMC = e(0.8403 ? ln(hardness)-3.572) where the 'ln hardness' is the natural logarithm of the water hardness. Likewise, the criterion continuous concentration (CCC, or 'chronic' criterion) was calculated as 0.37 mug/L cadmium using the hardness-dependent equation CCC = (e(0.6247 ? ln(hardness)-3.384)) ? (1.101672 - ((ln hardness) ? 0.041838))). Using data that were independent of those used to derive the criteria, the criteria concentrations were evaluated to estimate whether adverse effects were expected to the biological integrity of natural waters or to selected species listed as threatened or endangered. One species was identified that would not be fully protected by the derived CCC, the amphipod Hyalella azteca. Exposure to CCC conditions likely would lead to population decreases in Hyalella azteca, the food web consequences of which probably would be slight if macroinvertebrate communities were otherwise diverse. Some data also suggested adverse behavioral changes are possible in fish following long-term exposures to low levels of cadmium, particularly in char (genus Salvelinus). Although ambiguous, these data indicate a need to periodically review the literature on behavioral changes in fish following metals exposure as more information becomes available. Most data reviewed indicated that criteria conditions were unlikely to contribute to overt adverse effects to either biological integrity or listed species. If elevated cadmium concentrations that approach the chronic criterion values occur in ambient waters, careful biological monitoring of invertebrate and fish assemblages would be prudent to validate the prediction that the assemblages would not be adversely affected by cadmium at criterion concentrations.

Scientific Investigations Report↗
USGS2016

Paleomagnetic correlation of basalt flows in selected coreholes near the Advanced Test Reactor Complex, the Idaho Nuclear Technology and Engineering Center, and along the southern boundary, Idaho National Laboratory, Idaho

The U.S. Geological Survey, in cooperation with the U.S. Department of Energy, used paleomagnetic data from 18 coreholes to construct three cross sections of subsurface basalt flows in the southern part of the Idaho National Laboratory (INL). These cross sections, containing descriptions of the subsurface horizontal and vertical distribution of basalt flows and sediment layers, will be used in geological studies, and to construct numerical models of groundwater flow and contaminant transport. Subsurface cross sections were used to correlate surface vents to their subsurface flows intersected by coreholes, to correlate subsurface flows between coreholes, and to identify possible subsurface vent locations of subsurface flows. Correlations were identified by average paleomagnetic inclinations of flows, and depth from land surface in coreholes, normalized to the North American Datum of 1927. Paleomagnetic data were combined, in some cases, with other data, such as radiometric ages of flows. Possible vent locations of buried basalt flows were identified by determining the location of the maximum thickness of flows penetrated by more than one corehole. Flows from the surface volcanic vents Quaking Aspen Butte, Vent 5206, Mid Butte, Lavatoo Butte, Crater Butte, Pond Butte, Vent 5350, Vent 5252, Tin Cup Butte, Vent 4959, Vent 5119, and AEC Butte are found in coreholes, and were correlated to the surface vents by matching their paleomagnetic inclinations, and in some cases, their stratigraphic positions. Some subsurface basalt flows that do not correlate to surface vents, do correlate over several coreholes, and may correlate to buried vents. Subsurface flows which correlate across several coreholes, but not to a surface vent include the D3 flow, the Big Lost flow, the CFA buried vent flow, the Early, Middle, and Late Basal Brunhes flows, the South Late Matuyama flow, the Matuyama flow, and the Jaramillo flow. The location of vents buried in the subsurface by younger basalt flows can be inferred if their flows are penetrated by several coreholes, by tracing the flows in the subsurface, and determining where the greatest thickness occurs.

Idaho↗
USGS2023

Creek and quarry water quality at Pipestone National Monument and pilot study of pathogen detection methods in waterfall mist at Winnewissa Falls, Pipestone, Minnesota, 2018–19

Pipestone National Monument is a 301-acre site sacred to many Native American Tribes, providing cultural exhibits and walking trails to Pipestone Creek, Winnewissa Falls, and historical pipestone quarries for numerous visitors each year. However, the Minnesota Pollution Control Agency has determined turbidity and fecal coliform bacteria occur in Pipestone Creek in high enough numbers to be a potential health hazard. Concerns also were raised about exposure risk from waterfall mist to visitors and staff. The U.S. Geological Survey and the National Park Service collaborated on a study to collect 21 water-quality samples from 8 creek sites and 3 quarries in 2018 and analyzed them for over 250 water-quality parameters and contaminants. Additional samples were collected in August 2019 to assess the waterfall mists from Winnewissa Falls. Nutrient concentrations in the creek and quarries were elevated in 2018, indicating they are affected by agricultural inputs. All sample concentrations for nitrate and total nitrogen in Pipestone Creek exceeded Minnesota standards and U.S. Environmental Protection Agency nutrient criteria. Minnesota standards and U.S. Environmental Protection Agency nutrient criteria for total phosphorus also were exceeded in some of the quarry samples. Twenty of 210 micropollutants had measurable concentrations: 13 pesticides, 5 pharmaceuticals, and 2 other types of micropollutants. Atrazine, deethylatrazine, and metolachlor ethanesulfonic acid were detected in all 21 samples collected during the study. The five pharmaceuticals detected were acetaminophen, gabapentin, gemfibrozil, metformin, and oxycodone. Gabapentin (10 of 21 samples) and metformin (8 of 21 samples) were the most commonly detected pharmaceuticals. None of the detected micropollutant concentrations exceeded any Minnesota standards or U.S. Environmental Protection Agency aquatic life benchmarks, except the acute toxicity benchmark for nonvascular plants for atrazine. Two cyanotoxins, anatoxin-a and microcystin, were detected, but concentrations were below U.S. Environmental Protection Agency guidelines for swimming or recreation. Notably, total coliform, fecal coliform, and Escherichia coli were detected in all creek samples, and concentrations generally decreased downstream, suggesting contamination potentially occurred upstream from the monument. Mycobacterium avium ssp. paratuberculosis was not detected in any creek sediment samples but was detected in three water samples from the creek. Three organisms were detected in the 2019 water and mist sampling from Winnewissa Falls. Two of these organisms can cause illness in humans ( Cryptosporidium and Legionella ), and a third (ruminant Bacteroides ) is an indicator of manure contamination. Despite few samples, pathogen-positive water samples and air sampling demonstrated the feasibility and utility of the mist sampling approach outlined in this report.

Minnesota↗
USGS1998

Bedrock geology of the Paducah 1° x 2° CUSMAP quadrangle, Illinois, Indiana, Kentucky, and Missouri

The Paducah 1° x 2° quadrangle (hereafter referred to as the Paducah quadrangle) encompasses the eastern flank of the Ozark dome, the southern end of the Illinois Basin, and the northern end of the Mississippi Embayment. Resting on Proterozoic basement, sedimentary rocks of Cambrian through Permian age in the Illinois Basin and Ozark dome are overlapped by weakly lithified Cretaceous, Paleocene, Eocene, and Pliocene strata in the embayment. This is one of the most intensely faulted areas of the North American Midcontinent. A Proterozoic crustal terrane boundary (coincident with part of the Ste. Genevieve fault zone) and a failed intracratonic rift (Reelfoot rift and Rough Creek graben) have been reactivated repeatedly under various stress fields from Proterozoic through late Tertiary times.

Illinois, Indiana, Kentucky, Missouri↗
USGS1908

The geology and ore deposits of the Coeur d'Alene district, Idaho

The area commonly known as the Coeur d'Alene district (although for purposes of record and administration it has been divided into a number of local mining districts) is situated, so far as its productive part is concerned in Shoshone County, in that narrow portion of Idaho which extends northward between the States of Washington and Montana to the international boundary. It lies almost entirely upon the western slope of Coeur d'Alene Mountains, a broad and rather complex member of the North American Cordillera.

Idaho;Montana;Washington↗
USGS1988

Late Cenozoic offsets on the offshore connection between the Fairweather and Queen Charlotte faults off southeast Alaska

Closely spaced seismic reflection profiles permit us to extend the onshore Fairweather fault across the continental margin off southeast Alaska to the Queen Charlotte fault. Evidence for Quaternary movement along this major plate boundary includes 20–40-m high sea-floor scarps, offset subsurface seismic reflectors, sea-floor bathymetry that indicates as much as 70 km of right-lateral offset in the last 1 m.y., 5–6 cm/yr of movement on the onshore Fairweather fault, and recorded seismicity along the fault. The Fairweather-Queen Charlotte fault system, similar in dimension to the San Andreas fault system, is a dextral transform fault that truncates the continental margin of North America. Much of the late Cenozoic motion between the Pacific and North American plates has been taken up along the fault system. The Fairweather-Queen Charlotte fault evolved to its present form after passage of the Yakutat block, the youngest of the allochthonous terranes that form southern Alaska.

Marine Geology↗
USGS2022

Volcano and earthquake monitoring plan for the Yellowstone Caldera system, 2022–2032

Executive Summary The Yellowstone Volcano Observatory (YVO) is a consortium of nine Federal, State, and academic agencies that: (1) provides timely monitoring and hazards assessment of volcanic, hydrothermal, and earthquake activity in and around Yellowstone National Park, and (2) conducts research to develop new approaches to volcano monitoring and better understand volcanic activity in the Yellowstone region and elsewhere. The U.S. Geological Survey (USGS) arm of YVO is also responsible for monitoring and reporting on volcanic activity in the Intermountain West of the United States. The previous YVO monitoring plan for the Yellowstone region spanned 2006–2015 and focused on strengthening the region-wide coverage, or backbone, of monitoring systems (Yellowstone Volcano Observatory, 2006). The goals of that plan have largely been achieved thanks to significant investments in instrumentation and infrastructure, especially by the National Science Foundation EarthScope Plate Boundary Observatory (now known as the Network Of The Americas, or NOTA) and the American Reinvestment and Recovery Act. This revision of the monitoring plan, covering 2022–2032, builds upon these improvements to monitoring systems in the Yellowstone region while also accounting for new insights into the dynamics of the area’s seismic, volcanic, and hydrothermal activity. These additional improvements are designed to fill gaps in the monitoring network and to better understand and track hazards associated with hydrothermal processes. These improvements include: Conversion of remaining analog seismic stations to digital, Addition of Global Positioning System (GPS) stations in the vicinity of Norris Geyser Basin and other areas where changes in deformation rate and style have been observed, Implementation of continuous gas monitoring in several areas of Yellowstone National Park, and Improvements to lake, meteorological, and hydrological monitoring to better track hydrothermal activity, including that occurring on lake bottoms, and to aid in understanding of whether such activity might be influenced by external forces, like environmental conditions. The 2022–2032 monitoring plan for the Yellowstone volcanic system also proposes to improve monitoring of hydrothermal areas to better understand these dynamic systems and their associated hazards. To date, only a single seismometer has been placed within one of Yellowstone National Park’s geyser basins because seismic noise associated with boiling water can hinder interpretation of overall seismic and magmatic activity, but this concern has been mitigated by improvements to backbone monitoring. Deployment of geophysical, geochemical, hydrological, and geological monitoring instruments in geyser basins will be accompanied by campaigns to measure gas and water chemistry and flux, as well as aerial and satellite surveys of gas and thermal emissions. Close collaboration between YVO member institutions and other research agencies is needed to achieve these monitoring goals and to use the derived data to advance understanding of how Yellowstone Caldera and similar volcanic systems work. At the same time, attention must be paid to minimize the impact of monitoring efforts and infrastructure on the environment. YVO thus commits to serving as stewards of the natural, cultural, and historical resources in and around Yellowstone National Park while maximizing scientific gain for the betterment of society.

Wyoming↗
USGS2014

Mode of igneous intrusion in La Plata Mountains, Colorado

The La Plata Mountains, in southwestern Colorado, have long been known as an example of a mountain group of the laccolithic type, although it has been recognized that the igneous geology was much more complex than that of typical laccoliths. A restudy of the ore‐deposits of the District, now in progress, has thrown new light on the mode of intrusion of the igneous rocks (E. B. Eckel, Resurvey of the geology and ore‐deposits of the La Plata Mining District, Colorado, Proc. Colorado Sci. Soc, v. 13, No. 9, pp. 508–546, 1936). The Mountains, which include parts of La Plata and Montezuma Counties, are 8 to 18 miles northwest of Durango and occupy an oval area 10 to 15 miles in diameter. The altitude ranges from about 8000 to 13,225 feet above sea‐level. ©1937. American Geophysical Union. All Rights Reserved.

Colorado↗
USGS2000

1890 and 1990 Bathymetry of Florida Bay

This Open File Report contains bathymetric data collected in Florida Bay by the US Geological Survey, South Florida Place-Based Studies Program using SANDS (System for Accurate Nearshore Depth Surveying). SANDS is a USGS developed, high precision bathymetric system which integrates depth soundings, boat motion, and GPS positioning needed for nearshore bathymetric mapping. Data acquisition occurred between 1995 and 1999 on a 22' shallow draft boat. Processed data points are in X, Y, Z format and relative to the North American Datum of 1983 (GRS80/NAD83) and the North American Vertical Datum of 1988 (NAVD88). Vertical control was derived from GPS data processed with Jet Propulsion Laboratory GIPSY software. Horizontal and vertical accuracies are within +/- 4 centimeters and +/- 8 centimeters, respectively.

Florida↗
USGS2014

Report of the committee on chemistry of natural waters, 1936–37

The membership of this Committee is as follows: C. S. Howard, Chairman, U. S. Geological Survey, Washington, D.C. D. G. Thompson, U. S. Geological Survey, Washington, D.C. A. C. Lane, 22 Arlington Street, Cambridge, Massachusetts C. S. Scofield, Bureau of Plant Industry, U. S. Dept. Agri., Washington, D. C. I. A. Denison, U.S. Bureau of Standards, Washington, D.C. T. G. Thompson, University of Washington, Seattle, Washington W. P. Kelley, Citrus Experiment Station, Riverside, California In order to provide for close cooperation between the work of the different research‐committees of the American Geophysical Union it was decided to have the chairmen of certain committees serve on other committees. The Chairman of the Committee on the Chemistry of Natural Waters is serving on the Committee of Underground waters and D. G. Thompson as Chairman of the Committee on Underground Waters is serving on the Committee on Chemistry of Natural Waters

Eos, Transactions, American Geophysical Union↗
USGS2013

U-Pb ages of detrital zircons from the Tertiary Mississippi River delta plain in central Louisiana: Insights into sediment provenance

The sources of the tremendous amount of Cenozoic siliciclastic sediment deposited in the Gulf of Mexico region remain debated because of a lack of definitive provenance-identifying characteristics. In an effort to build on prior provenance analysis, we present 101–160 single-grain detrital zircon U-Pb ages for each of 10 outcrop samples from Upper Paleocene to Upper Miocene sandstones from a ∼10,000 km2 swath of central Louisiana corresponding to the ancient Mississippi River Delta, the largest Cenozoic depocenter in the northern Gulf of Mexico region. Sample depositional age control is derived from biostratigraphy and/or regional lithostratigraphic correlation. U-Pb ages in each of the samples range from Cenozoic to Archean, and correspond to the ages of various geologic terranes that underlie the modern Mississippi River drainage basin. However, the prominence of various age distributions changes systematically through the Cenozoic stratigraphy, and pronounced shifts in the abundance of certain age distributions between stratal packages appear to be correlated to shifts in heavy mineral assemblages recorded across the northern Gulf of Mexico coastal plain. Comparison of coastal plain detrital zircon age distributions to age distributions from North American sedimentary cover and the ages of major North American crystalline basement rocks, aided by a sediment mixing model, illuminates the provenance of each of the stratal packages, and suggests that (1) the Mississippi River catchment has resembled its present configuration, at least in the east-west dimension, for much, if not all, of the Cenozoic, and (2) depositional episodes on the Louisiana coastal plain characterized by high sediment supply also corresponded to high proportions of sediment sourcing from the Sevier-Laramide region of the interior western United States. Sediment supply to the Louisiana coastal plain by the paleo–Mississippi River has generally been high during the Cenozoic, except for an anomalous low during the Middle Eocene, when the abundance of sediment derived from the Rocky Mountain region decreased dramatically relative to sediment derived from the Appalachian region.

Louisiana↗
USGS2019

Monitoring storm tide from Hurricane Michael along the northwest coast of Florida, October 2018

Hurricane Michael made landfall near Mexico Beach and Tyndall Air Force Base in the Florida Panhandle, with maximum sustained winds over 160 miles per hour, on October 10, 2018. The maximum recorded storm tide was 15.55 feet above the North American Vertical Datum of 1988 (NAVD 88). The elevation of the maximum high-water mark, found in Port St. Joe, Florida, exceeded 20 feet above NAVD 88. The storm tide and winds destroyed much of the tourist town of Mexico Beach and caused extensive damage to the surrounding communities, including Tyndall Air Force Base, Panama City Beach, Port St. Joe, and Cape San Blas, Fla. The U.S. Geological Survey (USGS), in cooperation with Federal Emergency Management Agency and Florida Division of Emergency Management, deployed a temporary monitoring network of water-level and barometric pressure sensors at 34 sites along the northwest coast of Florida to record the timing, areal extent, and magnitude of hurricane storm tide generated by Hurricane Michael. A total of 522 high-water marks were recovered and surveyed from 331 sites from Seaside, Fla. to Cedar Key, Fla. The USGS, in cooperation with Federal Emergency Management Agency and Florida Division of Emergency Management, displays real-time water-level data from long-term USGS streamflow stations, rapid deployment gages and National Oceanic and Atmospheric Administration tide-gage stations, updated hourly (or, in some cases, more frequently), through satellite telemetry, on the USGS Flood Event Viewer (https://stn.wim.usgs.gov/FEV/#Michael2018).

Florida↗
USGS2018

Correlation of the Eagle Ford Group, Woodbine Group, and equivalent Cenomanian-Turonian Mudstones using regional wireline-log cross sections across the Texas Gulf Coast, U.S.A.

As part of the U.S. Geological Survey’s 2018 hydrocarbon assessment of the Eagle Ford Group and associated Cenomanian-Turonian strata, a series of regional wireline-log cross sections were constructed to examine geologic characteristics of this stratigraphic interval across the Texas Gulf Coast from Mexico to Louisiana. The cross sections were used to help define six continuous assessment units based, in part, on stratigraphic thickness, lateral extent, and lithology. The locations of the strike and dip cross sections were selected to address questions pertinent to the hydrocarbon assessment. Stratigraphic correlation of the Eagle Ford Group and corresponding Cenomanian-Turonian mudstones has been debated for many years, and differences in interpretations remain. Formation tops published in the literature, from IHS Markit TM , as well as information from a commercial biostratigraphic database were used to define consistent criteria to construct these cross sections from interpreted wireline logs. Specific units of interest include the Austin Chalk, upper and lower Eagle Ford Group, mudstones of the Woodbine Group, and the Buda Limestone. Wireline gamma-ray (GR) logs through the Eagle Ford Group have values greater than 100 American Petroleum Institute (API) units in several areas of this study, including the Maverick Basin, the Karnes Trough, and the Brazos Basin. High GR values in mudstones may be interpreted to represent potential organic-rich intervals. These high GR zones provide a criterion to identify the lateral variability in potential Cenomanian-Turonian source rock intervals from South Texas to the Texas-Louisiana border.

Gulf Coast Association of Geological Societies Tra↗
USGS2004

Ground-Water System in the Chimacum Creek Basin and Surface Water/Ground Water Interaction in Chimacum and Tarboo Creeks and the Big and Little Quilcene Rivers, Eastern Jefferson County, Washington

A detailed study of the ground-water system in the unconsolidated glacial deposits in the Chimacum Creek Basin and the interactions between surface water and ground water in four main drainage basins was conducted in eastern Jefferson County, Washington. The study will assist local watershed planners in assessing the status of the water resources and the potential effects of ground-water development on surface-water systems. A new surficial geologic map of the Chimacum Creek Basin and a series of hydrogeologic sections were developed by incorporating LIDAR imagery, existing map sources, and drillers' logs from 110 inventoried wells. The hydrogeologic framework outlined in the study will help characterize the occurrence of ground water in the unconsolidated glacial deposits and how it interacts with the surface-water system. Water levels measured throughout the study show that the altitude of the water table parallels the surface topography and ranges from 0 to 400 feet above the North American Vertical Datum of 1988 across the basin, and seasonal variations in precipitation due to natural cycles generally are on the order of 2 to 3 feet. Synoptic stream-discharge measurements and instream mini-piezometers and piezometers with nested temperature sensors provided additional data to refine the positions of gaining and losing reaches and delineate seasonal variations. Chimacum Creek generally gains water from the shallow ground-water system, except near the community of Chimacum where localized losses occur. In the lower portions of Chimacum Creek, gaining conditions dominate in the summer when creek stages are low and ground-water levels are high, and losing conditions dominate in the winter when creek stages are high relative to ground-water levels. In the Quilcene Bay area, three drainage basins were studied specifically to assess surface water/ground water interactions. The upper reaches of Tarboo Creek generally gain water from the shallow ground-water system throughout most of the year and the lower reaches have little or no gains. The Big Quilcene River generally gains water from the shallow ground-water system after it emerges from a bedrock canyon and loses water from the town of Quilcene to the mouth of the river in Quilcene Bay. The Little Quilcene River generally loses water to the shallow ground-water system, although two localized areas were found to have gaining conditions. The Big Quilcene and Little Quilcene Rivers incur significant losses on the alluvial plain at the head of Quilcene Bay. Each of the creeks examined had a unique pattern of gaining and losing reaches, owing to the hydraulic conductivity of the streambed material and the relative altitude of the surrounding water table. Although the magnitudes of gains and losses varied seasonally, the spatial distribution did not vary greatly, suggesting that patterns of gains and losses in surface-water systems depend greatly on the geology underlying the streambed.

Scientific Investigations Report↗