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Research about Colorado

Source-linked reports with geographic coverage including Colorado.

At least 1,333 records · Page 74Linked to original sources
USGS1990

Brood habitat use of Rio Grande wild turkeys

Habitat use of 14 Rio Grande wild turkey ( Meleagris gallopavo ) broods was studied in riparian habitats in northeast Colorado in 1986-87. Of 191 locations, 78% were within the riparian zone, 11 % in agricultural uplands, and 11 % on the edge between these habitats. Use of habitats was dependent on time of day. Within the riparian zone, older broods used grazed areas more often than young broods. Microhabitat use was examined at 35 brood and 29 random locations within the riparian zone. Plots used by young broods had higher frequencies of grasses than random plots.

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USGS1989

Comparison of on-site and laboratory toxicity tests: derivation of site-specific criteria for un-ionized ammonia in a Colorado transitional stream

Acute tests with fathead minnows ( Pimephales prornelas Rafinesque), johnny darters ( Etheostoma nigrum Rafinesque), white suckers ( Catostomus commersoni Lacépède) and acute and chronic tests with Ceriodaphnia dubia were conducted to evaluate whether characteristics of the St. Vrain River in Colorado would ameliorate or enhance toxicity of un-ionized ammonia compared to laboratory (well) water and LC50 values found in the literature. Concurrently, tests were conducted on dilutions of Longmont, Colorado, wastewater to evaluate its toxicity in differing ammonia concentrations. Tests were conducted at two temperatures (approximately 6 and 20°C) to simulate seasonal differences. LC50s for fishes in the St. Vrain River water were similar to LC50s in laboratory water, indicating there was no site water effect. LC50s derived for fishes tested in warm conditions were within a factor of about two or three of literature values. However, the constituents in or characteristics of the wastewater appeared to enhance ammonia toxicity. Literature values (LC50s) for resident aquatic organisms and the new LC50 value for johnny darters tested on-site were used to derive site-specific criteria for un-ionized ammonia. Greater sensitivities of species to ammonia at cold versus warm temperatures suggests that colder, low-flow conditions may be a critical period for warm-water aquatic communities with regard to ammonia toxicity.

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USGS1989

A reinterpretation of the δD H 2 O of inclusion fluids in contemporaneous quartz and sphalerite, Creede mining district, Colorodo: a generic problem for shallow orebodies?

Water extracted from fluid inclusions in quartz from shallow epithermal ore deposits often has a hydrogen isotope composition (δD) different from that of water extracted from inclusions in associated minerals. This difference is usually attributed to the involvement of primary fluids from multiple sources. Isotopic and homogenization and freezing temperature determinations on fluid inclusions from contemporaneous quartz and sphalerite from the epithermal, silver and base metal orebodies of the OH vein, Creede district, Colorado, suggest an alternative explanation. In near-surface deposits, differences between δD H 2 O of inclusion fluids in ore minerals and quartz may result, instead, from contamination during extraction of the fluids contained in primary inclusions by shallow ground water trapped in pseudosecondary inclusions in quartz. Quartz from the OH vein contains two principal petrographically distinct populations of fluid inclusions: primary and pseudosecondary. The primary inclusions have salinities ranging from 5 to 10 equiv wt percent NaCl, and the salinities of pseudosecondary inclusions cluster between 0 and 1 percent. Primary inclusions in quartz from one locality have a measured δD H 2 O value of -69 per mil, while pseudosecondary inclusions at the same locality have a δD H 2 O value of -102 per mil. Both salinity and isotopic values for primary inclusions in quartz are similar to those for primary inclusions in contemporaneous sphalerite. Homogenization temperatures for primary and pseudosecondary inclusions in quartz range from 191° to 280° C and from 199° to 278° C, respectively. The δD H 2 O value measured on fluid inclusions from bulk crystals ranges between -97 and -85 per mil and represents a mixture of fluids from both primary and pseudosecondary inclusions. We interpret the data to indicate that one or more episodes of abrupt incursion of cooler, overlying ground water into the ore zone caused thermal cracking of the quartz crystals during the time interval of mineralization. Subsequent healing of the fractures trapped heated, low-salinity ground water in pseudosecondary inclusions. The abrupt incursions of overlying ground water are speculated to have resulted from either collapse of a transient vapor-dominated region of the ore zone, or catastrophic venting of the system through hydrothermal eruption(s). The unusually high contrast between the salinities of the ore-depositing fluids and the ground water overlying the ore zone allowed recognition of this phenomenon at Creede. It is likely, however, that Creede is not unique. Similar phenomena may be common in shallow ore zones where rapid fluctuation of an interface between a deep, high-temperature thermal plume and an overlying, cooler ground water may be expected to occur. Careful study of the origins of fluid inclusions, particularly in quartz, is essential to characterize the primary ore fluids and to assess the role of ground water in the hydrology of shallow ore deposits.

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USGS1989

Uranium-series nuclides in the Golden fault, Colorado, U.S.A.: Dating latest fault displacement and measuring recent uptake of radionuclides by fault-zone materials

Concentrations and isotopic ratios of U, Th and Ra were measured in a fault zone near Golden, Colorado where major displacement occurred between about 190 and 615 ka. Faulting created new surfaces for leaching and provided the pathways for U-rich ground water. Uranium and 230 Th, the latter produced by the decay of dissolved 234 U, are adsorbed by fault gouge, hematite-stained sand and brecciated sand- and claystones. The observed U enrichment is as much as six times baseline value and the simultaneous enrichment of 230 Th is estimated at about ninefold relative to 238 U. The adsorption of radionuclides chemically analogous to Th, such as Pu (IV) and Np, and 237 Np decay products, on fault-zone materials would contribute to the immobilization of high-level radioactive waste in the vicinity of a repository in the event of leakage from engineered barriers into fractured rock-mass.

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USGS1989

Geochemical evidence for Paleozoic oil in Lower Cretaceous O Sandstone, northern Denver basin

Organic geochemical properties of the oil produced from the Lower Cretaceous O sandstone on the eastern flank of the Denver basin indicate that this oil has been derived from a different source rock than other Cretaceous oils in the basin. O sandstone oil is characterized by low pristane/phytane ratio, high isoprenoid/n-alkane ratios, high asphaltene content, high sulfur content, and slight predominance of even-carbon numbered n-alkanes in the C 25+ fraction. These features are evidence of a Paleozoic source and indicate a carbonate rock is the likely source. Preliminary source rock evaluation and correlation data suggest that calcareous black shales and marls of Middle Pennsylvanian (Desmoinesian) age are the source of the O sandstone oil. This is the first rep rted occurrence of oil from Paleozoic source rocks in a Cretaceous reservoir in the Denver basin. Two important implications for further exploration are evident if vertical migration from Paleozoic source rocks has occurred. First, Paleozoic rocks of Middle Pennsylvanian age or younger are potential exploration objectives where reservoirs and suitable trapping mechanisms are present. Second, future exploration for oil in the O sandstone and upper Paleozoic rocks should consider stratigraphic relationships between possible source and reservoir rocks and possible migration conduits.

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USGS1989

Surficial geologic map of the Meeker 30' x 60' quadrangle, Garfield, Moffat, Rio Blanco and Routt Counties, Colorado

This map is one of a series of four 30' x 60' surficial geologic maps (1:100,000 scale) intended to provide basic geologic information for planning for energy resource development and growth in northwestern Colorado. An effort is made to characterize all surficial materials, regardless of origin. Hence, residuum is given much more emphasis than is customary, and this results in several departures from conventional geologic maps: bedrock geology is deemphasized; the part of the map symbol denoting geologic age is omitted for surficial units because all surficial units shown are believed to be of Quaternary age; and faults are not shown because none in this map area was observed to displace surficial materials. Few exposures of most map units exist, except in manmade excavations, such as gravel pits and road cuts. Consequently, thicknesses usually are estimated, and data on stratification, clast size, and relative proportions of matrix and framework clasts are limited to a few localities for each map unit. The Wentworth scale is used to describe grain sizes. Mapping was done chiefly on aerial photographs taken in 1953. Hence, landslides and modifications resulting from gravel mining since 1953 may not show on this map. The scales of the aerial photographs (about 1:60,000) and the map (1:100,000) governed the minimum size of the deposits mapped. The minimum thickness of the depostis mapped is about 1.5m in most places. Deposit thickness, although not a mapping criterion, influences the topographic expression of many landforms, and landform is the basis for delineating the surficial deposits shown.

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USGS1989

Maps showing trace-element geochemistry of the Sangre de Cristo Wilderness Study Area, south-central Colorado

A trace-element geochemical study of the Sangre de Cristo Wilderness Study Area included the collection of 710 heavy-mineral-concentrate samples, 767 minus-80 mesh stream-sediment samples, and 145 rock samples. All samples were analyzed for 31 elements by semiquantitative emission-spectrographic methods, and some stream-sediment and rock samples were also analyzed for selected elements by wet chemical methods.

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USGS1989

Hydrogeologic characteristics of the Valley-Fill aquifer in the Arkansas River valley, Prowers County, Colorado

The hydrogeology of the valley-fill aquifer of the Arkansas River valley in Prowers County, Colorado is presented in a series of three maps. The map shows: (1) the altitude and configuration of the bedrock surface beneath the valley-fill material; (2) the altitude and configuration of the water table in the spring of 1966; and (3) the saturation thickness of the valley-fill aquifer in the spring of 1966. (

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USGS1989

Hydrogeologic characteristics of the Valley-Fill aquifer in the Arkansas River valley, Crowley and Otero Counties, Colorado

The hydrogeology of the valley-fill aquifer of the Arkansas River valley in Crowley and Otero Counties, Colorado is presented in a series of three maps. The map shows: (1) the altitude and configuration of the bedrock surface beneath the valley-fill material; (2) the altitude and configuration of the water table in the spring of 1966; and (3) the saturation thickness of the valley-fill aquifer in the spring of 1966.

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USGS1989

Hydrogeologic characteristics of the Valley-Fill aquifer in the Arkansas River valley, Pueblo County, Colorado

The hydrogeology of the valley-fill aquifer of the Arkansas River valley in Pueblo County, Colorado is presented in a series of three maps. The map shows: (1) the altitude and configuration of the bedrock surface beneath the valley-fill material; (2) the altitude and configuration of the water table in the spring of 1966; and (3) the saturation thickness of the valley-fill aquifer in the spring of 1966.

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USGS1989

Summary of water-resources activities of the U.S. Geological Survey in Colorado– Fiscal year 1989

The biennial summary of water resources activities in Colorado is presented for fiscal year 1989. The report includes an introduction of these activities and names of the management personnel to whom information requests may be addressed, a summary of the U.S. Geological Survey mission and of the Water Resources Division mission, and a discussion of the water resources in Colorado in fiscal year 1989, including data collection on surface water and groundwater. All current Colorado hydrologic investigations are listed--their problems, objectives, approaches, progress, and plans for fiscal year 1989. A list of current cooperators, for fiscal year 1989 and a list of reports published or released during fiscal years 1987, 1988, and 1989 also are given. (USGS)

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USGS1989

Simulation of streamflow in small drainage basins in the southern Yampa River basin, Colorado

Coal mining operations in northwestern Colorado commonly are located in areas that have minimal available water-resource information. Drainage-basin models can be a method for extending water-resource information to include periods for which there are no records or to transfer the information to areas that have no streamflow-gaging stations. To evaluate the magnitude and variability of the components of the water balance in the small drainage basins monitored, and to provide some method for transfer of hydrologic data, the U.S. Geological Survey 's Precipitation-Runoff Modeling System was used for small drainage basins in the southern Yampa River basin to simulate daily mean streamflow using daily precipitation and air-temperature data. The study area was divided into three hydrologic regions, and in each of these regions, three drainage basins were monitored. Two of the drainage basins in each region were used to calibrate the Precipitation-Runoff Modeling System. The model was not calibrated for the third drainage basin in each region; instead, parameter values were transferred from the model that was calibrated for the two drainage basins. For all of the drainage basins except one, period of record used for calibration and verification included water years 1976-81. Simulated annual volumes of streamflow for drainage basins used in calibration compared well with observed values; individual hydrographs indicated timing differences between the observed and simulated daily mean streamflow. Observed and simulated annual average streamflows compared well for the periods of record, but values of simulated high and low streamflows were different than observed values. Similar results were obtained when calibrated model parameter values were transferred to drainage basins that were uncalibrated. (USGS)

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