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At least 1,405 records · Page 78Linked to original sources

USGS1996

Hydrogeology of structurally extended terrain in the eastern Great Basin of Nevada, Utah, and adjacent states, from geologic and geophysical models

The Great Basin of the western United States encompasses most of Nevada and western Utah (fig. 1). The climate of the region is semiarid to arid, with most precipitation falling as winter Show. The region is characterized by internal drainage (generally no hydrologic outlet to the ocean). Water resources in the region are limited and nearly all reliable surface-water sources have been allocated for use. The most commonly used aquifers arc sand-and-gravel basin-fill deposits in structural basins of the region. In many basins, pumpage from the basin-fill aquifers is as much as (or more than) the safe yield. Consequently, aquifers other than basin fill are being assessed in the eastern Great Basin to determine where and how much additional ground water is present and what might be the effects of development. This study was part of the Nevada Carbonate Aquifers Program, in cooperation with the State of Nevada, Las Vegas Valley Water District, City of North Las Vegas, and the Bureau of Reclamation. This atlas presents a conceptual model of the geologic and hydrologic features of structurally extended terrains in the eastern Great Basin. First, the model is described and major structural features are compared with regional groundwater flow patterns. Second, the validity of the conceptual hydrogeologic model is evaluated using geophysical data and geologic models derived from geophysical profiles.

Nevada;Utah↗

USGS2011

Geologic map of the Chisos Mountains, Big Bend National Park, Texas

The Chisos Mountains form some of the highest ground in Texas, second only to Guadalupe Peak near the New Mexico border. The northern half of the range is mostly above 5,500 feet with Emory Peak the high point at 7,825 feet. The mountains are centrally located in Big Bend National Park between Panther Junction and Punta de la Sierra. Big Bend National Park lies near the diffuse border between the Great Plains Province to the northeast and the Sonoran section of the Basin-and-Range structural province to the west and southwest. These geologically unique regions are distinguished from one another by large differences in their landscape and by the amount and style of internal structural deformation. The Great Plains Province is characterized by flat-lying or gently dipping sedimentary strata, low topographic relief, shallow stream valleys, and by a general lack of faulting. Very little active deposition is occurring on the plains, except in the bottoms of active stream valleys. In southwestern Texas the plains stand at average elevations of 2,000 to 3,300 feet and slope gently east toward the Mississippi River and the Gulf of Mexico. The Great Plains have remained relatively unchanged for the last 65 million years, except that they have been uplifted to their present height from lower elevations probably in the last 5 million years. The Basin-and-Range province is characterized by linear parallel mountain ranges, deep sediment-filled valleys, and high structural and topographic relief. The eastern part of the province is at a slightly higher average elevation than the plains. The province is known for its complex patterns of Cenozoic faulting. Today it bears little resemblance to the way it was during the Paleocene when the entire Trans-Pecos region was a simple lowland that was near or slightly below sea level.

Scientific Investigations Map↗

USGS1984

Geologic evolution, sedimentation, and paleoenvironments of the Angola Basin and adjacent Walvis Ridge: Synthesis of results of Deep Sea Drilling Project Leg 75

The section recovered at Site 530 (Holes 53OA and 530B) consists of eight sedimentary units and one basalt unit. The composition of the basalt recovered in Hole 53OA is distinct from typical mid-ocean ridge basalts (MORBs) but is similar to that of Hawaiian tholeiites and basalt from the central part of Walvis Ridge. Throughout most of its history, the southern Angola Basin received large volumes of redeposited material in the form of turbidites and, most recently, debris-flow deposits. Most of this material was derived from Walvis Ridge to the south, but thickness trends of acoustic units suggest that some of the sediment was derived from the African continental margin to the east. The basal sedimentary unit (Albian to Santonian) at Site 530 contains 262 beds of black shale that are interbedded with green and red claystone. Black shale makes up less than 10% of the total section, but in two cores of early Turonian age, black shale beds compose about 50% of the section. The black shales contain up to 19% organic carbon (average of about 5%) that is mainly of autochthonous marine origin but with significant contributions from terrigenous organic matter. The origin of these more- and less-reduced interbedded lithologies with varying amounts and types of organic matter, and variable amounts of pelagic, hemipelagic, and turbiditic sediment is complex and cannot be explained by any one simple process. Many factors affecting the concentration of dissolved oxygen in the bottom waters of the Angola Basin varied throughout the middle Cretaceous to produce bottom-water conditions that fluctuated between mildly oxic and oxygen-deficient, but most of the time bottom-waters and sediment-interstitial waters were sufficiently oxic to permit the accumulation of red oxidized sediment. A relatively complete sedimentary record of the Cretaceous/Tertiary boundary was recovered within a sequence of mudstone and marlstone turbidites in Hole 530A. There is a significant increase in the concentration of iridium above background levels at the boundary. High concentrations of many other elements also occur within the same stratigraphic interval as the iridium anomaly. Furthermore, there is a marked decrease in CaCO3 in the Tertiary strata above the iridium anomaly which suggests that the production of shallow-water carbonate also may have been affected by whatever caused elevated concentrations of iridium and other elements. These observations are consistent with the asteroid-impact theory proposed to explain the worldwide occurrence of an iridium anomaly at the Cretaceous/Tertiary boundary. The Cenozoic history of the Angola Basin was controlled mainly by (1) restriction of bottom-water flow from the south by Walvis Ridge; (2) development of glaciation on Antarctica; (3) opening of circulation passages in the southern oceans; (4) rapid turnover of cold, nutrient-rich waters that resulted in high productivity of diatoms; (5) influx of terrigenous sediment mainly by turbidity currents; and (6) production and preservation of carbonate sediment. The most distinctive Cenozoic event recorded in the section at Site 530 is the beginning of extensive glaciation on Anarctica and concomitant initiation of modern thermohaline bottom-water circulation that is manifested as a middle Eocene to middle Oligocene unconformity or compressed section accompanied by a drastic decrease in accumulation of CaCO3. Diatom abundances in HPC cores from Walvis Ridge (Site 532) and Angola Basin (Hole 53OB) indicate that Benguela upwelling in these areas began in the late Miocene, reached a peak in the late Pliocene to early Pleistocene, and declined thereafter. Short-term variations in sediment composition at Site 532 are manifested as cyclic variations in concentrations of clay, CaCO3, and organic carbon with average periodicities of about 30-60 k.y. The main variability that produced the cycles probably was the influx of terrigenous clastic material which diluted the CaCO3. The sediment at Site 532 also contains several percent organic carbon that is dominantly of marine origin, but with significant terrigenous components. Data from multichannel seismic, gravity, and magnetic surveys were used to define the regional stratigraphic and structural evolution of Walvis Ridge and adjacent Cape and Angola basins. Six structural provinces are recognized, four on Walvis Ridge and two additional provinces that correspond to the Cape and Angola basins. The two eastern structural provinces on Walvis Ridge are underlain by continental crust. The two western structural provinces are underlain by oceanic basement. Two main directions of faults are evident in seismic profiles, one trending N 10° and one trending N 60°. The N 60° trend corresponds to the general orientation of the northern and southern flanks of Walvis Ridge as well as to the dominant direction of fracture zones. During the first phase of separation of Africa from South America (ca. 120-130 m.y. ago), a voluminous mass of volcanics was emplaced simultaneous with the emplacement of basalt in the Parana Basin of Brazil and the Kaokoveld Region of South Africa. This period of volcanism also formed the series of seaward-dipping internal basement reflectors that are characteristic of the two structural provinces of Walvis Ridge. A system of fault blocks developed in the brittle upper part of the newly formed crust. During the second phase of rifting, which ended before late Aptian, more tilted fault blocks were created in the upper brittle stratified continental crust. Magnetic lineations in basement rocks in the Angola and Cape basins in the vicinity of Walvis Ridge are not distinct but suggest that oceanic crust began to be emplaced between 120 and 112 m.y. ago (Barremian to early Aptian). At least part of the oceanic crust of the central plateau of eastern Walvis Ridge (structural province 3) may have been emplaced before any oceanic crust formed in the adjacent basins. A ridge jump occurred during the late Aptian to early Albian in the southern part of the Angola Basin which translated the previously formed oceanic crust and its overlying evaporite deposits on the South American side. Several ridge jumps occurred on both sides of Walvis Ridge during the Late Cretaceous and early Tertiary to produce a 500-km-long segment of mid-ocean ridge.

Initial Reports of the D.S.D.P.↗

USGS2002

Geologic Map of the Diana Chasma Quadrangle (V-37), Venus

Introduction The Diana Chasma quadrangle (V-37), an equatorial region between 0° to 25° S. and 150° to 180° E. that encompasses ~8,400,000 km 2 , is broadly divided into southern Rusalka Planitia in the north, eastern Aphrodite Terra in the central region, and unnamed regions to the south. Geologic mapping constrains the temporal and spatial relations of the major features, which include a tessera inlier, Markham crater, six large coronae (300-675 km diameter), four smaller coronae (150-225 km diameter), Diana and Dali chasmata, a large fracture zone, and southern Rusalka Planitia. Eastern Aphrodite Terra, marked here by large coronae, deep chasmata, and an extensive northeast-trending fracture zone, extends from Atla Regio to Thetis Regio. The large coronae are part of a chain of such features that includes Inari Corona to the west-southwest and Zemina Corona to the northeast. V-37 quadrangle is bounded on the north by Rusalka Planitia and on the south by Zhibek Planitia. International Astronomical Union (IAU) approved and provisional nomenclature and positions for geographic features within Diana Chasma quadrangle are shown on the geologic map. [Note: Atahensik Corona was referred to as Latona Corona in much previously published literature.] Diana Chasma quadrangle hosts some of the steepest topography on Venus. Altimetry measurements range from -2.5 to 4.7 km (0.0 = mean planetary radius), with a surface mean of 0.6 km. Fractures and faults within the central fracture/rift zone create large blocks of down-dropped material, especially along the east-central edge of the map area. The Dali and Diana chasmata display slopes of >30°, the steepest and deepest trenches on Venus. Both chasmata host landslide deposits presumably sourced from the steep chasmata walls. The tessera inlier, coronae, and ridge belts sit topographically above Rusalka and Zhibek planitiae. Rusalka Planitia topography describes broad undulations having northwest-trending ridges spaced ~200 km apart. The most distinctive ridge, Vetsorgo Dorsum, centered at 6.5° S., 163° E., is a Class I ridge belt owing to its simple arch morphology. The central interior of Markham crater sits topographically lower than the surrounding region, which slopes downward to the east.

IMAP↗

USGS2021

Alaska Landbird Conservation Plan

Alaska is a land of extremes. The diversity of its avifauna reflects the heterogeneity of its landscape, with more than 500 species of birds recorded in the state. Species inhabiting primarily terrestrial habitats, known collectively as landbirds, constitute the largest and most ecologically diverse component of the Alaska avifauna. Habitats used by landbirds range from temperate rainforests in southeastern Alaska to Arctic tundra across much of northern Alaska. Most of these landbird species are migratory, and four major global migration flyways converge on rich breeding areas in Alaska. Alaska has one endemic landbird species, the McKay’s Bunting, and is home to an impressive number of landbird populations for which it hosts a large proportion of the regional, continental, or global population. Thus, Alaska has a significant stewardship responsibility for these particular landbird species and subspecies. Habitats in Alaska remain largely pristine due to the region’s remote nature, vast size, and small human population. Alaska’s growing population and attendant economic development, however, present many challenges that could affect all wildlife, including landbirds. Threats in Alaska are often considered to be less significant than those occurring elsewhere, where habitats are being altered by more rapidly increasing anthropogenic pressures, but they carry far-reaching consequences nonetheless. Habitats and ecosystem dynamics are changing rapidly due to the magnitude of climate warming at high latitudes. As such, effective landbird conservation in Alaska requires a broad, landscape-scale approach. Conservation of landbirds over such an extensive and diverse landscape also demands that we integrate efforts in habitat management, population monitoring, research, education, and outreach at local, regional, continental, and international scales. Information on distribution and habitat requirements of landbirds should be incorporated into land-use planning decisions. Synthesizing information on distribution and population trends of landbirds is a critical, time-sensitive task. Such information should be provided in a form that is readily available to land managers and policy decision-makers. The primary objectives of this plan are to (1) describe the region and Alaska’s landbird avifauna; (2) identify species of concern, important habitats, and key information needs; (3) highlight major conservation issues and threats to landbirds; and (4) identify potential conservation actions. We first examine landbird conservation at the statewide level within broad perspectives (regional, continental, and global), then take a detailed look at the specific issues, information needs, and potential conservation actions within each Bird Conservation Region in Alaska.

Alaska↗

USGS1999

Biomonitoring of Environmental Status and Trends (BEST) Program: Field Procedures for Assessing the Exposure of Fish to Environmental Contaminants

This document describes procedures used to collect information, tissues, and fluids for documenting the exposure of fish to environmental contaminants. For the procedures described here, fish are captured (preferably by electrofishing) and held alive until processing (generally <1 h). Fish are weighed, measured, and examined for grossly visible external lesions and pathologies. A blood sample is collected by caudal veinipuncture using a needle and syringe. The fish is subdued and it's abdominal cavity opened. The internal organs are dissected from the fish for examination. The sex of the fish is determined by direct observation of its gonads. The liver is weighed (most species) and cut into small cubes and flash-frozen in cryogenic vials, which are stored and shipped in dry ice or liquid nitrogen. Additional liver cubes plus all grossly visible anomalies are preserved for histopathology. The gonads and spleen are weighed, and samples are preserved for histopathology. The kidneys are examined, and histopathology samples collected. A gill sample is also collected and preserved. All remaining tissues are returned to the carcass, which is wrapped in foil, labeled for chemical analysis, and chilled. Individual fish carcasses are composited by station, species, and gender; frozen; and shipped to the analytical laboratory. Procedures are also described for record keeping; processing blood to obtain serum and plasma; flash-freezing samples; cleaning equipment; and preventing the transport of living organisms among waterways. A list of necessary equipment and supplies is also provided.

Information and Technology Report↗

USGS1989

Genetic differentiation among lake trout strains stocked into Lake Ontario

The lake trout Salvelinus namaycush is the focus of an international effort by fishery management agencies to restore this once‐native species to Lake Ontario. Evaluation of reproductive success and comparisons among stocked lake trout strains require genetic markers. We used allozyme variation to make genetic comparisons among strains of lake trout stocked into Lake Ontario. Forty‐two proteins presumed to be encoded by 102 loci were resolved electrophoretically; 18 loci were polymorphic. Among 16 samples from five principal origins (Finger Lakes, Great Lakes basin, northern New York–Adirondack, Manitoba, and mixed origins–Lake Ontario), the average observed heterozygosity was 0.029, and the proportion of polymorphic loci was 0.125. Significant differences occurred among the 16 samples at all 18 possible locus comparisons. The average F st value was 0.14. Hierarchical analysis indicated that the variation among samples within an origin was greatest within the Great Lakes basin, which included the greatest number of samples and represented the largest geographic area. Most variation observed among samples, however, occurred among origins. The 1983 and 1984 hatchery year classes produced from the 1978 Seneca brood stock did not differ significantly. The 1981 Seneca brood stock more closely resembled the sample of wild lake trout from Seneca Lake than progeny from the 1978 brood stock. The closer affinity of the 1981 brood stock to wild Seneca lake trout may be due to the larger number of wild adults from Seneca Lake used to found these fish than was used to establish the 1978 brood stock. Siscowet (“fat”) and “lean” lake trout from Lake Superior were significantly different from each other; however, the level of variation between them was not greater than that among samples from other origins, and thus did not support recognition of siscowet lake trout as a distinct subspecies. The Jenny Lake strain possessed a genetic affinity to the siscowet sample from Lake Superior. Historical reports about the origin of this strain suggest that siscowet lake trout from northern Lake Michigan may have been used to found this strain. Therefore, the Jenny Lake strain may serve as a gene source for the establishment of the siscowet lake trout in Lake Ontario. The substantial differentiation among lake trout strains reported here supports the feasibility of using allozyme markers to identify the parental sources of naturally produced young.

Lake Ontario↗

USGS2017

Description of chronostratigraphic units preserved as channel deposits and geomorphic processes following a basin-scale disturbance by a wildfire in Colorado

The consequence of a 1996 wildfire disturbance and a subsequent high-intensity summer convective rain storm (about 110 millimeters per hour) was the deposition of a sediment superslug in the Spring Creek basin (26.8 square kilometers) of the Front Range Mountains in Colorado. Spring Creek is a tributary to the South Platte River upstream from Strontia Springs Reservoir, which supplies domestic water for the cities of Denver and Aurora. Changes in a superslug were monitored over the course of 18 years (1996–2014) by repeat surveys at 18 channel cross sections spaced at nearly equal intervals along a 1,500-meter study reach and by a time series of photographs of each cross section. Surveys were not repeated at regular time intervals but after major changes caused by different geomorphic processes. The focus of this long-term study was to understand the evolution and internal alluvial architecture of chronostratigraphic units (defined as the volume of sediment deposited between two successive surveys), and the preservation or storage of these units in the superslug. The data are presented as a series of 18 narratives (one for each cross section) that summarize the changes, illustrate these changes with photographs, and provide a preservation plot showing the amount of each chronostratigraphic unit still remaining in June 2014. The most significant hydrologic change after the wildfire was an exponential decrease in peak discharge of flash floods caused by summer convective rain storms. In response to these hydrologic changes, all 18 locations went through an aggradation phase, an incision phase, and finally a stabilization phase. However, the architecture of the chronostratigraphic units differs from cross section to cross section, and units are characterized by either a laminar, fragmented, or hybrid alluvial architecture. In response to the decrease in peak-flood discharge and the increase in hillslope and riparian vegetation, Spring Creek abandoned many of the nearly horizontal erosional and depositional surfaces and left a landscape consisting of a series of cut-and-fill terraces as a legacy of this wildfire disturbance.

Colorado↗

USGS1984

Water quality in the New River from Calexico to the Salton Sea, Imperial County, California

The New River enters the United States at Calexico, Calif., after it crosses the international boundary. Water-quality data from routine collection indicated that the New River was degraded by high organic and bacterial content. Intensive sampling for chemical and physical constituents and properties of the river was done May 9-13, 1977, to quantify the chemical composition of the water and to identify water-quality problems. Concentrations of total organic carbon in the New River at Calexico ranged from 80 to 161 milligrams per liter and dissolved organic carbon ranged from 34 to 42 milligrams per liter; the maximum chemical oxygen demand was 510 milligrams per liter. Intensive sampling for chemical and biological characteristics was done in the New River from May 1977 to June 1978 to determine the occurrence of the organic material and its effects on downstream water quality. Dissolved-oxygen concentration was measured along longitudinal profiles of the river from Calexico to the Salton Sea. A dissolved-oxygen sag downstream from the Calexico gage varied seasonally. The sag extended farther downstream and had lower concentrations of dissolved oxygen during the summer months than during the winter months. The sag of zero dissolved-oxygen concentration extended 26 miles in July 1977. In December 1976, the sag extended 20 miles but the minimum dissolved-oxygen concentration was 2.5 milligrams per liter. The greatest diel (24-hour) variation in dissolved-oxygen concentration occurred in the reach from the Calexico gage to Lyons Crossing, 8.8 miles downstream. High concentrations of organic material were detected as far as Highway 80, 19.5 miles downstream from the international boundary. Biological samples analyzed for benthic invertebrates showed that water at the Calexico and Lyons Crossing sites, nearest the international boundary, was of such poor quality that very few bottom-dwelling organisms could survive. Although the water was of poor quality at Keystone Road, 36 miles downstream, it was able to support a benthic community. The April sample had more than 9,150 organisms on a multiplate sampler, 8,770 of which were of one species. Farther downstream at the Westmorland gage, the water quality, as indicated by the number and diversity of organisms, had improved over that at the Keystone site. The Alamo River at its outlet to the Salton Sea--the control site--had the greatest diversity of all the study sites. This diversity, when compared with the diversity at the Westmorland gage, indicated that the effects of the degraded water quality observed at the New River at Calexico are detected as far as 62 miles downstream. Standard bacteria indicator tests indicate that fecal contamination exists in the New River. Counts of fecal coliform bacteria ranged from 180,000 to 2,800,000 colonies per 100 milliliters for the 20-mile reach from Calexico to Highway 80, and fecal streptococcal bacteria ranged from 5,000 to 240,000 colonies per 100 milliliters.

California↗

USGS2004

Potential health impacts of burning coal beds and waste banks

Uncontrolled release of pollutants from burning coal beds and waste banks presents potential environmental and human health hazards. On a global scale, the emissions of large volumes of greenhouse gases from burning coal beds may contribute to climate change that alters ecosystems and patterns of disease occurrence. On regional and local scales, the emissions from burning coal beds and waste banks of acidic gases, particulates, organic compounds, and trace elements can contribute to a range of respiratory and other human health problems. Although there are few published reports of health problems caused by these emissions, the potential for problems can be significant. In India, large numbers of people have been displaced from their homes because of health problems caused by emissions from burning coal beds. Volatile elements such as arsenic, fluorine, mercury, and selenium are commonly enriched in coal deposits. Burning coal beds can volatilize these elements, which then can be inhaled, or adsorbed on crops and foods, taken up by livestock or bioaccumulated in birds and fish. Some of these elements can condense on dust particles that can be inhaled or ingested. In addition, selenium, arsenic, lead, tin, bismuth, fluorine, and other elements condense where the hot gaseous emissions come in contact with ambient air, forming mats of concentrated efflorescent minerals on the surface of the ground. These mats can be leached by rainwater and washed into local water bodies providing other potential routes of exposure. Although there are little data linking burning coal beds and waste banks to known health problems, a possibly analogous situation exists in rural China where mineralized coal burned in a residential environment has caused widespread and severe health problems such as fluorosis and arseniasis. ?? 2004 Elsevier B.V. All rights reserved.

International Journal of Coal Geology↗

USGS1996

Snow-depth and water-equivalent data for the Fairbanks area, Alaska, spring 1995

Snow depths at 34 sites and snow-water equivalents at 13 sites in the Fairbanks area were monitored during the 1995 snowmelt period (March 30 to April 26) in the spring of 1995. The U.S. Geological Survey conducted this study in cooperation with the Fairbanks International Airport, the University of Alaska Fairbanks, the Alaska Department of Natural Resources-Division of Mining and Water Management, the U.S Army, Alaska, and the U.S. Army Corps of Engineers-Alaska District. These data were collected to provide information about potential recharge of the ground-and surface-water systems during the snowmelt period in the Fairbanks area. This information is needed by companion geohydrologic studies of areas with known or suspected contaminants in the subsurface. Data-collection sites selected had open, boggy, wooded, or brushy vegetation cover and had different slope aspects. The deepest snow at any site, 27.1 inches, was recorded on April 1, 1995; the shallowest snow measured that day was 19.1 inches. The snow-water equivalents at these two sites were 5.9 inches and 4.5 inches, respectively. Snow depths and water equivalents were comparatively greater at open and bog sites than at wooded or brushy sites. Snow depths and water equivalents at all sites decreased throughout the measuring period. The decrease was more rapid at open and boggy sites than at wooded and brushy sites. Snow had completely disappeared from all sites by April 26, 1995.

Open-File Report↗

USGS2021

Assessment of a claimed ultra-low frequency electromagnetic (ULFEM) earthquake precursor

The rate of occurrence of anomalous ultra-low frequency electromagnetic (ULFEM) pulses has been claimed to have increased days to weeks prior to the M5.4 2007 and M4.0 2010 Alum Rock earthquakes. We re-examine the previously reported ultra-low frequency (ULF: 0.01–10 Hz) magnetic data recorded at a QuakeFinder site located 9 km from the earthquake hypocentre, and compare to data from a nearby Stanford-USGS site located 42 km from the hypocentre, to analyse the characteristics of the pulses and assess their origin. Using pulse definitions and pulse-counting algorithms analogous to those previously reported, we corroborate the increase in pulse counts before the 2007 Alum Rock earthquake at the QuakeFinder station, but we note that the number of pulses depends on chosen temporal and amplitude detection thresholds. These thresholds are arbitrary because we lack a clear physical model or basis for their selection. We do not see the same increase in pulse counts before the 2010 Alum Rock earthquake at the QuakeFinder or Stanford-USGS stations. In addition, the majority of pulses in the QuakeFinder data and Stanford-USGS data do not match temporally, indicating the pulses lack a common origin and are not from lightning or solar-driven ionospheric/magnetospheric disturbances. Our assessment of the temporal distribution of pulse counts shows pulse counts increase during peak human activity hours, suggesting these pulses result from local cultural noise and are not tectonic in origin. The many unknowns about the character and even existence of precursory earthquake pulses means that standard numerical and statistical tests cannot easily be applied. Yet here we show that exhaustive investigation of many different aspects of ULFEM signals can be used to properly characterize their origin.

California↗

USGS2023

Evaluation of portable Raman spectroscopic analysis for source-rock thermal maturity assessments on bulk crushed rock

This study presents a simplified method and empirical relationships for determining organic matter thermal maturity using a portable Raman system equipped with a 785 nm laser, for analysis of crushed, whole-rock samples. Suites of rocks represented by shale and coal samples with various mineralogical composition, thermal maturity, and total organic carbon (TOC) were used to test the method and build correlations between Raman band separation (RBS) values and traditional thermal maturity indicators, organic matter reflectance (Ro), and programmed temperature pyrolysis (Tmax) values. A set of disparate shale samples, where both vitrinite and solid bitumen reflectance values were reported, have Ro values that range from 0.40 to 4.62%. Above 3.35% Ro, the corresponding RBS values plateau at ∼290 cm−1, thus correlations were evaluated with a linear regression (R2 = 0.96) between 0.40 and 3.35% Ro. Shale samples with Ro < 2% and Tmax < 551 were also used to correlate Tmax and RBS, yielding a linear correlation with an R2 of 0.94. For the coal data set, Ro values range from 1.21 to 4.08% and correlated RBS values plateau at ∼250 cm−1 above Ro = 3.0%, suggesting its correlative application below this maturity level. Several sample preparation methods were tested on cuttings material and standard deviation values for RBS were minimized by washing, drying, and hand crushing the material to pass through a 40-mesh sieve, although less preparation can still yield reliable results. The high degrees of correlation between whole-rock RBS data and two thermal maturity indicators demonstrate the utility of this approach for generating source rock thermal maturity data from minimally processed, whole-rock samples which could easily be applied in field or laboratory settings.

International Journal of Coal Geology↗

USGS2015

Future wave and wind projections for United States and United-States-affiliated Pacific Islands

Changes in future wave climates in the tropical Pacific Ocean from global climate change are not well understood. Spatially and temporally varying waves dominate coastal morphology and ecosystem structure of the islands throughout the tropical Pacific. Waves also impact coastal infrastructure, natural and cultural resources, and coastal-related economic activities of the islands. Wave heights, periods, and directions were forecast through the year 2100 using wind parameter outputs from four atmosphere-ocean global climate models from the Coupled Model Inter-Comparison Project, Phase 5, for Representative Concentration Pathways (RCP) scenarios 4.5 and 8.5 that correspond to moderately mitigated and unmitigated greenhouse gas emissions, respectively. Wind fields from the global climate models were used to drive a global WAVEWATCH-III wave model and generate hourly time-series of bulk wave parameters for 25 islands in the mid to western tropical Pacific for the years 1976–2005 (historical), 2026–2045 (mid-century projection), and 2085–2100 (end-of-century projection). Although the results show some spatial heterogeneity, overall the December-February extreme significant wave heights, defined as the mean of the top 5 percent of significant wave height time-series data modeled within a specific period, increase from present to mid-century and then decrease toward the end of the century; June-August extreme wave heights increase throughout the century within the Central region of the study area; and September-November wave heights decrease strongly throughout the 21st century, displaying the largest and most widespread decreases of any season. Peak wave periods increase east of the International Date Line during the December-February and June-August seasons under RCP4.5. Under the RCP8.5 scenario, wave periods decrease west of the International Date Line during December-February but increase in the eastern half of the study area. Otherwise, wave periods decrease throughout the study area during other seasons. Extreme wave directions in equatorial Micronesia during June-August undergo an approximate 30° clockwise rotation from primarily west to northwest. September-November RCP4.5 extreme mean wave directions rotate counterclockwise by approximately 30 to 45° in equatorial Micronesia; September-November RCP8.5 extreme mean wave directions within equatorial Micronesia rotate clockwise by approximately 20 to 30°. Extreme wind speeds decreased within both scenarios, with the largest decreases occurring in the September-November season. Extreme wind directions under RCP4.5 rotated clockwise by more than 60° in equatorial Micronesia during the September-November season and by approximately 30° during June-August. RCP8.5 extreme wind directions rotated counterclockwise during September-November within the same region by 30 to 50° and clockwise by 30 to 40° at one island. The spatial patterns and trends are similar between the two different greenhouse gas emission scenarios, with the magnitude and extent of the trends generally greater for the higher (RCP8.5) scenario.

Micronesia, Pacific Ocean↗

USGS2002

A two-dimensional hydrodynamic model of the St. Clair-Detroit River waterway in the Great Lakes basin

The St. Clair-Detroit River waterway connects Lake Huron with Lake Erie in the Great Lakes basin to form part of the international boundary between the United States and Canada. A two-dimensional hydrodynamic model is developed to compute flow velocities and water levels as part of a source water assessment of public water intakes. The model, which uses the generalized finite-element code RMA2, discretizes the waterway into a mesh formed by 13,783 quadratic elements defined by 42,936 nodes. Seven steady-state scenarios are used to calibrate the model by adjusting parameters associated with channel roughness in 25 material zones. An inverse modeling code is used to systematically adjust model parameters and to determine their associated uncertainty by use of nonlinear regression. Calibration results show close agreement between simulated and expected flows in major channels and water levels at gaging stations. Sensitivity analyses describe the amount of information available to estimate individual model parameters, and quantify the utility of flow measurements at selected cross sections and water-level measurements at gaging stations. Further data collection, model calibration analysis, and grid refinements are planned to assess and enhance two-dimensional flow simulation capabilities describing the horizontal flow distributions in St. Clair and Detroit Rivers and circulation patterns in Lake St. Clair.

St. Clair-Detroit River waterway↗

USGS2022

Hawaii and Landsat

Hawaii stands apart from the rest of the United States, literally and figuratively. The nearest of the eight islands that make up the Hawaiian archipelago is 2,000 miles from the U.S. mainland. Like every bit of land mass within the State, it emerged from the Pacific Ocean after thousands of years of undersea volcanic activity. Kona International Airport, on the “Big Island” of Hawai‘i, was built atop 220-year-old lava flows from the Hualālai volcano. The volcanic soils and tropical vegetation that stretch across Hawaii’s postcard-perfect peaks and valleys, as well as the trade winds that blow precipitation northeast across the islands and the warm Kona winds that move in from the south, are among the factors that make the study of the State’s landscapes distinct from the rest of the Nation. Six active volcanoes continue to alter the land surface. Some of them, like the constantly erupting Kīlauea or Mauna Loa, the world’s largest active volcano, can threaten human life and property. Man-made changes to the islands, such as the long-term agricultural production of sugar cane or pineapple, along with the introduction of non-native species, have also affected the health of the State’s ecosystems. Landsat satellites, with 50 years of repeat Earth observations and decades of data from infrared and thermal instruments capable of tracking lava flows, can offer unique opportunities for the study of Hawaii’s ever-changing landscapes. Here are a few examples of how Landsat benefits the State.

Hawaii↗

USGS2002

Visualization of a drifting buoy deployment on Lake St. Clair within the Great Lakes Waterway from August 12-15, 2002

Lake St. Clair is a 430 square mile lake between the state of Michigan and the province of Ontario, which forms part of the international boundary between the United States and Canada in the Great Lakes Basin. Lake St. Clair receives most of its inflow from Lake Huron through St. Clair River, which has an average flow of 182,000 cubic feet per second. The lake discharges to Detroit River, where it flows 32 miles to Lake Erie. Twelve drifting buoys were deployed on Lake St. Clair for 74 hours between August 12-15, 2002 to help investigate flow circulation patterns as part of a source water assessment study of the susceptibility of public water intakes. The buoys contained global positioning system (GPS) receivers to track their movements. Buoys were released in a transect between tethered buoys marking an 800-foot wide navigational channel in the north-central part of the lake just downstream of St. Clair River, and about 15.5 miles northeast of Detroit River. In addition, an acoustic Doppler current profiler (ADCP) was used to measure velocity profiles in a grid of 41 points that spanned the area through which the buoys drifted. Computer animations, which can be viewed through the Internet, were developed to help visualize the results of the buoy deployments and ADCP measurements.

Lake St. Clair↗

USGS2001

Transboundary movement of airborne pollutants — A methodology for integrating spaceborne images and ground based data

The availability of relevant and accurate environmental information is essential for environmental policy-makers. Recent improvements in satellite remote sensing technologies, groundbased monitors, and data access have resulted in the ability to observe and assess major atmospheric and ecological events around the world on a timely basis Each of these monitoring technologies reveals different and useful information, yet rarely are the resulting data sets used together in an integrated manner. The U.S. Environmental Protection Agency (EPA) and the United Nations Environment Programme (UNEP) Global Resource Information Database (GRID) office in Sioux Falls identified an environmental issue of global interest as a test case for applying an integrated approach: the transboundary movement of atmospheric pollutants. Transboundary movement of atmospheric pollutants has ramifications for human and environmental health, as well as economic impacts. As a result, it is the focus of many bilateral, regional, and international policy efforts. A central question with atmospheric pollutant transport is how to monitor pollutant movement and how to merge different monitoring datasets into useful information. Highly visible regional plumes of dust, smoke, and urban haze can be seen with satellite sensors, while ground-based monitoring of air pollutants such as fine particulates, SO2 , and toxics occurs at the local level. Integration of these two kinds of measurements allows the user to remotely observe large environmental effects in many areas of the world, while obtaining more detailed information from ground-based monitors. Hence, the combination of satellite-based sensor data and ground-based monitoring data promotes greater understanding of the movement of pollutants than either data set alone. Combined data sets are important for use by both scientists and international policy-makers. A standard methodology did not exist to guide and encourage integrated use of satellite images and ground-based data to monitor and understand major pollution events, such as air pollution. Thus, a small team was assembled to develop a methodology for the integration of satellite images and ground-based data. First, we conducted a literature and project review covering past and current integrated remote and ground-based data projects, a literature search of published work, and a search of data sets and technologies that could be used in a combined form. Second, based on this search and documentation, a general methodology was developed for using integrated spaceborne and ground-based data sets, intended as a guide for general scientists and policy-makers. Third, we found an existing project that was willing to be a pilot for testing the methodology: a U.S. EPANOAA project that was using aerial and ground-based sampling to learn more about the airborne sources of mercury deposition in the Florida Everglades. This document presents the results of the literature and project review, the complete methodology, and the outcome of the Florida Everglades pilot project.

Report↗