bluuebunny/crossref_metadata_2025 huggingface dataset:
THE ST. LAWRENCE VALLEY SYSTEM: A NORTH AMERICAN EQUIVALENT OF THE EAST AFRICAN RIFT VALLEY SYSTEM
Authors: Kumarapeli P. S. , Saull V. A.
Published: April 2011

The St. Lawrence valley system (including the St. Lawrence, Ottawa, and Champlain valleys, and the St. Lawrence or Cabot trough) is coextensive with a well-defined pattern of seismic activity. The valley system is in a region of general updoming, normal faulting, and alkaline igneous activity of a distinctive type. The main phase of tectonic activity probably dates back to Mesozoic time. The above and other evidence presented in this paper indicate the existence of a major rift valley system that may be called the St. Lawrence rift system.The Rough Creek – Kentucky River fault zone, and the normal fault zones in Texas and Oklahoma, and the Lake Superior fault zone probably represent extensions of the St. Lawrence rift system. However, current seismicity indicates that the present tectonic activity is along a straight zone running through lakes Ontario and Erie into the Mississippi embayment. The St. Lawrence rift system may also be connected with the mid-Atlantic rift, in the region of the Azores plateau.The rift hypothesis presented may be useful as a regional guide in the search for niobium-bearing alkaline complexes and diamond-bearing kimberlites.Crustal tension in the St. Lawrence region may be genetically related to the opening of the Atlantic basin as postulated in the hypothesis of continental drift.
SOME FUNDAMENTAL CONSIDERATIONS ON GLACIER MAPPING
Authors: Blachut T. J. , Müller F.
Published: April 2011

Five glacier maps at scales of 1:5 000 and 1:10 000 were produced by the Photogrammetric Research Section of the National Research Council and the Axel Heiberg Island Expedition of McGill University for use in glaciological research in the Canadian Arctic. After general comments on the need for and scope of glacier mapping, the authors discuss in some detail the main problems encountered. It is maintained that glacier maps belong to the class of 'special maps' and that the specifications for them should be set by the glaciologists.Accuracy requirements, choice of mapping scale and contour interval, delineation of various glacier units, extent of detail plotting, etc. are critically reviewed, The 1:10 000 map of the entire White Glacier catchment area, accompanying this paper, is an example of a map which serves various glaciological purposes, primarily calculations of mass change. To facilitate future glacier mapping, the authors suggest that clear definitions of glaciological terms such as 'active glacier' or 'glacierized area' should be established and that their cartographical presentation should he further standardized.
MEASURING AND MAPPING OF GLACIER VARIATIONS
Authors: Kick W.
Published: April 2011

One of the main purposes of glacier mapping is to determine the temporary state of glaciers and to investigate glacier variations by successive mappings. The author illustrates this work with particular reference to terrestrial photogrammetric surveys of mountain glaciers in the Nanga Parbat region of the Himalaya and of the Tunsbergdalsbre in southwest Norway, in both cases 24 years after R. Finsterwalder's original surveys. The author shows that the most important index of variation is the height variation of the surface level in the region of the firn line. The accuracy necessary for measuring the height variation and the scale of map plotting are discussed. Field methods are also discussed, and information is given on the measurement of volumetric changes from contourline shifts and on the measurement of velocity profiles by terrestrial photogrammetry.
APPLICATIONS OF PHOTOGRAMMETRY TO SURVEYS OF GLACIERS IN CANADA AND ALASKA
Authors: Konecny Gottfried
Published: April 2011

The paper emphasizes that the choice of a proper procedure is essential for efficient glacier surveying. Terrestrial versus aerial photogrammetry and the use of electronic surveying procedures versus triangulation have been tested in surveys on the Athabasca and Saskatchewan glaciers, and on glaciers in northern Ellesmere Island, southeastern Alaska, and the Yukon Territory. The Otto Fiord glacier survey in northern Ellesmere Island demonstrates that no ground control is needed for volumetric glacier studies. Accurate maps needed for other studies depend on the establishment of control. Control can most efficiently be determined by tellurometer and phototheodolite with helicopter support, as shown in Alaskan glacier surveys. For large glaciers phototopography provides a good means of extending control from tellurometer traverse stations, as demonstrated in the Mount Kennedy survey. Simple one-color maps are an economical means of preserving survey results for future glaciological evaluation.
SOME PROBLEMS OF GLACIER MAPPING EXPERIENCED WITH THE 1:10 000 MAP OF THE ALETSCH GLACIER
Authors: Kasser P. , Roethlisberger H.
Published: April 2011

The difficulties of the aerial survey of the Aletsch Glacier lay in establishing ground control in the high mountains and locally on the moving glacier surface, and in plotting featureless névés on the autograph. The major problem in plotting proved to be the delineation of the margins of active glaciers where marginal zones were thickly covered with debris or fresh snow, or where it was necessary to define the boundary between the active glacier and stagnant ice. The distinction between active and stagnant ice is based on movement and nourishment, that is, on characteristics not directly visible in the air photographs, and the boundary is too often a matter of personal judgment. The authors hold that this boundary would be better omitted on an accurate map of the type discussed, while the glacierized area should be represented only in so far as ice is clearly indicated by surface features. A further provisional boundary might be given to indicate suspected buried ice. The paper emphasizes the importance of favorable glacier conditions when the control photographs are taken, to facilitate the mapping and interpretation of glaciological features.
SURFACE COLORING OF GLACIERS FOR AIR PHOTOGRAPHY
Authors: Østrem Gunnar
Published: April 2011

To make glacier mapping possible in white firn areas where stereo-effect is difficult to obtain, a large number of surface markers were placed on the glacier before air photographs were taken. Experiments proved that 3- to 5-kg powdered dye (yellow or brown ochre, or lamp black), packed in paper bags, made excellent surface markers when thrown from between 50- and 100-m elevation above the glacier surface. Color circles, applied by hand, also proved to be a good means for identifying ablation stakes, etc., in the firn area. An example of a map is given where the construction of contour lines was based upon the easily determinable dye markers that were clearly visible on vertical photographs taken from 7 300-m altitude.
THE GLACIOLOGICAL MAPS OF MEIGHEN ISLAND, N.W.T.
Authors: Arnold K. C.
Published: April 2011

The small ice cap on Meighen Island has been studied since 1959 by scientists working with the Polar Continental Shelf Project, Department of Mines and Technical Surveys, Ottawa. The Surveys and Mapping Branch of the same Department has produced a glaciological map of the ice cap, at the scale of 1:25 000, from special photography taken from a height of 2 280 m in 1960, and a 1:50 000 map of the whole island, showing features of glaciological interest, from standard mapping photography taken from a height of 9 150 m in 1959. The control, photography, and compilation methods used in producing these maps are discussed, and an account is given of the special features shown on them.
METAMORPHISM OF THE MEGUMA GROUP OF NOVA SCOTIA
Authors: Taylor F. C. , Schiller E. A.
Published: April 2011

The Meguma group of lithic greywacke, feldspathic quartzite, slate siltstone, and argillite is Early Ordovician or older in age and has undergone both regional and contact metamorphism. Both types of metamorphism have resulted in recrystallization and locally in orientation of newly formed minerals. Metasomatism and retrogressive metamorphism are subordinate and only locally important. Regionally metamorphosed rocks are divided into greenschist and almandine–amphibolite facies, although some assemblages cannot be assigned with certainty. Locally, biotite and garnet isograds are mappable within the greenschist zone.Relationships between regional metamorphism and structural elements (folding) show that deformation preceded regional metamorphism. Intrusion of granitic rocks has produced a zone of contact metamorphism (hornblende–hornfels facies) that is superimposed upon regional greenschist facies rocks, which shows that granite emplacement occurred after the regional grade was reached. Gold–quartz veins are confined to areas lying in the greenschist zone of regional metamorphism, which suggests that the almandine–amphibolite zone is not favorable.
NEW OCCURRENCES OF MONOTIS FROM CANADA (TRIASSIC PELECYPODA)
Authors: Westermann G. E. G.
Published: April 2011

Monotis typica (Kipar.), M. cf. M. haueri Kittl, and M. cf. M. daonellaeformis Kipar. are for the first time described from Canada. M. typica occurs in the Pardonet formation of British Columbia, doubtfully in the Lower Norian, and probably throughout the Middle Norian. Associated with the upper Middle Norian Himavatites columbianus ammonoid assemblage of the same area is M. obtusicostata sp. nov.; it occurs with the first usually sparse M. pinensis West. and the last Halobia.M. pinensis usually flourishes just above this assemblage. Monotis cf. M. haueri occurs in the Upper Norian 'formation D' of the Lewes River group in southern Yukon. M. cf. M. daonellaeformis is described from the Middle Norian of Axel Heiberg Island in the Arctic. The Monotis sequences of British Columbia and Japan compare closely, while the Canadian and Siberian Arctic faunas show great similarity.
INFLUENCE OF SURFACE CONDITIONS ON GROUND TEMPERATURE
Authors: Gold L. W.
Published: April 2011

Ground temperatures were measured under two parking lots, one of which was cleared of snow in winter, and monthly and annual average surface temperatures were estimated by extrapolation. The surface temperatures were compared with monthly and annual surface and air temperatures measured at a nearby grassed site. A dependence of the difference between the monthly average surface and air temperatures on snow cover and convective loss was observed. A correlation was found to exist between the monthly average of the daily global solar radiation and the difference between monthly average air temperature and monthly average parking lot surface temperature. It was demonstrated that, because of a change in surface conditions, there was a change in annual average ground temperature beneath a parking lot. The observations are discussed with reference to the formation of sporadic permafrost.
ADDITIONAL MEASUREMENTS OF THE ISOTOPIC COMPOSITION OF LEAD FROM STRATIFORM DEPOSITS
Authors: Ostic R. G. , Russell R. D. , Stanton R. L.
Published: April 2011

This paper pursues the study of an apparent correlation between lead isotope abundance characteristics and features of the deposits in which the lead is discovered. New and precise analyses have been carried out on 55 galena samples, mostly From Australasian ore deposits classified as stratiform. To help clarify the interpretation, certain vein leads related to those which are stratiform have been included, as has one analysis of volcanic cotunnite.New evidence is offered that all leads began their isotopic evolution in a unique primary system which has very restricted spatial variation in the ratios U/Pb and Th/Pb. Leads from certain stratiform deposits approach more closely in isotopic composition the products of the primary system than do vein leads, many of which involve extensive crustal histories thai further modify the isotope ratios. The analyses presented here have sufficient precision to permit a close examination of the differences in isotope ratios between stratiform leads and the products of a simplified model for the primary system. The differences are significant and important.Novel aspects of the experimental technique are discussed.
PALEOMAGNETISM OF THE ALLARD LAKE ANORTHOSITE SUITE
Authors: Hargraves R. B. , Burt D. M.
Published: April 2011

Analysis of paleomagnetic data on 112 samples of Precambrian anorthosite, norite, pyroxene–syenite and hemo-ilmenite ore from four main localities in the Allard Lake area reveals: (1) A relatively soft magnetic component resides in magnetite, which is of variable abundance in all rock types. The magnetite remanent magnetic vector is of normal polarity, and is more or less directly opposed to a hard component residing in hemo-ilmenite, the predominant oxide. Self-reversal of the permanent magnetism in the hemo-ilmenite is the favored explanation. (2) Disregarding polarity, the stable remanent magnetic vector has similar orientation in all rock types from all four localities (N = 4, α95 = 18.0). This precludes significant differential rotation of individual structural blocks since the rocks became magnetized. Furthermore, either no polar wander occurred during the emplacement and cooling of the entire igneous rock suite, or all these rock types acquired their magnetism simultaneously during subsequent metamorphism. (3) On the centered-axial-dipole model for the earth's magnetic field, the remanent vector in the Allard Lake rocks gives a pole southeast of New-foundland, at coordinates 38°36′ N., 39°36′ W. (α95 = 18.0).
A STRATIGRAPHIC ANALYSIS OF THE SUBSURFACE DATA RELATING TO THE CHAZY GROUP IN THE ST. LAWRENCE LOWLAND OF EASTERN CANADA
Authors: Roliff W. A.
Published: April 2011

Previous descriptions of the Chazy Group of the St. Lawrence Lowland of Eastern Canada based on the study of the surface exposures and the logs of seven holes, indicated the Chazy to be composed mainly of calcareous shales, shaly limestones, limestones, and some sandstones.The Chazy sediments, as indicated by subsurface data from 30 additional wells, vary laterally from limestone with some shale and sandstone, in the belt bordering the Precambrian Shield, to predominantly dolomite with some limestone, shale, and sandstone in the basinward region southeast of the St. Lawrence River. The character of the sediments suggests a platform or foreland type of deposit, the product of a transgressing sea.The absence of dolomite in the surface exposures and the similarity of the sandstones to those of the older Beekmantown and Potsdam Groups, has misled geologists in logging, and subsequent interpretation, of the subsurface data in a number of wells, particularly in the Three Rivers area. Recognition of these mistakes makes it possible to explain the apparently anomalous thickness of the Chazy, as reported in published logs of these wells.Additional evidence is also presented bearing on the Chazy–Black River relationship.
THE ORIGIN OF SOME VARVES IN TORONTO, CANADA
Authors: Lajtai Emery Zoltan
Published: April 2011

A section of varved clays exposed by excavations for the University–Bloor–Danforth Subway in Toronto is described. The individual varves are noted, in general, for such irregular features as erosional structures, poor sorting and grading, sublaminations, and angular fragments of unconsolidated material scattered in the coarse-grained layer. The most characteristic property of an individual varve is the sorting and grading of the coarse-grained layer. On this basis three groups can be distinguished: graded, complex, and diamictic varved clays. Deposition from a special type of turbidity current, the meltwater bottomflow, offers the best explanation for the origin of these varves. The deposition of complex varves, which are the typical varves of the section, probably takes place from continuous meltwater bottomflows that vary in sediment load. Because of the continuity of meltwater currents, sedimentation occurs under the influence of three independent but overlapping processes: settling from a graded suspension, addition of coarse sediments rolled along the bottom, and deposition from a uniform clay suspension. Complex varve structures and textures reflect variations in the coarse sediment load that is ultimately controlled by short-term (commonly diurnal) and long-term temperature variations (chiefly seasonal) affecting the rate of melting at the glacier and consequently the discharge and competence of meltwater currents. The deposition of graded and diamictic varved clays, on the other hand, probably takes place from either single overflows or single bottomflows.
POTASSIUM–ARGON AGE DETERMINATIONS IN THE MADOC–BANCROFT AREA IN THE GRENVILLE PROVINCEOF THE CANADIAN SHIELD
Authors: Macintyre R. M. , York Derek , Moorhouse W. W.
Published: April 2011

Thirty K–Ar ages are reported for metasediments, metavolcanics, granites, and pegmatites from the Madoc–Bancroft area of the Grenville Province of the Canadian Shield. When these data are compared with dates available in the literature it is seen that K–Ar ages of biotites are in general systematically lower than Rb–Sr whole rock and U–Pb ages for the area. This is interpreted to be the result of a long cooling history for this part of the Grenville Province, during which the Rb–Sr and U–Pb clocks began to record time at least 100 m.y. before the K–Ar clocks. It seems probable that the K–Ar ages are separated in time by an indefinite interval from the event or events they are usually considered to represent. The commencement of argon retention by biotites occurred about 950 m.y. ago whereas U–Pb and Rb–Sr whole rock dating indicate that the major igneous and metamorphic events in the Grenville Province took place1000–1300 m.y. ago.
CRUSTAL STRUCTURE UNDER HUDSON BAY
Authors: Hobson George D. , Overton A. , Clay D. N. , Thatcher W.
Published: April 2011

A crystal refraction experiment was conducted in August 1965 in Hudson Bay in which nine university and government crews participated. Good quality data were obtained from 41 shots providing sufficient data to permit time-term analyses of both Pnand P1arrivals. No consistent intermediate arrivals were identified leading to the consideration of a two-layer crustal model. Pntime-terms indicate that the depth of the Mohorovicic discontinuity is between 26 and 41 km.
SPECTRAL STUDY OF SHORT-PERIODP-WAVES
Authors: Leblanc Gabriel , Howell Jr. Benjamin F.
Published: April 2011

The variability of 37 short-period P-wave spectra was studied. Amplitude level is affected by distance and crustal effects. Similarity of the over-all shape of the spectra is attributed to the source. An oscillatory character, present on almost all spectra, is related to the crustal effect. Acting as a mask, the crustal effect prevents quantitative measurements of the attenuation and of the radiation pattern. By an averaging of spectra, the crustal masking can be partly overcome, and an approximation of the spectrum of the pulse incident at the mantle-crust boundary obtained. Selected average spectra suggest that over the frequency range 0.4 to 0.9 cps, very little, if any, differential attenuation takes place. The use of crustal inverse filtering, difficult though it may be, seems required for any quantitative results.
THE ORIGIN OF HYDROCHEMICAL PATTERNS IN HUMMOCKY MORAINE
Authors: Rozkowski A.
Published: April 2011

Hydrochemical investigations were carried out in a small local basin in hummocky moraine of southern Saskatchewan. The 'basin' consisted of a hill and surrounding permanent sloughs. The constructed Teledeltos flow model shows the typical pattern of groundwater flow near permanent lakes, where the hills are areas of recharge and the sloughs areas of discharge. Based on the chemical analyses of soil and till extracts as well as on the chemical analyses of slough and groundwater, the development of certain hydrochemical patterns in hummocky moraine can be explained.Three hydrochemical zones can be distinguished: SO4–Ca–Mg in the recharge area, SO4–Mg–Ca in the transmission zone, and SO4–Mg–(Na) in the discharge area. The increase of groundwater salinity from the recharge area to the discharge area is due to evapotranspiration as well as to the poor permeability of the glacial deposits.The SO4–Mg–Ca type of water of the recharge area is already formed in the zone of aeration. The subsequent changes of groundwater chemistry in the zone of saturation are induced by the enrichment of easily soluble salts and by the steady precipitation of poorly soluble salts. The sharp increase in salinity and the significant enrichment of the SO4–Mg type of water by easily soluble salts take place in the shallow zone of the discharge area close to the surface. The study of water extracts suggests the presence of groundwater discharge in the region of the capillary fringe of the recharge area also.The delivery of ions to the sloughs takes place by groundwater flow and inter-flow; therefore, the hydrochemistry of sloughs is primarily determined by the chemistry of these waters. The further metamorphosis of slough water is produced mainly by intensive evaporation as well as by ion exchange within the slough.
THERMOMAGNETIC ANALYSIS AND ORE GENESIS
Authors: Schwarz E. J.
Published: April 2011

The potential of rock magnetism in studies on the genesis of ore deposits is examined. It is suggested that techniques based on magnetic properties other than the direction of the stable part of the natural remanent magnetization might prove usefully applicable. More specifically the analysis of the type of remanent magnetization in ores and their wall rocks is suggested as a worthwhile approach in the study of ore genesis. Other methods suggested are based on the occurrence of chemical or physical changes affecting ferromagnetic minerals in ores during heating. It may be possible to relate the results of such experiments to the thermal conditions prevailing at the time of either formation of minerals in ore deposits or acquisition of stable remanent magnetization.
THE PLEISTOCENE SEQUENCE AT ZORRA, SOUTHWESTERN ONTARIO
Authors: Westgate J. A. , Dreimanis A.
Published: April 2011

The Pleistocene sequence at the Canada Cement Plant No. 4 quarry at Zorra is remarkable for the large number of till sheets it contains; nine physically distinct tills, intercalated with stratified drift, are present. These glacial deposits, laid down by Erie, Huron, and Georgian Bay ice lobes, are continuously exposed along a [Formula: see text]-mile long face that reaches a height of 70 ft in places.Lithologic and till fabric studies, analysis of striae on bedrock and boulder pavements, plus observations on the orientation of streamlined glacial landforms in the Zorra district, were carried out in an attempt to determine the parent ice lobe of each till. Erie lobe deposits constitute the lower part of the sequence (units A and B); units C and D were deposited by Georgian Bay and Huron ice lobes respectively; units E, F, and G are related to an Erie lobe whereas units H and I were laid down by a Huron ice lobe.On the basis of lithology, till fabric, and stratigraphic position, the Zorra tills have been correlated with tills exposed along the Nith River and in the area between Thames River and Lake Erie, southwestern Ontario. From the proposed correlation it follows that units A and B are of Early Wisconsin age; units C and D, of Mid-Wisconsin age; all younger units are of Main or Late Wisconsin age.
POSITION OF THE LOWER JURASSIC GENUS FANNINOCERAS McLEARN AND THE AGE OF THE MAUDE FORMATION ON QUEEN CHARLOTTE ISLANDS
Authors: Frebold Hans
Published: April 2011

The Lower Jurassic ammonite genus Fanninoceras McLearn hitherto considered to belong to the family Hildoceratidae Hyatt is now assigned to the Family Oxynoticeratidae Hyatt. Its age is probably early Pliensbachian. The Maude Formation of the Queen Charlotte Islands hitherto considered to be entirely Toarcian in age is shown to include upper Sinemurian and lower Pliensbachian. In the underlying Kunga Formation ?Arniotites indicate lower Sinemurian.
PALEOMAGNETISM OF PRECAMBRIAN ROCKS NEAR COBALT, ONTARIO
Authors: Symons D. T. A.
Published: April 2011

A paleomagnetic study was made on 32 hand samples from Precambrian rock units in the Silverfeilds Mine, Cobalt, Ontario. The samples from the Keewatin lavas proved unsuitable for paleomagnetic study. The Cobalt Group sediments and Nipissing diabase sill have stable primary remanences, which yield pole positions of 82.5°E, 21.5 °S and 74.4 °E, 11.9 °N respectively after alternating-field demagnetization. The upper slate member of the Cobalt Group is in contact with the sill and its primary remanence has been altered by contact metamorphism.
Phosphate diagenesis of carbonate sediments as a mode of in situ formation of marine phosphorites: Observations in a core from the eastern Pacific
Authors: d'Anglejan Bruno F.
Published: April 2011

Carbonate-fluorapatite, the mineral of marine phosphorite, is found to form contemporaneously within the sediments by the replacement of skeletal carbonate in a core sample of foraminiferal ooze from the eastern tropical Pacific. A systematic downward increase in apatite within the core suggests that replacement is continuing at a decreasing rate in the sediments. The widespread distribution of foraminiferal ooze on the California borderland and its common association with phosphorite suggest that this material may play a role in the phosphorite accumulation there. The reaction of CaCO3 with soluble phosphate in conditions favoring the slow dissolution of the carbonate mineral may result within the sediments in an increase of the carbonate ion concentration, which appears to control the rate of replacement.
Optical absorption spectra of octahedrally bonded Fe3+ in vesuvianite
Authors: Manning P. G.
Published: April 2011

The optical absorption spectra of green vesuvianite crystals from Lowell County, Vermont, are reported in the energy range 12 000 cm−1 to 30 000 cm−1. The principal absorptions have been attributed to octahedrally bonded Fe3+ and the individual bands have been assigned to spin-forbidden electronic transitions from the 6A1 ground state to excited states in Fe3+. In particular, the 6A1 → 4A14E(G) transition is marked by a relatively sharp band at 21 600 cm−1.
Glacial history of Northeastern Ontario II. The Timiskaming–Algoma area
Authors: Boissonneau A. N.
Published: April 2011

The surficial deposits, ice movements, and glacial lakes within an area of 34 500 square miles in northeastern Ontario are described. Some of the moraines of the study are tentatively correlated with moraines to the west in the upper peninsula of Michigan, in the Nipigon area, and along the north shore of Lake Superior. The glaciolacustrine deposits and sequence of events in the study area in relation to the glacial features and chronology of the southern Great Lakes basin provide a basis for a partial glacial chronology for the study area. A knowledge of the glacial features of this area further elucidates the integration of movements of two advancing ice lobes, which was observed in northwestern Quebec.
Correlation of air temperature normals for the Canadian Great Plains with latitude, longitude, and altitude
Authors: Hopkins J. W.
Published: April 2011

As an aid to interpolatory estimation, normals of monthly mean, mean maximum, and mean minimum recorded at 206 climatological stations have been graduated by least squares formulae constructed from polynomials of moderate degree in latitude, longitude, and altitude coordinates. Seasonal variation was evident in all computed temperature gradients, indicated elevation effects being maximal in summer and those associated with latitude and longitude most pronounced in winter and spring. These empirical formulae did not account completely for all systematic features of the data, but resulted nevertheless in correlation coefficients of r ≥ 0.95 between recorded and calculated mean temperatures for all months in this relatively homogeneous geographical region. An illustration is given of their possible application to approximate isotherm location by inverse interpolation.
A dinosaur bone from Willow Creek beds in Montana
Authors: Russell Loris S.
Published: April 2011

The right tibia of an ornithopod dinosaur has been found in supposed Willow Creek beds in the Two Medicine valley southeast of Browning, Montana. This is the first report of dinosaur bones from the formation on the east side of the Alberta syncline. The specimen is referred to Thescelosaurus? sp., but there is some suggestion of the earlier genus Camptosaurus.
A geological interpretation of the Bouguer anomalies adjacent to the Churchill–Superior boundary in northern Manitoba
Authors: Gibb R. A.
Published: April 2011

The Bouguer anomaly map of nothern Manitoba and part of northeastern Saskatchewan was updated by a gravity survey in 1965. Density determinations of some 2000 Precambrian rock samples provide a sound basis for interpretation of the Bouguer anomalies in terms of relatively near-surface mass distributions in the upper crust. In some parts of the area there is excellent correlation between the surface rocks, their densities, and the Bouguer anomalies. The Nelson River gravity high outlines a belt of dense granulites. To the northwest three gravity lows are interpreted as the gravity effects of granitic intrusions, of which one is exposed at Split Lake and the others are largely subjacent, although their presence is supported by the occurrence of numerous mappable stocks of granite within the gravity lows. The Nelson River gravity high is separated from these lows by a steep gravity gradient, which marks a boundary between rocks of predominantly different ages (Hudsonian and Kenoran) between latitudes 54 °N and 56 °N. Age determinations are consistent with an interpretation of the Pikwitonei subprovince as an inlier of Kenoran age within the Churchill Province. The main Churchill–Superior boundary may then be moved south to what is at present the southern limit of the Cross Lake subprovince, which is a return to approximately the position originally selected by M. E. Wilson.
Model studies of the coast effect on geomagnetic variations
Authors: Hermance John F.
Published: April 2011

The effect of a highly conducting ocean on geomagnetic variations has been studied by means of an analog model. Analog model results for a straight coastline show good agreement with analytical results derived for the case of a concentrated current source over the edge of an infinitely conducting ocean. The analog model was extended to the case of a poorly conducting island of irregular shape in a highly conducting ocean by cutting a hole the desired shape (in this case Iceland) from a large thin sheet of lead. Although anomalous contributions in the H, D, and Z components are observed, the distortion of the horizontal field components is restricted to the seaward side of the coast. Over the interior of the island only the vertical field is affected. The model study was undertaken to provide corrections to measurements made in Iceland for deep conductivity studies. Some field observations were in fact made near the coastline, which show general agreement with the model results, but suggest that the model overemphasized the coast effect through complete neglect of the finite conductivity of the island. The field measurements indicate that at distances of 50 km or more from the coast, for periods longer than a few minutes, the coast effect can be neglected.
Studies of formation waters in Western Canada: Geochemistry and hydrodynamics
Authors: Everdingen R. O. van
Published: April 2011

The existence of major flow systems in the Western Sedimentary Basin of Canada is reflected in the chemical composition and degree of concentration of the formation waters involved. Subsurface salt solution and collapse, and accumulation and destruction of hydrocarbon 'deposits' are directly related to such flow systems. Many occurrences of 'anomalies' in pressure, chemical composition, and concentration may be explained on the basis of membrane behavior of shales. The presence of organic matter may have an important influence on the composition of the formation waters. More sophisticated sampling techniques combined with more detailed analysis of formation waters are needed to develop the full potential benefit of formation-water studies for the petroleum industry.
The geology and geochronology of the basement complex of the central Transantarctic Mountains
Authors: Faure Gunter , Murtaugh J. G. , Montigny R. J. E.
Published: April 2011

The central part of the Transantarctic Mountain chain consists of a basement complex of igneous and metamorphic rocks overlain nonconformably by sedimentary rocks of late Paleozoic age, including Permian tillites and coal measures. The basement complex is exceptionally well exposed in the Wisconsin Range of the Horlick Mountains, which are located about 500 km from the South Pole. In this area clastic metasedimentary rocks and overlying metavolcanic rocks of probable pyroclastic origin are intruded by a variety of granitic rocks of the Wisconsin Range batholith, including rapakivi granites and quartz diorites, which are in turn cut by bodies of quartz monzonite, and aplite and pegmatite dikes. The basement complex elsewhere in the central Transantarctic Mountains also includes Cambrian limestones overlain by acid volcanic pyroclastic rocks and lava flows.Age determinations by the Rb–Sr method applied to suites of total rock specimens suggest the presence of two orogenic events accompanied by intrusions of granitic plutons. The first of these occurred about 630 ± 25 m.y. ago and was accompanied by the formation of rapakivi granites. The second took place during the Ordovician Period about 480 ± 10 m.y. ago and involved the intrusion of quartz monzonite and pegmatite dikes. The metasedimentary rocks, which were intruded by both of the granitic rocks, give an apparent age of 460 ± 16 m.y., while the overlying pyroclastic unit was dated at 633 ± 13 m.y. A Precambrian age for the metasedimentary and metavolcanic rocks is consistent with the dating and the field evidence. Rhyolites from localities in the Byrd Mountains and the Long Hills were dated at 489 ± 30 and 498 ± 45 m.y. and are late Cambrian to early Ordovician in age.
Metamorphic chronology of the Precambrian provinces of South India
Authors: Aswathanarayana U.
Published: April 2011

There are three Precambrian provinces in southern India — the Dharwars (metavolcanics, metasediments, charnockites and granites), the Eastern Ghats (metasediments, charnockites and granites), and the Cuddapahs (essentially flat-lying continental sediments disturbed at the margins) — with chronostratigraphic histories dovetailing into one another. The Dharwars bear the impress of three episodes (about 3000 m.y., 2600–2300 m.y., and about 2000 m.y.) of folding, metamorphism, and emplacement of granites, the second being the most important. The pelitic sediments deposited in the Eastern Ghats geosyncline during the post-Dharwar times (upper limit, 2600 m.y.) were later folded and metamorphosed about 1600 m.y. ago into garnet-sillimanite-graphite gneisses (khondalites). Important deposits of mica pegmatites developed during this episode. Charnockites and granites associated with the Eastern Ghats were emplaced 1520–1300 m.y. ago. The Eastern Ghats rocks were subsequently cross-folded and metamorphosed about 500 m.y. ago. The sedimentation in the Cuddapah Basin was initiated sometime after the Eastern Ghats orogeny (1600 m.y. ago) but before 1160 m.y. ago. The Cuddapahs were subjected to regional metamorphism about 500 m.y. ago.
The isotope geology of the Precambrian of the Baltic Shield
Authors: Kratz K. O. , Gerling E. K. , Lobach-Zhuchenko S. B.
Published: April 2011

Recent radiometric mineral dating carried out by K–Ar, Rb–Sr, and U–Th–Pb methods makes it possible to estimate the age boundaries for the main geological formations of the Baltic Shield.The relevant radiometric age zonation does not point to a zonation of continuous growth of the Baltic Shield from the center to the periphery. In its Precambrian history three main stages can be recognized. Most of this territory developed continuously from 3500 m.y. to 1650 m.y. ago. During this first, greatest period the main structural features of the Shield were formed.The following, Gothian period, corresponding to a time interval 1500–1000 m.y. was characterized by consolidation of the Shield and deposition of continental sediments. The main feature of the third, Riphean period beginning approximately at 1000 m.y. was the formation of the Sveco–Norwegian structural belt in the southwestern part of the Shield, discordant to the older formations.
Two gravity profiles in the Manicouagan-Wabush area of west-central Québec
Authors: Grant F. S.
Published: April 2011

Gravity traverses were made along the Rivière aux Pékans and along the Mushalagan River in west-central Québec in 1964 and 1966 in order to make a closer investigation of the large, negative Bouguer anomaly discovered near the Grenville Front in west-central Québec by field parties of the Dominion Observatory in 1956. Detailed elevations were available on both of these traverses from hydrological studies carried out earlier by the Department of Natural Resources of the Province of Québec and by Hydro-Québec.Both gravity profiles traversed the main negative feature plus a large positive rise in the Bouguer anomaly immediately south of the Grenville Front. There are very few clues from the surface geology as to what might be the causes of these effects. The combined analysis of gravitational and aeromagnetic data suggests that one possible interpretation is that the negative anomaly is caused by a deep infold of lighter, non-magnetic (possibly metasedimentary) material quite near the surface, and that the positive rise is due to a slight increase in the average density within the intermediate zone of the Grenville crust.
Intensité et stabilité d'aimantation des basaltes de l'Oregon et Washington et leurs applications à l'expansion du fond de l'Océan et à d'autres problèmes géophysiques
Authors: Irving E. , Roy Jean L.
Published: April 2011

It is shown that the intensity and stability of magnetization of reversed and normal Upper Tertiary lava flows from the United States of America can be summarized by average decay curves of very simple form. When first measured the intensity of normally magnetized specimens is one third greater than that of reversely magnetized specimens, and this is interpreted as being due to secondary viscous components (mean intensity 0.77 × 10−3 gauss) imposed by the recent field on a stable primary component (mean intensity 3.02 × 10−3 gauss). The differences between normal and reversed samples in low demagnetizing fields (<100 Oe) can be used to discover polarity in unoriented rock, and this could be useful in the study of dredge samples from the deep oceans, where, in order to test the hypothesis of ocean floor spreading it is desirable to relate the bottom rock polarity to the sign of the field anomaly observed at the surface. After demagnetization in alternating magnetic fields of 100 Oe (peak), the secondary magnetization disappears and the stable magnetization in normal and reversed samples is indistinguishable whether in its magnitude or its decay characteristics. This suggests that the mean intensity of the field at the time of extrusion was the same irrespective of polarity, and that the mineralogical variations (notably oxidation) affecting remanent intensity are the same in both normal and reversed rocks. The coherent decay of both secondary and primary components suggests a new method of determining intensity of the field in the geological past.
Azolla from the Upper Cretaceous Edmonton Formation, Alberta, Canada
Authors: Srivastava S. K.
Published: April 2011

Four species of Azolla are described from the Upper Cretaceous Edmonton Formation of southern Alberta (Canada). Based on glochidia, two new species—A. hamata and A. sagittifera—are formally designated. Paleoecologic, stratigraphic, and evolutionary significances of Azolla in the Edmonton Formation are discussed.
Paleolacustrine arenites in the Holleford meteorite crater, Ontario
Authors: St. John Brian E.
Published: April 2011

The Holleford meteorite crater is about 20 miles northwest of Kingston, Ontario. It forms a circular structural depression 1.46 miles in diameter and about 950 ft deep. It is filled by sedimentary rocks of Late Proterozoic and Early Paleozoic age with a maximum thickness of 850 ft.The rocks of this section and the polymictic breccia underlying them have been divided into seven lithic units. The bulk of the sequence consists of microlaminated calcareous quartz arenites with lesser amounts of argillaceous and carbonaceous material. These arenites are unlike any rocks found locally outside the crater. They are overlain by carbonates and shales of the Black River Group with apparent unconformity.The origin postulated for the arenite sequence in the crater is a Late Proterozoic or Early Paleozoic fresh-water lake. This lake existed in a subtropical to temperate climate and only rarely froze over. It is probable that it was meromictic for part of its existence, but later became holomictic.Later compaction of the underlying breccias and the paleolacustrine arenites formed a shallow structural basin in the Black River carbonates.
The continental margin of the eastern United States
Authors: Drake Charles L. , Ewing John I. , Stockard Henry
Published: April 2011

Geophysical and geological data of many types are now available from the continental margin of the eastern United States. These include seismic reflection and refraction data, gravity and magnetic measurements, cores of sediments and dredge hauls of rocks, underwater photographs, echo sounding data, and a large body of surface and subsurface geological data from the adjacent land.Major differences in the sedimentary pattern and sedimentary types occur from north to south and reflect not only source differences but also differences in means of transport and deposition. The data indicate a continuity of structure from Newfoundland to the Bahamas, interrupted only by the Kelvin-New England seamount group and associated structures ashore. They suggest that the ocean basin west of Bermuda is at least as old as Paleozoic.
Pleistocene stratigraphy of the Saskatoon area, Saskatchewan, Canada
Authors: Christiansen E. A.
Published: April 2011

Pleistocene sediments in the Saskatoon area are subdivided into the Sutherland and Saskatoon Groups on the basis of dolomite content of tills. The Sutherland Group generally comprises one till, but locally it comprises a lower and upper till. The overlying Saskatoon Group comprises two tills, which are in ascending order the Floral and Battleford Formations.Forty feet of partial leaching of carbonates in till in the upper part of the Sutherland Group suggests a hiatus of interglacial proportions. The hiatus between the deposition of the Floral and Battleford Formations is Mid-Wisconsin and the Battleford Formation is Woodfordian.
Seismic-profiler investigation of the continental margin northeast of Newfoundland
Authors: Grant A. C.
Published: April 2011

Continuous seismic profiler recordings over the continental shelf northeast of Newfoundland show an accumulation of unconsolidated sediments ranging in thickness from 30 to 150 m, unconformably over-lying bedrock that dips gently eastward toward the continental slope. The distribution of these unconsolidated sediments indicates that the banks that compose the 'shelf-edge rise' are not primarily morainal material, but rather they are areas of positive relief on the bedrock surface. Anomalous strike-dip relationships associated with these bank areas suggest that they may also have structural significance. The underlying bedrock layers are truncated by the continental slope, and there is reversal in the dip of these layers from eastward to westward beneath the slope. The axial zone of the resulting fold apparently coincides very nearly with the axis of a large magnetic anomaly that extends along the continental margin in this region. A Tertiary to post-Tertiary age is suggested for the fold, as well as the structural disturbance associated with the topographic relief on the continental shelf. Within the continental rise an area of irregular bottom topography is considered to be due to the accumulation of large masses of sediment by slumping. Subbottom reflectors at depths beyond the continental rise show crumpling, which is assumed to be further evidence of mass-movement due to gravity. Superficially, the continental margin northeast of Newfoundland appears similar to parts of the continental margin to the south, on the flank of the Appalachian structural complex.
Barren halite bodies in the sylvinite mining zone at Esterhazy, Saskatchewan
Authors: McIntosh R. A. , Wardlaw N. C.
Published: April 2011

The potash-rich sylvinite zone mined at Esterhazy, Saskatchewan, contains irregular bodies of halite referred to as salt horses. Cuts through the salt horses range from less than 20 sq. ft to more than 200 sq. ft. Contacts between salt horses and the enclosing ore beds are normally irregular but well defined.There is significantly more bromide in both halite and sylvite in the salt horses (mean bromide 102 ppm and 1470 ppm respectively) than in adjacent ore beds (mean bromide 81 ppm and 1020 ppm respectively) although bromide contours within a horse bear little relationship to the geometric form of the horse.Rubidium in sylvite, unlike bromide, is not significantly different in the ore beds and salt horses (mean rubidium 37 ppm and 33 ppm respectively).Details of stratification, principally layers of clay–carbonate, can be traced from normal ore sections through the smaller salt horses. This suggests that the horses formed either contemporaneously with the ore beds or by later modification of the ore beds, without complete destruction of primary layering.It is suggested that the salt horses were formed by localized leaching of sylvite from the ore beds by brines saturated in sodium chloride. Some halite would be precipitated as sylvite dissolved. Prior to leaching, residual brines associated with the ore beds, capable of precipitating sylvite containing 1300 ppm bromide (near the upper range of bromide in sylvite of the ore beds), would be saturated in sodium chloride and potassium chloride. Up to 30% dilution of these residual brines with sodium chloride saturated brines (formed by the dissolution of halite) would produce brines which, in contact with the ore section, would dissolve sylvite and simultaneously precipitate halite. The resulting halite would contain about the same amount of bromide as the halite in the salt horses.No significant change in bromide or rubidium could be detected in the ore beds as a salt horse is approached. It is therefore unlikely that these trace elements can be used to predict the proximity of a salt horse during mine development. However, the higher bromide of the salt horses provides a possible means to differentiate, in drill core, between a barren hole due to a salt horse and a barren hole due to non-deposition, or erosion, of an ore zone.
Current, temperature, and depth data from a moored oceanographic buoy
Authors: Grant D. A.
Published: April 2011

This report presents the data obtained by an oceanographic buoy moored 300 nautical miles southeast of Halifax, Nova Scotia, in a depth of 4316 m for a period of 38 days in August–September, 1966. Data pertaining to ocean current, temperature, and depth of recording units were collected and are analyzed in this report. The oceanographic buoy was launched and recovered without difficulty, and during the mooring period it withstood sea states up to and including sea state 7. Analysis of the data indicated that current speed and depth variations of the recording unit correlated with the semi-diurnal tidal effect.