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At least 1,189 records · Page 66Linked to original sources
USGS2007

Water and sediment quality in the Yukon River and its tributaries between Atlin, British Columbia, Canada, and Eagle, Alaska, USA, 2004

The Yukon River basin is the fourth largest watershed in North America at 855,300 square kilometers (km 2 ). Approximately 126,000 people live within the basin and depend on the Yukon River and its tributaries for drinking water, commerce, subsistence and recreational fish and game resources. Climate warming in the Arctic and Sub arctic regions encompassing the Yukon basin has recently become a concern because of possible far-reaching effects on the ecosystem. Large amounts of carbon and nutrients are stored in permafrost and have potential for release in response to this warming. These changes in carbon and nutrient cycling may result in changes in stream chemistry and productivity, including salmon populations, and ultimately changes in the chemistry and productivity of the Bearing Sea. To address these concerns, the U.S. Geological Survey (USGS) conducted a 5-year comprehensive water-quality study of the Yukon River and its major tributaries starting in 2000. The study included frequent water-quality sampling at a fixed site network as well as intensive sampling along the Yukon River and its major tributaries. This report contains observations of water and sediment quantity and quality of the Yukon River and its tributaries in Canada during 2004. Chemical, biological, physical, and discharge data are presented for the reach of river between Atlin, British Columbia, Canada, and Eagle, Alaska, USA.

Alaska, British Columbia, Yukon↗
USGS2007

Chemical data for rock, sediment, biological, precipitate, and water samples from abandoned copper mines in Prince William Sound, Alaska

Introduction In the early 20th century, approximately 6 million metric tons of copper ore were mined from numerous deposits located along the shorelines of fjords and islands in Prince William Sound, Alaska. At the Beatson, Ellamar, and Threeman mine sites (fig. 1), rocks containing Fe, Cu, Zn, and Pb sulfide minerals are exposed to chemical weathering in abandoned mine workings and remnant waste piles that extend into the littoral zone. Field investigations in 2003 and 2005 as well as analytical data for rock, sediment, precipitate, water, and biological samples reveal that the oxidation of sulfides at these sites is resulting in the generation of acid mine drainage and the transport of metals into the marine environment (Koski and others, 2008; Stillings and others, 2008). At the Ellamar and Threeman sites, plumes of acidic and metal-enriched water are flowing through beach gravels into the shallow offshore environment. Interstitial water samples collected from beach sediment at Ellamar have low pH levels (to ~3) and high concentrations of metals including iron, copper, zinc, cobalt, lead, and mercury. The abundant precipitation of the iron sulfate mineral jarosite in the Ellamar gravels also signifies a low-pH environment. At the Beatson mine site (the largest copper mine in the region) seeps containing iron-rich microbial precipitates drain into the intertidal zone below mine dumps (Foster and others, 2008). A stream flowing down to the shoreline from underground mine workings at Beatson has near-neutral pH, but elevated levels of zinc, copper, and lead (Stillings and others, 2008). Offshore sediment samples at Beatson are enriched in these metals. Preliminary chemical data for tissue from marine mussels collected near the Ellamar, Threeman, and Beatson sites reveal elevated levels of copper, zinc, and lead compared to tissue in mussels from other locations in Prince William Sound (Koski and others, 2008). Three papers presenting results of this ongoing investigation of sulfide oxidation in Prince William Sound are in press. Koski and others (2008) provide an overview of rock alteration, surface water chemistry, and the distribution of metals at the Ellamar, Threeman, and Beatson mine sites. Based on a 60-day, stream-discharge experiment at Beatson in 2005, Stillings and others (2008) analyze changes in water chemistry during storm events and the flux of metals to the shoreline. Foster and others (2008) investigate the biomass and diversity of microbial communities present in surface waters (streams, seeps, pore waters) using fatty acid methyl ester (FAMES) data and principal component analysis. The publications cited above contain a subset of the total chemical data for rock, sediment, biological, precipitate, and water samples collected from the three mine sites in 2003 and 2005. The purpose of this report is the presentation of complete chemical data sets for all samples collected during the two field periods of fieldwork. Data for a small number of samples collected at two other mines (Schlosser and Fidalgo, fig. 1), visited in 2003, are also included in the tables.

Alaska↗
USGS2007

Chemical data for rock, sediment, biological, precipitate, and water samples from abandoned copper mines in Prince William Sound, Alaska

In the early 20th century, approximately 6 million metric tons of copper ore were mined from numerous deposits located along the shorelines of fjords and islands in Prince William Sound, Alaska. At the Beatson, Ellamar, and Threeman mine sites (fig. 1), rocks containing Fe, Cu, Zn, and Pb sulfide minerals are exposed to chemical weathering in abandoned mine workings and remnant waste piles that extend into the littoral zone. Field investigations in 2003 and 2005 as well as analytical data for rock, sediment, precipitate, water, and biological samples reveal that the oxidation of sulfides at these sites is resulting in the generation of acid mine drainage and the transport of metals into the marine environment (Koski and others, 2008; Stillings and others, 2008). At the Ellamar and Threeman sites, plumes of acidic and metal-enriched water are flowing through beach gravels into the shallow offshore environment. Interstitial water samples collected from beach sediment at Ellamar have low pH levels (to ~3) and high concentrations of metals including iron, copper, zinc, cobalt, lead, and mercury. The abundant precipitation of the iron sulfate mineral jarosite in the Ellamar gravels also signifies a low-pH environment. At the Beatson mine site (the largest copper mine in the region) seeps containing iron-rich microbial precipitates drain into the intertidal zone below mine dumps (Foster and others, 2008). A stream flowing down to the shoreline from underground mine workings at Beatson has near-neutral pH, but elevated levels of zinc, copper, and lead (Stillings and others, 2008). Offshore sediment samples at Beatson are enriched in these metals. Preliminary chemical data for tissue from marine mussels collected near the Ellamar, Threeman, and Beatson sites reveal elevated levels of copper, zinc, and lead compared to tissue in mussels from other locations in Prince William Sound (Koski and others, 2008). Three papers presenting results of this ongoing investigation of sulfide oxidation in Prince William Sound are in press. Koski and others (2008) provide an overview of rock alteration, surface water chemistry, and the distribution of metals at the Ellamar, Threeman, and Beatson mine sites. Based on a 60-day, stream-discharge experiment at Beatson in 2005, Stillings and others (2008) analyze changes in water chemistry during storm events and the flux of metals to the shoreline. Foster and others (2008) investigate the biomass and diversity of microbial communities present in surface waters (streams, seeps, pore waters) using fatty acid methyl ester (FAMES) data and principal component analysis. The publications cited above contain a subset of the total chemical data for rock, sediment, biological, precipitate, and water samples collected from the three mine sites in 2003 and 2005. The purpose of this report is the presentation of complete chemical data sets for all samples collected during the two field periods of fieldwork. Data for a small number of samples collected at two other mines (Schlosser and Fidalgo, fig. 1), visited in 2003, are also included in the tables.

Alaska↗
USGS2009

A Collection of Chemical, Mineralogical, and Stable Isotopic Compositional Data for Green River Oil Shale from Depositional Center Cores in Colorado, Utah, and Wyoming

For over half a century, the U.S. Geological Survey and collaborators have conducted stratigraphic and geochemical studies on the Eocene Green River Formation, which is known to contain large oil shale resources. Many of the studies were undertaken in the 1970s during the last oil shale boom. One such study analyzed the chemistry, mineralogy, and stable isotopy of the Green River Formation in the three major depositional basins: Piceance basin, Colo.; Uinta basin, Utah; and the Green River basin, Wyo. One depositional-center core from each basin was sampled and analyzed for major, minor, and trace chemistry; mineral composition and sulfide-mineral morphology; sulfur, nitrogen, and carbon forms; and stable isotopic composition (delta34S, delta15N, delta13C, and delta18O). Many of these data were published and used to support interpretative papers (see references herein). Some bulk-chemical and carbonate-isotopic data were never published and may be useful to studies that are currently exploring topics such as future oil shale development and the climate, geography, and weathering in the Eocene Epoch. These unpublished data, together with most of the U.S. Geological Survey data already published on these samples, are tabulated in this report.

Open-File Report↗
USGS2010

West Florida Shelf: A natural laboratory for the study of ocean acidificiation

Declining oceanic pH and carbonate-ion concentrations are well-known consequences of increased atmospheric and surface-ocean partial pressure of carbon dioxide (pCO2). The possible subject of shifts in seawater carbonate chemistry on biocalcification and survival rates of marine organisms provides questions amenable to both experimental and field study (Kleypas and Langdon, 2006). To date, limited quantitative data exist with which to formalize and test hypotheses regarding such impacts, particularly in continental-shelf settings. The continental shelves of Florida provide an ideal natural laboratory in which to test latitudinal (and temperature and depth) shifts in habitat ranges of calcifying organisms. Both the east and west Florida shelves extend from warm temperate to subtropical latitudes; additionally, the west Florida shelf has very little siliciclastic influx to mask the carbonate production. This study utilizes the natural laboratory of the west and southwest Florida shelf (fig 1.1) to examine the transition from foramol (predominately foraminifera and molluscan) carbonate sediments, characteristic of the west-central Florida shelf, to chlorozoan (algal and coral) sediments characteristic of the southwest Florida shelf. The west Florida shelf is a mixed siliciclastic carbonate ramp that to the south transitions to the carbonate-dominated southwest Florida shelf (Enos, 1977; Brooks and others, 2003). The west Florida shelf is a distally steepened carbonate ramp that is ~250 kilometers (km) wide (Read, 1985). It is covered by a veneer of unconsolidated sediment consisting of mainly biogenic carbonate and quartz in the near shore, with subordinate amounts of phosphate. The sediment-distribution pattern is largely a function of proximity to source, with physical processes playing a minor role in distribution. The carbonate sand-and-gravel fraction is produced by organisms within the depositional basin of the west Florida shelf (Brooks and others, 2003). The southwest Florida shelf is a rimmed carbonate margin where organisms produce virtually all of the substrate; it also exhibits a greater sediment thickness as compared to the west Florida shelf (Enos, 1977). Temperature, which is usually associated with latitude, plays a major role in locations of foramol versus chlorozoan assemblages, but other factors beyond latitude influence temperature on the west and southwest Florida shelves. The potential of cooler, deep-water upwelling and transport over the bottom waters of the shelf may have a significant role in the species assemblage at the sediment/water interface and ultimately on location of foramol versus chlorozoan production. Deep water transported onto and over the shelf may also have environmental ramifications beyond temperature by bringing in water of different chemistry.

Open-File Report↗
USGS2010

Monitoring and assessment of ocean acidification in the Arctic Ocean-A scoping paper

Carbon dioxide (CO2) in the atmosphere is absorbed at the ocean surface by reacting with seawater to form a weak, naturally occurring acid called carbonic acid. As atmospheric carbon dioxide increases, the concentration of carbonic acid in seawater also increases, causing a decrease in ocean pH and carbonate mineral saturation states, a process known as ocean acidification. The oceans have absorbed approximately 525 billion tons of carbon dioxide from the atmosphere, or about one-quarter to one-third of the anthropogenic carbon emissions released since the beginning of the Industrial Revolution. Global surveys of ocean chemistry have revealed that seawater pH has decreased by about 0.1 units (from a pH of 8.2 to 8.1) since the 1700s due to absorption of carbon dioxide (Raven and others, 2005). Modeling studies, based on Intergovernmental Panel on Climate Change (IPCC) CO2 emission scenarios, predict that atmospheric carbon dioxide levels could reach more than 500 parts per million (ppm) by the middle of this century and 800 ppm by the year 2100, causing an additional decrease in surface water pH of 0.3 pH units. Ocean acidification is a global threat and is already having profound and deleterious effects on the geology, biology, chemistry, and socioeconomic resources of coastal and marine habitats. The polar and sub-polar seas have been identified as the bellwethers for global ocean acidification.

Open-File Report↗
USGS2015

Carbon dioxide storage in unconventional reservoirs workshop: summary of recommendations

“Unconventional reservoirs” for carbon dioxide (CO 2 ) storage—that is, geologic reservoirs in which changes to the rock trap CO 2 and therefore contribute to CO 2 storage—including coal, shale, basalt, and ultramafic rocks, were the focus of a U.S. Geological Survey (USGS) workshop held March 28 and 29, 2012, at the National Conservation Training Center in Shepherdstown, West Virginia. The goals of the workshop were to determine whether a detailed assessment of CO 2 storage capacity in unconventional reservoirs is warranted, and if so, to build a set of recommendations that could be used to develop a methodology to assess this storage capacity. Such an assessment would address only the technically available resource, independent of economic or policy factors. At the end of the workshop, participants agreed that sufficient knowledge exists to allow an assessment of the potential CO 2 storage resource in coals, organic-rich shales, and basalts. More work remains to be done before the storage resource in ultramafic rocks can be meaningfully assessed. In order to assess the CO 2 storage capacity of coals and organic-rich shales, the workshop participants agreed that the following several factors are key: sorption mechanisms and capacity, pore fluid composition and saturation, thermal maturity, formation thickness, and whether hydrocarbons have been extracted from the formation previously (for example, by enhanced gas or oil recovery). In order to assess the CO 2 storage capacity of basalts, the workshop participants agreed that key factors include temperature, pressure, pH, water chemistry, mineral chemistry, organic content, mineralogy, porosity, permeability, relative permeabilities, and CO 2 phase. The storage capacity for all unconventional reservoirs may be modeled using a volumetric equation starting with the extent of the rock unit and adjusted using these key factors and reaction terms. The ideas that were developed during this workshop can be used by USGS scientists to develop a methodology to assess the CO 2 storage resource in unconventional reservoirs. This methodology could then be released for public comment and peer review. After completing this development process, the USGS could then use the methodology to assess the CO 2 storage resource in unconventional reservoirs.

Open-File Report↗
USGS2020

Environmental data associated with sites infected with white-nose syndrome (WNS) before October 2011 in North America

White-nose syndrome (WNS) is an emerging infectious disease of hibernating bats caused by a fungus previously known as Geomyces destructans and reclassified as Pseudogymnoascus destructans . The disease was first documented in 2006 in New York, has since spread across much of eastern North America, and as of January 2012, had caused the death of at least 5.7 to 6.7 million bats. Previous studies have suggested that environmental conditions play a strong role in WNS mortality. However, to predict where and when the disease will spread to new sites is difficult because detailed site information and associated environmental data are notably sparse. This paper presents a chronology of where and when WNS was detected in North America before October 2011 and indicates who reported the infections. This paper also presents available data on WNS-infected site elevation, geology, sediment chemistry and biota, air temperature, and relative humidity. By the end of September 2011, at least 241 known WNS-infected sites were in North America and the number of infected sites per winter season had increased each year since 2006. The progressive increase in the number of infected sites per winter season suggests that the number of WNS infections had not peaked as of the 2010–11 winter season. WNS-infected sites include caves and mines, but the sites are not restricted by elevation, lithology, or strata age. Available data on site sediment chemistry are sparse but present a wide range of values, suggesting that caves and mines may contain a great range of microenvironments that are still poorly understood. The distribution of WNS may be restricted by air temperature and relative humidity. Published air temperature values from WNS-infected sites range from −15 to 33 degrees Celsius (but most temperature values are less than 20 degrees Celsius), and relative humidity values range from 50 to 100 percent. The spread of WNS may be restricted by a cave or mine temperature threshold of 20 degrees Celsius (which is likely to be south of most of the continental United States) and by some yet to be determined threshold of low relative humidity. These results indicate that WNS may not spread south into Mexico or to Puerto Rico.

Connecticut, Delaware, Indiana, Kentucky, Maine, M↗
USGS2024

Determination of antimycin–a in a liquid formulation by high performance liquid chromatography–mass spectrometry

Pesticide formulations containing the active ingredient antimycin–a (ANT–A) have been used by fisheries and aquaculture managers for several decades to remove nuisance fish species. Analytical methods for measuring ANT–A during pesticide treatments have been done using high performance liquid chromatography (HPLC) paired with multiple detection methods (for example, electrochemical, ultraviolet, fluorescence, mass spectrometry). However, instruments and analytical chemistry methods can advance over time because of the need to develop timely, reliable, cost effective, and reproducible methods. Subsequently, ANT–A analytical chemistry methods and sample processing techniques also have improved over the past several decades. In the present study, we describe a liquid chromatography–mass spectrometry method and its verification across three analysts. Each analyst group created a single calibration curve and verified ANT–A in a liquid formulation using the averaged total response of all major ANT–A homologs (A1, A3, A3, A4). The advantage of this technique is that it creates a more resilient ANT–A quantification method amendable to batch-batch differences in major homologs. The method demonstrated how ANT–A can be effectively measured with high accuracy (98–99 percent), precision (2.7–16.2 percent), and specificity within a pesticide liquid formulation using a method applicable for Federal registration requirements.

Open-File Report↗
USGS1976

Numerical modeling of subsurface radioactive solute transport from waste seepage ponds at the Idaho National Engineering Laboratory

Aqueous chemical and low-level radioactive effluents have been disposed to seepage ponds since 1952 at the Idaho National Engineering Laboratory. The solutions percolate toward the Snake River Plain aquifer (135 m below) through interlayered basalts and unconsolidated sediments and an extensive zone of ground water perched on a sedimentary layer about 40 m beneath the ponds. A three-segment numerical model was developed to simulate the system, including effects of convection, hydrodynamic dispersion, radioactive decay, and adsorption. The first segment uses an analytical solution to simulate transport from the ponds to the 25-m thick perched-water lens, assuming steady vertical flow through a 15-m long saturated homogeneous column. The second segment simulates two-dimensional horizontal transport in the perched-water body using finite-difference methods, assuming complete vertical mixing with vertical leakage from the bottom. The third segment of the model simulates vertical solute transport from the perched-water body toward the aquifer, by assuming unsaturated but steady water flow in a series of contiguous, nonhomogeneous independent vertical columns. The transport equation is solved by a "hop-scotch" finite-difference scheme for each column. Simulated hydraulics and solute migration patterns for all segments agree adequately with the available field data. The model can be used to project subsurface distributions of waste solutes under a variety of assumed conditions for the future. Although chloride and tritium reached the aquifer several years ago, the model analysis suggests that the more easily sorbed solutes, such as cesium-137 and strontium-90, would not reach the aquifer in detectable concentrations within 150 years for the conditions assumed. However, a change in chemistry or hydraulic conditions could increase the mobility of adsorbed waste solutes. Such changes might result from changes in waste disposal practices and effluent chemistry, flooding from the Big Lost River, or future irrigation activity.

Idaho↗
USGS1977

Mineralogical, chemical, and physical properties of the regolith overlying crystalline rocks, Fairfax County, Virginia: a preliminary report

Undisturbed cores of saprolite developed on crystalline rocks of the Piedmont Province in Fairfax County, Virginia have been obtained using a combination of Shelby tubes, Denison sampler, and modified diamond core-drilling. The principal purpose of the core study is to correlate variations in chemistry, mineralogy and texture with engineering properties throughout the weathering profile. Coring sites were chosen to obtain a maximum depth of weathering on diverse lithologies. The rocks investigated include pelitic schist, metagraywacke, granite, diabase and serpentinite. Four to twelve samples per core were selected, depending on thickness of 1) the weathering profile (from about 1 m in serpentinite to more than 30 m in pelitic schist) and on 2) megascopic changes in saprolite character for analysis of petrography, texture, clay mineralogy andd major element chemistry. Shear strength and compressibility were determined on corresponding segments of core. Standard penetration tests were performed adjacent to coring sites to evaluate engineering properties in situ. Geochemical changes of saprolite developed from each rock type follow predictable trends from fresh rock to soil profile, with relative Increases in Si, Ti, Al, Fe3+ and H20; variable K; and relative loss of Fe 2+, Mg, Ca, and Na. These variations are more pronounced in the weathering profiles over mafic and ultramafic rocks than metagraywacke. Clay minerals in granite, schist and metagraywacke saprolite are kaolinite, dioctahedral vermiculite, interlayered micavermiculite, and minor illite. Gibbsite is locally developed in near-surface samples of schist. Standard penetration test data for the upper 7 m of saprolite over schist and metagraywacke suggest alternations between stronger and weaker horizons than probably reflect variations in lithology including the presence of quartz lenses. Results for granite saprolite are most consistent but indicate lower strength. Shear strength increases fairly regularly downward in the weathering profile. The engineering behavior of diabase saprolite is controlled by a dense, plastic, near-surface clay layer (montmorillonite and kaolinite)overlying rock which is weathered to a granular state (grus), while engineering properties of serpentinite are determined by a very thin weathering profile.

Open-File Report↗
USGS1977

Geochemistry of the Mattole River in Northern California

The chemical composition of streams can vary greatly with changing discharge during storm runoff. These chemical changes are related to the pathways of various water parcels from the time they fall as rain until they enter the stream, and to the interactions between water and sediment during transport downstream. In order to understand better the chemical variations during storms, an extensive investigation was made of the Mattole River, a chemically clean coastal stream in Mendocino County, California. The Mattole drains a topographically mature basin of 620 sw km which has relief of about 1200 m, a long summer dry season, and mean annual rainfall of about 2300 mm. The stream flow is composed of seasonally varying proportions of four flow components, namely, surface runoff, quick-return flow (rainfall having brief and intimate contact with the soil before entering the surface drainage), delayed-return flow, and base runoff. Each component is identified by its characteristic chemistry and by the time delay between rainfall and entrance into the stream. Information is also presented on rain chemistry, adsorption reactions of suspended sediments in the fresh and brackish environments, and compositional variation of river sediments with particle size. (Woodard-USGS)

Open-File Report↗
USGS1981

Magnitude and chemical quality of base flow of Otter Creek, Tongue River, and Rosebud Creek, southeastern Montana, October 26-November 5, 1977

Hydrologic and chemical data were collected during base-flow conditions on three streams in southeastern Montana from October 26 to November 5, 1977, to characterize groundwater discharge. Maximum measured flow of Otter Creek, an interrupted stream, was 1.2 cubic feet per second. The water chemistry was dominated by sodium, magnesium, and sulfate ions, with a maximum dissolved-solids concentration of 3,540 milligrams per liter. Chemistry of groundwater inflow is dominated by sodium, magnesium, and sulfate. A discharge of 156 cubic feet per second from the Tongue River Reservoir into the Tongue River complicated interpretation of groundwater discharge to the reach downstream from the reservoir. Many reaches of gain and loss were observed along the Tongue River; the flow near the mouth was 233 cubic feet per second. Minor changes in quality of the base flow indicate groundwater discharges dominated by sodium, sulfate, and bicarbonate plus carbonate. Dissolved-solids concentration increased from 506 milligrams per liter near the dam to 630 milligrams per liter near the mouth. Maximum measured flow of Rosebud Creek was 19.0 cubic feet per second. Water quality in the upper reaches was dominated by magnesium, calcium , and bicarbonate, with dissolved-solids concentrations ranging from 560 to 703 milligrams per liter. Sodium, sulfate, and dissolved solids increase downstream.

Montana↗
USGS1980

Geochemistry of water in the Fort Union Formation of the northern Powder River basin, southeastern Montana

Shallow water in the coal-bearing Fort Union Formation of southeastern Montana was investigated to provide a better understanding of the geochemistry. Springs, wells less than 200 feet deep, and wells greater then 200 feet deep were observed to have different water qualities. Overall, the ground water exists as two systems: a mosaic of shallow, chemically dynamic, and localized recharge-discharge cells superimposed on a deeper, chemically static regional system. Water chemistry is highly variable in the shallow system, whereas sodium and bicarbonate waters characterize the deeper system. Within the shallow system , springs, and wells less than 200 feet deep show predominantly sodium and sulfate enrichment processes from recharge to discharge. These processes are consistent with the observed aquifer mineralogy and aqueous chemistry. However, intermittent mixing with downward moving recharge waters or upward moving deeper waters, and bacterially catalyzed sulfate reduction, may cause apparent reversals in these processes. (USGS)

Open-File Report↗
USGS1981

Deepwell monitoring of strain-sensitive parameters over the greater Southern California uplift

Several wells and springs near active faults in southern California have been monitored for the concentration of Rn, Na + , K + , Mg +2 , and Cl - for periods of up to 24 months, in an effort to see if any of these constituents show variations which may be related to seismic activity. Radon might reflect either a change in the rock surface area to pore volume ratio or a change in groundwater flow characteristics. The chemistry may change with a change in the flow characteristics. Only a few of these sites have shown significant fluctuations in either radon or chemistry. Data from cold springs are consistent with a model in which ionic constituents are controlled by reactions in the soil zone and radon concentrations are controlled by flow rates in the aquifer.

California↗
USGS1982

Water-quality data for streams in the southern Yampa River basin, northwestern Colorado

Increases in coal mining in Colorado have raised questions regarding the impact of mining on the quality of surface water. An area where increases have caused particular concern is in northwestern Colorado, in the southern part of the Yampa River basin. In order to identify the changes produced by mining in the area it is necessary first to identify the water chemistry resulting from the geology, climate, and land use. To answer the above questions, a program for the synoptic collection of water-quality data was developed in which a network of sampling sites was established to determine the surface-water chemistry. This study was begun in April 1981. Water-quality samples were collected from sites on all continuously flowing streams in the southern part of the Yampa River basin from the Oak Creek drainage near Steamboat Springs on the east to the surface-water gaging station on the Yampa River near Maybell on the west. Each water-quality site was sampled repetitively as changes occurred in discharge and specific conductance. Water-quality data from surface-water gaging stations in the area for water years 1976 to 1981 are included in the report.

Open-File Report↗
USGS1983

Reconnaissance geologic map of the Harrat Tuffil Quadrangle, sheet 20/39 B, Kingdom of Saudi Arabia

The Harrat Tuffil quadrangle, sheet 20/39 B, is located between lat 20°30’ and 21°00’ N. and long 39°30’ and 40°00’ E. about 50 km southeast of Jiddah. A western belt of Proterozoic metapelites and related rocks, defined as the Sa’diyah formation, structurally underlies and locally is interlayered with Proterozoic metabasaltic rocks of oceanic chemical affinity to the east. The Sa’diyah formation and the metabasaltic rocks are tentatively correlated with the Sabya formation and Baish group. These rocks may represent a miogeosynclinal tectonic setting in the 800 to 850 Ma period of development of the southwestern Arabian Shield. The presence of aluminous metasediments suggest a continental source area, probably west of oceanic and (or) immature island-arc rocks of the Baish(?) igneous suite. The Sa’diyah formation and metabasaltic rocks are intruded by a granite gneiss batholith, probably about 600 Ma old, and by small plutons of granodiorite and syenogranite. Peraluminous monzogranite occurs within the western part of the Sa’diyah formation belt and may provide an alternate source for the aluminous politic rocks. Tentative correlation of an isolated exposure of Jurassic(?) dolomite with the Hanifa Formation significantly extends the areal range of possible Jurassic sedimentary rocks in the Tihamat province. An intense dike swarm intrudes all of the pre-Miocene rocks in the quadrangle. This Damm dike complex is named for Wadi ad Damm. Dike chemistry shows both subalkaline and alkaline bimodal suites. The Sita formation is broadly coeval with the Damm Dike complex and contains volcanic rocks with similar bimodal chemistry. The Sita formation conformably overlies and is locally interbedded with the Sumaysi formation, which is palynologically dated in the Makkah quadrangle as Eocene (~50 Ma). Potassium-argon dating indicated intrusion and volcanism over the period ~50Ma to ~20 Ma ago. The Tertiary volcanic, hypabyssal, and plutonic rocks are all light rare-earth element enriched as would be expected in a rift-related tectonic setting. These rocks represent proto-Red Sea igneous activity and are correlated with the Jizan group. Shama rhyolite near Harrat Tuffil is unconformably overlain by a boulder conglomerate correlated with the Bathan formation. Miocene alkali basalt forms a large paleovalley-fill lava flow at Harrat ad Damm and small flow remnants north of Jabal Sita. Erosional downcutting at Harrat ad Damm averaged ~10 m per MA over the past 11 Ma. Pliocene alkali basalt unconformably overlies Bathan formation and Shama rhyolite at Harrat Tuffil. The uplift of Quaternary reef limestone along the Red Sea coast indicates recent faulting as shown in the adjoining Shu’ayba and Al Ghalah quadrangles. A perlite deposit at Jabal Shama may be suitable as light aggregate for concrete. Sparse barite veins were discovered in the lower Shumaysi formation. Relatively small deposits of Sa’diyah formation marble may be of interest for local use in building or cement. The Jurassic dolomite is locally quite pure and may have economic applications.

Open-File Report↗
USGS1985

Selected trace-element data for streams in the southern Yampa River basin, northwestern Colorado

Increases in coal mining in northwestern Colorado have increased concerns about the impact of mining on the chemical quality of surface water. One area of particular concern is in the southern part of the Yampa River basin. To identify the possible changes in water quality produced by mining in this area, it is first necessary to determine the present water chemistry resulting from the geology, climate, and land use. Because few data were available, a program for the synoptic collection of water-quality data was developed in which sampling sites were selected to determine the surface-water chemistry. (USGS)

Open-File Report↗