bluuebunny/crossref_metadata_2025 huggingface dataset:
A Tertiary Lamprophyre Dike Province in Southeastern Alaska
Authors: Smith James G.
Published: April 2011

Mapping in southeastern Alaska along the British Columbia border has shown the presence of hundreds of aligned Tertiary Lamprophyre dikes. Most dikes occur in northeast-trending swarms that cut across northwest-trending structures in the bedrock. More than 60% of the dikes dip within 10° of vertical and strike between N35°E and N80°E. Major topographic features such as fjords and streams have the same trend; differential erosion along the dike swarms and parallel joint sets, not faulting, is responsible for this northeast topographic grain.The dikes show various degrees of deuteric alteration. In relatively unaltered rocks, phenocrysts are subcalcic augite and rarely plagioclase, altered olivine, or amphibole. Deuterically altered dikes have a texture of interlocking milky plagioclase and black amphibole needles.The dikes form an undifferentiated homogeneous suite of alkali olivine basalt composition with an average SiO2 content of 48.8% and a total alkali content of 5.3%. Their chemistry closely resembles Quaternary volcanic rocks in British Columbia and Alaska.Structural setting, extent, and chemistry of the dikes suggest a mantle source and rapid intrusion without time for differentiation.
The Distribution and possible Genesis of some Organic Terrain Patterns in the Southern Mackenzie River Valley
Authors: Crampton C. B.
Published: April 2011

Terrain types in the southern Mackenzie River valley can be arranged into morphological series which are, in part, continuous and, in part, discontinuous, so as to allow speculation on the probable evolution of organic terrain in the area from frozen to unfrozen landscapes, accompanying the long-term amelioration of the climate during postglacial times. Stipploid terrain on gentle slopes retained its lineated character during progressive thawing. Similarly, polygoid terrain on frozen flats retained its reticulate character, though progressive thawing locally was probably associated with increasingly diffuse pattern boundaries, ultimately yielding marbloid organic terrain. Some frozen terrazoid terrain of raised peat probably evolved into unfrozen polygoid peatland by a progressive enlargement of water-filled depressions.
Surficial Sediments of Barkley Sound and the Adjacent Continental Shelf, West Coast Vancouver Island
Authors: Carter Lionel
Published: April 2011

The bathymetry and sediment distribution of Barkley Sound and the adjacent continental shelf off the west coast of Vancouver Island have been markedly affected by the late Pleistocene glaciation and modern sedimentary processes. Several fjords widen and coalesce to form the sound, which is continuous with glacially eroded basins on the inner continental shelf. These basins are flanked by flat-topped banks, the larger of which merge with the outer shelf—a gently sloping plain that terminates at the 200 m isobath, 58 km from shore.Modern sediments are restricted mainly to Barkley Sound where the glaciated "basin and sill" bathymetry and an estuarine circulatory system prevent the predominantly muddy detritus from reaching the continental shelf. Relict sands and gravels cover most of the shelf except within basins and drowned river valleys where muds prevail. This relict cover was initially dispersed by glaciers and meltwater streams, then later inundated during the Holocene Transgression, and is now being partly reworked by the present hydraulic regime. Near the shelf-break relict sediments are sparse and authigenic sands (glaucontized mudstone pellets) predominate together with residual sediments derived from submarine exposures of Tertiary mudstone.
Microbiological Leaching of Porphyry Copper Type Mineralizations Post-Leaching Observations
Authors: Duncan D. W. , Drummond A. D.
Published: April 2011

The metallic and silicate phases of a saussuritized quartz diorite were examined after 21 months of microbiological leaching. Essentially all the chalcocite and malachite disappeared. The chalcopyrite was not completely oxidized, but the mineral surfaces were discolored and etched. The molybdenite was unetched. The most abundant sulfide mineral present, was pyrite which was tarnished a deep yellow and heavily etched (Swiss cheese appearance). This etching suggests direct microbiological attack. Model experiments using pyrite from the same source confirmed that the etching only occurred when Thiobacillus ferrooxidans was present.
Upper Devonian Echinoderm Debris Beds with Graded Texture, District of Mackenzie, Northwest Territories
Authors: MacKenzie W. S.
Published: April 2011

A sequence of Upper Devonian echinoderm debris beds with graded texture, interbedded with shale, overlies the Middle Devonian Ramparts Formation in the subsurface at McDermott Canada GCO South Maida Creek G-56 well on the south side of Mackenzie River near Carcajou Ridge.The interval of echinoderm debris can be divided into thick 2- to 7-ft (0.6- to 2.1-m) beds of graded skeletal remains lacking shale, and thinner intervals from 1 to 2 ft (0.3 to 0.6 m) thick of graded skeletal remains with interbedded black shale. The echinoderm beds, not present in the subsurface at nearby wells, are probably of local origin. Similar beds of echinoderm debris with graded texture, also of probable local origin, crop out at Powell Creek in the Mackenzie Mountain foothills.
Analysis of Anisotropic Magnetotelluric Measurements at Victoria, B.C.
Authors: Nienaber W. , Auld D. R. , Dosso H. W.
Published: April 2011

Magnetotelluric data were recorded at the University of Victoria for a wide period range since the summer of 1968. Data for periods between 10 s and 104 s were used for interpretation. Telluric signals were found to be strongly anisotropic for the entire frequency range. Several possible causes of this anisotropy including the land–sea interface and a geological fault at Victoria are discussed.In order to obtain a 'model' for the subsurface conductivity structure, the apparent resistivity curves for both electric field components (E parallel and E perpendicular to the direction of polarization) are combined into one interpretation. The model proposes a thin, highly conducting layer near the surface of a highly resistive earth.The validity of the rotation used in transforming anisotropic telluric data before interpretation was tested experimentally.
A Multistage History for Flin Flon Lead
Authors: Slawson W. F. , Russell R. D.
Published: April 2011

New analyses are presented to show a multistage evolutionary growth for lead from the Flin Flon, Manitoba area. A first order interpretation suggests a very ancient separation of lead from a homogeneous source region. All single-stage interpretations of lead isotope data must be made with utmost caution.
The Mid-Atlantic Ridge Near 45 °N. XXI. Magnetic Results from Basalt Drill Cores from the Median Valley
Authors: Ade-Hall James , Aumento Fabrizio , Ryall Patrick J. C. , Gerstein Robert E. , Brooke John , McKeown David L.
Published: April 2011

Natural remanence inclinations and paleointensities have been obtained from six drill cores of oceanic tholeiite pillow basalt taken from within a 4 km by 3 km area of the median valley of the Mid-Atlantic Ridge near 45 °N. Only two of the remanence inclinations agree with the predicted value for the area of +64°. Two others are of normal polarity but at +37 °and +47 °are significantly shallower than the predicted inclination. The remaining two cores have reverse inclinations of −14 °and −47°. Bottom photographs suggest that at least the +37 °and −47 °drill cores were obtained from in situ material.The paleointensities are uniformly high, ranging from 0.63 Oe to 1.17 Oe.The combined remanence inclination and paleointensity results are consistent with the presence on the floor of the median valley of basalts erupted during the Laschamps event, a conclusion in line with the fission-track ages for the basalts.It is suggested that the general lack of agreement between measured and predicted remanence inclinations, a feature that may be widespread in North Atlantic submarine basalts, is a side effect of the tectonic process responsible for the transport of new crust from the floor of the Median Valley to the adjacent crestal mountains.
Rb–Sr Isotopic Ages and Petrologic Studies of the Rocks in the Lac St. Jean Area, Quebec
Authors: Frith R. Anthony , Doig Ronald
Published: April 2011

The granulite facies meta-igneous and metasedimentary rocks that surround the Lac St. Jean anorthosite yield an Rb–Sr age of 1480 m.y. Intrusive monzonite, possibly genetically associated with the anorthosite, was emplaced slightly prior to 1513 m.y. ago. pre-anorthosite rocks were variously affected by the intrusion of the anorthosite and related rocks and affected again by the Grenvillian orogeny. Intrusive monzonite, granite, and syenite associated with the Grenvillian orogeny yield Rb–Sr ages between 1300 and 1000 m.y. Amphibolite facies rocks to the east of the anorthosite–monzonite granulite terrain were not as intensely affected during the Grenvillian orogeny. These granitic paragneisses record a metamorphic age of 1380 m.y. which suggests, in this area, continuous metamorphism between 1550 and 1000 m.y. ago. Thermal peaks at 1500 and 1100 m.y. are considered probable.
Effect of Rock Composition on Appearance of Garnet in Anorthosite–Charnockite Suites
Authors: Martignole J. , Schrijver K.
Published: April 2011

Fe2+/Mg and normative An/Ab ratios of 55 rocks of the Adirondack anorthosite–charnockite suite subdivide the compositional field in two domains; one without garnet (at low ratios) and one commonly with garnet (at high ratios). A similar subdivision is shown by 27 rocks of the Morin Complex. On the other hand, this subdivision is not valid for small anorthosite–charnockite complexes in the southern, Canadian, part of the Grenville Province, nor for the huge Nain (Labrador) anorthosite–adamellite massif.These different relations can be explained by: (1) formation of garnet during cooling under high confining pressure in the southern part of the Grenville Province, the size of the anorthosite–charnockite body determining the rate of cooling and (2) cooling of the Nain massif under lower confining pressure.
Revision of the March Formation (Tremadocian) in Southeastern Ontario
Authors: Bond Ivor J. , Greggs Robert G.
Published: April 2011

Reference sections are proposed for the revised March Formation (Tremadocian) along the MacDonald–Cartier Freeway a few miles west of Brockville, Ontario. The sequence of the March Formation delineated by these sections yields nearly a complete stratigraphic succession for this formation in southeastern Ontario. The lithology, thickness, and sedimentary environment are described, and the known conodont fauna is recorded.The establishment of a nearly complete reference section allows better understanding of the March as represented in the type area west of Ottawa, Ontario and permits more precise definition of the upper and lower contacts of the formation. The upper boundary of the March Formation as revised coincides with a probable Tremadoc–Arenig boundary: the lower boundary, also lithologically distinct coincides with the abrupt first appearance of conodonts in the Lower Paleozoic succession in southeastern Ontario.
Changes in Beach Profiles at Chedabucto Bay, Nova Scotia, Following Large-scale Removal of Sediments
Authors: Owens E. H. , Drapeau G.
Published: April 2011

The effects of sediment removal on three beaches have been monitored during a one year period following attempts to clean up an oil spill in Chedabucto Bay, Nova Scotia. Profiles of these beaches are compared with those surveyed on a high energy beach on Crichton Island which was not affected by cleaning operations. It is apparent on beaches affected by cleaning operations that sediments removed from areas beyond the limit of normal wave action have not been replaced. Excessive sediment removal can seriously alter the equilibrium of a beach and this was demonstrated by a 20-m retreat of the beach crest at the eastern end of Indian Cove.
Piemontite-bearing Explosion Breccia in Archean Rocks, Labrador, Newfoundland
Authors: Taylor F. C. , Baer A. J.
Published: April 2011

An explosion breccia, 4 km east of Hopedale, Labrador, occurs in Archean migmatite forming part of the Hopedale Gneiss. The breccia, 105 by 60 m, consists of angular to well-rounded fragments compositionally similar to the country rock. Extensive development of piemontite and epidote is characteristic of the breccia. Two narrow mafic dikes post-date and fill fractures in the breccia. An electron probe analysis of piemontite and epidote shows the former contains 1.86% Mn2O3 and the latter 0.21%. A genesis of the breccia involving fluidization with subsequent development of piemontite by hydrothermal activity is suggested.
Quadrithyris Zone (Lower Devonian) Near-reef Brachiopods from Bathurst Island, Arctic Canada; with a Description of a New Rhynchonellid Brachiopod Franklinella
Authors: Lenz A. C.
Published: April 2011

A brachiopod fauna from the off-, eef equivalent of the small, reef-knobs in the Stuart Bay Formation of central, eastern Bathurst Island contains a number of species in common with, and readily correlatable with, the Spirigerina fauna (probably Gedinnian) of Royal Creek, Yukon, and the coeval Quadrithyris Zone fauna of Nevada. The Spirigerina–Quadrithyris fauna is therefore known to have a north–south range of at least several thousand miles.A new genus and species of rhynchonellid brachiopod, Franklinella pedderi, is described from Spirigerina (= Quadrithyris Zone) beds of Bathurst Island and Royal Creek, Yukon. This species appears to be ancestral to the genus Thliborhynchia Lenz.
A Pattern of Muskeg—A Key to Continental Water
Authors: Radforth Norman W. , Bellamy David J.
Published: April 2011

The paper investigates the relationships that exist between the airform pattern, hydrology, and ontogeny of the muskegs of Canada. A new interpretive classification based on the concept of hydroform is proposed and some practical examples of its application are given.
Weathering and Clay Formation in a Dunite Deposit at Asbestos
Authors: Kimpe C. R. De , Zizka J.
Published: April 2011

Chemical and mineralogical analyses of a profile derived from dunite suggested that the serpentine transformed into chlorite and montmorillonite. The parent dunite was formed by lizardite plus clino-chrysotile mainly, but also contained brucite and magnetite. Brucite was rapidly dissolved in the early stage of weathering. Thereafter, there was a further loss of MgO and constitution H2O and a corresponding increase in SiO2. In the clay fraction, serpentine transformed, through interstratified minerals, into montmorillonite and chlorite (part of which was made of Al-montmorillonite).Feldspar, hornblende, and quartz were restricted to some fractions in the upper part of the profile, and this suggests that the deposit had not been extensively reworked by the glaciers.The weathering conditions at the site favored the formation of an Orthic Melanic Brunisol.
Sedimentation on the Western Delta-front of the Fraser River, British Columbia
Authors: Luternauer J. L. , Murray J. W.
Published: April 2011

The broad patterns of sedimentation and erosion on the western delta-front of the Fraser River are described on the basis of a detailed sedimentological survey and three successive bathymetric surveys.The surveyed portion of the delta-front can be subdivided into three sedimentary environments: salt marsh, main platform, and upper fore-slope. The salt marsh lies near high tide level and is a flat to hummocky, vegetated zone about 0.5 mi (1 km) wide, having sediments with a mean grain size finer than [Formula: see text] (0.063 mm). The main platform (which includes the tidal flats below the salt marsh) is the zone that slopes gradually for about 4 mi (6 km) from the salt marsh to the break in slope at approximately 30 ft (9 m) below lowest normal tide level. It is mantled mainly with [Formula: see text] to [Formula: see text] (0.35 mm to 0.125 mm) rippled sand. The upper fore-slope has here been designated as that portion of the delta-front extending from the main platform to the limit of the bathymetric survey (− 300 ft) (− 90 m). The gradient of the upper fore-slope is variable and attains a maximum inclination of approximately 12°. Upper fore-slope sediments are muddy at, and north of the main river channel, but consist mostly of sand south of there. The sharp transition between platform sand and muddy fore-slope sediment north of the main channel suggests that the − 30 ft (− 9 m) contour there denotes the maximum depth of vigorous wave and current action.Bathymetric surveys conducted in 1968 and April and August 1972 coupled with a calculation of the gross sediment budget of the western delta-front reveal that, as a consequence probably of local physical oceanography and confinement and dredging of the main channel, yearly freshet deposition is promoting the advance of the delta-front principally off the main channel and seems sufficient, at least, to maintain the stability of the upper fore-slope north of there. However, on the southernmost segment of the western delta-front, prevailing conditions have brought about the retreat of the upper fore-slope at least during the period 1968–1972.
Interpretation of Gravity and Magnetic Measurements across the Continental Margin of British Columbia, Canada
Authors: Srivastava S. P.
Published: April 2011

Contoured free air and Bouguer gravity and magnetic anomaly maps have been produced for the continental margin off the west coast of Canada from sixteen new profiles and previous data. Models produced from gravity, magnetic, and seismic reflection data indicate a deepening of the oceanic basement towards the continent off Vancouver Island. These results, along with folding and faulting of the large thickness of sediments at the base of the slope, indicate that there is present or very recent subduction in this area. In contrast, off the Queen Charlotte Islands, the basement is nearly horizontal and faulting is predominant, probably representing strike-slip motion along the Queen Charlotte Fault.
K-Ar Dating—Loading Techniques in Argon Extraction Work and Sources of Air Argon Contamination
Authors: Baksi A. K.
Published: April 2011

Replicate argon analyses on two 'rocks' show how improper loading techniques can lead to the delineation of "mixing lines" or false isochron plots. Methods of reducing blanks in argon extraction work are discussed.
Lower Oxfordian (Upper Jurassic) Sediments at Harrison Lake, British Columbia, and the Age of the 'Agassiz Orogeny'
Authors: Brookfield M. E.
Published: April 2011

New finds of ammonites in the Harrison Lake area indicate marked facies change in the Lower Oxfordian, and together with some structural re-interpretation that the late Callovian 'Agassiz Orogeny' of Crickmay should be updated to the interval Upper Oxfordian – Tithonian.
Paleomagnetism and Age of Nonacho Group Sandstones and Associated Sparrow Dikes, District of Mackenzie
Authors: McGlynn J. C. , Hanson G. N. , Irving E. , Park J. K.
Published: April 2011

The Nonacho Group is a folded sequence of sedimentary rocks resting on a crystalline basement of probable Archean age. Both sedimentary and basement rocks are intruded by the Sparrow dikes. Fifty-four samples from 10 dikes have a stable magnetization with mean direction after a.f. cleaning of 131°, +51 °(N = 10, k = 50, α95 = 7°) and a corresponding pole at 12 °N, 069 °W. The presence of reversals and the approximate agreement between dikes and their baked contracts are taken to indicate that the dikes were probably magnetized at the time of intrusion. 40Ar–39Ar studies suggest that the probable age of intrusion was about 1700 m.y. The magnetization of the Nonacho sedimentary rocks collected at 12 sites (40 samples) have a mean direction after thermal cleaning of 148°, + 57 °(N = 12, k = 11, α95 = 14°) without correction for geological dip. The corresponding pole is at 13 °N, 086 °W. The precision after correction for geological dip is low (k = 3), so the magnetization is predominantly post-folding. The thermal decay characteristics and the geometry of the directions indicate that the magnetization of the sedimentary rocks was acquired during cooling following a period of mild heating presumably owing to deep burial. This process of secondary magnetization apparently reached its culmination between about 1700 and 1600 m.y., and continued with diminishing intensity until about 1400 m.y. These results are used to modify the apparent polar wandering path for the Canadian Shield, so that the path now has a sharp bend (Hairpin 40) at about 1800 m.y. rather than at 1950 m.y. as previously postulated.
Crustal Structure of Baffin Bay from the Earthquake-generated Lg Phase
Authors: Wetmiller R. J.
Published: April 2011

The Lg phase generated by earthquakes is used to infer the gross crustal structure of Baffin Bay. The principle of interpretation is that the presence of the Lg phase on an earthquake record is sufficient proof of the existence of continental crustal structure along the entire propagation path, while the absence of the Lg phase is a consequence but not sufficient proof of the existence of a section of oceanic crust somewhere along the propagation path. Examples are given of earthquake records involving propagation paths through three distinct types of gross crustal structure, namely shield-type continental, intermediate-type continental, and oceanic. These examples are used to interpret the records at four seismic observatories located around Baffin Bay for eleven earthquakes, which occurred in and around the Bay in the years 1965 to 1967. The records reveal two areas of Baffin Bay that appear to have oceanic crust, one in the northern part of the Bay at the entrance to Nares Strait, and one in the deep central part of the Bay separated by a bridge of continental crust from Cape York on Greenland to Cape Macculloch on Baffin Island.
Progresses in R– and Q–Mode Analysis: Correspondence Analysis and its Application to the Study of Geological Processes
Authors: David M. , Campiglio C. , Darling R.
Published: April 2011

This paper essentially introduces a new statistical technique of data analysis together with a practical application. The technique is Correspondence Analysis and it is designed to extract the maximum information from a two dimensional array of positive numbers, such as the concentrations of various elements in several samples. It combines the advantages of R– and Q–mode analysis and also considerably reduces the problems encountered in the practical application of these techniques: Scaling problems and computer costs. The diagrams, which are produced by projecting at the same time samples and variables on the same plane with proper scaling, aid the interpretation of geological processes. The example that is discussed concerns the Bourlamaque batholith, where igneous differentiation and metamorphism have been clearly identified as the major factors controlling its geochemistry. The complete mathematical formulation is given since it has apparently never been published in the geological literature of North America.
An Example of the Use of Dilatancy Diagrams to Obtain Net Slip
Authors: Brown Anton
Published: April 2011

An approximate net slip for the No. 3 Vein fault at Opemiska Copper Mines (Que.) Ltd. property, in northwestern Quebec, has been obtained by comparing ore widths with the potential dilation from several possible fault movements. A reference plane of 096 °strike, 71 °north dip, has been chosen as a compromise between the two common attitudes of the vein. The ore stays close to the footwall of the fault, so that footwall topography has been used to calculate dilation. The zero dilation contours for 10 rectilinear movements and one rotation have been constructed, and their correspondence with the boundary between ore and waste used to choose a net slip of 41 m (135 ft) downward for the footwall, along a line pitching 50° in the reference plane, as the best solution. A close match between ore widths and more detailed dilation contours confirms this choice.
First Subbottom Acoustic Reflector and Thickness of Recent Sediments in the Upper Estuary of the St. Lawrence River
Authors: d'Anglejan B. F. , Brisebois Michel
Published: April 2011

A hydroacoustic survey has outlined the extent of a shallow buried reflecting horizon in the upper estuary of the St. Lawrence River, between Quebec City and the Saguenay River. This surface is considered to represent the contact of postglacial estuarine alluvium with Pleistocene sediments. The depth of the reflector below the bottom changes from place to place, recording regional variations in the thicknesses of the estuarine deposits. Only at a few localities are these deposits more than 30 m thick. The reflector varies in characteristics throughout the estuary: It may represent Champlain Sea sediments where flat or gently undulating, and late Pleistocene glacial material, where rugged and contorted.
Zeolite Fades Metamorphism of the Late Cretaceous Nanaimo Group, Vancouver Island and Gulf Islands, British Columbia
Authors: Stewart Richard J. , Page Richard J.
Published: April 2011

Laumontite and heulandite are extensively developed as metamorphic minerals in sandstones of the Late Cretaceous Nanaimo Group, Vancouver Island and Gulf Islands, British Columbia. Major post-depositional changes in the sandstones also include widespread carbonate cementation and replacement, alteration of plagioclase and biotite, and development of a phyllosilicate matrix. The sequence apparently is depth-zoned, with heulandite present only in the upper 1000 m of section, and laumontite developed in the upper 2500 m. The zeolite assemblages probably were developed during burial metamorphism, as subject to controls of permeability and suppression by a high chemical potential of CO2. Comparable assemblages should be expected in similar clastic sequences found in other portions of the Cordillera, particularly the thick Mesozoic successions of the Intermontane and Insular Fold Belts.
Mammoth from Babine Lake, British Columbia
Authors: Harington C. R. , Tipper H. W. , Mott R. J.
Published: April 2011

Remains of a partially articulate mammoth skeleton were exposed during stripping operations at a mining site on Babine Lake, central British Columbia. The bones lay in silty pond deposits in a bedrock depression, and were overlain by a thin layer of gravel and a thick layer of glacial till. Although no molar teeth were found, limb proportions show that the specimen was a large mammoth, like the Columbian mammoth (Mammuthus cf. M. columbi). Two radiocarbon dates of 42 900 ± 1860 yr B.P. and 43 800 ± 1830 yr B.P. on wood from the silty fossiliferous layer, and another of 34 000 ± 690 yr B.P. on mammoth bone suggest that the animal sank in sticky pond deposits and died there. Paleobotanical evidence indicates that, during this part of the Olympia Interglaciation, the vegetation near Babine Lake was similar to present shrub tundra just beyond the treeline in northern Canada.
Pole Position for the Neohelikian Nemegosenda Carbonatite Complex, Ontario
Authors: Symons D. T. A. , Garber J.
Published: April 2011

Paleomagnetic data from 17 sites (76 cores; 152 specimens) reveals that the Nemegosenda carbonatite complex retains a primary remanence magnetization of low stability. The pole position of 43 °N, 178 °W (P0.05: 15°, 24°) for the complex is concordant with a group of poles from other rock units in the Superior Province in the age range of 1000 to 1115 m.y. It is concluded that interpreting the 1036 m.y. K-Ar date as the age of emplacement of the complex is in agreement with the mean magnetization direction having been preserved without structural rotation since the body cooled.
Continental Shelf Sediments off Eastern Newfoundland: A Preliminary Investigation
Authors: Slatt Roger M.
Published: April 2011

Surficial sediment samples from the continental shelf off eastern Newfoundland were analyzed for grain-size distribution (302 samples) and CaCO3 content (257 samples). The results were compared with those of previous investigations.Gravel covers the inner Grand Banks. Clean, well-sorted sand covers most of the outer banks, but significant quantities of gravel (greater than 10%) are present locally. Biogenic carbonate sand is irregularly distributed on the Grand Banks.The presence of gravel as far seaward as the shelf break indicates the Pleistocene ice sheet once extended across the Grand Banks and the sediments are relict. Other lines of evidence that indicate the sediments are relict include: a radiocarbon date of 17 000 yrs. B.P. on biogenic sand, the occurrence on parts of the shelf of littoral sand now in 90 m of water as well as glacially derived residual sediments, the presence of moraines and a Quaternary shelf sedimentary section 20–200 m thick, and the presence of relict sediments on continental shelves both north and south of the Newfoundland shelf. It is concluded that gravel on the inner Grand Banks is reworked glacial or glacio-fluvial sediment that was deposited during Pleistocene lower stands of sea level and that sand on the outer banks probably was derived by in situ reworking of the Pleistocene substrate during the Holocene transgression.It has previously been suggested that the gravel–sand boundary, which occurs more than 150 km from shore, defines the seaward limit of the Wisconsin ice sheet. This possibility cannot be discounted, however, the presence on the shelf of a transgressive sand sheet, and relict biogenic carbonate sand near this boundary and intermixed with gravel, as well as the Wisconsin glacial history of eastern Newfoundland and Nova Scotia, which suggests late-Wisconsin ice didn't extend offshore a distance of 150 km, all indicate the gravel–sand boundary does not define the seaward limit of Wisconsin ice. The late-Wisconsin ice limit may have been further shoreward.On the North Newfoundland Bank (Ritu Bank) and adjacent areas of the northeast Newfoundland shelf, post-depositional winnowing probably has size-sorted residual sediment according to water depth.
A Refraction Survey across the Canadian Cordillera at 54 °N
Authors: Forsyth D. A. , Berry M. J. , Ellis R. M.
Published: April 2011

Record sections from partially reversed refraction lines in northern British Columbia show that the amplitudes of upper mantle arrivals vary smoothly with distance, while the pattern of crustal arrival amplitudes is not smooth. Normalization of the seismograms to remove the effects of varying shot size and instrument response show that Pn amplitudes are largely site-independent.Models derived from ray theory indicate a crust which thins from about 40 km in the Omineca Crystalline Belt to about 25 km in the Insular Trough. The average Pn velocity is 8.06 km s−1, and the average crustal velocity is 6.4 km s−1. The secondary energy indicates that the models are greatly simplified.A time–term profile between the Omineca Crystalline Belt and the Coast Mountains suggests a Mohorovičić transition which is characterized by two significant topographic wavelengths. The shorter (200 km) wavelength correlates roughly with the Cordilleran structural elements of Wheeler and Gabrielse (1972). The larger (800 km) wavelength may have tectonic significance.
Heinze Gas-Volugraph: for Recording Gas Evolved versus Time
Authors: Dyck J. H. , Perkins E. H.
Published: April 2011

The Heinze gas-volugraph is an instrument designed to measure gas-volume changes at ambient temperature and pressure and to record changes in gas-volume corrected to 'standard' temperature and pressure. This instrument is used in the quantitative volumetric determination of carbon dioxide evolved from the reaction of acid with prepared samples of rock containing carbonates.The instrument records the amount of gas evolved as a function of time and presents this information as a graph. Other important features include: (1) a liquid dispenser mechanism which combines the liquid and sample in such a manner as to eliminate the need for volume corrections; and (2) a compensator mechanism which permits direct recording of gas volumes corrected to STP conditions.In Saskatchewan the carbonate content of tills has been determined gasometrically by geologists using this apparatus. The results have been used to trace the stratigraphic succession of tills across parts of the province.
Conceptual Frameworks for Geographic-Botanical Affinities of Fossil Resins
Authors: Broughton Paul L.
Published: April 2011

Solid-state analytical techniques have been applied to natural resins to establish paleo-geographic-botanical frameworks. Infrared spectroscopy, X-ray diffraction, and differential thermal analysis were the techniques utilized. Fossilized resins (ambers) and recent to modern natural resins (gums and copals) from 47 world-wide localities were used in the study.North American fossil resins have distinctive infrared and thermal characteristics which distinguish them from type Baltic Sea coast ambers. Examination of recent gums and copals by solid-state analytical techniques indicates significantly higher volatile component fractions than in the more fossilized resins.
A P Travel-Time Model for the Canadian Shield obtained by a Joint Epicenter Determination Method
Authors: Hashizume M.
Published: April 2011

The P arrival-times for nine very shallow earthquakes under the Canadian Shield and the surrounding area were studied. P arrival-times were assumed to be a function of the hypocenter, origin-time, and specified travel-time curve. Using as starting point the hypocenters and origin times taken from the Preliminary Determination of Epicenters (PDE) listings and the travel-time curve from the "Seismological Tables for P Phases" by Herrin et al. (1968), calculations were conducted so as to minimize the residuals between the observed P arrival-times and the calculated travel-times in a search for the best hypocenters, origin-times, and travel-time curve. The deviations from the travel-time curve were assumed to be represented by a sixth-order polynomial. The differences of the new epicenters from those of the PDE listings are small and generally less than about 10 km. The significant result is that the new travel-time curve obtained by this technique is similar to those obtained from seismic explosion studies in the eastern part of North America.
Large-Scale Fold Interference Structures in the Mudjatik River Area of Northern Saskatchewan
Authors: Pearson David E. , Lewry John F.
Published: April 2011

The Mudjatik River area of Northern Saskatchewan is underlain by granitic gneisses interlayered with subordinate metasediments and pyribolites, all of which contain granulite facies mineral assemblages.Four fold-forming deformations (D1 to D4), of presumed Hudsonian age, have resulted in closed and arcuate strike patterns that contrast with the linear domain of the Wollaston Lake fold-belt. Fold superposition involving second and third generation (D2 and D3) major structures is considered the most likely cause of this basin and dome geometry.The orientation and geometry of the fold interference structures are explained by a variation in the amplitude/wavelength (a/w) ratios of the two fold sets involved. Where the a/w ratios of the constituent folds are similar, structural isotropy prevails; where these ratios are markedly different, structural elongation results.An increase in the a/w ratio of the D3 fold set is postulated to account for the eastward transitional passage into the linear pattern of the Wollaston Lake fold-belt.
Magnetic Susceptibility of the Surface Tills of Southern Ontario
Authors: Gravenor C. P. , Stupavsky M.
Published: April 2011

The tills of southwestern Ontario derived their igneous and metamorphic rock and mineral content from areas of the Canadian Shield north of Lake Ontario and north and northeast of Lake Huron. The magnetic susceptibility (MS) of samples of till taken from the area north of Lake Ontario is significantly higher than that for samples taken from the area north and northeast of Lake Huron.The MS of samples of surface till deposited from the Ontario and Erie ice lobes reflects the higher values of MS from that area of the Shield north of Lake Ontario and these samples are significantly higher in magnetic material than samples taken from the Huron lobe on the east side of Lake Huron. Thus the MS of till may be used to differentiate tills in southwestern Ontario on the basis of source area.Measurements of MS from two tills of differing age in the Toronto area show that the two have significantly different MS values and consequently the mean MS values may be used to trace these tills in the subsurface and in areas remote from the sampled sections.The results indicate that the MS of tills provides a rapid and accurate technique for the glacial geologist to identify the source area of tills and to differentiate tills found south of the Precambrian–Paleozoic boundary.
On Planetary Voltages, Ocean Tides, and Electrical Conductivity below the Pacific
Authors: Duffus H. J. , Fowler N. R.
Published: April 2011

Voltages observed between the ends of various underwater telegraph cables up to 9660 km long are analyzed in terms of planetary electric fields, deep ocean tides, wind driven surface currents, and geomagnetic induction.It is concluded that the average planetary electric field, which may originate from the internal processes generating the geomagnetic field, is not more than 0.038 mv/km ± 20% between Fiji and Vancouver Island. This is almost an order of magnitude less than previously reported.The average resistivity of the sea bed to a scale depth of 130 ± 20 km, treated as a single homogeneous plane layer, is 37 ± 5 ?m off the coast of Vancouver Island. This is similar to what is observed below the adjacent land.No statistically significant model was found relating the voltages on the 9660 km cable to tide heights at the shore, and geomagnetic field changes. However, it was found that the geomagnetically induced voltages between the ends of the 85 and 23 km cables were larger than the tidally induced voltages. A satisfactory model of these cable voltages was developed in terms of tidal heights, measured at the shore, and geomagnetic fields measured at a nearby observatory.All the cables were broken at sea, and the data are therefore of special interest because it is unlikely they will ever be duplicated.
The St. Eugene Formation and the Development of the Southern Rocky Mountain Trench
Authors: Clague John J.
Published: April 2011

The Tertiary history of the southern Rocky Mountain Trench is inferred from a study of the distribution, stratigraphy, fabric, lithologic composition, structure, and palynology of the Miocene St. Eugene Formation in southeastern British Columbia.The St. Eugene Formation consists of flood-plain and fan facies and represents the upper part of up to about 1500 m of sediments which accumulated in the proto-Rocky Mountain Trench upon cessation of Laramide deformation and after initiation of extension and block faulting in the eastern Cordillera during Eocene or early Oligocene time. Deep Tertiary basins in the southern Rocky Mountain Trench are bounded on the east and west by high-angle faults parallel to the Trench margins and on the north and south by faults transverse to the trend of the Trench. Block faulting of a half-graben style was probably contemporaneous with sediment deposition, but at least 600 m of displacement on the east boundary fault postdates deposition of the St. Eugene Formation. Although there is no present seismic activity along the Rocky Mountain Trench north of latitude 49°N, Holocene fault scarps and earthquakes in a zone along the Rocky Mountains of the United States attest to the continuation of block faulting south of 49°N.The St. Eugene microflora includes at least 39 genera of ferns, gymnosperms, and anthophytes. Phytogeographic reconstruction based upon the habitats of extant counter-parts indicates floral elements growing on poorly drained lowlands, adjacent slopes, and montane uplands; thus, there was moderate to high relief in southeastern British Columbia during St. Eugene time. The climate apparently was temperate, with warm summers, mild winters, and abundant, uniformly distributed precipitation. This contrasts with the present climate of the southern Rocky Mountain Trench which is semiarid with hot summers and cold winters, and suggests that the mountain barriers which presently restrict cool, moist, Pacific maritime air masses to the coast were lower during the Miocene, or that the polar seas were relatively warm.
The Precambrian Shield and the Lower Paleozoic Shelf: The Unstable Provenance of the Lower Paleozoic Flysch Sandstones and Conglomerates of the Appalachians between Beaumont and Bic, Quebec
Authors: Lajoie Jean , Héroux Yvon , Mathey Bernard
Published: April 2011

Three sections of lower Paleozoic flysch in the Quebec Appalachians were sampled at Beaumont, Bic, and Trois Pistoles in order to determine the position, composition, and relief of the source area. At Beaumont, the mean flow direction of sediment transport is east-southeasterly; at Trois Pistoles and Bic it is south-southeasterly. Locally there is strong dispersion of the data but no northerly directions have been observed.Albite is the common plagioclase in all Cambrian sandstones; grains generally show polysynthetic twins, but in a few beds only untwinned albite is present. Oligoclase and andesine are the dominant plagioclases in Lower Ordovician rocks. The accessory suite has few diagnostic species; pink garnet is present in all sections, but absent in the basal unit at Bic. Diopside, sphalerite, and barite are found only in the Lower Ordovician rocks at Beaumont. At the three localities, the feldspar content, grain size, and sand/shale ratio vary up-section.The original source area for the sandstones and conglomerates consisted of an early Paleozoic shelf and a Precambrian land-mass. The oldest sands were derived from Precambrian metasediments, Paleozoic shelf sediments, Precambrian sodic plutons, and to a minor degree from gneisses. In Late Cambrian time the major contributors were sedimentary rocks of the shelf, sodic plutons, and gneisses. By Early Ordovician time most of the sands were derived from Grenvillian gneisses and shelf sedimentary rocks.The relief of the Grenvillian Orogenic Belt was high and denudation rapid from Early Cambrian to Late Cambrian, suggesting continuous, but irregular uplift. Uplift of the shelf began early in Cambrian, with major movements occurring in Late Cambrian when the Grenvillian source was rejuvenated. The source area was stabilized by Early Ordovician time.
Paleomagnetism of Jurassic Rocks from Southern Alaska, and the Tectonic Implications
Authors: Packer D. R. , Stone D. B.
Published: April 2011

Oriented samples of rocks of Jurassic age were collected from 24 separate sites located in southern and southwestern Alaska. Paleomagnetic measurements were made on these rocks, and various selection criteria were applied to obtain a mean Jurassic paleopole position of 50°N and 295°E with an α95 of 14.2°. This pole position is displaced from the mean paleopole of North America in the opposite direction to that predicted by Carey's orocline hypothesis for the development of Alaska. Based on this pole position, northward movement and clockwise rotation of southern Alaska must have occurred since Jurassic times, perhaps in a manner analogous to the motion of Baja California today. This Baja–Alaska model for the tectonic development of southern Alaska is currently being tested.
Paleomagnetism of miscellaneous Franklin and Mackenzie Diabases of the Canadian Shield, and their adjacent Country Rocks
Authors: Park J. K.
Published: April 2011

This paper brings together the paleomagnetic results from miscellaneous unmetamorphosed diabases and their remagnetized adjacent country rocks collected from widely separated locations within the Canadian Shield. Most of these diabases are tentatively assigned to the Franklin and Mackenzie Igneous Episodes on the basis of their paleomagnetic poles and their geological relationships with previously assigned diabases. The tentative Mackenzie pole from the present work is 02.5°N, 169.8°W (N = 12, K = 35, A93 = 7.4).
Pleistocene Glacial Lake Sequences in the Foothills, Southwestern Alberta, Canada
Authors: Alley N. F. , Harris S. A.
Published: April 2011

Three separate advances of Laurentide ice during the preWisconsin and Early Wisconsin led to the formation of proglacial lakes in the Foothills of southwestern Alberta. Lakes formed in both the advance and recessional stages, the most extensive occurring during the latter. Evidence of lakes formed by the first advance is fragmentary, but for the later advances, the occurrence of extensive glaciolacustrine deposits and related features attests to the presence of former large bodies of water. Two lakes (Glacial Lakes Oldman and Westrup) resulted from the second advance of Laurentide ice into the Foothills. Damming of Cordilleran meltwaters by the third (Early Wisconsin) Laurentide ice sheet to affect the area, led to the formation of Glacial Lake Caldwell and the development of complex flights of valley train terraces along the Oldman and Crowsnest River valleys.The relationship of the proglacial lakes to the ice fronts substantiates the stratigraphic evidence that the Cordilleran and Laurentide ice-maxima during each advance were not synchronous and that the valley glaciers had receded considerably before the Continental ice sheet advanced into the Foothills of southwestern Alberta.
A Gravity Survey of the Continental Shelf south of Cape Sable, Nova Scotia
Authors: Watts A. B.
Published: April 2011

The western part of the continental shelf off Nova Scotia is associated with a region of relatively low Bouguer gravity anomalies. The gravity 'low' reaches a minimum of −23 mgal about 20 km south of Cape Sable Island, Nova Scotia. Computations suggest the 'low' can be explained by an outward sloping body about 40 km wide and up to 15 km thick. The gravity 'low' is interpreted as caused by granites or granitic rocks which intrude the pre-Mesozoic basement rocks underlying the shelf. The granites or granitic rocks may extend to within about 50 km of the eastern Canada continental margin.
A Middle Campanian, Nonmarine Occurrence of the Cretaceous Toothed Bird Hesperornis Marsh
Authors: Fox Richard C.
Published: April 2011

An occurrence of the Cretaceous toothed bird Hesperornis Marsh is recorded from a tarsometatarsus found in the middle Campanian Foremost Formation, Alberta. The discovery may be the geologically youngest record of Hesperornis known and provides the only well documented nonmarine occurrence of the genus.
Methane in Recent Sediments of the Labrador Shelf
Authors: Vilks Gustavs , Rashid Mohammad A. , Van Der Linden Willem J. M.
Published: April 2011

Methane was found in Recent sediments of two basins on the Labrador continental shelf. These basins are carved in what are believed to be Tertiary and Mesozoic strata resting on Precambrian and possibly Paleozoic rocks. Geochemical and foraminiferal analyses of sediments from one piston core indicate that the gas is a product of anaerobic fermentation of organic matter. Mildly anaerobic conditions existed in subsurface sediments, which were deposited under marine conditions shortly after the retreat of the last Pleistocene glaciation.
Middle Devonian Conodonts from the Harrogate Formation, Southeastern British Columbia
Authors: Chatterton Brian D. E.
Published: April 2011

A fauna of Middle Devonian conodonts from the Harrogate Formation is described. The conodont evidence favors a middle to late Eifelian age rather than a Givetian age for this unit. A new form species of Icriodus, I. stelcki s.f., a new multielement species of Polygnathus, P. parawebbi, and a new multielement species of Coelocerodontus, C. Klapperi are described. A discussion of some of the problems of applying multielement taxonomy to conodont faunas is included.