bluuebunny/crossref_metadata_2025 huggingface dataset:
Tectonic Evolution of the Lac Rouvray Anorthosite Mass, Quebec
Authors: Kehlenbeck Manfred Max
Published: April 2011

Bedrock in the area can be classified into four major groups: (I) a quartzo–feldspathic gneiss complex, (II) anorthosite, (III) a porphyritic silicic igneous complex, and (IV) granitic and alaskitic veins.The gneiss complex forms a pre-Grenville basement which acted as the host for the intrusions of anorthosite and silicic rocks. The intrusive rocks follow dominant north–south trends, whereas structures in the basement gneisses are varied.The anorthosite and its associated silicic rocks overlie the basement gneisses and underlie typical Grenville group lithologies. The intrusion thereby occupies a major stratigraphic boundary. An unconformity may be such a boundary.
The Clay Mineralogy and some Properties of Bottom Sediments of the St. Lawrence River near Kingston, Ontario
Authors: Rutherford G. K.
Published: April 2011

In order to investigate the bottom conditions existing along a transect of the St. Lawrence River, where it flows out of Lake Ontario, sediments were collected at two depths by scuba divers. The samples were analyzed using soil chemical, physical, and mineralogical methods.The medium to fine silt fraction dominates the non-acid treated samples, while the action of HCl increases the clay content some ten times. Although Ca is the dominant exchange cation exchangeable Mn is unusually high, perhaps reflecting the presence of manganiferous shales in the watershed. Dissolved Ca is the dominant cation in the sediment waters but the high Na is probably derived from the Canadian Shield element in the surrounding lithoiogy. Semi-quantitative clay mineralogy suggests that illite and illite–chlorite interstratifications are most common while the absence of montmorillonite, a common constituent of Podzol A2 horizons, is noteworthy.
Arthropod Trace Fossils in the Lower Devonian Jacquet River Formation of New Brunswick
Authors: Greiner Hugo
Published: April 2011

Two varieties of tracks and trails from sandstone in the Lower Devonian Jacquet River Formation (lower Dalhousie Group; i.e. Helderberg) from northern New Brunswick are attributed to arthropod, possibly phyllocarid and eurypterid, activity. A very nearshore-marine environment is inferred.Two ichnospecies, Arthropodichnus jacquetenis and A. chelopodus are described.
The Petrology of Late Tertiary Dolerite Plugs in the South Cariboo Region, British Columbia
Authors: Farquharson R. B.
Published: April 2011

The petrology of four plugs of fresh, coarse-grained olivine dolerite, of Pliocene age, is described in this paper. Two plugs, which exhibit textural and mineralogical variations, are described in detail. Major element analyses and selected trace element analyses for fifteen samples illustrate the chemical nature of the dolerite as well as fractionation in small marginal portions of the plugs. Strontium isotope values indicate that the plugs represent basaltic magma that was not contaminated by crastal matter. Both the mineralogy and the chemistry of the plugs indicate that the magma was mildly alkaline, and suggest that it was a differentiate of a primary olivine basalt magma, perhaps derived through crystal fractionation in a high-level magma chamber.
Lithium Distribution in Canadian Granitoid Rocks
Authors: Mulligan R.
Published: April 2011

Analytical data on the lithium content of granitoid rocks mainly from the Cordilleran and Appalachian regions of Canada are presented and compared with published data for various areas of the Canadian Precambrian Shield. The comparison suggests that the average lithium content of granitic rocks in whole geological regions and provinces in which lithium deposits are numerous is not appreciably higher, if at all, than in those where lithium deposits are rare or absent. It is appreciably higher in some granitic rocks, especially muscovite-bearing granite, in limited areas in which lithium deposits are numerous, but is high also in muscovitic and greisenized granite in some areas where lithium deposits are scarce or absent.
Gravitational Effects on the Vertical Observed by the Ottawa PZT
Authors: Woolsey E. G.
Published: April 2011

The deflection of the vertical due to the combined gravitational attraction of both the sun and moon appears in the observations made with the Ottawa PZT during the years 1962–1970. The values are very small, but the 95% confidence level shows they are real. The Love number (1 + k − l) was determined as 1.3 ± 0.9 from latitude readings, and 0.9 ± 0.8 from longitude, where the uncertainties quoted in both cases are the 95% confidence limits. The coefficient of correlation between observed and calculated residuals is 0.7 for longitude and for latitude readings.
Taconic and Acadian Folds in Northern and Western Gaspé Peninsula, Quebec
Authors: Carrara A. , Fyson W. K.
Published: April 2011

The earliest tectonic structures recognized in northern and western Gaspé Peninsula are intrafolial, isoclinal folds with an axial-surface schistosity or slaty cleavage closely parallel to bedding. Most of these structures are confined to low-grade metamorphic rocks in the lower part of a Cambro–Ordovician volcanic and flysch succession; locally they affect rocks of a formation that is dated elsewhere as mainly Middle Ordovician. Later folds of variable shape and size, usually with steep axial surfaces, affect all the succession. Both fold sets are reinterpreted to have developed during the Taconic orogeny (mid to late Ordovician).Acadian (mid-Devonian) folds in cover rocks trend closely parallel to those in the Taconic basement, but deformation of the basement was mainly limited to late warping, which formed major anticlinoria and synclinoria that determine the outcrop pattern.
Composantes du Mouvement de Rebondissement Isostatique d'Après des Données de Remblaiements Alluviaux. (Exemple de la Rivière Saskatchewan Sud)
Authors: Kugler Marianne , St-Onge Denis A.
Published: April 2011

During the retreat of the last ice age isostatic rebound occurred propagating like a damped wave parallel to the ice front. Beaches of large glacial lakes show this clearly. In areas where such lakes were too short lived to develop well defined beaches evidence of rebound must be sought elsewhere. In regions where the general slope of the land is towards the retreating ice front, rebound will trigger incision of the down valley section. If a bed is uplifted which is more resistant than the rate of incision, aggradation will occur in an upstream section of the river. This mechanism seems to best explain the fill in the South Saskatchewan River Valley at Elbow. In this case a bouldery till near Saskatoon appears to behave as a resistant layer. Minimum deformation derived from the evidence available is comparable to that measured on Lake Agassiz shorelines.
Sedimentology, Stratigraphy, and Crustal Evolution of the Archean Greenstone Belt near Sioux Lookout, Ontario
Authors: Turner Colin C. , Walker Roger G.
Published: April 2011

In the Archean greenstone belt at Sioux Lookout, N.W. Ontario, a lowermost belt of volcanic rocks is unconformably overlain by sediments of the Abram Group. Our mapping has subdivided the Abram Group into three formations. The lowest (Ament Bay Formation) consists of interbedded conglomerates and sandstones. The sandstones contain large-scale cross-stratification, and the conglomerates and sandstones both lack graded bedding. The depositional environment was a subaerial alluvial fan—this is the first description of such a feature based upon modern sedimentological work in Archean rocks. The Daredevil Formation conformably overlies the Ament Bay Formation, and is composed of felsic and basic tuffs, and some interbedded turbidites. The uppermost (Little Vermilion) Formation is composed entirely of turbidites.The petrography of the sand, and large clasts, in the Ament Bay Formation indicates derivation from a dominantly granodioritic terrain. Some granodiorite boulders contain greenstone xenoliths, implying intrusion of the granodiorite after formation of the lowermost belt of volcanic rocks.In a final section of the paper, we define two Archean facies associations—a Resedimented association containing turbidites, pebbly mudstones, resedimented conglomerates, and basinal black argillites; and a Continental association, containing alluvial fan deposits, and possible coastal deposits from South Africa and Australia. The facies sequence in the Sioux Lookout belt is Continental followed by Resedimented facies, the reverse of the normal geosynclinal flysch (resedimented) → molasse (continental) sequence.
Application of Apatite Fission-track Dating to the Study of Porphyry Type Mineral Deposits
Authors: Christopher Peter A.
Published: April 2011

Apatite fission-track ages for weakly altered rocks from the Syenite Range and Burwash Landing area of the Yukon Territory, and Cassiar area of British Columbia are shown to be consistent and generally concordant with K–Ar ages obtained on biotite from the same samples. More intensely altered rocks from Granisle Mine and the Copper Mountain area of British Columbia have discordant ages, due in part to alteration of apatite grains and, for samples from the Copper Mountain intrusions, to a Cretaceous (?) thermal event.
Evaluation of Rb–Sr Dating Methods Applied to the Matachewan, Abitibi, Mackenzie, and Sudbury Dike Swarms in Canada
Authors: Gates T. M. , Hurley P. M.
Published: April 2011

Re-evaluation of the age of Canadian dike swarms using Rb–Sr whole-rock data give the following results:[Formula: see text]Detailed studies of the Matachewan dike swarm show that in most cases Rb–Sr mineral isochron age values from individual samples are concordant with the Rb–Sr whole-rock age values for the dike swarm as a whole and are clearly greater than K–Ar age values on the same material. The fact that the mineral isochron ages and the whole-rock ages by the Rb–Sr method are similar suggests that there has been no significant thermal overprinting of these particular dikes since their emplacement and solidification or contamination by radiogenic 87Sr from the host environment. Furthermore, the general scatter and lack of significant grouping of the lower K–Ar values similarly suggests that there was no single period of thermal resetting of the K–Ar ratios. It is observed that the K–Ar age values are greater in samples containing mica, and are more scattered and lower in samples in which potassium is contained in late-stage or principal phases other than mica. Therefore, it seems likely that significant loss of argon may result at near or normal surface temperatures and that the rate of diffusion is dependent on the mineralogy of the sample. It is concluded that reasonably good age determinations can be made on diabase dike rocks of ancient age by the Rb–Sr whole-rock isochron method, if the mineral isochrons are concordant.
Middle Ordovician Fish-bearing Beds from the St. Lawrence Lowlands of Quebec
Authors: Eliuk Leslie S.
Published: April 2011

Ostracoderm tubercles were recovered from the lower portion of two Black River Group sections between Montreal and Quebec City. Some of these fish remains seem identical to tubercles of Astraspis desiderata from the Harding Sandstone of Colorado. The age of the Quebec remains is questionably earliest Blackriveran or basal Caradocian of the European standard. The remains were found in sandy carbonates probably laid down in the supratidal to shallow marine environments. It is concluded that these remains may represent part of a continent-wide, biostratigraphically useful vertebrate fauna and that bulk sampling and acid residuing might be a technique whereby sparse, fragmentary, earliest Paleozoic fish remains could be found.
Potassium–Argon Dating of Slates from the Meguma Group, Nova Scotia
Authors: Reynolds P. H. , Kublick E. E. , Muecke G. K.
Published: April 2011

Recent reconstructions of the geologic evolution of Atlantic Canada based on plate-tectonic models have aroused new interest in the timing of orogenic events on both sides of the Atlantic. K–Ar apparent ages ranging from 332–403 m.y. are reported for 15 whole-rock slate and hornfels samples from the Halifax Formation of the Meguma Group. Four biotite concentrates from spatially associated granitic intrusions yield K–Ar ages of 364–369 m.y. A minimum age of about 390 m.y. for the regional metamorphic event is deduced from the whole-rock slate data. Granitic intrusion at approximately 367 m.y. profoundly affected the argon clock in many Halifax slates and resulted in its partial resetting even in slates which do not display mineralogic or textural effects of superimposed thermal metamorphism. The 390 m.y. minimum age for regional metamorphism supports suggestions by other workers that the currently widely-accepted 395 m.y. date for the Devonian–Silurian boundary may need revision.
Paleomagnetic Results from the Jurassic Topley Intrusions near Endako, British Columbia
Authors: Symons D. T. A.
Published: April 2011

The Upper Jurassic Topley Intrusions intrude rocks of the tectonically stable Interior Plateau in central British Columbia. A stable primary remanent magnetization of both normal and reversed polarity was isolated after a.f. demagnetization in 19 of 22 sites (109 cores; 208 specimens) representing several of the plutonic units present in this sialic complex of quartz monzonite affinity near Endako, B.C. The unit mean remanence directions support some petrological correlations suggested by Carr, Bright, and White et al., but do not support others. The pole position derived from 13 sites representing 6 plutonic units with a K–Ar radiomelric age of 139 ± 4 m.y. (White et al.) is 128.6 °E, 70.0 °N(δm = 14.4°; δp = 11.4°). This position indicates a smooth polar wander path during the Jurassic between the well defined Upper Triassic and Lower Cretaceous pole positions. It also indicates that the northern Interior Plateau has not been tectonically rotated or translated since emplacement relative to the stable North American craton.
The Terrascope
Authors: Geuer Juan W.
Published: April 2011

An instrument for producing hemispherical paleogeographical maps with minimal distortion by a direct photographic method is described. In essence the procedure is to compile a map by assembling models of lithospheric plates on a globe, and then to transfer this assembly into a hollow hemispherical template where it is photographed from the inside. The procedure is simple and rapid and the product visually realistic.
A Total-time Approach for Estimating Depth to Bedrock in Glaciated Mountain Valleys
Authors: MacAulay H. A.
Published: April 2011

A seismic method is described by which depth to bedrock in valleys can be estimated without the need to traverse the valley surface with conventional refraction or reflection techniques. A short detector array on rock outcrop on one side of the valley is used to measure compressional waves from a shot on outcrop on the opposite side, and to measure the seismic velocity of the rock. The shortest travel-time path across the valley follows the bedrock overburden interface, and when the bedrock velocity is known, the length of the path can be computed. The ratio of the length of the bedrock path to the direct distance between source and receiver is a function of the depth to bedrock at the valley center. The success of the method requires that certain valley-shape configurations be reasonably predictable and that the bedrock velocity be uniform throughout. Depth calculations for several field examples have been made using graphical techniques.
Early Paleozoic Volcanism and Metamorphism of the Moretons Harbour–Twillingate Area, Newfoundland
Authors: Strong D. F. , Payne J. G.
Published: April 2011

In the Moretons Harbour area, at the eastern end of the Lushs Bight terrane of central Newfoundland, the volcanic rocks of the "Lushs Bight Supergroup" are divided into two new groups, viz, the Moretons Harbour Group and the Chanceport Group. The former is separable into four formations, consisting primarily of variable proportions of basaltic pillow lavas and volcanoclastic sediments, with a composite thickness in excess of 6 km, or around 8 km including an extensive area of 'sheeted' diabase dikes. These formations are steeply dipping and face southwest; they are separated by the Chanceport fault from the Chanceport Group to the south. The latter consists of interbedded basaltic pillow lavas with graywackes and banded red and green cherts, all facing north and steeply dipping to overturned, with a composite thickness of approximately 3 km.The Moretons Harbour Group has been intruded by the Twillingate trondhjemitic granite–granodiorite pluton and abundant basic dikes intrude the granite, indicating that the mafic and felsic magmatism were coeval. Both have undergone intense deformation and the volcanics show a change from greenschist to amphibolite facies mineralogy within a distance of 2 km on approaching the pluton, a result of buttressing by the pluton during deformation, and not an intrusive effect.Base metal sulfides are common throughout the area, but the main occurrences of Cu, As, Sb, and Au are concentrated in the Little Harbour Formation, a 2600 m thick sequence of volcanoclastic rocks within the Moretons Harbour Group.The great thickness of volcanic rocks is interpreted as having formed in an island arc environment, although it is possible that the lowermost parts of the sequence represent oceanic crust. It is unlikely that the sheeted diabases of the Moretons Harbour area were produced by sea-floor spreading.
Sulfur Isotope Analyses of Some Sudbury, Ontario, Ores
Authors: Schwarcz H. P.
Published: April 2011

Cu-Ni ores from seven mines in the Sudbury ore camp have been analyzed. Together with older analyses, they indicate a weighted mean δ34S for all ore of + 2.1‰ (CDT), a range from + 0.5 to 7.2‰. Individual deposits have characteristic δ34S means, and small dispersions compared to whole camp. 34S-content is not correlated with ore type, as defined by sulfide-silicate association; δ34S increases with depth in south-range deposits; north-range ores are heavier still, as if deposits had been uplifted relative to south-range, contrary to conventional structural interpretation.Fractionation between pyrrhotite and chalcopyrite (Δpc = δSPo – δScp) ranges from − 0.8 to + 0.9‰. Negative fractionations may be quenched in from high temperatures. Δpc is positively correlated with δSpo. Both variables may be responding to increasing depth of emplacement, δSpo by progressive fractionation through extraction of S-32 enriched crystals from sulfide magma; Δpc through decreased cooling (quenching) rate. Alternately, Δpc – δpo variations may represent partial exchange of pyrrhotite with an 32S-rich fluid after ore deposition.Overall δS of ore suggests that primary sulfide magma is fractionated with respect to primitive basaltic sulfur, possibly by loss of S-32 enriched vapor.
Uranium-Series Ages of Some Quaternary Deposits Near Medicine Hat, Alberta, Canada
Authors: Szabo B. J. , Stalker A. MacS. , Churcher C. S.
Published: April 2011

230Th and 231Pa dates were obtained on 10 bone samples from Quaternary deposits near Medicine Hat, Alberta. The youngest date so obtained (9500 ± 1500 years) agrees reasonably well with a radiocarbon date (11 200 ± 200 years) from the same site. In addition, where samples were collected from more than one bed at the same bluff the results are in the correct chronological order. A Sangamon bed containing chipped stones, thought to be artifacts, gave a date of 72 000 ± 6000 years, which is acceptable, though at the younger end of the previously estimated age range of between 200 000 and 70 000 years for the bed.In general, however, the results reveal large discrepancies with the estimated ages of the beds that yielded the bones. Although several causes for the discrepancies are possible, in two or three instances the uranium-series dates themselves appear to be incorrect, and the other dates must be treated with caution.
Strontium Isotopes in some Seamount Basalts from the Northeastern Pacific Ocean
Authors: Subbarao K. V. , Clark G. S. , Forbes R. B.
Published: April 2011

87Sr/86Sr ratios in seven seamount basalts from the northeastern Pacific Ocean range from 0.7022 to 0.7034 and correlate significantly with chemical composition as expressed by the ratio K2O/(K2O + Na2O). These basalts seem to be similar to oceanic island basalts in alkali element concentrations, 87Sr/86Sr and K2O/(K2O + Na2O) ratios suggesting similar mantle source materials, possibly least depleted in dispersed elements. However, in places, seamount basalts also appear to resemble ridge tholeiites. Large differences in 87Sr/86Sr and Rb/Sr ratios for the samples from the Cobb seamount appear to indicate isotopic variations in the source materials, perhaps resulting in the formation of different lava flows within the seamount.
Fault Rotation of Paleomagnetic Directions in Coppermine River Lavas and their Revised Pole
Authors: Baragar W. R. A. , Robertson W. A.
Published: April 2011

The paleomagnetic pole of a segment of lavas from the upper part of the Coppermine River Group is displaced relative to that previously obtained for the lower part of the group by a 28-degree, counter-clockwise rotation. The inclinations are approximately the same. This segment of lavas is separated from the lower part of the group by a fault zone. Elsewhere where the stratigraphic sequence is continuous, sediments and lavas of the upper part of the group give pole positions, which, although scattered, are in large part close to that of the lower part of the group. Hence, the displaced pole can reasonably be attributed to local rotation along a fault rather than to apparent polar wandering. Recognition of the tectonic rotation of the paleomagnetic pole leads to an interpretation of the faulting in the Coppermine River flows as rift faulting closely following extrusion of the lavas.New Coppermine River pole positions are calculated combining the data previously obtained from the lower part of the Coppermine River Group with that from lavas (4 sites) and sediments (5 sites) from the upper part of the group. The new Coppermine River pole from the lavas is at 02N, 180E and from lavas and sediments combined is at 03N, 182E (dp = 3, dm = 6). The latter is the pole recommended for use. That this is a Coppermine River pole rather than a Mackenzie pole is emphasized with the thought that the various elements of the Mackenzie magmatic events may ultimately resolve into a succession of discrete episodes.
Pole Positions from the Mamainse Point Lavas and their Bearing on a Keweenawan Pole Path and Polarity Sequence
Authors: Robertson W. A.
Published: April 2011

Thermal and alternating field studies of the remanent magnetization of the Mamainse Point lavas, on the east shore of Lake Superior, indicate stable magnetization. The flows form two groups of normally magnetized (N) flows, each overlying reversely magnetized (R) flows. It is suggested that the sequence consists of a single sequence of R flows overlain by N flows, the sequence being repeated by faulting. A mean pole position calculated from 15 N sites is 30 °N, 183 °E, (dp = 5, dm = 8), and the pole position from 12 R sites is 49 °N, 232 °E (dp = 14, dm = 16). Reasons are given for believing that this difference in pole position between the older (R) and younger (N) flows was caused by relative movement of the Keweenawan area and the rotation axis of the earth, and not to secondary components of magnetization acquired since the rocks cooled. Review of the Keweenawan paleomagnetic data reveals a consistent picture of an older reversely magnetized and younger normally magnetized magnetic field (if allowance is made for radiogenic errors). The time at which the field switched from reversed to normal polarity may provide a valuable time datum traceable in the rocks from continent to continent.
A Seismic Reflection Model of the Crust near Edmonton, Alberta
Authors: Ganley D. C. , Cumming G. L.
Published: April 2011

Reflection profiles shot about 10 km north of the Edmonton seismic observatory (EDM) indicate dips within the crust of 15 to 20° southeast, with a prominent reflecting horizon at 20 km apparently being offset 4 km by a fault. The average velocity in the crust to this horizon is 6.3–6.4 km/s. Deeper reflections tentatively correlated with the "Riel" discontinuity mapped in southern Alberta indicate a velocity in a second layer of 6.5 km/s to a depth of 32 km, with the base of the crust being essentially horizontal at 35.5 km. The lowermost portion of the crust appears to be significantly thinner here than in southern Alberta, although the general features of the seismic records appear similar in both locations.Velocities are determined by a modified version of the velocity spectrum technique, which does not require common depth point data.
Taphonomy and Taxonomy of the Early Ordovician Gastropod Ceratopea canadensis (Billings), 1865
Authors: Yochelson Ellis L. , Copeland M. J.
Published: April 2011

Several hundred silicified specimens of Pleurotomaria canadensis Billings, 1865 and other rare fossils indicative of a late Canadian age have been collected from the Oxford Formation, southwest of Ottawa, Ontario. Redescription of this neglected gastropod species permits its assignment to the genus Ceratopea, even though no ceratopean opercula have been found.Rare faunal elements include ribeirioids and open coiled gastropods that may have lived, respectively, in and on a mud bottom. There is no evidence that they have been transported. It is suggested that Ceratopea canadensis lived on algal mats some distance away from the shore and from where it is now found. After death, the soft parts of this gastropod decayed and the heavy operculum rotted off. The lightened shell, filled with gas, floated shoreward, likely under conditions of relatively calm water. Discovery of opercula within the Oxford Formation would provide evidence to support this hypothesis.
Magnetic and Paleomagnetic Studies of the Nipissing Diabase, Lake Matinenda Area, Ontario
Authors: Patel J. P. , Palmer H. C.
Published: April 2011

Samples of the Nipissing diabase were collected for rock-magnetic and paleomagnetic studies around and west of Lake Matinenda, Ontario. The specimens have been classified into three groups, based on their stability of natural remanent magnetism, using the alternating field demagnetization technique.Opaque petrological studies showed that the specimens which possessed magnetite–ilmenite exsolution were magnetically very stable. The specimens without any exsolution possessed weak and unstable magnetization.Sphene was identified in the alteration product of ilmenite using X-ray techniques. Curie point measurements indicated low titanium content in the specimens which contained exsolution of ilmenite in magnetite.The pole position, calculated from five significant sites located around and west of Lake Matinenda is 69.9 °W, 15.6 °S (A95 = 6.1°).
Markov Chain and Substitutability Analysis of a Turbidite Succession, Cloridorme Formation (Middle Ordovician), Gaspé, Quebec
Authors: Doveton John H. , Skipper Keith
Published: April 2011

Numerical analyses were made of the sequential ordering of divisions within the turbidite succession of the β1 Member, Cloridorme Formation, logged at the type section at Grand Étang in the Gaspé Peninsula, Quebec. The sequence is satisfactorily described by a first order Markov chain model, whose transition structure includes and corresponds in part to a Bouma model of sedimentation. Additional second order Markov modifications differentiate two types of parallel-laminated division associated with high (a minority) and ?low flow regimes (the majority). Substitutability analysis reinforces many of the genetic interpretations based on the Markov model. The results of autocorrelation and correlation of logarithmically transformed division thicknesses suggest the deposition of successive turbidites as essentially discrete events and the operation of two different depositional mechanisms within the history of at least two types of turbidite unit. However, there appears to be a positive association between successive basal clastic division thicknesses, possibly indicating a longer term control in the budgeting of coarse sediment available for deposition. The succession is characterized by three types of unit with distinctive internal division thickness relationships, lithology and associated bedforms.
Galena-Bearing Pyrite Nodules in the Nelway Formation, Salmo, British Columbia
Authors: Mills Joseph W.
Published: April 2011

Pyrite nodules composed of radiating elongate pyrite crystals and including some galena are found in the sparry dolomite matrix of a dolomite breccia within the middle Cambrian Nelway Formation, Salmo map-area, British Columbia.Similar textures, mineralogy, host rock, and stratigraphic position for the nodules and some pyritic zinc-lead ores in northeastern Washington are taken to indicate a common lineage. Favored is an hypothesis calling for the formation of solution-collapse breccias and their filling by dolomite and sulfides precipitated from low temperature solutions. Later deformation and metamorphism erased or concealed the record of these early events in many of the ore deposits.
Certain Aspects of Magnetic Studies of Charnockites at Waltair, India—Field Investigations
Authors: Aravamadhu P. S.
Published: April 2011

A detailed magnetic survey conducted in the Waltair area indicated that the charnockite rocks are more magnetic than the country rocks, khondalites and leptynites. The magnetic data suggest the possible occurrence of some unexposed charnockites. Some inferences regarding the depth of occurrence, width, and the direction of magnetization of the causative bodies have been drawn.
Rain and Snow Gauge Comparisons
Authors: Harris R. E. , Carder A. C.
Published: April 2011

The performance of four types of rain gauges and three methods of measuring snow-fall were compared over a 10 year period. Under the conditions of the test the United States Weather Bureau's (now National Weather Service, NOAA) standard precipitation gauge proved most reliable for measuring rain at all intensities, whereas the Meteorological Service of Canada's (now Atmospheric Environment Service of Canada) Nipher gauge was superior to other snow gauges for measuring snowfall.The Atmospheric Environment Service of Canada's standard rain gauge sometimes seriously undercaught in times of intense rain. Wind velocity did not seem to be the cause, but rather the intensity of the rain itself.Under blizzard conditions both the snow board and the United States National Weather Service's Alter shielded gauge proved unsuitable for measuring snowfall.
The Geological–Structural Types of Granitoids
Authors: Zaridze G. M.
Published: April 2011

The existence of five natural geological structural types of granitoids is argued: (1) early orogenic (early folding or intrageanticlinal); (2) late orogenic, including granitoids of block-mountain areas; (3) tele-early orogenic; (4) tele-late orogenic; and (5) cratogenic.The early orogenic granitoids are formed during an early stage of folding (early orogenic stage) in relation to first uplifts (intrageanticlines) in an (eu) geosynclinal trough. The late orogenic granitoids also originate in the orogenic areas, but during a late stage of folding (orogenic stage), when intense fault-block movements occur and folded mountain systems are formed. The tele-early orogenic granitoids appear beyond the limits of a geosyncline, within the early consolidated geosynclinal frame, and are simultaneous to the first type granitoids. The tele-late orogenic granitoids occur in the same area, but are formed simultaneously to the second type granitoids. The cratogenic granitoids originate on platforms and shields and are not related either in time or in space to the granitoids of folded areas.
A Method for the Evaluation of Vertical Crustal Movement from Scattered Geodetic Relevellings
Authors: Vaníček P. , Christodulidis D.
Published: April 2011

The existing techniques for the quantitative evaluation of vertical crustal movements from geodetic spirit levelling have one common feature. They can deal only with a complete network of systematically relevelled connected lines. This paper presents a method, based on the least-squares fitting of a velocity surface, capable of using scattered as well as connected relevelled segments. A facility to choose a specific level of statistical significance of the results is built in. The performance of the method is tested on data for the vicinity of Chesapeake Bay. The results compare well with those of the U.S. National Geodetic Survey.
Ischyrhiza (Chondrichthyes: Pristidae) from the Upper Cretaceous Foremost Formation (Campanian) of Alberta
Authors: Storer John E. , Johnson Hope
Published: April 2011

Rostral teeth from the Foremost Formation are referred to Ischyrhiza mira mira, and comparisons are made with species of Ischyrhiza. This is the first record of ganopristine sawfish for Alberta and for Canada.
Quench Plagioclase from some Archean Basalts
Authors: Pearce T. H.
Published: April 2011

Quench plagioclase has been recognized in well preserved Archean submarine basalts from four localities in the superior province of the Canadian Shield. The crystals are skeletal in form with hollow cross sections and swallow tail terminations. In some cases the microphenocrysts are zoned. The widespread occurrence of quench plagioclase suggests that this feature was rather common in Archean basalts, but it is only locally preserved.
Investigations of Groundwater Flow Systems in Big Creek and Big Otter Creek Drainage Basins, Ontario
Authors: Novakovic Blagoje , Farvolden R.N.
Published: April 2011

Big Creek and Big Otter Creek are two small streams that drain southward into Lake Erie. Five hydrostratigraphic units can be defined in the glacial deposits. The upper permeable zone of the carbonate bedrock is regarded as the sixth. This latter zone is considered to be a continuous hydrostratigraphic unit because of the pattern of potential distribution.In these near-surface materials there are only two orders of flow systems—local and intermediate—with no evidence for regional flow toward Lake Erie. Recharge and discharge zones have been recognized both from potential distribution and field observations. Finite element analyses were used to verify the flow patterns in several sections.The pinch-out of aquifers accounts for anomalous locations of discharge zones (flowing wells) as shown in the theoretical models of Freeze and Witherspoon (1967).Most water-level data were obtained from drillers reports of domestic wells in the bedrock. The water-levels in such wells provide a close approximation of the hydraulic potentials in the aquifer. Of 331 such water wells, only three had reported water levels that were anomalous according to the potentiometric map of the bedrock aquifer unit. On the other hand, data from seventeen carefully installed piezometers confirmed the interpretation of potential distribution and thus the pattern of groundwater flow systems.
Network Geometry of Veins in Polycrystalline Ice
Authors: Langham E. J.
Published: April 2011

Polycrystalline ice contains a three-dimensional network of water filled veins, whose size is a function of temperature among other parameters. In order to study heat transfer to and from these veins, a model of their arrangement around a crystal is necessary. The geometrical constraints of this arrangement are discussed and a model is proposed. This is compared to various other models, including that used by Frank (1968) for convection in the earth's mantle.
Deglaciation of Port Hood Island, Nova Scotia
Authors: Terasmae J.
Published: April 2011

A palynological study and radiocarbon dating of surficial deposits on Port Hood Island, Nova Scotia, have indicated that deglaciation occurred more than 11 000 yr B.P., and that the presence of an 'upper till' in local depressions is attributable to soil-creep processes under cold and wet climatic conditions some 11 000 to 10 000 yr B.P. No evidence was found of an ice advance younger than 11 000 yr B.P. in western Cape Breton Island.
Uraloporella Korde in the Devonian of Alberta
Authors: Riding Robert , Jansa L. F.
Published: April 2011

The first record of Uraloporella variabilis Korde outside the Carboniferous of Eurasia is made from the Givetian–Frasnian of Alberta, Canada. This problematic tubiform calcareous microfossil occurs in the subsurface Swan Hills Formation of west-central Alberta and in the Cairn Formation exposed in the Rocky Mountains of southwest Alberta. It is always fragmentary and occurs in shelf–shoal facies of the interior of carbonate platforms, usually in peloid packstones and wackestones associated with calcispheres and dendroid stromatoporoids. Locally it is very common. The specimens differ from the original diagnosis by exhibiting septa and rare branching. The presence of septa is confirmed in the type material from Russia and the genus is amended accordingly. A dasycladacean affinity is excluded and the assumed algal nature of the genus is questioned.
Pattern Recognition and Geochemical Data: An Application to Monteregian Hills
Authors: Dagbert Michel , David Michel
Published: April 2011

The development of rapid and efficient methods of chemical analysis of major and minor elements in rocks has given rise to the production of large sets of data constituting a comprehensive 'picture' of the chemical composition of a rock unit or a rock group in a given area.The complex structure of this multidimensional picture is globally analyzed by 'correspondence analysis' as an interpretative method of pattern recognition. Significative trends of variation are determined and expressed in geological terms. Density distribution of representative points in the factor space is evaluated in search of homogeneous substructures inside the global one. The resulting 'natural clustering' is compared to an a priori partitioning of the structure on the basis of petrographic criteria.The whole analysis is performed by a computer program that can accommodate some 600 samples measured on more than 20 variables. The analysis of a chemical picture of the Monteregian petrographic province is given to illustrate the method.
Evidence for Recent Deformation in the Montreal Area
Authors: Saull V. A. , Williams D. A.
Published: April 2011

Pop-ups (elongated domes) in quarries at Terrebonne and St. Eustache near Montreal suggest that the region is in nearly east-west compression. Wrench faulting on pre-existing normal faults could be an important response to this stress, as it was to similar stress during the late Paleozoic, and this concept may therefore be important in assessing earthquake hazard in the region.
Lower Huronian Sandstones; Correlation Problems and Uranium; Morin Township Area, Ontario
Authors: Chandler F. W.
Published: April 2011

Huronian feldspathic sandstones 30 km north of Thessalon (the Morin Township area) rest noncomformably upon Archean rocks and are overlain by the Huronian Gowganda Formation. They contain uraniferous pyritic quartz-pebble orthoconglomerate, similar to the uraniferous conglomerate ore of the Elliot Lake – Blind River area. The sandstones also contain paraconglomerate units at several stratigraphic levels which are lithologically similar to the Ramsay Lake and Bruce Formations.Trends in Huronian stratigraphy on the North Shore of Lake Huron suggest that in the Morin Township area the Quirke Lake Group is absent and the McKim and Pecors Formations, which contain much argillite, are likely to be very thin or absent. Thus the feldspathic sandstones of the Morin Township area are assigned to the Matinenda and the Mississagi Formations. The most continuous paraconglomerate unit might be correlated with the Ramsay Lake Formation.Huronian feldspathic sandstones lying nonconformably upon Archean rocks 16 km northeast of Sault Ste Marie (the 'Soo Series') and 50 km north of Sudbury, have many features in common with the sequence of the Morin Township area. Stratigraphic subdivision of these two sequences and finer delimitation of potential uraniferous units may be aided by using paraconglomerates such as the Ramsay Lake Formation as marker units. Such subdivision however will be uncertain until the number, exact stratigraphic position and the areal continuity of these paraconglomerates can be assessed better.
A Comparison of the Thermal Characters of Shields
Authors: Rao R. U. M. , Jessop Alan M.
Published: April 2011

The heat flow and heat generation from Precambrian areas has been examined with reference to the concept of heat-flow provinces. In nonshield areas of exposed Precambrian rocks, the heat flow is governed by Phanerozoic tectonic events, rather than by the age of the exposed rock. A plot of heat flow against heat generation of all data from shields yields a heat-flow intercept of 0.7 HFU, compared with 0.8 HFU for the Eastern U.S.A. Even within the stable Precambrian shields, heat flow is more closely related to rock type than to age of the rocks. The analysis supports the linear relation of heat flow to heat generation in shield areas.
The Leopold Formation: An Upper Silurian Intertidal/Supratidal Carbonate Succession on Northeastern Somerset Island, Arctic Canada
Authors: Jones Brian , Dixon Owen A.
Published: April 2011

The name Leopold Formation is proposed for a thick and distinctive Upper Silurian stratigraphic succession, approximately 1000 ft (305 m) thick, on northeastern Somerset Island. This new formation consists largely of dolomitic rocks which formed in tidal flat environments analogous to those around the modern Persian Gulf. Dolostone, dolomitic limestone, sandy limestone, sandy dolostone and rocks containing mixtures of micritic calcite, dolomite and detrital material are predominant, and are associated with minor amounts of sandstone, evaporites and micritic, shelly, intraclastic and oncolitic limestone. Most of the dolomite is secondary and complex facies patterns in the formation reflect initial complexity in sediment distribution that was accentuated by irregular but extensive diagenetic dolomitization of the tidal flat sediments.The distribution of the intertidal/supratidal rocks and the nature of the immature detrital materials they contain are strong evidence of an important, but previously unrecognized, contemporaneous land mass north and northeast of Somerset Island.The formation contains a markedly restricted in situ fauna of eurypterids, ostracods, gastropods, ostracoderms and rare brachiopods. Stromatolites are common and some stromatolitic units are sufficiently distinctive and laterally persistent to be used for local correlation.Conodonts and other faunal elements indicate that the Leopold Formation is of Pridolian age (Upper Silurian). It correlates with the upper part of the Read Bay Formation to the west and northwest, a succession which, in contrast, consists predominantly of subtidal marine limestones.
Longshore Current Generation by Internal Waves in the Strait of Georgia
Authors: Thomson Richard E.
Published: April 2011

Presented in this paper is a derivation of the longshore current generated by breaking lowest mode internal waves in a two layer fluid of slowly shallowing depth, with emphasis on the nearshore region of the Fraser River delta in the Strait of Georgia. It is proposed that such a current, having a maximum speed of order 104/μv cm3/s2 (equal to 102 cm/s for reasonable vertical eddy viscosities, μv, of 102 cm2/s) and a width of order kilometers based on measured water properties and internal wave characteristics in the Strait, is responsible for the persistent northward flow observed to be associated with the delta in summer. Accordingly, it is suggested that the longshore current would have important implications to sedimentation rates and pollutant dispersal in the delta area, with greatest effects possibly occurring in summer and fall when the stratification in the Strait of Georgia is most pronounced.
Sudbury Basin Sediments and the Meteoritic Impact Theory of Origin for the Sudbury Structure
Authors: Beales F. W. , Lozej G. P.
Published: April 2011

The Whitewater Group preserved within the Sudbury Basin structure conforms to a logical succession of beds to be expected for sediments accumulated in a large impact-generated crater. The lowest beds of the Group, the lower Onaping Formation, represent impact-generated breccia and fall-back material, the upper Onaping Formation and the overlying Onwatin Slates represent the restricted crater series, while the succeeding Chelmsford Sandstone represents an open marine turbidite sequence. The turbidites swept across the area at a time when the crater rim was no longer influencing sea bottom current circulation. The apparent anomaly of the occurrence of sediments deposited in an extensive marine environment and presently only found within the Sudbury Basin is attributed to preferential preservation, due to compaction-generated subsidence over the crater and impact-fractured area.
Tectonic Results from Paleomagnetism of the Aphebian Nipissing Diabase at Gowganda, Ontario
Authors: Symons D. T. A. , Londry J. W.
Published: April 2011

A total of 30 sites (150 cores, 300 specimens) of the 2165 ± ~25 m.y. Nipissing diabase were collected from around the Miller Lake basin at Gowganda. After alternating field demagnetization a stable primary remanence was isolated at 10 sites of which eight were reversely polarized. A fold test shows that the basinal structure is primary at the 95% confidence level. The pole position of 106°W, 14°S (P0.05:9°, 14°) is statistically indistinguishable from previous Nipissing poles from the Cobalt and Elliot Lake areas. The evident conclusion is that the Superior and Southern geologic provinces have not undergone significant relative tectonic translation or rotation in the last 2165 m.y. Combining the remanence directions from the 37 available reliable sites of Nipissing diabase, they give a highly reliable pole position of 94.1°W, 14.5°S (P0.05:5.7°, 8.8°) for Nipissing time on the polar wander curve for these two provinces of the Canadian Precambrian Shield. Only four of the 37 sites are normally polarized suggesting that the Nipissing event reflects a dominantly reversed paleofield.
Pyrite Concretions in Sediment from South Bay, Lake Huron
Authors: Dell C. I.
Published: April 2011

Sand-size concretions composed of aggregates of pyrite spherules are associated with organic matter in a postglacial lacustrine clay from South Bay, Lake Huron. These concretions resemble pyrite described in the literature, however, the origin of the characteristic framboidal form remains uncertain. Although it is a rare mineral in Great Lakes sediments, pyrite may have formed in this clay because of the presence of sufficient sulphur, possibly derived from sulphate-bearing ground water.
Anhydrite Replacements of Gypsum (Satin-Spar) Veins in the Mississippian Caprocks of Southeastern Saskatchewan
Authors: Kendall A. C.
Published: April 2011

Sheets of anhydrite, up to 5 cm thick, occur abundantly in southeastern Saskatchewan within dolomitized Mississippian carbonates where these are unconformably overlain by Watrous red beds. The sheets are interpreted as former gypsum veins that have lost structural water as a result of later burial. Replacement by anhydrite was accompanied by no loss of volume and the fibrous vein structure of the former gypsum is partially mimicked by the anhydrite.Gypsum veining is believed to have occurred as a result of the migration of calcium sulphate-rich brines through the Mississippian carbonates after the deposition of the Watrous red beds.