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Research about Canada, United States

Source-linked reports with geographic coverage including Canada, United States.

At least 1,225 records · Page 68Linked to original sources
USGS1988

An overview of a habitat suitability index model for moose: Lake Superior region

A three-day workshop was held to develop a model for evaluation of moose habitat in the Lake Superior region. The ultimate goal of the workshop was to provide planning tools to enhance habitat management for moose and maximize the integration of those management objectives with silvicultural goals. An abstract of the models resulting from the workshop is presented and model validation concepts are discussed.

Lake Superior region↗
USGS1987

Low-flow traveltime, longitudinal-dispersion, and reaeration characteristics of the Souris River from Lake Darling Dam to J. Clark Salyer National Wildlife Refuge, North Dakota

As part of the Souris River water-quality assessment, traveltime, longitudinal-dispersion, and reaeration measurements were made during September 1983 on segments of the 186-mile reach of the Sour is River from Lake Darling Dam to the J. Clark Salyer National Wildlife Refuge. The primary objective was to determine traveltime, longitudinal-dispersion, and reaeration coefficients during low flow. Streamflow in the reach ranged from 10.5 to 47.0 cubic feet per second during the measurement period. On the basis of channel and hydraulic characteristics, the 186-mile reach was subdivided into five subreaches that ranged from 18 to 55 river miles in length. Within each subreach, representative test reaches that ranged from 5.0 to 9.1 river miles in length were selected for tracer injection and sample collection. Standard fluorometric techniques were used to measure traveltime and longitudinal dispersion, and a modified tracer technique that used ethylene and propane gas was used to measure reaeration. Mean test-reach velocities ranged from 0.05 to 0.30 foot per second, longitudinal-dispersion coefficients ranged from 4.2 to 61 square feet per second, and reaeration coefficients based on propane ranged from 0.39 to 1.66 per day. Predictive reaeration coefficients obtained from 18 equations (8 semiempirical and 10 empirical) were compared with each measured reaeration coefficient by use of an error-of-estimate analysis. The predictive reaeration coefficients ranged from 0.0008 to 3.4 per day. A semiempirical equation that produced coefficients most similar to the measured coefficients had the smallest absolute error of estimate (0.35). The smallest absolute error of estimate for the empirical equations was 0.41.

North Dakota↗
USGS1986

Stratigraphy and correlation of the glacial deposits on the Montana Plains

Till units representing at least three pre-Illinoian continental glaciations, at least one Illinoian glaciation, and a late Wisconsin glaciation have been identified on the Montana Plains. Early Wisconsin or middle Wisconsin till units have not been identified. The southernmost limit of late Wisconsin glaciation is in Montana, more than 170 km south of the Lethbridge moraine in Alberta, Canada (Figs 1 and 2). An interpretation that the Lethbridge moraine is the limit of late Wisconsin glaciation (Stalker, 1977, 1980, 1983b; Stalker and Harrison, 1977; Rutter, 1980, 1981; Jackson, 1983) is incompatible with stratigraphic and morphologic evidence from Montana.

Montana, North Dakota↗
USGS1986

Does pH affect fish species richness when lake area is considered?

Numerous surveys have shown that fish species richness (number of species) is positively correlated with lake pH. However, species richness of fish communities is also correlated with lake size, and low‐pH lakes are often small. Thus, conclusions drawn from examination of fish community structure relative to spatial (among‐lake) variation in pH have been limited by uncertainties regarding the confounded effects of lake area. We used two statistical methods, analysis of covariance and a nonparametric blocked comparison test, to remove effects of lake area and compare fish species richness in low‐pH and high‐pH lakes. Data from six previous surveys of water chemistry and fish communities in lakes of Ontario and northern Wisconsin were examined. Lakes with low pH (≤6.0) contained significantly fewer fish species than lakes with high pH (>6.0) when the effect of lake area was considered. A simple probabilistic model showed that the ability to detect differences in species richness is low when lake areas and the pool of potential colonizing species are small. We recommend the blocked comparison test for separating the effects of lake area and pH on species richness and urge critical examination of inferences based on analyses of fish communities in small lakes.

Ontario, Wisconsin↗
USGS1985

Review of radiometric data from the Yukon crystalline terrane, Alaska and Yukon Territory

The results of more than 20 years of geochronological studies in the Yukon Crystalline Terrane in east-central Alaska and the western Yukon Territory suggest at least six igneous and thermal (metamorphic?) events. Plutonism during Mississippian, Early Jurassic, mid-Cretaceous, Late Cretaceous, and early Tertiary times is indicated. Evidence also indicates that Mississippian, Early Jurassic, late Early Cretaceous, and late Cretaceous thermal (metamorphic?) events have affected parts of the terrane. The western part of the terrane was affected by a significant regional metamorphic event in late Early Cretaceous time, followed by a terrane-wide mid-Cretaceous plutonic event. The pattern of K–Ar ages allows division of the terrane into domains, bounded by northeast-trending lineaments.

Alaska, Yukon Territory↗
USGS1985

The occurrence of extractable elements in soils from the northern Great Plains

The modes of occurrence of extractable elements from 21 A and C horizon samples of uncultivated soils were examined using R-mode factor analysis. The extractants (DTPA, EDTA, HCl, hydroquinone, magnesium nitrate, and ammonium oxalate) cover a wide range of chemical attack. Four major elements (Ca, K, Mg, and Na) and eight trace elements (Cd, Co, Cu, Fe, Mn, Ni, Pb, and Zn) were determined in each extractant solution. A variety of chemical, mineralogical, and physical variables were also determined on each sample. Four varimax factors (clay, organic, Fe and Mn oxides, and soluble-Na) accounted for 74.2% of the total variance of the 90 variables for the A horizon. Seven varimax factors (Fe and Mn oxides, clay, CEC, soluble-Na, organic, Fe and Mn, and plagioclase) accounted for 77.2% of the total variance of the 79 variables for the C horizon. A and C horizon extractable trace elements are most generally related to Fe and Mn oxides, as indicated by loadings on the Fe and Mn oxide factor for both the A and C horizons. Each extractant generally operates on different modes of occurrence of an element in soil. For example, substantial differences occur between the HCl-, oxalate-, and hydroquinone-extractable trace elements. However, the modes of occurrence for trace elements removed by DTPA and EDTA were very similar, suggesting strong relationships between elements dissolved by these two extractants. The modes of occurrence for each individual major element are similar with each of the six extractants. A horizon Ca and Mg, and C horizon K and Mg are strongly related to a clay factor. C horizon Ca and A horizon K are strongly related to the CEC and organic factors, respectively. Both A and C horizon extractable Na are very strongly related to the soluble-Na factor. These results suggest that extractable major elements are water-soluble and are associated with the constituents that are responsible for that factor. Consequently, strong relationships should occur for any individual major element dissolved by any pair of extractants.

northern Great Plains↗
USGS1985

Procedural guide for International Gauging Stations on boundary waters between Canada and the United States of America

Since 1909, the United States of America (U.S.A.) and Canada have employed a system of monitoring stream-flow and water levels for shared waters based upon professionalism, trust and goodwill. This document has been prepared in considerable detail for use by managers and field officers at all levels of government in Canada and the United States. Its purpose is to serve as a guide in attaining uniform procedures in the designation and operation of International Gauging Stations. For special situations where these procedures do not apply, specific mention is made in appropriate sections of the guide. This guide supersedes that of November 4, 1969, and the guide entitled "The Procedural Guide for Operation of International Gauging Stations, St. Mary-Milk Rivers," dated March 12, 1979.

Open-File Report↗
USGS1984

Neogene molluscan stages of the West Coast of North America

Neogene marine sediments of the West Coast of North America were deposited in a series of widely spaced basins that extended geographically from the western and northern Gulf of Alaska (60°N) to southern California (33°N). Rich molluscan faunas occur extensively throughout these deposits and form the basis for biostratigraphic schemes that are useful for correlating within and between individual basins. Early biostratigraphic work was concerned with faunas from particular horizons and with the stratigraphic range of diverse taxa, such as Pecten and Turritella , without reference to other fossil groups. Succeeding work increasingly dealt with the relationships of molluscan zones to benthic and, later, planktonic foraminiferal stages. In recent years the age limits of Neogene molluscan stages have become better documented by reference to planktonic microfossils from dated DSDP cores and onshore faunas. Neogene molluscan faunas from California, the Pacific Northwest states (Oregon and Washington), and southern Alaska have been treated separately due to differences in faunal composition and geographic isolation. As a result, a different biostratigraphic sequence has been described for each region. Pacific Northwest stages have been formally named and defined, and their names are also used informally for Alaskan faunas. California Neogene stages were proposed early in this century, are in need of redescription, and their usage is informal. Precise correlations between the three regional sequences have not yet been achieved, due to the low number of co-occurring species and the general lack of planktonic microfossils in these largely shallow-water faunas. The objectives of ongoing research include: fuller documentation of the faunas of California and Pacific Northwest stages; formal description of California stages; improved correlation between regional stage sequences; refinement of age estimates for stage boundaries; and, establishment of Neogene stages for Alaskan faunas.

California, Oregon, Washington↗
USGS1984

Chronology of late Wisconsinan glaciation in middle North America

We propose a chronology of late Wisconsinan glacial fluctuations in middle North America, from Alberta to Wisconsin, based on radiocarbon dates derived solely from wood. Previous chronologies of the southwestern margin of the North American Continental Ice Sheet have depended to a considerable degree on radiocarbon dates from fine-grained organic sediment. This material is commonly contaminated with older carbon, resulting in chronologic confusion. By using only dates from wood, much of the confusion disappears. However, because of the scarcity of wood dates, only four of the sixteen identified fluctuations are accurately dated: an advance into Iowa about 14,000 to 13,500 BP, an advance into South Dakota and Iowa about 12,300 BP, an advance into the Lake Michigan basin about 11,700 BP, and an advance into the Lake Superior basin about 9900 BP. In addition, the beginning of late Wisconsinan glaciation, before 20,000 BP, is fairly well documented. None of the fluctuations in the western part of the region are accurately dated.

middle North America↗
USGS1984

Disruption of the terrestrial plant ecosystem at the Cretaceous-Tertiary boundary, western interior

The palynologically defined Cretaceous-Tertiary boundary in the western interior of North America occurs at the top of an iridium-rich clay layer. The boundary is characterized by the abrupt disappearance of certain pollen species, immediately followed by a pronounced, geologically brief change in the ratio of fern spores to angiosperm pollen. The occurrence of these changes at two widely separated sites implies continentwide disruption of the terrestrial ecosystem, probably caused by a major catastrophic event at the end of the period.

North America western interior↗
USGS1984

Potential impacts of water diversion on fishery resources in the Great Lakes

Uses of Great Lakes water within the Great Lakes basin are steadily increasing, and critical water shortages elsewhere may add to the demands for diversions of water out of the basin in the near future. The impacts of such diversions on fish in the Great Lakes must be considered in the context of in-basin uses of the water, because in-basin uses already adversely affect the fishery resources. Temporary in-basin water withdrawals from Lake Michigan by industry in 1980 equaled 260% of the total volume of water between the shoreline and the 10-meter depth—the littoral waters most heavily used by fish as spawning and nursery grounds. Nearly 100% of the fish removed by these water withdrawals were killed. Enough young alewives (Alosa pseudoharengus) and rainbow smelt (Osmerus mordax) in Lake Michigan and young yellow perch (Perca flavescens) in western Lake Erie have been removed at water intakes in recent years to reduce the productivity and biomass of adult fish stocks. Out-of-basin diversions of water at Chicago and at the Welland Canal, channel modifications in the St. Clair River, and in-basin consumptive water withdrawals have lowered the annual mean water level of Lakes Michigan and Huron by about 27 cm and that of Lake Erie by about 10 cm, dewatering wetlands that historically served as spawning and nursery habitat for many valuable fish species. The dollar value of fish lost to water diversions and withdrawals has not yet been estimated, but water withdrawals alone have already reduced the annual economic impact of the Great Lakes fisheries, which has been estimated to be 1.16 billion dollars.

Great Lakes, Lake Erie, Lake Huron, Lake Michigan,↗