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At least 811 records · Page 45Linked to original sources
USGS2002

The Effect of Selected Cleaning Techniques on Berkshire Lee Marble: A Scientific Study at Philadelphia City Hall

This report describes a scientific investigation of the effects of eight different cleaning techniques on the Berkshire Lee marble component of the facade of the East Center Pavilion at Philadelphia City Hall; the study was commissioned by the city of Philadelphia. The eight cleaning techniques evaluated in this study were power wash (proprietary gel detergent followed by water rinse under pressure), misting (treatment with potable, nebulized water for 24-36 hours), gommage (proprietary Thomann-Hanry low-pressure, air-driven, small-particle, dry abrasion), combination (gommage followed by misting), Armax (sodium bicarbonate delivered under pressure in a water wash), JOS (dolomite powder delivered in a low-pressure, rotary-vortex water wash), laser (thermal ablation), and dry ice (powdered-dry-ice abrasion delivered under pressure). In our study approximately 160 cores were removed from the building for laboratory analysis. We developed a computer program to analyze scanning-electron-micrograph images for the microscale surface roughness and other morphologic parameters of the stone surface, including the near-surface fracture density of the stone. An analysis of more than 1,100 samples cut from the cores provided a statistical basis for crafting the essential elements of a reduced-form, mixed-kinetics conceptual model that represents the deterioration of calcareous stone in terms of self-organized soiling and erosion patterns. This model, in turn, provided a basis for identifying the variables that are affected by the cleaning techniques and for evaluating the extent to which such variables influence the stability of the stone. The model recognizes three classes of variables that may influence the soiling load on the stone, including such exogenous environmental variables as airborne moisture, pollutant concentrations, and local aerodynamics, and such endogenous stone variables as surface chemistry and microstructure (fracturing, roughness, and so on). This study showed that morphologic variables on the mesoscale to macroscale are not generally affected by the choice of a cleaning technique. The long-term soiling pattern on the building is independent of the cleaning technique applied. This study also showed that soluble salts do not play a significant role in the deterioration of Berkshire Lee marble. Although salts were evident in cracks and fissures of the heavily soiled stone, such salts did not penetrate the surface to a depth of more than a few hundred micrometers. The criteria used to differentiate the cleaning techniques were ultimately based on the ability of each technique to remove soiling without altering the texture of the stone surface. This study identified both the gommage and JOS techniques as appropriate for cleaning ashlar surfaces and the combination technique as appropriate for cleaning highly carved surfaces at the entablatures, cornices, and column capitals.

Professional Paper↗
USGS2007

A brief history of oil and gas exploration in the southern San Joaquin Valley of California:

The Golden State got its nickname from the Sierra Nevada gold that lured so many miners and settlers to the West, but California has earned much more wealth from so-called “black gold” than from metallic gold. The San Joaquin Valley has been the principal source for most of the petroleum produced in the State during the past 145 years. In attempting to assess future additions to petroleum reserves in a mature province such as the San Joaquin Basin, it helps to be mindful of the history of resource development. In this chapter we present a brief overview of the long and colorful history of petroleum exploration and development in the San Joaquin Valley. This chapter relies heavily upon the work of William Rintoul, who wrote extensively on the history of oil and gas exploration in California and especially in the San Joaquin Valley. No report on the history of oil and gas exploration in the San Joaquin Valley would be possible without heavily referencing his publications. We also made use of publications by Susan Hodgson and a U.S. Geological Survey Web site, Natural Oil and Gas Seeps in California (http://seeps.wr.usgs.gov/seeps/index.html), for much of the material describing the use of petroleum by Native Americans in the San Joaquin Valley. Finally, we wish to acknowledge the contribution of Don Arnot, who manages the photograph collection at the West Kern Oil Museum in Taft, California. The collection consists of more than 10,000 photographs that have been scanned and preserved in digital form on CD-ROM. Many of the historical photographs used in this paper are from that collection. Finally, to clarify our terminology, we use the term “San Joaquin Valley” when we refer to the geographical or topographical feature and the term “San Joaquin Basin” when we refer to geological province and the rocks therein.

California↗
USGS2015

Arctic Alaska’s Lower Cretaceous (Hauterivian and Barremian) mudstone succession—Linking lithofacies, texture, and geochemistry to marine processes

We present new images and descriptions of the lithofacies and organic facies of the pebble shale unit and lower part of the Hue Shale (Lower Cretaceous) of Arctic Alaska at a high magnification that illustrates their textural characteristics. Our aims were to describe and determine the distribution of facies in these petroleum source rocks and to identify the processes that formed them. We sampled at high-resolution and applied new petrographic techniques combined with scanning electron microscopy and geochemical analyses to samples collected from three widely spaced sections—located in exposures along the Canning River and continuous core from the Mikkelsen Bay State 1 and Orion 1 wells. Results from these three locations indicate that this succession consists primarily of clay-rich mudstones that are variously silt- or sand-bearing and clay-dominated mudstones that exhibit mainly relict, 2–5 millimeter thick bedding and common but variable microbioturbation, rare macrobioturbation, and common fabrics of pelleted clay and silt. These mudstones contain rare, poorly sorted, silt-rich basal laminae that are often discontinuous and have wavy, sharp bases and crude upward fining. In addition, mud-supported, outsized clasts (dropstones) of fine sand to pebble size are present throughout the succession as isolated clasts or in clusters. We interpret these textures and much of this succession to result from intermittent deposition by suspension settling from melting seasonal sea ice—sometimes sediment-laden—and associated primary productivity. Overall, this mudstone succession fines and deepens upward from the pebble shale unit into the Hue Shale. In the Hue Shale of the Orion well, however, different processes intermittently deposited thin, discrete intervals of coarser sediment that probably represent deposition from density currents. Also in the Hue Shale of the Orion well, several thicker sandstone and silt-dominated mudstone units with discordant, scoured bases and cut and fill structures represent erosion during higher energy events such as major storms. Other lithofacies within the succession are graded tuffs/bentonites and tuffaceous/bentonitic mudstones from episodic volcanic ash falls; these are abundant in the Hue Shale, and very rare in the pebble shale unit of the two wells. Organic-carbon rich strata associated with volcanic ash intervals of the pebble shale unit and Hue Shale in the Mikkelsen 1 well have some of the best petroleum source rock potential determined for this succession. Authigenic pyrite and carbonate-cement-dominated mudstone are also present in both units of all three sections. The carbonate-cemented units indicate breaks in sedimentation and are common in the Hue Shale and in sections of the pebble shale unit interpreted to be more distal, such as along the Canning River. Our results document the variation in facies and textures of the Hauterivian and Barremian Lower Cretaceous mudstone succession of Arctic Alaska. Comparison of these characteristics to the products of modern processes on the North Slope of Alaska, in the Beaufort Sea, and elsewhere suggest that this succession formed primarily from depositional processes related to seasonal sea ice with intermittent fluvial-sourced sediment deposited by density currents and episodic erosion and reworking by storms and other currents.

Alaska↗
USGS2016

Conditions and processes affecting sand resources at archeological sites in the Colorado River corridor below Glen Canyon Dam, Arizona

This study examined links among fluvial, aeolian, and hillslope geomorphic processes that affect archeological sites and surrounding landscapes in the Colorado River corridor downstream from Glen Canyon Dam, Arizona. We assessed the potential for Colorado River sediment to enhance the preservation of river-corridor archeological resources through aeolian sand deposition or mitigation of gully erosion. By identifying locally prevailing wind directions, locations of modern sandbars, and likely aeolian-transport barriers, we determined that relatively few archeological sites are now ideally situated to receive aeolian sand supply from sandbars deposited by recent controlled floods. Whereas three-fourths of the 358 river-corridor archeological sites we examined include Colorado River sediment as an integral component of their geomorphic context, only 32 sites currently appear to have a high degree of connectivity (coupled interactions) between modern fluvial sandbars and sand-dominated landscapes downwind. This represents a substantial decrease from past decades, as determined by aerial-photograph analysis. Thus, we infer that recent controlled floods have had a limited, and declining, influence on archeological-site preservation. Within the study area, overland-flow (gully) erosion is less severe in sand landscapes with active aeolian sand than in landscapes that lack aeolian transport; gullies terminate more commonly in active sand (sand that is mobile by wind rather than stabilized by biologic soil crust). We infer that these characteristics largely result from aeolian sand transport being an effective gully-limiting and gully-annealing mechanism. Aeolian sand activity in the river corridor varies substantially as a function of reach morphology and dominant wind direction relative to the river-corridor orientation, factors that control accommodation space for river-derived sand and the modern sand supply to aeolian dunes. These attributes, together with an inverse correlation between aeolian sand activity and gully occurrence, define varying degrees of net long-term gully-erosion risk for sediment deposits and associated archeological sites in different regions of the river corridor. Over most of the river corridor, including some of the archeologically richest regions, sand is too inactive with respect to aeolian transport to anneal gullies effectively. At eight selected archeological sites that we studied with high-resolution terrestrial lidar scans for more than a year, sand loss by overland flow (gully erosion) and aeolian deflation generally exceeded deposition, such that erosion dominated over most monitoring intervals—even at four sites with strong connectivity to modern sand supply. The Glen Canyon reach of the river corridor appears especially vulnerable to gully erosion. Among the sites that we monitored in detail, erosion generally dominated over deposition to a greater degree at four Glen Canyon sites with no modern sand supply than at four Marble–Grand Canyon sites with aeolian sand supply from controlled-flood sandbars. Although gross annual-scale erosion rates were similar among the Glen Canyon sites and among the Marble–Grand Canyon sites, a relative lack of depositional processes led to greater net erosion at the Glen Canyon sites. Having found no differences in weather patterns to suggest greater erosive forcing in Glen Canyon, and no conclusively influential differences in the slope or watershed area contributing to gully formation, we attribute the greater erosion at the Glen Canyon sites to a combination of inherent geomorphic context (high terraces that do not receive modern sediment supply) and pronounced effects of postdam sediment-supply limitation. We conclude that most of the river-corridor archeological sites are at elevated risk of net erosion under present dam operations. In the present flow regime, controlled floods do not simulate the magnitude or frequency of natural floods, and are not large enough to deposit sand at elevations that were flooded at annual to decadal intervals in predam time. For archeological sites that depend upon river-derived sand, we infer elevated erosion risk owing to a combination of reduced sand supply (both fluvial and aeolian) through (1) the lower-than-natural flood magnitude, frequency, and sediment supply of the controlled-flooding protocol; (2) reduction of open, dry sand area available for wind redistribution under current normal (nonflood) dam operations, which do not include flows as low as natural seasonal low flows and do include substantial daily flow fluctuations; and (3) impeded aeolian sand entrainment and transport owing to increased riparian vegetation growth in the absence of larger, more-frequent floods. If dam operations were to increase the supply of sand available for windblown transport—for example, through larger floods, sediment augmentation, or increased fluvial sandbar exposure by low flows—and also decrease riparian vegetation, the prevalence of active aeolian sand could increase over time, and the propensity for unmitigated gully erosion could decrease. Although the evolution of river-corridor landscapes and archeological sites has been altered fundamentally by the lack of large, sediment-rich floods (flows on the order of 5,000 m 3 /s), some combination of sediment-rich flows above 1,270 m 3 /s, seasonal flows below 226 m 3 /s, and riparian-vegetation removal might increase the preservation potential for sand-dependent archeological resources in the Colorado River corridor.

Arizona↗
USGS2023

Chromium in minerals and selected aquifer materials

Between 1952 and 1964, hexavalent chromium, Cr(VI), was released into groundwater from a Pacific Gas and Electric Company (PG&E) compressor station in Hinkley, California, in the western Mojave Desert 80 miles northeast of Los Angeles, California. In 2015, the extent of anthropogenic Cr(VI) in groundwater in Hinkley and Water Valleys was uncertain, but some Cr(VI) in groundwater may be naturally occurring from rock and aquifer material. To evaluate potential sources of natural Cr(VI), chromium and other selected trace-element concentrations were measured by inductively coupled plasma-mass spectrometry (ICP-MS), with multi-acid digestion, on 34 samples of surficial alluvium and core material from Hinkley and Water Valleys, California, and on 2 samples of alluvium from the mafic Sheep Creek fan to the southwest. Chromium concentrations in Hinkley and Water Valleys ranged from 2 to 110 milligrams per kilogram (mg/kg), with a median concentration of 14 mg/kg; concentrations were highest in weathered mafic hornblende diorite associated with Iron Mountain. High chromium concentrations also were present within fine-textured materials and visually abundant iron- and manganese-oxide coatings on the surfaces of mineral grains. For comparison, chromium concentrations as high as 170 mg/kg were measured in mafic alluvium from the Sheep Creek fan. In contrast, chromium concentrations were lowest in Mojave-type deposits (Mojave River stream and lake margin deposits), with a median of 6 mg/kg. Chromium concentrations measured by ICP-MS compared favorably with concentrations measured by portable (handheld) X-ray fluorescence (pXRF; chapter B), on the basis of least-squares regression results and a coefficient of determination (R 2 ) of 0.97. Minerals in bulk samples and the heavy (dense) mineral fractions isolated from those samples were identified using optical techniques, X-ray diffraction (XRD), and scanning electron microscopy (SEM). Quartz and feldspar were the most abundant minerals, especially within recent and older Mojave River deposits. Chromium concentrations were as high as 1,250 mg/kg in the heavy-mineral fraction, with specific gravity greater than 3.32. Chromium was not commonly detected in the light-mineral fraction, with specific gravity less than 2.85. Most chromium within the heavy-mineral fraction was substituted within magnetite mineral grains less than 100 micrometers (μm) in diameter, and almost no chromite was present within the heavy-mineral fraction. Although magnetite is resistive to weathering, weathering of magnetite to hematite was identified (1) in Miocene materials underlying unconsolidated deposits in the western subarea of Hinkley Valley and (2) in alluvium within Water Valley that contains weathered minerals eroded from Miocene rock. Less-dense, more easily weathered chromium-containing amphiboles, such as actinolite in older Mojave River alluvium and hornblende in locally derived alluvium from Iron Mountain, were identified optically. Magnetite was not identified in weathered hornblende diorite and was less abundant in locally derived materials and in Miocene materials than in Mojave-type deposits. A comparison of ICP-MS data and sequential extraction data shows that approximately 90 percent of chromium in aquifer material within Hinkley and Water Valleys was not extractable and was interpreted to reside within unweathered mineral grains. Most extractable chromium was within the strong acid extractable fraction. Chromium within the weakly sorbed, and specifically sorbed extractable fractions in oxide accumulations within the regulatory Cr(VI) plume is potentially mobile into groundwater with changes in ionic strength or pH. Although Hinkley and Water Valleys are regionally low in chromium, natural geologic sources of chromium may be present in aquifer materials penetrated by wells completed in (1) weathered hornblende diorite bedrock underlying the western subarea; (2) Miocene deposits underlying the western subarea and unconsolidated material in the northern subarea and Water Valley containing basalt or weathered minerals eroded from Miocene deposits; (3) unconsolidated material containing visually abundant iron- and manganese-oxide coatings on the surfaces of mineral grains that are present near the water table and near lithologic or geologic contacts; and (4) brown clay and mudflat/playa deposits in the northern subarea. Brown clay and mudflat/playa deposits in the eastern subarea near Mount General have a low-chromium, felsic mineralogy similar to Mojave River deposits and do not contain high concentrations of chromium; however, manganese(IV) oxides within these materials may facilitate oxidation of trivalent chromium, Cr(III), to Cr(VI).

California↗
USGS2023

Sequestration and reoxidation of chromium in experimental microcosms

Groundwater containing hexavalent chromium, Cr(VI), downgradient from the Pacific Gas and Electric Company (PG&E) Hinkley compressor station in the Mojave Desert, 80 miles northeast of Los Angeles, California, is undergoing bioremediation using added ethanol as a reductant in a volume of the aquifer defined as the in situ reactive zone (IRZ). This treatment reduces Cr(VI) to trivalent chromium, Cr(III), which is rapidly sequestered by sorption to aquifer particle surfaces and by co-precipitation within iron (Fe) or manganese (Mn) bearing minerals forming in place as reduction proceeds. Successful mitigation of the Cr(VI) plume is projected to require 10–95 years, at which time bioremediation with ethanol will likely cease. This projection assumes that Cr(VI) removal is permanent and that no Cr(III) will oxidize back to Cr(VI) in the event of changing hydrologic conditions that may cause oxygen-rich water to re-enter the IRZ. Laboratory microcosm experiments were done to explore the process of reductive sequestration of Cr(VI) to Cr(III) and the potential for reoxidation of Cr(III) to Cr(VI). In reductive sequestration experiments, batch microcosms were prepared with aquifer materials collected from sites upgradient of the Cr(VI) regulatory plume. Control microcosms were prepared using Fe- and Mn-coated quartz sand. Unfiltered Mojave River groundwater containing an added tracer of isotopically labeled chromium-50 were reacted with microcosm materials for up to 2 years; during this time, bio-reduction was stimulated by repeated additions of diluted ethanol to maintain reduced conditions within appropriate ranges, avoiding sulfate reducing or methanogenic conditions as much as possible while mimicking field conditions. Analysis of chromium-50, Fe, and Mn obtained by sequential extraction from microcosms harvested (incubation terminated and microcosm contents analyzed) at various times showed that some aqueous chromium (Cr) was sorbed to particle surfaces within hours; reduction to Cr(III) and incorporation into amorphous and crystalline solid phases occurred during the next few months. Amorphous Cr-containing fractions included Fe and Mn hydroxides and organic matter. Ultimately, most of the chromium-50 tracer was present in the less reactive crystalline phase. However, Fe and Mn were broadly distributed at later stages of reduction, and both were spatially co-located with Cr on a micrometer (μm) scale. Solid-phase data collected using scanning electron microscopy with energy dispersive spectroscopy (SEM-EDS) and X-ray absorption spectroscopy (XAS) indicated that some Cr(III) was associated with mixed valence Fe oxides like magnetite and Fe-Mn oxides like jacobsite. Additionally, Cr(III) was observed within several μm of Fe and Mn embedded in clays and in mineral coatings. To evaluate the potential for reoxidation of Cr(III) to Cr(VI), additional batch microcosms of aquifer materials and mixtures of Fe- and Mn-coated sand were first reduced for more than 1 year and subsequently oxidized for almost 2 years. Hexavalent chromium was formed and was available for release to the aqueous phase during oxidation of all materials; however, the timing and amount of Cr(VI) formed and released varied among substrates. Artificial substrates containing more Mn produced more Cr(VI). Site material characteristic of recent Mojave River deposits contained within the IRZ produced the least Cr(VI) during oxidation, while site materials composed of older Mojave River aquifer material (containing more Mn) produced more Cr(VI). Site material collected from within the IRZ contained more Cr but produced an intermediate amount of Cr(VI) following oxidation. The combined results of microcosm chemistry and solid-phase analyses showed that the nature and locus of Cr(III) sequestration influenced its vulnerability to reoxidation to Cr(VI). It was concluded that co-location of Cr with Mn at later stages of reduction influenced the susceptibility of Cr(III) to reoxidation in microcosms. Reoxidation of Cr(III) to Cr(VI) was observed in experiments with previously reduced material after just 14 days exposure to oxygen. As much as 10 percent of added Cr was oxidized to Cr(VI) in microcosms prepared using recent Mojave River aquifer material, and as much as 20 percent of added Cr was oxidized to Cr(VI) in microcosms prepared using older Mojave River aquifer material. Less Cr(VI) (less than 3 percent of Cr added before reduction) was released to the aqueous phase, and this release occurred following longer oxygen exposure. Site managers may need to plan for long-term monitoring and the possibility of active maintenance of anoxic conditions within the IRZ to ensure permanent sequestration of Cr after bioremediation with ethanol ceases.

California↗
USGS2021

Geologic and geophysical maps of the Santa Maria and part of the Point Conception 30'×60' quadrangles, California

This report presents digital geologic, gravity, and aeromagnetic maps for the onshore parts of the Santa Maria and Point Conception 30'x60' quadrangles at a compilation scale of 1:100,000. The map depicts the distribution of bedrock units, surficial deposits, paleontological data, geophysical data and structural features in the Santa Maria basin and the Santa Ynez Mountains to the south, an area corresponding to 26 contiguous 7.5-minute quadrangles. The map also includes offshore faults from the Hosgri fault, a major structural feature, east to the shoreline. This new map revises and supersedes two earlier versions of the 30'x60' Santa Maria quadrangle that were produced as part of the U.S. Geological Survey’s investigations of onshore oil and gas resources of the Santa Maria province (Keller, 1995). The first map was released as a scanned black-and-white image of hand-drawn compilation (Tennyson, 1992); the second map was a digital release that is no longer available (Tennyson and others, 1995). This new map also includes the geology of the onshore part of the adjacent Point Conception 30'x60' quadrangle that encompasses the Santa Ynez Mountains of the western Transverse Ranges. The digital database also contains magnetic and gravity data for the entire region, paleontological data, and interpretation of major offshore structural features that bear on the continuity and connection of the mapped onshore structures.

California↗
USGS2024

Colored shaded relief bathymetry and acoustic backscatter of Ozette Lake, Washington

Offshore of the Pacific Northwest of the United States is the Cascadia Subduction Zone, a 1,000-kilometer-long tectonic boundary defined by a large fault, called a megathrust, that extends from the Mendocino Junction off northern California to the Nootka Fracture Zone off Vancouver Island, Canada (U.S. Geological Survey, 2023). The Juan de Fuca and Gorda oceanic plates to the west of this boundary subduct under the North America continental plate to the east. Several other smaller faults that cut through the North America plate crust also affect the region. Although their effects upon Ozette Lake are uncertain, geological evidence for past earthquakes, such as underwater landslides, may be found in Pacific Northwest lakes. Underwater landslides caused by past earthquakes should be well preserved in these relatively undisturbed lake environments. The floor of Ozette Lake, Washington, located along the Pacific coast of the United States, west of the Puget Sound region and about 140 kilometers east of the megathrust was mapped by the U.S. Geological Survey in July of 2019 to search for evidence of past earthquakes. Mapping was completed using a SWATHplus-M 234-kHz interferometric side scan sonar system pole-mounted on the U.S. Geological Survey research vessel San Lorenzo. The system collected full-coverage bathymetric and acoustic backscatter data that were processed to 2-meter spatial resolution (Dartnell and others, 2024). This two-map series displays the results of this mapping. A colored shaded relief bathymetry map (sheet 1) and an acoustic backscatter map (sheet 2) show the lake floor morphology and backscatter intensities, respectively, that can be analyzed for evidence of past earthquakes.

Washington↗
USGS2025

Colored shaded-relief bathymetry and acoustic backscatter of Lake Sammamish, Washington

Evidence of strong earthquakes (such as underwater landslides and associated deposits) may be recorded within the lacustrine sediments of Pacific Northwest lakes. The floor of Lake Sammamish, Wash., an approximately 11 kilometer (6.8 mile) long, 2 kilometer (1.2 mile) wide, and 35 meter (114.8 feet) deep lake located in a populated region just east of Seattle, was mapped by the U.S. Geological Survey in November of 2021 to search for evidence of past earthquakes. Mapping was conducted using a SWATHplus-M 234-kHz interferometric side-scan sonar system was pole-mounted on the U.S. Geological Survey research vessel Parke Snavely, and the system collected full-coverage bathymetric and acoustic backscatter data, which were processed to 2-meter spatial resolution. Two maps were created, a colored shaded-relief bathymetric map showing lake floor morphology (sheet 1), and an acoustic-backscatter map showing backscatter intensities (sheet 2). The results may then be utilized together to investigate past earthquake activity.

Washington↗
USGS2005

Stream-sediment geochemistry in mining-impacted streams: Sediment mobilized by floods in the Coeur D'Alene-Spokane River system, Idaho and Washington

Environmental problems associated with the dispersion of metal-enriched sediment into the Coeur d'Alene-Spokane River system downstream from the Coeur d'Alene Mining District in northern Idaho have been a cause of litigation since 1903, 18 years after the initiation of mining for lead, zinc, and silver. Although direct dumping of waste materials into the river by active mining operations stopped in 1968, metal-enriched sediment continues to be mobilized during times of high runoff and deposited on valley flood plains and in Coeur d'Alene Lake (Horowitz and others, 1993). To gauge the geographic and temporal variations in the metal contents of flood sediment and to provide constraints on the sources and processes responsible for those variations, we collected samples of suspended sediment and overbank deposits during and after four high-flow events in 1995, 1996, and 1997 in the Coeur d'Alene-Spokane River system with estimated recurrence intervals ranging from 2 to 100 years. Suspended sediment enriched in lead, zinc, silver, antimony, arsenic, cadmium, and copper was detected over a distance of more than 130 mi (the downstream extent of sampling) downstream of the mining district. Strong correlations of all these elements in suspended sediment with each other and with iron and manganese are apparent when samples are grouped by reach (tributaries to the South Fork of the Coeur d'Alene River, the South Fork of the Coeur d'Alene River, the main stem of the Coeur d'Alene River, and the Spokane River). Elemental correlations with iron and manganese, along with observations by scanning electron microscopy, indicate that most of the trace metals are associated with Fe and Mn oxyhydroxide compounds. Changes in elemental correlations by reach suggest that the sources of metal-enriched sediment change along the length of the drainage. Metal contents of suspended sediment generally increase through the mining district along the South Fork of the Coeur d'Alene River, decrease below the confluence of the North and South Forks, and then increase again downstream of the gradient flattening below Cataldo. Metal contents of suspended sediment in the Spokane River below Coeur d'Alene Lake were comparable to those of suspended sediment in the main stem of the Coeur d'Alene River above the lake during the 1997 spring runoff, but with somewhat higher Zn contents. Daily suspended-sediment loads were about 100 times larger in the 1996 flood (50-100-year recurrence interval) than in the smaller 1997 floods (2-5-year recurrence intervals). Significant differences in metal ratios and contents are also apparent between the two flood types. The predominant source of suspended sediment in the larger 1996 flood was previously deposited, metal-enriched flood-plain sediment, identified by its Zn/Pb ratio less than 1. Suspended sediment in the smaller 1997 floods had metal ratios distinct from those of the flood-plain deposits and was primarily derived from metal-enriched sediment stored within the stream channel, identified by a Zn/Pb ratio greater than 1. Sediment deposited during overbank flooding on the immediate streambank or natural levee of the river typically consists of sandy material with metal ratios and contents similar to those of the sandy streambed sediment in the adjacent river reach. Samples of overbank deposits in backlevee marshes collected after the 1996 flood have metal ratios similar to those of peak-flow suspended sediment in the same river reach, but generally lower metal contents.

Idaho, Washington↗
USGS2007

Bathymetry of Walker Lake, West-Central Nevada

Walker Lake lies within a topographically closed basin in west-central Nevada and is the terminus of the Walker River. Much of the streamflow in the Walker River is diverted for irrigation, which has contributed to a decline in lake-surface altitude of about 150 feet and an increase in dissolved solids from 2,500 to 16,000 milligrams per liter in Walker Lake since 1882. The increase in salinity threatens the fresh-water ecosystem and survival of the Lahontan cutthroat trout, a species listed as threatened under the Endangered Species Act. Accurately determining the bathymetry and relations between lake-surface altitude, surface area, and storage volume are part of a study to improve the water budget for Walker Lake. This report describes the updated bathymetry of Walker Lake, a comparison of results from this study and a study by Rush in 1970, and an estimate of the 1882 lake-surface altitude. Bathymetry was measured using a single-beam echosounder coupled to a differentially-corrected global positioning system. Lake depth was subtracted from the lake-surface altitude to calculate the altitude of the lake bottom. A Lidar (light detection and ranging) survey and high resolution aerial imagery were used to create digital elevation models around Walker Lake. The altitude of the lake bottom and digital elevation models were merged together to create a single map showing land-surface altitude contours delineating areas that are currently or that were submerged by Walker Lake. Surface area and storage volume for lake-surface altitudes of 3,851.5-4,120 feet were calculated with 3-D surface-analysis software. Walker Lake is oval shaped with a north-south trending long axis. On June 28, 2005, the lake-surface altitude was 3,935.6 feet, maximum depth was 86.3 feet, and the surface area was 32,190 acres. The minimum altitude of the lake bottom from discrete point depths is 3,849.3 feet near the center of Walker Lake. The lake bottom is remarkably smooth except for mounds near the shore and river mouth that could be boulders, tree stumps, logs, or other submerged objects. The echosounder detected what appeared to be mounds in the deepest parts of Walker Lake, miles from the shore and river mouth. However, side-scan sonar and divers did not confirm the presence of mounds. Anomalies occur in two northwest trending groups in northern and southern Walker Lake. It is hypothesized that some anomalies indicate spring discharge along faults based on tufa-like rocks that were observed and the northwest trend parallel to and in proximity of mapped faults. Also, evaporation measured from Walker Lake is about 50 percent more than the previous estimate, indicating more water is flowing into the lake from sources other than the Walker River. Additional studies need to be done to determine what the anomalies are and whether they are related to the hydrology of Walker Lake. Most differences in surface area and storage volume between this study and a study by Rush in 1970 were less than 1 percent. The largest differences occur at lake-surface altitudes less than 3,916 feet. In general, relations between lake-surface altitude, surface area, and storage volume from Rush's study and this study are nearly identical throughout most of the range in lake-surface altitude. The lake-surface altitude in 1882 was estimated to be between 4,080 feet and 4,086 feet with a probable altitude of 4,082 feet. This estimate compares well with two previous estimates of 4,083 feet and 4,086 feet. Researchers believe the historic highstand of Walker Lake occurred in 1868 and estimated the highstand was between 4,089 feet and 4,108 feet. By 1882, Mason Valley was predominantly agricultural. The 7-26 feet decline in lake-surface altitude between 1868 and 1882 could partially be due to irrigation diversions during this time.

Scientific Investigations Report↗
USGS2010

Bathymetric surveys at highway bridges crossing the Missouri River in Kansas City, Missouri, using a multibeam echo sounder, 2010

Bathymetric surveys were conducted by the U.S. Geological Survey, in cooperation with the Missouri Department of Transportation, on the Missouri River in the vicinity of nine bridges at seven highway crossings in Kansas City, Missouri, in March 2010. A multibeam echo sounder mapping system was used to obtain channel-bed elevations for river reaches that ranged from 1,640 to 1,800 feet long and extending from bank to bank in the main channel of the Missouri River. These bathymetric scans will be used by the Missouri Department of Transportation to assess the condition of the bridges for stability and integrity with respect to bridge scour. Bathymetric data were collected around every pier that was in water, except those at the edge of the water or in extremely shallow water, and one pier that was surrounded by a large debris raft. A scour hole was present at every pier for which bathymetric data could be obtained. The scour hole at a given pier varied in depth relative to the upstream channel bed, depending on the presence and proximity of other piers or structures upstream from the pier in question. The surveyed channel bed at the bottom of the scour hole was between 5 and 50 feet above bedrock. At bridges with drilled shaft foundations, generally there was exposure of the upstream end of the seal course and the seal course often was undermined to some extent. At one site, the minimum elevation of the scour hole at the main channel pier was about 10 feet below the bottom of the seal course, and the sides of the drilled shafts were evident in a point cloud visualization of the data at that pier. However, drilled shafts generally penetrated 20 feet into bedrock. Undermining of the seal course was evident as a sonic 'shadow' in the point cloud visualization of several of the piers. Large dune features were present in the channel at nearly all of the surveyed sites, as were numerous smaller dunes and many ripples. Several of the sites are on or near bends in the river, resulting in a deep channel thalweg on the outside of the bend at these sites. At structure A5817 on State Highway 269, bedrock exposure was evident in the channel thalweg. The surveyed channel bed at a given site from this study generally was lower than the channel bed obtained during Level II scour assessments in 2002. At piers with well-defined scour holes, the frontal slopes of the holes were somewhat less than recommended values in the literature, and the shape of the holes appeared to be affected by the movement of dune features into and around the holes. The channel bed at all of the surveyed sites was lower than the channel bed at the time of construction, and an analysis of measurement data from the U.S. Geological Survey continuous streamflow-gaging station on the Missouri River at Kansas City, Missouri (station number 06893000), confirmed a lowering trend of the channel-bed elevations with time at the gaging station. The size of the scour holes observed at the surveyed sites likely was affected by the moderate flood conditions on the Missouri River at the time of the surveys. The scour holes likely would be substantially smaller during conditions of low flow.

Scientific Investigations Report↗
USGS2011

Bathymetric surveys at highway bridges crossing the Missouri and Mississippi Rivers near St. Louis, Missouri, 2010

Bathymetric surveys were conducted by the U.S. Geological Survey, in cooperation with the Missouri Department of Transportation, on the Missouri and Mississippi Rivers in the vicinity of 12 bridges at 7 highway crossings near St. Louis, Missouri, in October 2010. A multibeam echo sounder mapping system was used to obtain channel-bed elevations for river reaches ranging from 3,280 to 4,590 feet long and extending across the active channel of the Missouri and Mississippi Rivers. These bathymetric scans provide a snapshot of the channel conditions at the time of the surveys and provide characteristics of scour holes that may be useful in the development of predictive guidelines or equations for scour holes. These data also may be used by the Missouri Department of Transportation to assess the bridges for stability and integrity issues with respect to bridge scour. Bathymetric data were collected around every pier that was in water, except those at the edge of water or in extremely shallow water, and one pier that was surrounded by a large debris raft. Scour holes were present at most piers for which bathymetry could be obtained, and ranged from 0 to 16 feet deep except at piers on channel banks or those near or embedded in rock dikes. Scour holes observed at the surveyed bridges were examined with respect to frontal slope and shape, and scour holes near railroad bridges in the vicinity of the highway bridges also were examined. Although exposure of parts of foundational support elements was observed at several piers, the exposure likely can be considered minimal compared to the overall substructure that remains buried at these piers. At piers with well-defined scour holes, the frontal slopes of the holes ranged from 1.70 to 2.94 feet per foot (computed as run over rise), which were similar to recommended values in the literature (generally ranging from 1.0 to 2.0), and the shapes of the scour holes were not substantially affected by the movement of sand waves into the holes. Spur dikes near several of the piers caused localized flow disturbances that caused the resultant scour holes to display characteristics of skewed approach flow. The channel bed in the 2010 surveys was as much as 16 feet lower than the channel bed at the time of construction at the two oldest surveyed bridges, and the range varied with age of the structure, indicating the channel-bed elevations have lowered with time. However, other research has indicated the extremely dynamic nature of the channel bed on the Mississippi River. The size of the scour holes observed at the surveyed sites likely was affected by the low to moderate flow conditions on the Missouri and Mississippi Rivers at the time of the surveys. The scour holes likely would be larger during conditions of increased flow. Artifacts of horizontal positioning errors were present in the data, but an analysis of the surveys indicated that most of the bathymetric data have a total propagated error of less than 0.33 foot.

Scientific Investigations Report↗
USGS2012

Bathymetric and velocimetric surveys at highway bridges crossing the Missouri River in and into Missouri during summer flooding, July-August 2011

Bathymetric and velocimetric surveys were conducted by the U.S. Geological Survey, in cooperation with the Kansas and Missouri Departments of Transportation, in the vicinity of 36 bridges at 27 highway crossings of the Missouri River between Brownville, Nebraska and St. Louis, Missouri, from July 13 through August 3, 2011, during a summer flood. A multibeam echo sounder mapping system was used to obtain channel-bed elevations for river reaches ranging from 1,350 to 1,860 feet and extending across the active channel of the Missouri River. These bathymetric scans provide a "snapshot" of the channel conditions at the time of the surveys and provide characteristics of scour holes that may be useful in the development of predictive guidelines or equations for scour holes. These data also may be used by the Kansas and Missouri Departments of Transportation to assess the bridges for stability and integrity issues with respect to bridge scour during floods. Bathymetric data were collected around every pier that was in water, except those at the edge of water, in extremely shallow water, or surrounded by debris rafts. Scour holes were present at most piers for which bathymetry could be obtained, except at piers on channel banks, those near or embedded in lateral or longitudinal spur dikes, and those on exposed bedrock outcrops. Scour holes observed at the surveyed bridges were examined with respect to depth and shape. Although exposure of parts of foundational support elements was observed at several piers, at most sites the exposure likely can be considered minimal compared to the overall substructure that remains buried in bed material; however, there were several notable exceptions where the bed material thickness between the bottom of the scour hole and bedrock was less than 6 feet. Such substantial exposure of usually buried substructural elements may warrant special observation in future flood events. Previous bathymetric surveys had been done at several of the sites, and comparisons between bathymetric surfaces from the previous surveys and those of this study indicate substantial variability in the response of the channel bed to the 2011 summer flood conditions. At sites in Kansas City, there was no consistent deepening of the channel or increase in the size of scour holes, despite substantially more discharge and a higher water-surface elevation in the 2011 surveys, which implies the high-flow conditions during the 2011 surveys created a similar scour scenario to the previous surveys. At Jefferson City and the St. Louis sites, there was a consistent deepening of the channel, and a slight to substantial increase in the depth of scour holes in the 2011 surveys compared to previous surveys, although the effects of the higher flow appeared to be mitigated by the shape and alignment of the piers at most sites in St. Louis. Construction activities related to a new bridge at the Atchison, Kansas, site likely have contributed to the substantial additional scour observed there in a previous survey during the 2010 flooding, and the subsequent aggradation of the channel bed observed in the 2011 survey. Pier size, nose shape, and alignment to flow also had a profound effect on the size of the scour hole observed for a given pier.

Missouri;Nebraska↗
USGS2013

Settlement of the USS Arizona, Pearl Harbor, Hawaii

The U.S. Geological Survey, in collaboration with the National Park Service Submerged Resources Center, undertook investigations at the USS Arizona Memorial at Pearl Harbor, Hawaii, in 2002, 2003, and 2005 to characterize geological factors affecting the deterioration and movement of the hull of the USS Arizona. Since sinking on the morning of December 7, 1941, the hull of the USS Arizona has been slowly but steadily disappearing below the surface of Pearl Harbor. Continuous sediment coring at three of four locations around the hull of the Arizona was only partially successful, but it was sufficient to identify a varied sedimentary substrate beneath the hull. A boring near the stern reveals a thick, continuous sequence of soft, gray clay to the bottom of the boring. In contrast, borings near the bow and starboard side, below about 5 meters subbottom depth, indicate the presence of very stiff, brown clay and coral debris and an absence of soft clay. Multisensor core logger scanning of the recovered cores distinguishes the lower density of the soft, gray clay at the stern from the higher density of the stiff, brown clays and coral debris at the bow and starboard side. Uniaxial consolidation testing of the soft gray clay indicates a normally consolidated sequence, whereas the stiff, brown clay and coral debris are overconsolidated. Profiles of shear wave velocity vs. depth obtained through spectral analysis of interface wave testing around the perimeter of the hull in 2005 identified areas of higher velocity, stiffer sediment at the bow and starboard side, which correspond to the dense, stiff clay recovered near the bow and starboard borings. Low shear-wave velocities at the port midship and quarter of the hull correlate with the lower density, softer sediment recovered from the boring at the stern. Cross sections of the subbottom of the Memorial combine results from the sediment borings and geophysical surveys and depict a wedge of soft clay unconformably overlying the stiff clays and coral debris beneath the aft half of the USS Arizona and thickening toward the stern. The 2008 position of the hull has been documented using both tide-based and differential Global Positioning System (GPS) measuring systems. Analysis of historical and recent photographs was done to create a record of settlement from the time of sinking in 1941 to the present. By examining shadows in suitable photos, the sun azimuth, local time of day, and tide levels were determined to derive tide-adjusted and sea-level-rise-corrected elevations for structures on the hull and from these elevations to obtain settlement and tilt trends. The settlement trends, most complete for barbette 3, have two components. An early, nonlinear component ends on December 9, 1941, and represents the initial penetration and displacement of the bottom sediment by the hull. A linear, long-term trend of normal consolidation continues to the present day. Long-term settlement rates are greatest at the stern and decrease linearly to the midship, showing that the aft half of the hull is moving as an intact, rigid body. The recent rate of settlement at the stern is about 3.5 mm/year; rates at the starboard midship and forward part of the hull are less than one-third of the stern rate. The aft half of the USS Arizona hull presently tilts about 2 degrees to port, an increase of at least 1.5 degrees since the initial sinking of the ship. The results of this study identify differential settlement of the Arizona hull, due to the wedge of soft clay underlying the aft half of the hull, as the cause of the movement of the hull beneath the surface of Pearl Harbor. Calculation of sediment consolidation using lab-determined properties of the soft clay demonstrates that the observed settlements can be reproduced by projecting appropriate clay thicknesses beneath the hull. Several of the high-quality photographs analyzed for the historical settlement analysis highlight some of the limitations of this retrospective technique for determining tide-based elevations. In these cases, calculated structure elevations do not conform to the settlement trend, indicating that there can be complicating factors affecting the interpretation of the photos. Conflicting dates for events during the salvage operations were also encountered.

Hawai'i↗
USGS2013

Erosion monitoring along the Coosa River below Logan Martin Dam near Vincent, Alabama, using terrestrial light detection and ranging (T-LiDAR) technology

Alabama Power operates a series of dams on the Coosa River in east central Alabama. These dams form six reservoirs that provide power generation, flood control, recreation, economic opportunity, and fish and wildlife habitats to the region. The Logan Martin Reservoir is located approximately 45 kilometers east of Birmingham and borders Saint Clair and Talladega Counties. Discharges below the reservoir are controlled by power generation at Logan Martin Dam, and there has been an ongoing concern about the stability of the streambanks downstream of the dam. The U.S. Geological Survey, in cooperation with Alabama Power conducted a scientific investigation of the geomorphic conditions of a 115-meter length of streambank along the Coosa River by using tripod-mounted terrestrial light detection and ranging technology. Two surveys were conducted before and after the winter flood season of 2010 to determine the extent and magnitude of geomorphic change. A comparison of the terrestrial light detection and ranging datasets indicated that approximately 40 cubic meters of material had been eroded from the upstream section of the study area. The terrestrial light detection and ranging data included in this report consist of electronic point cloud files containing several million georeferenced data points, as well as a surface model measuring changes between scans.

Alabama↗
USGS2016

Hydrogeologic investigations of the Miocene Nogales Formation in the Nogales Area, Upper Santa Cruz Basin, Arizona

Hydrogeologic investigations were conducted to evaluate the groundwater resource potential for the Miocene Nogales Formation in the Nogales area, southern Arizona. Results indicate that parts of the formation may provide new, deeper sources of groundwater for the area. Geologic mapping determined the hydrogeologic framework of the formation by defining lithologic, mineralogic, and stratigraphic characteristics; identifying potential aquifers and confining units; and mapping faults and fractures which likely influence groundwater flow. Geophysical modeling was used to determine the basin geometry and thickness of the Nogales Formation and younger alluvial aquifers and to identify target areas (deep subbasins) which may prove to be productive aquifers. Volcaniclastic sandstone samples from the formation were analyzed for porosity, bulk density, saturated hydraulic conductivity, and fabric. Effective porosity ranges from 16 to 42 percent, bulk density from 1.6 to 2.47 grams per cubic centimeter, and saturated hydraulic conductivity (SHC) from 4 to 57 centimeters per day (4.9×10 -5 to 6.7×10 -4 centimeters per second). Thin sections show that sandstone framework grains consist of quartz, feldspar, biotite, hornblende, pumice, volcanic glass, and opaque minerals. The matrix in most samples consists of pumice fragments, and some contain predominantly silt and clay. Samples with a mostly silt and clay matrix have lower porosity and SHC compared to samples with mostly pumice, which have higher and wider ranges of porosity and SHC. Pore space in the Nogales Formation sediments includes moldic, intercrystalline, and fracture porosity. Some intercrystalline pore space is partially filled with calcite cement. About one third of the samples contain fractures, which correspond to fractures noted in outcrops in all members of the formation. Scanning electron microscope (SEM) and x-ray diffraction (XRD) analyses indicate that most of the samples contained the zeolite clinoptilolite and mixed-layer clay. X-ray diffraction analyses verified clinoptilolite as the only zeolite in Nogales Formation samples; they also verified the presence of smectite and illite clay and some kaolinite. Samples which contain greater amounts of clinoptilolite and lesser amounts of smectite have high porosity and SHC in narrow ranges. However, samples with abundant smectite and lesser amounts of clinoptilolite span the entire ranges of porosity and SHC for the formation. All members of the Nogales Formation are fractured and faulted as a result of Tertiary Basin and Range extensional deformation, which was broadly contemporaneous with deposition of the formation. These structures may have significant influence on groundwater flow in the upper Santa Cruz basin because, although many of the sediments in the formation have characteristics indicating they may be productive aquifers based only on porous-media flow, fracturing in these sediments may further enhance permeability and groundwater flow in these basin-fill aquifers by orders of magnitude.

Arizona↗
USGS2017

The discovery and character of Pleistocene calcrete uranium deposits in the Southern High Plains of west Texas, United States

This report describes the discovery and geology of two near-surface uranium deposits within calcareous lacustrine strata of Pleistocene age in west Texas, United States. Calcrete uranium deposits have not been previously reported in the United States. The west Texas uranium deposits share characteristics with some calcrete uranium deposits in Western Australia—uranium-vanadium minerals hosted by nonpedogenic calcretes deposited in saline lacustrine environments. In the mid-1970s, Kerr-McGee Corporation conducted a regional uranium exploration program in the Southern High Plains province of the United States, which led to the discovery of two shallow uranium deposits (that were not publicly reported). With extensive drilling, Kerr-McGee delineated one deposit of about 2.1 million metric tons of ore with an average grade of 0.037 percent U 3 O 8 and another deposit of about 0.93 million metric tons of ore averaging 0.047 percent U 3 O 8 . The west-Texas calcrete uranium-vanadium deposits occur in calcareous, fine-grained sediments interpreted to be deposited in saline lakes formed during dry interglacial periods of the Pleistocene. The lakes were associated with drainages upstream of a large Pleistocene lake. Age determinations of tephra in strata adjacent to one deposit indicate the host strata is middle Pleistocene in age. Examination of the uranium-vanadium mineralization by scanning-electron microscopy indicated at least two generations of uranium-vanadium deposition in the lacustrine strata identified as carnotite and a strontium-uranium-vanadium mineral. Preliminary uranium-series results indicate a two-component system in the host calcrete, with early lacustrine carbonate that was deposited (or recrystallized) about 190 kilo-annum, followed much later by carnotite-rich crusts and strontium-uranium-vanadium mineralization in the Holocene (about 5 kilo-annum). Differences in initial 234 U/ 238 U activity ratios indicate two separate, distinct fluid sources.

Texas↗