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Research about Canada

Source-linked reports with geographic coverage including Canada.

At least 289 records · Page 16Linked to original sources
USGS1978

Late Miocene mollusks from the Queen Charlotte Islands, British Columbia, Canada

A fauna of bivalve mollusks, scattered gastropods, and an echinoid from exposures of the Skonun Formation in the northeastern part of Graham Island is indicative of an early late Miocene age and correlation with the provincial Wishkahan Stage. The molluscan assemblages are from the upper 600 of the 1800-m-thick marine and nonmarine formation, which appears to be entirely of late Miocene age. The Skonun Formation is the strandline fa.cies of marginal marine and nonmarine deposits of the northwestern part of the Queen Charlotte basin, a Nieogene embayment paralleling the modern mainland coast. The molluscan fauna and associated lignite beds are known from a few widely scattered outcrops; they are indicative of alternating marine and nonmarine to brackish-water environments in the upper part of the formation. The Skonun fauna occurs near the northern boundary of the Pacific Northwest Neogene molluscan province. It is the only marine Neogene molluscan fauna known from the British Columbia coast. The fauna has strong taxonomic ties with the fauna of the Empire Formation of southwestern Oregon and has several species in common with the upper Miocene of the Lituya district, southeastern Alaska, implying that these three faunas are coeval.

Queen Charlotte Islands, Graham Island↗
USGS1976

Recent limnological changes in southern Kootenay Lake, British Columbia

n response to a significant abatement of phosphate loading and the construction of a dam on its major inflow (the Kootenay River), southern Kootenay Lake experienced a number of limnological changes between 1969 and 1974. Water temperatures in 1974–1975 were similar to those previously reported for 1966–1969. However, water transparency has increased, particularly during the spring months.Nitrate concentrations have remained unchanged since 1969, and ranged from 2 to 8 μ M between 6 June 1974 and 22 May 1975. However, ammonium levels have been reduced in the winter months when mean concentration was about 1 μ M . Dissolved phosphorus levels in 1966–1969 were consistently around 3 μ M , but never reached 1 μ M in 1974. Phytoplankton populations in 1974–1975 (measured as chlorophyll a ) were lower than those during the 1966–1969 period, and evidence is presented that suggests that major shifts have occurred in the species composition of the phytoplankton. Whereas Kootenay Lake experienced blue–green and green algal blooms during the 1960's, no such phenomena were observed in 1974–1975 when the plankton was dominated by diatoms. Population maxima of the three most common zooplankters ( Cyclops bicuspidatus , Diaptomus ashlandi , and Diaphanosoma leuchtenbergianum ) have increased since 1966–1969.

British Columbia↗
USGS1975

Leech (Hirudinea) infestations among waterfowl near Yellowknife, Northwest Territories

Fourteen species of aquatic birds, including 11 species of ducks, were infested with leeches Theromyzon rude and Placobdella ornata near Yellowknife, Northwest Territories. Leeches infested 88% of 41 American Wigeon (Anas americana) and 31% of 86 Lesser Scaup (Aythya affinis) examined after death. Lesser Scaup captured by drive-trapping contained significantly more leeches than undisturbed ducks. Leeches were attached to the host within the mucosa of the nasal chamber, to the conjunctiva of the eye and on the skin of the body. Although only two deaths of ducklings were directly attributed to leech infestations, other birds probably died as a result of parasitism by leeches.

Northwest Territories↗
USGS1974

Population dynamics of molting pintail drakes banded in south-central Saskatchewan

A total of 18,820 adult male pintails ( Anas acuta ) were trapped, banded, and released on Pel and Kutawagan marshes in south-central Saskatchewan in July 1955-58. Two hundred and fortyeight of these banded birds were recaptured on the same marshes during subsequent trapping operations, and 1,440 were recovered (shot or found dead) during legal hunting seasons, 1955-70. The size of the adult drake pintail population associated with Pel and Kutawagan marshes was estimated to have been approximately 313,600 in July 1956 and 232,800 in July 1957. Estimates of annual survival varied from approximately 60 percent to 85 percent with an average of 73 percent. Between July 1956 and July 1957, approximately 71,100 birds joined the population segment associated with Pel and Kutawagan marshes and 25,400 birds left the population segment for other areas. Indices to harvest pressure were low, varying from 2.26 in 1958 to 3.54 in 1956. Estimates of harvest rates varied from 5.6 percent to 8.8 percent, and kill rates varied from approximately 7.0 to 11.0 percent. The index to harvest pressure was highest in 1956, while survival during the 1956-57 period was the lowest, suggesting the possibility of an inverse relationship between harvest rate and total survival.

south-central Saskatchewan↗
USGS1971

Glacial marine sediments in the precambrian Gowganda formation at Whitefish Falls, Ontario (Canada)

Study of a well-exposed section of the Gowganda Formation at Whitefish Falls, Ontario, suggests criteria for the recognition of glacial marine sediments. Thickness of hundreds of feet, lateral continuity, faint internal stratification, sorted lenses of sandstone and conglomerate, and dropstones characterize much of the tillite. Thickness of hundreds of feet, lateral continuity, and marked development of irregular and lenticular laminae instead of varve structure characterize much of the argillite. These characteristics, together with evidence for a nearshore, marine-to-deltaic environment for the overlying beds, suggest a glacial marine interpretation even though no fossil evidence is available. Massive tillite, tillite containing faint stratification and lenses of sorted conglomerate and sandstone, and dropstone-bearing argillite, all of which interfinger, suggest a glacial marine environment composed of: ( 1 ) a subglacial facies; ( 2 ) a periglacial facies; and ( 3 ) a facies of marine ice rafting, respectively. Separation of the two tillite-bearing members by as much as 700 ft. of argillite containing no dropstones suggests two distinct ice ages during Gowganda time.

Ontario↗
USGS1971

Seismology in Canada

Explore the source record for details and available documents.

Earthquake Information Bulletin (USGS)↗
USGS1970

Summer foods of lesser scaup in subarctic taiga

Reports on the food of 25 adult and 38 juvenile Aythya affinis , collected in June-Sept 1967 along the Yellowknife Highway north of Great Slave Lake. The vegetation, physiography and ponds of the area, the collecting and statistical methods are briefly described. Approx 99% of the scaup diet was animal material; juveniles in mid-summer fed on freeswimming organisms such as Chaoborinae (phantom midges) and Conchostraca (clam shrimps); in late summer they, as did adults in June, fed on bottom organisms such as amphipods, odonates and corixids. Seeds, copepods and cladocerans were seldom or never eaten.

Northwest Territories↗
USGS1970

Waterfowl breeding habitat in agricultural and nonagricultural land in Manitoba

Waterfowl populations and habitat characteristics were examined on 33 potholes in each of two 16-square-mile study areas of agricultural and nonagricultural land in southwestern Manitoba. The agricultural land potholes, lacking in or incompletely surrounded by trees, received greater use by lesser scaup ( Aythya affinis ), canvasback ( A. valisineria ), redhead ( A. americana ), coot ( Fulica americana ), and three species of grebes ( Podicipedidae ). The nonagricultural land potholes, completely surrounded by trees, were more attractive to blue-winged teal ( Anas discors ), and mallard ( A. platyrhynchos ), and over twice as many dabbler broods were censused there. Abundant, undisturbed nesting cover may have been the reason for greater dabbler use on the nonagricultural land potholes since chemical and biological properties suggest more fertile conditions in the agricultural land.

Manitoba↗
USGS1969

Geochemistry and origin of formation waters in the western Canada sedimentary basin-I. Stable isotopes of hydrogen and oxygen

Stable isotopes of hydrogen and oxygen, together with chemical analyses, were determined for 20 surface waters, 8 shallow potable formation waters, and 79 formation waters from oil fields and gas fields. The observed isotope ratios can be explained by mixing of surface water and diagenetically modified sea water, accompanied by a process which enriches the heavy oxygen isotope. Mass balances for deuterium and total dissolved solids in the western Canada sedimentary basin demonstrate that the present distribution of deuterium in formation waters of the basin can be derived through mixing of the diagenetically modified sea water with not more than 2.9 times as much fresh water at the same latitude, and that the movement of fresh water through the basin has redistributed the dissolved solids of the modified sea water into the observed salinity variations. Statistical analysis of the isotope data indicates that although exchange of deuterium between water and hydrogen sulphide takes place within the basin, the effect is minimized because of an insignificant mass of hydrogen sulphide compared to the mass of formation water. Conversely, exchange of oxygen isotopes between water and carbonate minerals causes a major oxygen-18 enrichment of formation waters, depending on the relative masses of water and carbonate. Qualitative evidence confirms the isotopic fractionation of deuterium on passage of water through micropores in shales.

Alberta↗
USGS1969

Glacial sedimentology of the Precambrian Gowganda Formation, Ontario, Canada

The Gowganda Formation is part of the thick Huronián sequence of Precambrian sedimentary rocks that crop out in central Ontario from Lake Superior to Quebec. Although it has long been considered to be glacial, recent work on submarine slump and turbidite deposits has reopened the question of its origin. This study was made to determine its origin and paleogeography. Till-like conglomerates, varved argillites, and abundant dropstones characterize the Gowganda and provide strong evidence for a glacial origin. Pebble fabric parallel to regional paleocurrents, rare striated and grooved pavements, and abundant unweathered detritus are also in harmony with a glacial origin. Local thin-bedded sandstones contain flame structure, graded bedding, contorted bedding, and rippled tops, suggesting deposition by turbidity flows. Association of these sandstones with varved argillites and rafted stones indicates that Gowganda turbidites are glaciolacustrine. Along the southern margin of the Gowganda, at Whitefish Falls, thick, laterally continuous till-like conglomerates contain internal stratification indicative of subaqueous deposition. Argillites that lack varved structure and associated silty limestones suggest a glacial marine environment. In the Cobalt region the apparent long axes of pebbles in conglomerates show a predominant north-south alignment. In the Bruce Mines-Elliot Lake region, the orientation of the long axes of pebbles is more variable. Differences in orientation are related to stratigraphic position. Ripple cross-lamination in sandstones that are interbedded with argillite indicates south-trending paleocurrents. Distribution of varved argillite, silty limestone, and probable marine argillites suggests a northern fresh-water facies and a southern marine facies. Abundant plutonic pebbles and feldspar indicate that the Gowganda ice sheets eroded a northern plutonic terrane and deposited much of their sediment load on the underlying Huronian sediments to the south.

Ontario↗
USGS1969

Selective feeding by juvenile diving ducks in summer

Waterfowl often fail to use foods that seem plentiful to the investigator. The extent to which selective feeding or rejection of foods is a function of behavioral and morphological adaptations of the species, conditioned behavior of the individual, or individual preference for certain foods has not been appraised. The objectives of our study were to determine: (1) the extent of selective feeding among juvenile Canvasbacks ( Aytha valisineria ) and redheads ( A. americana ), (2) which food items were and which were not utilized, and (3) how selective use was related to the relative quality and availability of the food resource. In another paper (Bartonek and Hickey, MS) we present findings on the food habits of juvenile and adult Canvasbacks, Redheads, and Lesser Scaup ( Aytha affinis ) in southwestern Manitoba primarily during late spring and summer. Only a few of the limited number of investigations into the summer food habits of waterfowl correlate use of foods with the relative quantity and/or availability of potential foods (White, 1936; Beard, 1953; Keith, 1961; Chura, 1961; Perret, 1962; Collias and Collias, 1963). Perret (1962) concluded that seasonal variations in the food habits of Mallards ( Anas platyrhynchos ) were related to changes in the availability of foods.

Manitoba↗
USGS1968

Temperature, salinity, and origin of the ore-forming fluids at Pine Point, Northwest Territories, Canada, from fluid inclusion studies

Although the Pine Point ore is relatively poor in useable fluid inclusions, some sphalerite crystals from replacements, vugs, and from " colloform" crusts were found to contain primary or pseudosecondary liquid-gas inclusions adequate for study . Most (132 of 133) of these had low freezing temperatures, indicating exceedingly saline brines. The 112 inclusions suitable for filling- temperature determination homogenized at +51° to +97° C. A very small pressure correction must be added to obtain the trapping temperature .Dolomite crystals from some of the same vugs contain large numbers of primary inclusions, many of which have leaked. The twenty-three that presumably have not leaked had filling temperatures of 90°-100° C, but somewhat lower salinities. Inclusions in late calcite appeared to have similar gas-liquid ratios, but had still lower salinities.The significance of these data lies in the limitations they place on the choice of possible mechanisms of origin of these large deposits. This choice, in turn, may influence the success in prospecting for blind ore bodies. There is general agreement that the deposits are of Mississippi Valley type. Although the high salinities may reflect solution of salts from evaporites, as are now found to the south, the elevated temperatures seem to require deep circulation, perhaps through known faults in the underlying Pre-cambrian. The densities of these brines, even at their elevated temperatures, are well above that of fresh, cold surface water, thus restricting the possible modes of circulation during ore deposition.

northwest Canada↗