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At least 271 records · Page 15Linked to original sources
USGS1993

Geologic map of upper Eocene to Holocene volcanic and related rocks in the Cascade Range, Washington

Since 1979 the Geothermal Research Program of the U.S. Geological Survey has carried out a multidisciplinary research effort in the Cascade Range. The goal of this research is to understand the geology, tectonics, and hydrology of the Cascades in order to characterize and quantify geothermal resource potential. A major goal of the program is compilation of a comprehensive geologic map of the entire Cascade Range that incorporates modern field studies and that has a unified and internally consistent explanation. This map is one of a series presently being compiled that shows Cascade Range geology by fitting published and unpublished mapping into a province-wide scheme of lithostratigraphic units; map sheets of the Cascade Range in California and in Oregon complete the series. The complete series forms a guide to exploration and evaluation of the geothermal resources of the Cascade Range and will be useful for studies of volcanic hazards, volcanology, and tectonics. For geothermal reasons, the maps emphasize Quaternary volcanic rocks. Large igneous-related geothermal systems that have high temperatures are associated with Quaternary volcanic fields, and geothermal potential declines rapidly as age increases (Smith and Shaw, 1975). Most high-grade recoverable geothermal energy is likely to be associated with silicic volcanism less than 1 Ma. Lower grade (= lower temperature) geothermal resources may be associated with somewhat older rocks; however, volcanic rocks older than about 2 Ma are unlikely geothermal targets (Smith and Shaw, 1975).

Washington↗
USGS2014

Committee on glaciers, 1939–40

The Committee on Glaciers is now composed of the following members: 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; Lawrence Martin, Chief of the Division of Maps, Library of Congress, Washington, D.C.; J. E. Church, Professor of Meteorology, Agricultural Experiment Station, University of Nevada, Reno, Nevada; Wm. Osgood Field, Jr., Explorer, 18 West Twelfth Street, New York, N.Y.; Earl A. Trager, Chief of the Naturalist Division, National Park Service, Washington, D.C.; Oliver Kehrlein, Chairman, Committee on Glacier Studies, 1050 Mills Tower, 220 Bush Street, San Francisco, California; Kenneth N. Phillips, Associate Hydraulic Engineer, Water Resources Branch, United States Geological Survey, Chairman, Research Committee of the Mazamas, 606 Post‐Office Building, Portland, Oregon; William S. Cooper, Professor of Botany, University of Minnesota, Minneapolis, Minnesota; Gerald FitzGerald, Senior Topographic Engineer, Alaska Branch, United States Geological Survey, Washington, D.C.; Lawrence M. Gould, Professor of Geology, Carleton College, Northfield, Minnesota; François E. Matthes (Chairman), Senior Geologist, Section of Glacial Geology, United States Geological Survey, Washington, D.C. The international relations of the Committee have changed somewhat during the past year as a result of the consolidation of the International Commission of Glaciers with the International Commission of Snow. That consolidation was effected by the International Association of Scientific Hydrology (to which both commissions belonged) at the triennial meeting in Washington, in September, 1939. Inasmuch as the membership of the new International Commission of Snow and Glaciers comprises the personnel of the two former commissions, our Committee on Glaciers now automatically is represented on the new International Commission by four men—Church, Hobbs, Gould, and Matthes. Moreover, Church is acting President, and it is understood that he will become President as soon as the political situation in Europe permits the holding of a formal election of officers at which all nations interested can exercise their right of voting

Eos, Transactions, American Geophysical Union↗
USGS2002

Hydrogeologic and water-quality reconnaissance of the artesian aquifer under the Shoalwater Bay Indian Reservation and Tokeland Peninsula, Pacific County, Washington, 1998-99

The U.S. Geological Survey (USGS) collected and compiled hydrogeologic and water quality data from September 1998 through September 1999 to describe the hydrogeologic setting and to assess the quality of the water in the artesian aquifer under the Shoalwater Bay Indian Reservation and the adjacent Tokeland Peninsula area of Pacific County, Washington. Hydrogeologic data include descriptions of 38 wells, lithologic data for 27 wells, and water-level data for 17 wells and 1 tidal station. Water-quality data include field measurements for temperature, specific conductance, pH, alkalinity, bicarbonate, carbonate, dissolved oxygen, and laboratory analyses for major inorganic ions, metals, nutrients, methylene blue-active substances, and pesticides. None of the 93 field measurements or chemicals analyzed for exceeded the U.S. Environmental Protection Agency (USEPA) primary standards for drinking water and only 2 constituents (iron and manganese) exceeded the USEPA secondary standards. Sixty-six of the constituents (including all 53 pesticides) were at or below the reporting or detection levels established by the USGS National Water Quality Laboratory.

Water-Resources Investigations Report↗
USGS2001

Geologic map of the Silver Lake Quadrangle, Cowlitz County, Washington

This digital map database, compiled from previously published and unpublished data, and new mapping by the authors, represents the general distribution of bedrock and surficial deposits of the Silver lake 7.5 minute quadrangle. The database delineates map units that are identified by general age and lithology following the stratigraphic nomenclature of the U.S. Geological Survey. The scale of the source maps limits the spatial resolution (scale) of the database to 1:24,000 or smaller.

Miscellaneous Field Studies Map↗
USGS2017

Geologic map of the Beacon Rock quadrangle, Skamania County, Washington

The Beacon Rock 7.5′ quadrangle is located approximately 50 km east of Portland, Oregon, on the north side of the Columbia River Gorge, a scenic canyon carved through the axis of the Cascade Range by the Columbia River. Although approximately 75,000 people live within the gorge, much of the region remains little developed and is encompassed by the 292,500-acre Columbia River Gorge National Scenic Area, managed by a consortium of government agencies “to pro­tect and provide for the enhancement of the scenic, cultural, recreational and natural resources of the Gorge and to protect and support the economy of the Columbia River Gorge area.” As the only low-elevation corridor through the Cascade Range, the gorge is a critical regional transportation and utilities corridor (Wang and Chaker, 2004). Major state and national highways and rail lines run along both shores of the Columbia River, which also provides important water access to ports in the agricultural interior of the Pacific Northwest. Transmission lines carry power from hydroelectric facilities in the gorge and farther east to the growing urban areas of western Oregon and Washington, and natural-gas pipelines transect the corridor (Wang and Chaker, 2004). These lifelines are highly vulnerable to disruption by earthquakes, landslides, and floods. A major purpose of the work described here is to identify and map geologic hazards, such as faults and landslide-prone areas, to provide more accurate assessments of the risks associated with these features. The steep canyon walls of the map area reveal exten­sive outcrops of Miocene flood-basalt flows of the Columbia River Basalt Group capped by fluvial deposits of the ances­tral Columbia River, Pliocene lavas erupted from the axis of the Cascade arc to the east, and volcanic rocks erupted from numerous local vents. The Columbia River Basalt Group unconformably rests on a sequence of late Oligocene and early Miocene rocks of the ancestral Cascade volcanic arc, which underlies most of the map area. The resistant flood-basalt flows form some of the famous landforms in the map area, such as Hamilton Mountain. Extensive landslide complexes have devel­oped where the basalt flows were emplaced on weak volcani­clastic rocks.

Washington↗
USGS2013

Lidar-revised geologic map of the Olalla 7.5' quadrangle, King, Kitsap, and Pierce Counties, Washington

The Olalla 7.5' quadrangle, which lies almost in the center of the Puget Lowland, displays the broad range of geologic environments typical of the region. The upland plain is fluted by the passage of the great continental ice sheet that last covered the area about 17,000 (14,000 radiocarbon) years ago. The plain is cut by channel deposits, both late glacial and postglacial in age, and it is cleaved even more deeply by one of the major arms of Puget Sound, Colvos Passage, which here separates the west coast of Vashon Island from the Kitsap Peninsula. Beneath the deposits of the last ice sheet is a complex sequence of older Quaternary-age sediments that extends about 400 m below the modern ground surface. These older sediments are best exposed along the shorelines and beach cliffs of Puget Sound, where wave action and landslides maintain relatively fresh exposures. The older sediments typically are compact, having been loaded by ice during one or more episodes of glaciation subsequent to their deposition. Locally these sediments are also cemented by iron and manganese oxides and hydroxides, a consequence of many tens or hundreds of thousands of years of weathering and groundwater movement. Our map is an interpretation of a 6-ft resolution lidar-derived digital elevation model combined with the geology depicted on the "Geologic map of the Olalla 7.5' quadrangle, King, Kitsap, and Pierce Counties, Washington," by Booth and Troost (2005), which was described, interpreted, and located on the 1953 1:24,000-scale topographic map of the Olalla 7.5-minute quadrangle. The original topographic base map, derived from 1951 aerial photographs, has 20-ft contours, nominal horizontal resolution of circa 40 ft (12 m), and nominal mean vertical accuracy of circa 13 ft (4 m). This new DEM has a horizontal resolution of 6 ft (2 m) and mean vertical accuracy circa 1 ft (0.3 m). The greater resolution and accuracy of the lidar DEM facilitated a much-improved interpretation of many aspects of the surficial geology, especially the distribution and relative age of landforms and the materials inferred to comprise them.

Washington↗
USGS2018

Preliminary geologic framework developed for a proposed environmental monitoring study of a deep, unconventional Marcellus Shale drill site, Washington County, Pennsylvania

Background In the fall of 2011, the U.S. Geological Survey (USGS) was afforded an opportunity to participate in an environmental monitoring study of the potential impacts of a deep, unconventional Marcellus Shale hydraulic fracturing site. The drill site of the prospective case study is the “Range Resources MCC Partners L.P. Units 1-5H” location (also referred to as the “RR–MCC” drill site), located in Washington County, southwestern Pennsylvania. Specifically, the USGS was approached to provide a geologic framework that would (1) provide geologic parameters for the proposed area of a localized groundwater circulation model, and (2) provide potential information for the siting of both shallow and deep groundwater monitoring wells located near the drill pad and the deviated drill legs. The lead organization of the prospective case study of the RR–MCC drill site was the Groundwater and Ecosystems Restoration Division (GWERD) of the U.S. Environmental Protection Agency. Aside from the USGS, additional partners/participants were to include the Department of Energy, the Pennsylvania Geological Survey, the Pennsylvania Department of Environmental Protection, and the developer Range Resources LLC. During the initial cooperative phase, GWERD, with input from the participating agencies, drafted a Quality Assurance Project Plan (QAPP) that proposed much of the objectives, tasks, sampling and analytical procedures, and documentation of results. Later in 2012, the proposed cooperative agreement between the aforementioned partners and the associated land owners for a monitoring program at the drill site was not executed. Therefore, the prospective case study of the RR–MCC site was terminated and no installation of groundwater monitoring wells nor the collection of nearby soil, stream sediment, and surface-water samples were made. Prior to the completion of the QAPP and termination of the perspective case study the geologic framework was rapidly conducted and nearly completed. This was done for three principal reasons. First, there was an immediate need to know the distribution of the relatively undisturbed surface to near-surface bedrock geology and unconsolidated materials for the collection of baseline surface data prior to drill site development (drill pad access road, drill pad leveling) and later during monitoring associated with well drilling, well development, and well production. Second, it was necessary to know the bedrock geology to support the siting of: (1) multiple shallow groundwater monitoring wells (possibly as many as four) surrounding and located immediately adjacent to the drill pad, and (2) deep groundwater monitoring wells (possibly two) located at distance from the drill pad with one possibly being sited along one of the deviated production drill legs. Lastly, the framework geology would provide the lateral extent, thickness, lithology, and expected discontinuities of geologic units (to be parsed or grouped as hydrostratigraphic units) and regional structure trends as inputs into the groundwater model. This report provides the methodology of geologic data accumulation and aggregation, and its integration into a geographic information system (GIS) based program. The GIS program will allow multiple data to be exported in various formats (shapefiles [.shp], database files [.dbf], and Keyhole Markup Language files [.KML]) for use in surface and subsurface geologic site characterization, for sampling strategies, and for inputs for groundwater modeling.

Pennsylvania↗
USGS2011

Lidar-revised geologic map of the Wildcat Lake 7.5' quadrangle, Kitsap and Mason Counties, Washington

This map is an interpretation of a 6-ft-resolution (2-m-resolution) lidar (light detection and ranging) digital elevation model combined with the geology depicted on the Geologic Map of the Wildcat Lake 7.5' quadrangle, Kitsap and Mason Counties, Washington (Haeussler and Clark, 2000). Haeussler and Clark described, interpreted, and located the geology on the 1:24,000-scale topographic map of the Wildcat Lake 7.5' quadrangle. This map, derived from 1951 aerial photographs, has 20-ft contours, nominal horizontal resolution of approximately 40 ft (12 m), and nominal mean vertical accuracy of approximately 10 ft (3 m). Similar to many geologic maps, much of the geology in the Haeussler and Clark (2000) map-especially the distribution of surficial deposits-was interpreted from landforms portrayed on the topographic map. In 2001, the Puget Sound lidar Consortium obtained a lidar-derived digital elevation model (DEM) for Kitsap Peninsula including all of the Wildcat Lake 7.5' quadrangle. This new DEM has a horizontal resolution of 6 ft (2 m) and a mean vertical accuracy of about 1 ft (0.3 m). The greater resolution and accuracy of the lidar DEM compared to topography constructed from air photo stereo models have much improved the interpretation of geology in this heavily vegetated landscape, especially the distribution and relative age of some surficial deposits. Many contacts of surficial deposits are adapted unmodified or slightly modified from Haugerud (2009).

Washington↗
USGS2022

Element concentrations and grain size of sediment from the Similkameen River above Enloe Dam (Enloe Reservoir) near Oroville, Washington, 2019

In 2019, the U.S. Geological Survey conducted a reconnaissance survey of concentrations of 41 trace elements present in bed sediment in the reservoir on the Similkameen River upstream from Enloe Dam, near Oroville, Washington. The Similkameen River drains a watershed containing highly mineralized geologic deposits with current (2019) and historical mining activity. Results of this survey indicated that surface and subsurface sediment are substantially enriched in element concentrations of silver (Ag), arsenic (As), gold (Au), bismuth (Bi), cadmium (Cd), copper (Cu), manganese (Mn), antimony (Sb), selenium (Se), tin (Sn), and tellurium (Te) relative to average concentrations found in upper continental-crustal material. Conversely, concentrations of mercury (Hg) and lead (Pb) in sediment above Enloe Dam (Enloe Reservoir) were generally less than average concentrations in upper continental-crustal material (Hg = 0.05 milligrams per kilogram [mg/kg]; Pb =17 mg/kg). Concentrations of most trace elements were higher in the less than 63-micrometer fraction (silt) and tended to be higher in subsurface than in surface sediment. The concentrations of trace elements were compared to consensus-based aquatic toxicity reference concentrations, Washington State Department of Ecology sediment management standards, and average concentrations of upper continental-crustal material. Arsenic concentrations were consistently elevated above these criteria among samples and often exceeded sediment management standards and aquatic toxicity reference values (both threshold effects and probable effects concentrations). High concentrations of As were measured in sediment with proportionally more material in the less than 63-micrometer size fraction; this result may be related to the presence of ore-processing waste material that has entered the aquatic system from approximately 125 years of mining operations in the basin. Elevated concentrations of chromium and copper that exceed the same criteria as arsenic (As) were measured less consistently and predominantly in the fine-grain size fraction.

Washington↗
USGS2019

A 4000-year history of debris flows in north-central Washington State, U.S.A.: Preliminary results from trenching and surficial geologic mapping at the Pope Creek fan

Long-term records of the magnitude and frequency of debris flows on fans are rare, but such records provide critical information needed for debris-flow hazard and risk assessments. This study explores the history of debris flows on a fan with seasonally inhabited cabins at Pope Creek along the Entiat River about 48 km upstream from the town of Entiat, Washington. Motivation for this study was provided by the Duncan Fire, a wildfire which burned the Pope Creek basin in 2014 and resulted in debris flows and water-dominated floods on the fan between August 2014 and October 2016. We excavated and mapped seven 6-m long (2.4 m deep) trenches, mapped deposits on the surface of the fan, and constrained the ages of deposits using radiocarbon dating and the computer program OxCal. Preliminary results indicate that there have been at least 10 debris-flow events (DFEs) since 4000 cal yr BP. The mean recurrence interval between events was 433 +/-44 years, but intervals range from 724 to 20 years. The four most recent events have the shortest recurrence intervals. The largest event had an estimated sediment volume of 97,000 m3 and occurred at about 285 cal yr BP (1665 AD) during the Little Ice Age. The most recent debris-flow event that was triggered by rainstorms following the Duncan Fire was about 8x smaller than the largest event. These results may indicate that the largest DFE was triggered by an exceptional meteorological event that occurred during a cool, wet time, and that smaller DFEs were triggered by less exceptional meteorological events that occurred following wildfires.

Washington↗
USGS2015

Chemical concentrations and instantaneous loads, Green River to the Lower Duwamish Waterway near Seattle, Washington, 2013–15

In November 2013, U.S. Geological Survey streamgaging equipment was installed at a historical water-quality station on the Duwamish River, Washington, within the tidal influence at river kilometer 16.7 (U.S. Geological Survey site 12113390; Duwamish River at Golf Course at Tukwila, WA). Publicly available, real-time continuous data includes river streamflow, stream velocity, and turbidity. Between November 2013 and March 2015, the U.S. Geological Survey collected representative samples of water, suspended sediment, or bed sediment from the streamgaging station during 28 periods of differing flow conditions. Samples were analyzed by Washington-State-accredited laboratories for a large suite of compounds, including metals, dioxins/furans, semivolatile compounds including polycyclic aromatic hydrocarbons, pesticides, butytins, polychlorinated biphenyl (PCB) Aroclors and the 209 PCB congeners, volatile organic compounds, hexavalent chromium, and total and dissolved organic carbon. Metals, PCB congeners, and dioxins/furans were frequently detected in unfiltered-water samples, and concentrations typically increased with increasing suspended-sediment concentrations. Chemical concentrations in suspendedsediment samples were variable between sampling periods. The highest concentrations of many chemicals in suspended sediment were measured during summer and early autumn storm periods. Median chemical concentrations in suspended-sediment samples were greater than median chemical concentrations in fine bed sediment (less than 62.5 µm) samples, which were greater than median chemical concentrations in paired bulk bed sediment (less than 2 mm) samples. Suspended-sediment concentration, sediment particle-size distribution, and general water-quality parameters were measured concurrent with the chemistry sampling. From this discrete data, combined with the continuous streamflow record, estimates of instantaneous sediment and chemical loads from the Green River to the Lower Duwamish Waterway were calculated. For most compounds, loads were higher during storms than during baseline conditions because of high streamflow and high chemical concentrations. The highest loads occurred during dam releases (periods when stored runoff from a prior storm is released from the Howard Hanson Dam into the upper Green River) because of the high river streamflow and high suspended-sediment concentration, even when chemical concentrations were lower than concentrations measured during storm events.

Washington↗
USGS2012

Bathymetric and underwater video survey of Lower Granite Reservoir and vicinity, Washington and Idaho, 2009-10

The U.S. Geological Survey conducted a bathymetric survey of the Lower Granite Reservoir, Washington, using a multibeam echosounder, and an underwater video mapping survey during autumn 2009 and winter 2010. The surveys were conducted as part of the U.S. Army Corps of Engineer's study on sediment deposition and control in the reservoir. The multibeam echosounder survey was performed in 1-mile increments between river mile (RM) 130 and 142 on the Snake River, and between RM 0 and 2 on the Clearwater River. The result of the survey is a digital elevation dataset in ASCII coordinate positioning data (easting, northing, and elevation) useful in rendering a 3×3-foot point grid showing bed elevation and reservoir geomorphology. The underwater video mapping survey was conducted from RM 107.73 to 141.78 on the Snake River and RM 0 to 1.66 on the Clearwater River, along 61 U.S. Army Corps of Engineers established cross sections, and dredge material deposit transects. More than 900 videos and 90 bank photographs were used to characterize the sediment facies and ground-truth the multibeam echosounder data. Combined, the surveys were used to create a surficial sediment facies map that displays type of substrate, level of embeddedness, and presence of silt.

Washington;Idaho↗
USGS2013

Circulation exchange patterns in Sinclair Inlet, Washington

In 1994, the U.S. Geological Survey (USGS), in cooperation with the U.S. Navy, deployed three sets of moorings in Sinclair Inlet, which is a relatively small embayment on the western side of Puget Sound (fig. 1). This inlet is home to the Puget Sound Naval Shipyard. One purpose of the measurement program was to determine the transport pathways and fate of contaminants known to be present in Sinclair Inlet. Extensive descriptions of the program and the resultant information about contaminant pathways have been reported in Gartner and others (1998). This report primarily focused on the bottom boundary layer and the potential for resuspension and transport of sediments on the seabed in Sinclair Inlet as a result of tides and waves. Recently (2013), interest in transport pathways for suspended and dissolved materials in Sinclair Inlet has been rekindled. In particular, the USGS scientists in Washington and California have been asked to reexamine the datasets collected in the earlier study to refine not only our understanding of transport pathways through the inlet, but to determine how those transport pathways are affected by subtidal currents, local wind stress, and fresh water inputs. Because the prior study focused on the bottom boundary layer and not the water column, a reanalysis of the datasets could increase our understanding of the dynamic forces that drive transport within and through the inlet. However, the early datasets are limited in scope and a comprehensive understanding of these transport processes may require more extensive datasets or the development of a detailed numerical model of transport processes for the inlet, or both.

Washington↗
USGS2002

Geologic map of the Sauk River 30- by 60-minute quadrangle, Washington

Summary -- The north-south-trending regionally significant Straight Creek Fault roughly bisects the Sauk River quadrangle and defines the fundamental geologic framework of it. Within the quadrangle, the Fault mostly separates low-grade metamorphic rocks on the west from medium- to high-grade metamorphic rocks of the Cascade metamorphic core. On the west, the Helena-Haystack melange and roughly coincident Darrington-Devils Mountain Fault Zone separate the western and eastern melange belts to the southwest from the Easton Metamorphic Suite, the Bell Pass melange, and rocks of the Chilliwack Group, to the northeast. The tectonic melanges have mostly Mesozoic marine components whereas the Chilliwack is mostly composed of Late Paleozoic arc rocks. Unconformably overlying the melanges and associated rocks are Eocene volcanic and sedimentary rocks, mostly infaulted along the Darrington-Devils Mountain Fault Zone. These younger rocks and a few small Eocene granitic plutons represent an extensional tectonic episode. East of the Straight Creek Fault, medium to high-grade regional metamorphic rocks of the Nason, Chelan Mountains, and Swakane terranes have been intruded by deep seated, Late Cretaceous granodioritic to tonalitic plutons, mostly now orthogneisses. Unmetamorphosed mostly tonalitic intrusions on both sides of the Straight Creek fault range from 35 to 4 million years old and represent the roots of volcanoes of the Cascade Magmatic Arc. Arc volcanic rocks are sparsely preserved east of the Straight Creek fault, but dormant Glacier Peak volcano on the eastern margin of the quadrangle is the youngest member of the Arc. Deposits of the Canadian Ice Sheet are well represented on the west side of the quadrangle, whereas alpine glacial deposits are common to the east. Roughly 5000 years ago lahars from Glacier Peak flowed westward filling major valleys across the quadrangle.

IMAP↗
USGS2014

Report of committee on glaciers, 1940–41

The personnel of the Committee is now 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; Lawrence Martin, Chief of the Division of Maps, Library of Congress, Washington, D.C.; J. E. Church, Professor of Meteorology, Agricultural Experiment Station, University of Nevada, Reno, Nevada; Wm. Osgood Field, Jr., Explorer, 18 West Twelfth Street, New York, New York; Oliver Kehrlein, Chairman, Committee on Glacier Studies of Sierra Club, 1050 Mills Tower, 220 Bush Street, San Francisco, California; Kenneth N. Phillips, Associate Hydraulic Engineer, Water Resources Branch, United States Geological Survey, Chairman, Research Committee of the Mazamas, 606 Post‐Office Building, Portland, Oregon; William S. Cooper, Professor of Botany, University of Minnesota, Minneapolis, Minnesota; Gerald Fitzgerald, Senior Topographic Engineer, Alaska Branch, United States Geological Survey, Washington, D.C.; Laurence M. Gould, Professor of Geology, Carleton College, Northfield, Minnesota; Dr. Max Demorest, Department of Geology, Yale University, New Haven, Connecticut; François E. Matthes (Chairman), Senior Geologist, Section of Glacial Geology, United States Geological Survey, Washington, D.C.

Eos, Transactions, American Geophysical Union↗
USGS2006

Assessment of Undiscovered Gas Resources of the Eastern Oregon and Washington Province, 2006

Using a geology-based assessment methodology, the U.S. Geological Survey estimated a mean of 2.4 trillion cubic feet (TCF) of undiscovered natural gas in the Eastern Oregon and Washington Province. More than 90 percent, or 2.1 TCF, of the estimated undiscovered natural gas is continuous gas estimated to be trapped in Tertiary rocks overlain by the Columbia River Basalt Group.

Fact Sheet↗
USGS2011

Lidar-revised geologic map of the Uncas 7.5' quadrangle, Clallam and Jefferson Counties, Washington

In 2000 and 2001, the Puget Sound Lidar Consortium obtained 1 pulse/m 2 lidar data for about 65 percent of the Uncas 7.5' quadrangle. For a brief description of LIDAR (LIght Detection And Ranging) and this data acquisition program, see Haugerud and others (2003). This map combines geologic interpretation (mostly by Haugerud and Tabor) of the 6-ft (2-m) lidar-derived digital elevation model (DEM) with the geology depicted on the Preliminary Geologic Map of the Uncas 7.5' Quadrangle, Clallam and Jefferson Counties, Washington, by Peter J. Haeussler and others (1999). The Uncas quadrangle in the northeastern Olympic Peninsula covers the transition from the accreted terranes of the Olympic Mountains on the west to the Tertiary and Quaternary basin fills of the Puget Lowland to the east. Elevations in the map area range from sea level at Port Discovery to 4,116 ft (1,255 m) on the flank of the Olympic Mountains to the southwest. Previous geologic mapping within and marginal to the Uncas quadrangle includes reports by Cady and others (1972), Brown and others (1960), Tabor and Cady (1978a), Yount and Gower (1991), and Yount and others (1993). Paleontologic and stratigraphic investigations by University of Washington graduate students (Allison, 1959; Thoms, 1959; Sherman, 1960; Hamlin, 1962; Spencer, 1984) also encompass parts of the Uncas quadrangle. Haeussler and Wells mapped in February 1998, following preliminary mapping by Yount and Gower in 1976 and 1979. The description of surficial map units follows Yount and others (1993) and Booth and Waldron (2004). Bedrock map units are modified from Yount and Gower (1991) and Spencer (1984). We used the geologic time scale of Gradstein and others (2005). The Uncas quadrangle lies in the forearc of the Cascadia subduction zone, about 6.25 mi (10 km) east of the Cascadia accretionary complex exposed in the core of the Olympic Mountains (Tabor and Cady, 1978b). Underthrusting of the accretionary complex beneath the forearc uplifted and tilted eastward the Coast Range basalt basement and overlying marginal basin strata, which comprise most of the rocks of the Uncas quadrangle. The Eocene submarine and subaerial tholeiitic basalt of the Crescent Formation on the Olympic Peninsula is thought to be the exposed mafic basement of the Coast Range, which was considered by Snavely and others (1968) to be an oceanic terrane accreted to the margin in Eocene time. In this interpretation, the Coast Range basalt terrane may have originated as an oceanic plateau or by oblique marginal rifting, but its subsequent emplacement history was complex (Wells and others, 1984). Babcock and others (1992) and Haeussler and others (2003) favor the interpretation that the basalts were the product of an oceanic spreading center interacting with the continental margin. Regardless of their origin, onlapping strata in southern Oregon indicate that the Coast Range basalts were attached to North America by 50 Ma; but on southern Vancouver Island, where the terrane-bounding Leech River Fault is exposed, Brandon and Vance (1992) concluded that suturing to North America occurred in the broad interval between 42 and 24 Ma. After emplacement of the Coast Range basalt terrane, the Cascadia accretionary wedge developed by frontal accretion and underplating (Tabor and Cady, 1978b; Clowes and others, 1987). Domal uplift of the part of the accretionary complex beneath the Olympic Mountains occurred after ~18 Ma (Brandon and others, 1998). Continental and alpine glaciation during Quaternary time reshaped the uplifted rocks of the Olympic Mountains.

Washington↗