bluuebunny/crossref_metadata_2025 huggingface dataset:
Radiometric dating of the Coldbrook Group of southern New Brunswick, Canada
Authors: Cormier R. F.
Published: April 2011

The Coldbrook Group of southern New Brunswick is composed almost entirely of volcanic rocks and has been assigned a Precambrian age on the basis of field relationships. Rocks of the group are overlain by fossiliferous Lower Cambrian beds of the Saint John Group.Rubidium-strontium total-rock analyses of 46 samples of Coldbrook Group volcanic rocks have been carried out. Analysis of the data indicates the probable presence of two different isochron ages. One of these is apparently defined by those rocks in which the ratio 87Rb/86Sr is low, with values less than about 1.0. This isochron yields an age of 750 ± 80 million years, with an initial ratio 87Sr/86Sr of 0.7054 ± 0.0010. The other isochron is defined by rocks in which the value of the ratio 87Rb/86Sr is higher, with values greater than about 1.0. The age calculated from the second isochron is 370 ± 38 million years, with an indicated initial value for the ratio 87Sr/86Sr of 0.7135 ± 0.0010.The 750 million year age is interpreted to represent the time of extrusion of the Coldbrook volcanics. The 370 million year age appears to be secondary and related to metamorphism of the Coldbrook Group. This age is correlated with the Acadian orogeny, which strongly deformed this part of the northern Appalachians in Middle to Late Devonian time.
Paleomagnetism of the Cumberland Group and other Paleozoic formations
Authors: Roy J. L.
Published: April 2011

Thermal demagnetization of red bed samples from the Cumberland Group (Pennsylvanian) of Nova Scotia indicates that the fossil magnetization is composed mainly of a thermally distributed (up to 650 °C) magnetization. The direction changes between heatings are small, indicating that this magnetization was acquired in a field of constant polarity. A fold test (10 sites) shows that the magnetization predates the folding, which according to geological evidence occurred shortly after deposition. The results (direction 172°, + 16°; k = 85; pole 36 °N, 125° E) are compared with other results obtained from Paleozoic formations. Comparison between continents indicate that a 30° apparent polar change during the Paleozoic is probable. From the Dominion Observatory results, it is suggested that at least half of the change took place during late Paleozoic times and probably during the Pennsylvanian Period.
Airborne remote sensing for groundwater studies in Prairie environment
Authors: Chase M. E.
Published: April 2011

A deficiency of groundwater in an area of prairieland in southern Alberta prompted a survey by airborne remote sensors. Panchromatic and black and white true infrared photography coverages were obtained and studied, but were found to be of limited value. An infrared scanning survey, using the 2.5–5.6 μ band was flown at the same time and found to be more informative. Conditions of ground truth were not ideal, making the results less conclusive than desired. Till covers most of the area, with lake deposits in the eastern section. Soil moisture changes were registered on the imagery, but the depths of overburden to which these changes were recorded on the surface are unknown, due to the condition variations between the time of the survey and the drilling. Vegetation, surface water, soil moisture, and saline sloughs were found to have the strongest thermal signatures. Problems encountered in the survey are discussed and recommendations to eliminate them are given.
Early Cambrian coral-like fossils from the Northern Cordillera of Western Canada
Authors: Handfield Robert C.
Published: April 2011

Tabulaconus kordeae, n. gen., n. sp., is a coral-like fossil found in the Sekwi Formation, Mackenzie Mountains, District of Mackenzie and the Atan Group, Cassiar Mountains, British Columbia. The species consists of small, conical shells with a layered external wall and abundant tabulae. It is placed in the family Gastroconidae, previously known only from Siberia. Associated Archaeocyatha and Trilobita prove its Early Cambrian age.
Surges of the Vernagtferner in the Ötztal Alps since 1599
Authors: Hoinkes Herfried C.
Published: April 2011

The history of catastrophic advances of Vernagtferner (Ötztal Alps, Tyrol) is described briefly. To all appearances these advances were surges. They occurred periodically with a short active advance and a much longer time of retreat; the whole cycle lasted on an average 82 years. The mode of flow of the ice changed typically, i.e. speed during surges increased more than one order of magnitude with heavy crevassing. Dimensions of advance and of retreat were much larger than known from other glaciers in the area.
Geology of Belle Isle—northern extremity of the deformed Appalachian miogeosynclinal belt
Authors: Williams Harold , Stevens R. K.
Published: April 2011

Belle Isle, situated between northern Newfoundland and the southeast coast of Labrador, consists of an uplifted block of Precambrian plutonic rocks intruded by northeast-trending diabase dikes and uncomformably overlain by Lower Cambrian and earlier (?) sedimentary and volcanic rocks. The Precambrian rocks lie along strike and are similar to Grenville gneisses of the Long Range Complex of western Newfoundland. In the southwest part of Belle Isle, the cover rocks are gently dipping basaltic flows and agglomerates that are succeeded conformably by arkosic sandstones and fossiliferous upper Lower Cambrian shales. In the northeast, the basement rocks are overlain by steeply dipping boulder conglomerates and arkosic sandstones, followed conformably by white quartzites.Diabase dikes are inseparable from overlying flows, but do not penetrate higher sedimentary strata of the southwestern Lower Cambrian succession. Toward the northeast, plutonic boulder conglomerates and quartzites are cut by the dikes.The distribution of supracrustal rocks around the periphery of the island, combined with local steeply inclined surfaces of unconformity between basement and cover rocks, indicate a major anticlinal structure produced by Paleozoic deformation. The study also shows that at Belle Isle the established Lower Cambrian succession of southeast Labrador and western Newfoundland is locally underlain by basalts and conglomerates and quartzites that thicken southeastward and northeastward.
Crystal settling in sills: A model for suspension settling
Authors: Gray N. H. , Crain I. K.
Published: April 2011

A quantitative model which takes into account the temperature dependence of magma viscosity is developed to describe the distribution of cumulate crystals in a sill after its solidification, and is compared with natural examples. A precise comparison is not possible as data on the size-distribution and concentration of the cumulate crystals are not available. However, a preliminary analysis suggests that although several major features can be explained the simple model of crystal settling cannot account for the details of the olivine distribution in the Palisades sill and the Uwekahuna laccolith.
Geophysical investigations in the Ungava Bay – Hudson Strait region of Northern Canada
Authors: Grant A. C. , Manchester K. S.
Published: April 2011

Continuous seismic profiler surveys have defined the limits of the Paleozoic outlier in Ungava Bay, and indicate that similar rocks occur to the north beneath Hudson Strait. These surveys have shown also that the strata underlying Hudson Strait are down-warped to form a synclinal structure with its axis parallel to the bathymetric trend of the Strait. Extrapolations based upon the dips and thicknesses indicated on the seismic profiler records and on physiographic evidence, suggest that the southwestern side of Hudson Strait has been down-faulted relative to the block of Paleozoic strata in Ungava Bay. These relationships postulated on the basis of seismic profiler results are supported by aeromagnetic, sea-magnetometer, and sea-gravimeter data from that region. A seismic and magnetic profile from Frobisher Bay indicates that a Paleozoic outlier occurs there as well. Although the submarine physiography of this region is primarily controlled by structure and secondarily modified by sub-aerial erosion, glacial erosion may account for local detail.
The Mid-Atlantic Ridge near 45° N. XIII. Magnetic properties of basalt bore-core
Authors: Brooke J. , Irving E. , Park J. K.
Published: April 2011

Three bore-cores containing basalts have been obtained from the Mid-Atlantic Ridge at 45° N. The material is fresh and ideal for the study of physical properties. The drilling record and the nature of the core itself suggest that much of the basalt is from detached boulders, although one core may be in situ. In one core, variations in coercivity by a factor 2 occur within a distance of 5 cm. The coercive force spectra of anhysteretic and natural remanent magnetization are similar, but there are small differences due to secondary components which are used to predict correctly the polarity of 11 out of 12 specimens studied. This result may be of technical interest only since there is no guarantee that the material is in situ.
Mesozoic and Cenozoic History of the Grand Banks of Newfoundland
Authors: Bartlett Grant A. , Smith Leigh
Published: April 2011

Two wells drilled by Pan American in the Grand Banks of Newfoundland gave the first stratigraphic section of Cretaceous and Cenozoic age northeast of Long Island and the only Jurassic and possible Permian sections in the Atlantic Continental Margin of North America.Integrated analysis of lithic and faunal data showed a minimum of seven sequences present. These are Pleistocene, Middle and Upper Miocene, Intra-Eocene, Paleocene and lowest Eocene, Upper Cretaceous, Middle Cretaceous, and Neocomian in age.The rocks range from halite and anhydrite, of possible Permian depositional age, to limestones, in the Upper Jurassic, lower Upper Cretaceous, mid-Eocene and mid-Miocene, and sandstones, which dominate the Neocomian, Upper Eocene, and Middle Miocene. Variable proportions of shale and silty mudstone occur throughout.The microfaunas contain both Tethyan and Boreal elements, and suggest oceanic circulation changes, sea-floor spreading, or both.Depositional environments ranged from subaerial, for the quartz arenites, through very low-land, for stream and swamp deposits, to estuarine, lagoonal, bank and open-shelf warm-marine environments, in which were deposited fine sand to clay-size terrigenous sediment, or, in its absence, skeletal carbonates or lime muds. The first dominant cooling trend appeared in the Late Miocene.All erosional environments of the hiatal episodes appear to have been subaerial and humid.A salt dome intruded the Tors Cove well section, its last movement being in mid-Early Eocene.Periodic interregional tectonic oscillations produced the erosional and depositional episodes of the major baselevel transit cycles. Their total effect is a sedimentary wedge, thickening by preservation toward the continent's edge, and representing one-half or less of Upper Mesozoic and Cenozoic time.
The Hydrologic Response of The Eaton River Basin, Quebec
Authors: Carson M. A. , Sutton E. A.
Published: April 2011

This paper reports a parametric study of rainfall–runoff relations for 38 storms in the Eaton basin, southeastern Quebec, between 1950 and 1966. In addition to storm rainfall amounts, water table levels in the vicinity of the channel network, as indicated by baseflow prior to storms, appear to be very important in controlling the amount of response of the basin in different storms. Storm runoff is viewed as the product of direct interception by, and subsurface seepage into, expanded surface water systems in the valley floor areas of the basin. This is in agreement with the variable (partial) source area model developed over the last ten years by a number of hydrologists as an alternative to the Horton theory of runoff production.
Magnetotelluric Fields of a Gaussian Electrojet
Authors: Peltier W. R. , Hermance J. F.
Published: April 2011

In a previous paper (Hermance and Peltier 1970), integral expressions for the magnetotelluric fields of a line source over a stratified conductor were obtained and numerically evaluated for a sequence of simple conductivity structures. This calculation was intended to simulate the magnetotelluric 'source effect' which is anticipated at auroral and equatorial latitudes. The most serious flaw in this line source model of an electrojet is that it does not take into account the laterally diffuse nature of the real current distribution. By assuming that the current density in the electrojet has a Gaussian dependence upon the horizontal coordinate a more realistic source model can be constructed. Representative solutions to the induction problem employing this source are analyzed in an effort to obtain a more accurate measure of the effect of finite source geometry on magnetotelluric interpretations in auroral and equatorial regions where strong electrojets exist at E-layer altitudes. In tectonically active areas such as Iceland (which is under the auroral electrojet), it appears that Cagniard's assumption of a "plane-wave" source leads to a correct interpretation of the subsurface conductivity structure in the commonly employed U.L.F. frequency band (10−4 Hz–1 Hz). A relationship, Tozer (1969), is here assumed to exist between tectonism, anomalously high near surface temperatures, and corresponding increases in electrical conductivity. In tectonically stable shield areas, however, the effect of finite source geometry is more pronounced and could lead to significant errors in interpretation.
A Seismic Refraction Survey in Lake Superior
Authors: Halls H. C. , West G. F.
Published: April 2011

Thirty-three seismic refraction profiles have been obtained in Lake Superior using a single ship sonobuoy method. The seismic data have led to the following conclusions concerning the structure and stratigraphy of the late Precambrian Keweenawan basin that underlies the lake:(1) Faults with their north side downthrown at least 1–2 km, bound the north shores of Isle Royale and Michipicoten Island.(2) The northern limb of the Keweenawan basin just southeast of Isle Royale appears to have undergone a deformation that may be partly related to movement along the Isle Royale fault.(3) For those seismic profiles that have a certain degree of geological control, refraction velocities generally agree well with those estimated from sample measurements in the laboratory.(4) Late Keweenawan or early Cambrian Bayfield-Jacobsville sandstones appear to underlie most of Lake Superior. Their distribution and relative susceptibility to erosion compared with older rocks are the principal factors that have determined the shape of the lake depression.
The Mid-Atlantic Ridge Near 45 °N. XVI. Serpentinized Ultramafic Intrusions
Authors: Aumento F. , Loubat H.
Published: April 2011

Detailed descriptions of the mineralogy, petrography, geochemistry, and physical properties of serpentinized ultramafic rocks dredged from the Mid-Atlantic Ridge at 45° N support an interpretation of the events which affected these rocks after their original crystallization. Crystallization apparently took place in lopoliths emplaced at the Crust/Upper Mantle interface beneath the axis of the ridge under conditions quiet enough to permit gravity crystal differentiation and layering. The rocks were then fractured without hydration under high hydrostatic pressure, with a feeble directional component, possibly under conditions favoring solid-state recrystallization of interstitial minerals. Hydration (amphibolization) began during the last phases of intimate mechanical deformation and the commencement of rodingitic metasomatism. Further hydration resulted in multiple overlapping periods of serpentinization dependent on varying physical conditions. Hydrating fluids may have been derived both from juvenile waters and from sea water.
Five Measurements of Heat Flow in Southern Canada
Authors: Jessop Alan M. , Judge Alan S.
Published: April 2011

Five heat flow results from widely separated locations are reported. The results conform to existing heat flow patterns where established, but only very general interpretative comments are possible.
Glacial Marine Sedimentation and Stratigraphy of the Toby Conglomerate (Upper Proterozoic), Southeastern British Columbia, Northwestern Idaho and Northeastern Washington
Authors: Aalto K. R.
Published: April 2011

The outcrop of the Toby Conglomerate extends sinuously from southeastern British Columbia to northeastern Washington. It constitutes the basal part of the Windermere System (Upper Proterozoic), unconformably overlies the beveled Upper Purcell System, and conformably underlies either volcanic rocks or clastic Windermere sedimentary rocks of the Horsethief Creek Group and Monk Formation. The Toby Conglomerate consists chiefly of diamictite, which is complexly interstratified with conglomerates, sandstones, and argillites, the latter two containing dispersed megaclasts. Toby Conglomerate thickness ranges markedly from a few to nearly 2000 m. There is a dearth of tractive-current features within Toby sedimentary rocks. The presence of overlying pillow lavas and laminated argillites, turbidites, and grain flow deposits suggest that the basal Windermere System is of sub-aqueous origin. Paleogeographic reconstruction indicates deposition in the sea west of the orogenic landmass, Montania, peninsular to the Canadian Shield.Texture, composition, stratigraphie associations of Toby sedimentary rocks, and a lack of consistent regional variation suggest that the Toby Conglomerate was deposited by glacial marine sedimentation. Montania was overridden by ice traveling westward from the shield prior to Toby deposition. The basal Horsethief Creek Group and Monk Formation were produced largely by postglacial mass flow of slumped tills and deltaic deposits. This represents a new interpretation of the genesis of the Toby Conglomerate, one which accords with worldwide evidences of a Late Precambrian ice age.
Climatic Significance of Giant Tortoises from the Wood Mountain Formation (Upper Miocene) of Saskatchewan
Authors: Holman J. Alan
Published: April 2011

Giant land tortoises, Geochelone, occur at four collecting localities in the Wood Mountain Formation, southern Saskatchewan. These fossils suggest a subtropical climate in southern Saskatchewan during Upper Miocene (Barstovian) times.
X-ray Emission Microanalysis of Rock-forming Minerals. VIII. Amphiboles
Authors: Rucklidge J. C. , Gasparrini Elvira , Smith J. V. , Knowles C. R.
Published: April 2011

Fifty-six amphiboles, ranging widely in composition, have been analyzed by X-ray emission techniques for Na, Mg, Al, Si, K, Ca, Ti, Mn, Fe as well as a number of minor elements. The electron probe data have been referred to non-amphibole standards, and have been converted to oxide weight concentrations by computer applied theoretical correction procedures. The analyses, performed in two different laboratories, are compared with independent wet chemical analyses of the same material. The agreement is in general within 5% of the amount present, though zoning is often responsible for discrepancies. Al is the only element which is systematically lower in probe analyses. Elements such as Cr, Ni, Zn, and Cl are often present in minor amounts.
Paleomagnetism of the Triassic Guichon Batholith and Rotation in the Interior Plateau, British Columbia
Authors: Symons D. T. A.
Published: April 2011

The Guichon Batholith, located near the south end of the Interior Plateau in south–central British Columbia, is composed of unmetamorphosed massive felsic intrusive rocks in several distinct phases (Northcote 1969). Stratigraphic and radiometric evidence indicate that the batholith was emplaced during the Late Triassic (198 ± 8 m.y.) and unroofed by Early Jurassic. Analysis of the remanence of 92 cores (184 specimens) from 19 representative sites led to the isolation of a stable primary remanent magnetism at 15 sites after alternating-field demagnetization. Variance ratio analysis of the remanence directions indicates that the phases cannot be distinguished by the paleomagnetic method. This supports the evidence from contact relationships and K–Ar isotopic dating of biotites that the phases cooled nearly contemporaneously. The pole position determined for the Guichon Batholith (12.9° E, 65.6° N) is discordant with other Upper Triassic pole positions determined for North American formations. The discordance may be explained by a clockwise rotation 40° ± 10° of the batholith and surrounding rocks in the southern end of the Interior Plateau, with most of the Plateau to the north acting as a stable non-rotated tectonic block. Other evidence is cited which is consistent with this hypothesis.
A Granodioritic Drill Core from the Flemish Cap, Eastern Canadian Continental Margin
Authors: Pelletier B. R.
Published: April 2011

A 15-cm core of granodiorite with a K/Ar age of 592 ± 20 m.y. has been obtained from the Flemish Cap, a submarine knoll about 500 km east of Newfoundland.
Possible Late Ordovician Glaciation of Nova Scotia
Authors: Schenk Paul E.
Published: April 2011

A thin, poorly stratified, polymictic diamictite at the the base of the White Rock Formation (perhaps Caradocian or younger) contains unsorted, clustered, faceted, and grooved clasts apparently dropped into a shaly or sandy lithotope. Ice probably transported these stones from a distant source. Other lithosomes of the formation are of almost every sedimentary/volcanic lithology, shape, and extent. Supermature orthoquartzite may be eolian or beach dune, or intertidal; immature quartzites are channel-fills, probably fluvioglacial; bouldery diamictite may be morainic or glaciomarine. Underlying and overlying conformable formations are thick, graptolitic black slate. White Rock contacts may mark glacio-eustatic lowering and rising of sea-level. Locally at the top of the Halifax Formation, small-scaled folding resulting in detailed and superficial angular discordance with the overlying White Rock. Formation may be ice-thrust phenomena.Both the gross stratigraphic succession and detail of lithosomes of the White Rock Formation are remarkably similar to those of the latest Ordovician (Ashgillian) of northwest Africa. There, this stage records extensive continental glaciation well-established by sedimentology, stratigraphy, paleomagnetism, and paleontology. Ordovician–Silurian glaciation of North America is unknown. If the White Rock Formation is glacio-genetic, then it is Ashgillian and correlative with the Dunn Point Volcanics of northeastern Nova Scotia. Moreover the underlying Halifax Formation could encompass almost all of the Ordovician, and the overlying Kentville perhaps most of the Silurian. Furthermore the hypothesis would be supported that Nova Scotia and the rest of southeastern Canada is a remnant of northwestern Africa.
An Early Tertiary Outcrop in North-Central Baffin Island, Northwest Territories, Canada: Environment and Significance
Authors: Andrews J. T. , Ives J. D. , Guennel G. K. , Wray J. L.
Published: April 2011

A thin, impure limestone was found in situ on Precambrian bedrock at latitude 70°36.6′ N and longitude 75°20′ W some 26 km northwest of the Barnes Ice Cap. The unit consists of undulating laminations composed of alternating fine- and coarse-grained sediment, which are interpreted as a series of algal mats or algal-laminated sediments. An analysis of enclosed palynomorphs indicates the presence of Ulmus, Taxodiutm, Liriodendron, Carpinus, and Engelhardtia plus other genera. On the basis of the microflora a Paleogene age is assigned to the unit. The climate at that time was warm-temperate and the environment suggested is a freshwater marsh or swamp. The outcrop is restricted to a single hill summit and its location suggests considerable Neogene geomorphological activity, primarily river-cutting associated with vertical movements along the western margin of the Davis Strait/Baffin Bay Tift.
The Trilobite Genus Holasaphus Matthew, 1895 in the Middle Cambrian Rocks of Nova Scotia and Eastern Turkey
Authors: Dean W. T.
Published: April 2011

Holasaphus centropyge Matthew, 1895, the type species of the genus, is redescribed using known and new material from the Middle Cambrian of Nova Scotia. A new species, Holasaphus mesopotamicus, described from the Derik–Mardin district of southeastern Turkey, marks the only other known occurrence of the genus. The presence there of Holasaphus and the agnostid Peronopsis in the middle portion of the Sosink Formation suggests that the latter may be no younger than Middle Cambrian and lends additional support to evidence for the probable regional absence of Upper Cambrian strata.
The Empress Group in Southern Saskatchewan
Authors: Whitaker S. H. , Christiansen E. A.
Published: April 2011

The Empress Group comprises interbedded gravel, sand, silt, and clay occurring between till and bedrock in southern Saskatchewan. These sediments were laid down as fluvial, lacustrine, and colluvial deposits on the bedrock surface prior to and during glaciation. In the reference area the group comprises 2 units: a lower unit of quartzite and chert gravel and an upper unit of interbedded gravel, sand, silt, and clay. The Empress Group is Late Tertiary to Quaternary in age.
The Distribution of Mercury in the Sediments of Lake Ontario
Authors: Thomas R. L.
Published: April 2011

Total mercury has been analysed in the surface 3 cm of sediment taken from 287 sample stations on an 8 km grid on Lake Ontario during 1968. The mercury distribution shows well-defined trends which can be related to sediment type; the concentration of mercury increasing from the shallow nearshore coarse sediments outwards, into the central, deep-water basin sediments composed of fine silty clays and clays. The average concentration of mercury in the nearshore sediments is 355 ppb, in the basin sediments 997 ppb and the average for the whole lake is 651 ppb. Regions of high mercury concentration (in the order of 2000 ppb) occur along the southern margin of the main lake basin and in the western (Niagara) basin of the lake. The dispersion pathways of these two regions point to the Niagara River as the prime source of mercury input to Lake Ontario. Most of this mercury is believed to be of industrial origin. An additional area of high mercury concentration with values up to 20 000 ppb, occurs at the eastern end of Lake Ontario (Kingston Basin) in the region of the lake close to the outlet to the St. Lawrence River. These high values in organic-rich, fine sediments are likely related to processes of biological concentration. The concentrations of mercury observed in the recent sediments of Lake Ontario can be accounted for by an average minimum daily input of 125 lb (56.7 kg) of mercury of which an estimated 42 lb (19.0 kg) is of natural origin and the remaining 83 lb (37.6 kg) is from industrial sources. The vertical distribution of mercury in a selected sediment core suggests that industrial mercury input commenced about the turn of the century, rose rapidly to circa 1943 and, since then, has shown a slow but continued rise to the time of core retrieval in 1970.
Paleomagnetism of the Western Channel Diabase and Associated Rocks, Northwest Territories
Authors: Irving E. , Donaldson J. A. , Park J. K.
Published: April 2011

The stable remanent magnetization of the Western Channel diabase (1325–1785 m.y.) determined at 35 sites has a mean direction of 356, −50 (α95 = 6°) and a corresponding pole at 9 °N, 115 °W (A95 = 6°). Studies of rocks bordering the diabase show that this magnetization was acquired at the time of initial cooling. Preliminary results from older sediments, diabase, and porphyry (1770 m.y.) give directions of opposite sign, with corresponding poles in the same general region. These results, and others recently published, allow the path of apparent polar wandering, relative to the Canadian Shield, to be constructed in a preliminary fashion for the middle and earlier Proterozoic. This path, together with that previously obtained by other workers for the late Precambrian, suggests that during the Proterozoic the pole moved through two cycles of a roughly sinusoidal path with a peak-to-peak amplitude of about 90° of arc and a period of several hundred million years.
Magnetic Studies in Northern Lake Superior
Authors: Halls H. C.
Published: April 2011

Analysis of total field magnetic data, together with other geophysical evidence has led to the following conclusions concerning the structure and stratigraphy of late Precambrian Keweenawan rocks that underlie and border the northern part of Lake Superior:(1) The uppermost few hundred feet of the Osler Volcanic Series has a normal remanent magnetization. The normally magnetized mafic flows are separated from older, reversely magnetized ones which form the bulk of the Osler Series, by a thin zone of felsic igneous rocks with unknown magnetic polarity. The upper mafic unit appears from aeromagnetic data to outcrop on some of the outer islands at the mouth of Nipigon Strait, and represents the lowest part of a normally magnetized volcanic sequence that lies offshore, beneath the waters of Lake Superior.(2) The contact between the upper mafic unit and older rocks of the Osler Series is a stratigraphic rather than a faulted one. Aeromagnetic data show that mafic volcanics above and below this contact have the same strike, except toward the Thunder Bay and Schreiber regions. In these areas there is a convergence in strike between the two mafic units which may indicate an unconformity between them or a thinning of flows in the older unit. Ultimately the older, reversely magnetized unit appears to pinch out beneath the younger one to both the east and west.(3) The younger volcanics and overlying sediments occur in a large basin centered about 30 mi (50 km) WSW of the Slate Islands. Whether the older, reversely magnetized volcanics accumulated in this basin or in a smaller more northerly one is not entirely clear. The eastern margin of the main basin appears to be formed by a basement ridge extending from the Slate Islands southward to Superior Shoal, over which volcanics and younger sediments are relatively thin.
Offshore Permafrost and Ground Ice, Southern Beaufort Sea, Canada
Authors: Mackay J. Ross
Published: April 2011

The distribution and origin of offshore permafrost is discussed for the southern Beaufort Sea. Two types of permafrost are identified: permafrost which is in thermal equilibrium with negative sea bottom temperatures, and disequilibrium permafrost, which is not in equilibrium with either positive or negative sea bottom temperatures. The origin of permafrost is considered in terms of the Quaternary period when coastal areas were exposed to cold air temperatures and then submerged. The effect of warm river waters, primarily from the Mackenzie River, is shown to ameliorate coastal water temperatures and may be responsible for a thin active layer at some sites. Water quality and oxygen isotope ratios are given for some samples. The evidence suggests that some relic land permafrost, with ground ice, is present beneath the southern Beaufort Sea. Perforated permafrost should be present, but not extensive thermokarst depressions. By inference, permafrost probably underlies much of the Canadian Arctic waters, although ground ice is likely restricted to a relatively few shallow coastal zones.
Pole Position from Thermally Cleaned Sibley Group Sediments and its Relevance to Proterozoic Magnetic Stratigraphy
Authors: Robertson W. A.
Published: April 2011

Thermal cleaning of paleomagnetic samples of the Sibley Group shows that 3 directions of magnetization are present: a normal magnetization (240,+ 16), a reverse magnetization (048,−05), and a third direction (109,−69), which is parallel to that in the Logan Sills and presumed to have been acquired during their intrusion. The latter result confirms that the remanent magnetization of the Logan Sills was acquired at the time they cooled. Combining all relevant sites, a revised mean Logan Sills direction of 110,−73 yields a pole at 49N,138W, (dp = 7, dm = 7). The combined normal and reversed groups (232,+ 10) yield a pole position at 20S,214E. This result suggests that there is a bend in the North American polar wander curve between 1200 and 1400 m.y. ago. The curve is compared with the polar wandering curve derived from rocks of comparable age from southern Africa.
The Perturbation of Alternating Geomagnetic Fields by an Island Near a Coastline
Authors: Lines L. R. , Jones F. W.
Published: April 2011

The numerical method of Lines and Jones for investigating the problem of the perturbation of alternating geomagnetic fields by three-dimensional conductivity inhomogeneities embedded in a layered Earth is extended to include models in which vertical discontinuities may extend to the grid boundaries. The case considered is that in which the electric field vector is parallel to the strike of the discontinuities at such boundaries. A model which includes an island near a coastline is studied and contour plots as well as profiles of the electric and magnetic field component amplitudes at the surface of the Earth are given.
Additional Paleomagnetic Data on the Baffin Diabase Dikes and a Revised Franklin Pole
Authors: Fahrig W. F. , Schwarz E. J.
Published: April 2011

Paleomagnetic data were obtained from eleven additional sites on Baffin diabase dike intrusions (part of the Franklin diabases). The rock at four sites was found to be normally magnetized, at six sites reversely magnetized, and at one site the rock contained no primary remanent magnetization that could be isolated by alternating field (a.f.) demagnetization. Baffin Island is divisible into several zones within which the Baffin dikes are either normally or reversely magnetized. This may indicate that more than one reversal is represented. The ten sites yield a pole at 168 °E, 6 °N, α95 = 5°, and when combined with previously published data (total 46 sites) yield a revised Franklin diabase pole at 166 °E, 6 °N, α95 = 4°. At least 10 of the 11 new sites apparently lie outside the zone from within which Baffin dikes have yielded anomalous remanent magnetization directions. Thermomagnetic curves for representative material of the Baffin dikes indicate that the magnetic mineral of these rocks is almost pure magnetite. It does not explain the anomalous magnetization of the Franklin dikes that occur along the northeast coastal area.
Upper Bajocian – Lower Bathonian Ammonite Fauna and Stratigraphy of Smithers Area, British Columbia
Authors: Frebold Hans , Tipper H. W.
Published: April 2011

In the Smithers area of British Columbia, faunas are recognized below the beds with Lilloettia, Kepplerites, and other characteristic Lower Callovian ammonites. The upper one includes Arctocephalites (Cranocephalites) costidensus Imlay, Parareineckia cf. P. shelikofana (Imlay), P. cf. P. hickersonensis Imlay, Cobbanites talkeetnanus Imlay, Epizigzagiceras evolutum Frebold n. gen. n. sp., and Morrisiceras? dubium Frebold. This fauna is equivalent in age to a similar fauna in southern Alaska described by Imlay, and is assigned to the Lower Bathonian. The next older fauna includes Megasphaeroceras? aff. M. rotundum Imlay, Epizigzagiceras crassum Frebold n. gen. n. sp. Zemistephanus sp. indet., and Cobbanites talkeetnanus Imlay. The age is Bajocian, possibly Late Bajocian. Below are beds with pelecypods of uncertain, probably Bajocian age. The upper and middle faunas are new for British Columbia and other parts of Canada.
The Nature and Origin of a Series of Elongated Ridges in the Morley Flats Area of the Bow Valley, Alberta
Authors: Walker M. J. C.
Published: April 2011

Recent modifications to the Trans-Canada Highway approximately 65 km west of Calgary, Alberta, exposed deep sections through a series of elliptical ridges. These features had been variously described as moraines, drumlins, and crevasse-fillings. On the basis of field and laboratory evidence, it is concluded that the ridges are drumlins which formed by a process of basal accretion beneath ice of the Bow Valley glacier. Variations in ridge morphology are attributed partly to postdepositional deformation, and partly to dynamic conditions prevailing in the ice at the time of formation.
Distribution, Transport, and Composition of Suspended Matter in the St. Lawrence Estuary
Authors: d'Anglejan Bruno F. , Smith Eric C.
Published: April 2011

The distribution of total suspended matter in the estuary of the St. Lawrence River was studied by quantitative filtration through membrane filters. Tidal fluctuations in the vertical gradients of suspensoids were followed at fixed stations along the estuary. The concentrations varied from nearly 40 mg/1 below near Ile d'Orléans, to values less than 1 mg/1 at the downstream end of the upper estuary near the Saguenay River entrance. The tidal mean concentrations for the fixed stations ranged from 20 mg/1 to 2 mg/1. A turbidity maximum, which develops because of entrapments of particles by the tidal circulation, extends for 100 km below Quebec City. In this zone large vertical gradients changing in intensity with the tide by resuspension of settled material exist above the bottom. The total suspended matter is 60% to more than 90% inorganic by weight, and has a mean particle size between 5 and 7 μ. The annual rate of transport of suspended material out of the upper estuary at a section near the Saguenay River is estimated at less than 1 × 106 metric tons.Chemical and mineralogical analyses were performed on 23 suspensoid samples collected by centrifuging large volumes of water. The clay mineral composition of the less than 2 μ fraction is on the average 1.5% montmorillonite, 8% kaolinite, 31% chlorite, and 60% illite. However, large time and space variations are found both in the chemistry and mineralogy of the suspended matter.
Permian Sponges from Northwestern British Columbia
Authors: Rigby J. Keith
Published: April 2011

Three lithistid sponges, including Scheiia tuberosa Tschernyschew and Stepanov, 1916, Haplistion aff. H. aeluroglossa Finks, 1960, and a chiastoclonellid sponge (which is not generically identifiable because of fragmentary preservation) are reported from limestone of the Cache Creek Group. Fossils were collected from Artinskian(?) beds, near Dewar Peak in the McConnell Creek area, at the southeastern end of the Sustut Basin in northwestern British Columbia. These are the first reported lithistid sponges from the Upper Paleozoic section in that region. Related sponges have been described from Texas and Ellesmere Island, Northwest Territories.
Origin, Morphology, and Chronology of Sublacustrine Moraines, Generator Lake Baffin Island, Northwest Territories, Canada
Authors: Barnett D. M. , Holdsworth G.
Published: April 2011

The morphology and chronology of exposed sublacustrine moraines is discussed. These are shown to have been formed in a sublacustrine environment. The moraines are characterized by their occurrence in large numbers within a former ice dammed lake basin and by their asymmetric cross section. Using moraine volume estimates combined with the time control, a till depositional rate is calculated.A radiocarbon chronology for the Generator Lake area over the last 4500 years is presented.Hydrological relationships are established which are shown to influence the formation of sublacustrine moraines. The relationships are physically connected and are not empirical. Current studies of the calving ice front at Generator Lake show that moraines must be forming under the tapered ice ramps which flow into the lake. Measurements of debris content within the ice combined with ice flow rate measurements show that the present till supply rates are consistent with those calculated from the exposed moraine field.A model is set up which connects the lake hydrology with the existence or destruction of the ice ramps, as controlled by bending induced by buoyancy forces. The time of existence and subsequent behavior of the ramps is shown to influence the geometry and indirectly the spacing of the sublacustrine moraines.
Structure and Tectonics of the Continental Slope West of Southern Vancouver Island
Authors: Barr Sandra M.
Published: April 2011

The lower continental slope west of southern Vancouver Island consists of a series of ridges formed by folding, faulting, and uplift of Cascadia Basin deposits; underlying oceanic basement, at least initially, is not involved in this deformation. The middle and upper continental slope has probably formed by the same process, combined with deposition of overlying material coming directly from the continent. This compressive deformation is postulated to be a result of underthrusting of the America Plate by the Juan de Fuca Plate. Linear magnetic anomalies produced at the Juan de Fuca spreading center can be traced under the slope for at least 40 km, further evidence for underthrusting. Anomaly source depth calculations indicate that oceanic basement dips beneath the continental slope at an angle of more than 10°. A diffuse zone of earthquake epicenters extending northeast from the northern tip of Juan de Fuca Ridge may mark the present northern margin of the Juan de Fuca Plate.
The Age of the Acadian Deformation in Southwestern New Brunswick
Authors: Pajari Jr. G. E. , Trembath L. T. , Cormier R. F. , Fyffe L. R.
Published: April 2011

Deformed strata of early Devonian age in southwestern New Brunswick and adjacent Maine are intruded by die post-orogenic St. George pluton and similar intrusions in Maine. A Rb-Sr whole-rock isochron age of 394 ± 20 m.y. obtained from the St. George pluton defines an Early Devonian age for the pluton. The age of this post-orogenic intrusive event is supported by other radiometric dates. Therefore, the Acadian deformation in this area occurred in Early Devonian time.
Precambrian Zircon Age of Orthogneiss in the Shuswap Metamorphic Complex, British Columbia
Authors: Wanless R. K. , Reesor J. E.
Published: April 2011

Pb-U age determinations carried out on zircon from granodiorite gneiss of the core zone of Thor-Odin gneiss dome have provided isotopic evidence for involvement of Proterozoic basement rocks in the Mesozoic structures of the Shuswap Metamorphic Complex. The study has revealed that the zircons originally crystallized [Formula: see text] ago and suffered an episodic loss of lead [Formula: see text] ago.
Structural Evolution of Porphyry Mineralization at Highland Valley, British Columbia
Authors: Hollister V. F. , Allen J. M. , Anzalone S. A. , Seraphim R. H.
Published: April 2011

Three major orebodies and several smaller ore zones have been discovered in Highland Valley. All of these exhibit abundant evidence of a structural control which can be correlated to the evolution of a structural system comprising the Lornex and Highland Valley faults. This structural system may have originated early in the history of the Guichon batholith, and as it evolved, provided for the periodic escape of mineralizing solutions from the magma chamber into structurally prepared sites. The system is composed of the intersecting Lornex and Highland Valley faults and their displaced segments. Simultaneous movement on these faults created the tensional fractures which were filled with both dikes and the mineral components which now make up the ore bodies. A porphyry copper model that derives metals from a differentiating magma would best fit the data as interpreted in this paper.
Sudden Flood and Sorted Debris over the Winter Snowpack within Sentinel Glacier Basin, British Columbia
Authors: Mokievsky-Zubok O.
Published: April 2011

Part of the Sentinel Glacier Basin (5 km2) in British Columbia was subject to sudden winter flooding. Meteorological and hydrological data indicate that the flooding occurred in January, at subzero temperatures when winter streamflow was assumed to be negligible. A sudden release of water deposited a layer of sediment composed of silt, sand, gravel, and rock fragments, generally well sorted, that became incorporated within the snowpack. Deposition occurred when the ground was covered with snow several metres thick. The volume of transported material is estimated at 6.6 × 103 m3; the layer averaged about 10 cm in thickness over a distance of 1 km.
Post-Ophiolite Unconformity, Tilt Cove – Betts Cove Area, Newfoundland
Authors: Neale E. R. W. , Kean B. F. , Upadhyay H. D.
Published: April 2011

Subaerial sediments and silicic and mafic lavas of the Cape St. John Group in northern Newfoundland, were originally interpreted as younger than the Betts Cove ophiolite suite and the Lower Ordovician (Arenig) Snooks Arm pillow lavas and oceanic sediments, but recently have been considered as part of the pre-Ordovician Fleur de Lys Supergroup and hence older than the Snooks Arm Group. The volcanic rocks that underlie the Cape St. John were reinterpreted as a pre-Snooks Arm oceanic foundation to the Fleur de Lys rocks.Our work reaffirms the original interpretation of the Cape St. John rocks as unconformably above the Lower Ordovician pillow lavas and ophiolites and we tentatively correlate them with the Springdale and Mic Mac Groups and other nearby Silurian (?) clastic/volcanic sequences of Old Red Sandstone equivalence. The Cape St. John Group grades northward and westward into polydeformed rocks, hence its re-establishment as a post-ophiolite assemblage bears on the history of deformation of adjacent groups.
Origin of a Clastic Dike at St. Ludger, Quebec: An Alternative Hypothesis
Authors: Elson John A.
Published: April 2011

Structures visible in a recent photograph of a clastic dike protruding downward from 'till' into sand at St. Ludger, Quebec suggest that it may not be till as previously reported, but part of a layer of stony lake clay deposited beneath floating ice. Flame structures and faults indicate that the underlying sand changed from a plastic to an elastic state. Probably a layer of stony lake clay was drawn down into the underlying sand by reduced pore pressure developed in part of a closed system. This occurred when adjacent sand in the system was dilated by the shear stress resulting when floating glacier ice grounded. Glacial thrusting may have provided further intrusive impulse after the initial downward deflection.
Pyrogenic Evidence in Paleosols along the North Saskatchewan River in the Rocky Mountains of Alberta
Authors: Dormaar J. F. , Lutwick L. E.
Published: April 2011

Vertical sections of paleosols along the Upper North Saskatchewan River valley show horizons that have distinct brown to reddish-brown colors. Based on such criteria as time for water droplet penetration, magnetic susceptibility, and crystallization of Fe oxides, together with present conditions and vegetation of the fans and floodplain in that area, it was concluded that these brown horizons were fire-affected. The organic debris in the bogs before a fire is continually being enriched with silt blowing from the floodplain. The colored horizons are considered to be a combination of accessed eolian matter reddened in the layer of burning debris and some mineral matter reddened by conducted heat.