bluuebunny/crossref_metadata_2025 huggingface dataset:
Heat flow in the Maritime Provinces of Canada
Authors: Hyndman R. D. , Jessop A. M. , Judge A. S. , Rankin D. S.
Published: April 2011

Heat-flow values have been obtained at six new sites in Nova Scotia and New Brunswick. These values and six previously reported for Maritime Canada range from 45 to 79 mW m−2 (1.07 to 1.89 μcal cm−2 s−1) after correction for Pleistocene glaciation. The mean 62 ± 3 mW m−2 (1.48 ± 0.06 μcal cm−2 s−1) after a glacial correction and 54 ± 3 mW m−2 (1.29 ± 0.06 μcal cm−2 s−1) without the correction are in general agreement with the average for Paleozoic orogenic belts. High heat flows in New Brunswick are probably associated with acidic or felsic volcanics with high radioactive heat production. Low heat-flow values are associated with the deep Carboniferous sedimentary basin of Prince Edward Island and northwestern Nova Scotia. Probably the region was uplifted and the surface crystalline rocks with high radioactive heat production were eroded prior to Carboniferous time. During subsequent slow subsidence, low heat production sediments were deposited in the resulting basin. High heat flows in Nova Scotia are associated with the Devonian granites and the older Meguma sediments and metasediments, which have high radioactive heat production. The heat-flow data from Nova Scotia, together with estimates of the radioactive heat production of basement rocks, are consistent with the heat-flow–heat-production relations for the eastern United States, the Canadian Shield, and for other stable areas. The temperature at the base of the crust at 35 km depth is estimated to average about 750 °C.
Notes on pachycephalosaurid dinosaurs (Reptilia: Ornithischia) from North America, with comments on their status as ornithopods
Authors: Wall William P. , Galton Peter M.
Published: April 2011

Several biologically significant domes of pachycephalosaurid dinosaurs are described and figured. One unusual specimen from the Oldman Formation (Upper Cretaceous) of Alberta is placed into a new genus and another specimen from the same formation is assigned to a new species of Stegoceras. Domes referable to Stegoceras sp. (Judith River and Hell Creek Formations) are the first conclusive evidence of the presence of this genus in the United States. A large dome from the Oldman Formation of Alberta is referred to Pachycephalosaurus; this specimen is the oldest described to date and is the first record of this genus in Canada.Endocranial casts of Yaverlandia bitholus and Stegoceras validus are described along with a discussion of endocranial trends in pachycephalosaurids. The separation between the cerebrum and cerebellum found in Yaverlandia, and typical of ornithopods in general, is lacking in Stegoceras and Pachycephalosaurus. The loss of this separation may be the result of head butting.The family Pachycephalosauridae possesses sufficient ornithopod characters to justify their retention in that suborder. It does, however, represent an aberrant side branch of ornithopod evolution, which can best be visualized taxonomically by placing this family into a separate infraorder within the Ornithopoda.
The effects of surface mining of coal on water quality near Grande Cache, Alberta
Authors: Hackbarth Douglas A.
Published: April 2011

Streams and springs in and near surface coal mines located on the eastern slopes of the Canadian Rocky Mountains were sampled between 1972 and 1978. Streams unaffected by mining activity characteristically have calcium, magnesium, and bicarbonate as the dominant ions. Total dissolved solids concentration usually ranges between 125 and 231 mg/L. Sulfate is usually about 20% of the anions and has a concentration less than 75 mg/L. Relative amounts of sodium, potassium, chloride, and nitrate usually are less than 6% of the ions. Values of pH commonly range between 7.6 and 8.2.The effects of mining activity on water quality vary in intensity but follow a consistent pattern. The relative proportion of the various cations does not change; however, their concentrations may rise to four times background values. The concentration of anions also increases and there is a shift in the relative proportions from bicarbonate to sulfate and, at the more strongly affected sites, to nitrate. The distribution of pH values is not significantly different from unaffected sites.Enhanced oxidation of sulfide minerals, which account for less than about 0.07% of the loose, unsaturated spoil piles, probably is responsible for the increase in sulfate ions. The hydrogen ion produced during the oxidation of the sulfide minerals is consumed in the dissolution of the abundant carbonate minerals thus releasing calcium and magnesium. Elevated nitrate concentrations result from the use of ammonium nitrate for blasting.The estimated chemical denudation rate at sites unaffected by mining activity ranges from 4–18 mg/(s∙ha), while at affected sites it varies from 4–55 mg/(s∙ha).
The aeromagnetic mineralogy of igneous rocks
Authors: Haggerty Stephen E.
Published: April 2011

Magnetic minerals in igneous rocks are dominated by phases in the system FeO–Fe2O3–TiO2 and the system Fe–Ni–S. Complex solid solutions within both systems yield divergent magnetic signatures, which are dependent on primary mineralogy, on deuteric cooling, and on post-depositional alteration of the host rock. Intrinsic parameters such as temperature, oxygen fugacity, and sulfur fugacity, have effective buffering capacities, which influence the ratios Fe2+:Fe3+; (Fe2+ + Fe3+):Ti; Fe:S; and (Fe + Ni):S. These ratios are highly sensitive to environmental conditions and correlate with magnetic property measurements. In addition, bulk chemistry plays a major role, and for igneous rocks a striking pattern emerges in which oxygen fugacity is related to SiO2 (i.e., from basic to acid suites) regardless of total pressure. Acidic suites (granites and rhyolites) are more highly oxidized than basic suites (gabbros and basalts); hence. ulvöspinel (Fe2TiO4)-rich and ilmenite (FeTiO3)-rich constituents are characteristic of the latter, whereas magnetite (Fe3O4)-rich and hematite (αFe2O3)-rich components are typical of the former as primary precipitated oxides. Deep-seated equilibration results in exsolution and in low-intensity states of oxidation, and this is in contrast to extrusive suites in which intense states of high temperature oxidation are prevalent. Olivine decomposition in extrusive rocks, and the formation of magnetite solid-solution members in plagioclase and pyroxene in plutonic rocks, yield single domain particles, which in some instances are the dominant magnetic carriers. Sulfide minerals are rare in continental extrusive suites, are more abundant in oceanic basalts and in hypabyssal minor intrusives, and peak in plutonic environments.Within the context of deep crustal magnetic anomalies, and in the determination of Curie isotherms, it is proposed that the primary and secondary mineralogy of plutonic ultramafic rocks be carefully re-evaluated based on current models of serpentinization. Metallic iron and metal alloys of Fe–Ni–Co–Cu are widely recognized in these rock types, and because these minerals have elevated Curie temperatures (620–1100 °C) the depth detection limits of aeromagnetic anomalies need not be constrained by the accepted value of 580 °C, the Curie temperature of magnetite.
Paleocurrents and depositional environments of deep water conglomerates in the Cambro-Ordovician Cap Enragé Formation, Quebec Appalachians
Authors: Johnson Barry A. , Walker Roger G.
Published: April 2011

The Cap Enragé conglomerates are deep water, resedimented types associated with pebbly and massive sandstones. They resemble other deep water conglomerates in Quebec, especially those at Lévis-Lauzon, L'Islet Wharf, and Grosses Roches. All of these conglomerates were derived from a carbonate shelf to the northwest, and flow directions at Lévis and L'Islet are dominantly southward. By contrast, flow directions at Grosses Roches are to the west and southwest, suggesting deflection of conglomeratic flows by a topographic obstruction.In the Cap Enragé, only published flow directions from sandstones suggest flow toward south and southeast. One published conglomeratic flow direction indicates southwestward flow. Our paleoflow work on the entire outcrop length of the Cap Enragé conglomerates demonstrates dominantly westward and southwestward flow, reinforcing the idea of a topographic obstruction deflecting flows.We have demonstrated some consistent horizontally-fining facies relationships in the conglomerates. Beginning with massive, coarse cobble–boulder conglomerates, there are horizontal passages into finer conglomerates with crude stratification shown up by rows of cobbles and then pebbles, and finally into well stratified coarse sandstones with layers of granules and pebbles. Compared with local flow directions, these horizontally-fining relationships occur in upstream, downstream, and lateral directions.We suggest that southeastward, downslope-flowing currents were forced to swing southwestward by an obstruction, and hence the entire Cap Enragé Formation was deposited in a broad depression or channel trending parallel to the base of slope. Within this overall interpretation, we suggest that the conglomerate members of the Cap Enragé were deposited in meandering talweg channels, similar to those of the modern La Jolla submarine fan channel. Upstream-, downstream-, and laterally-fining facies sequences may be related to the filling of large scours within the talweg, or to facies changes from the talweg to adjacent terraces.
The nature, origin, and significance of the Carmanville ophiolitic mélange, northeastern Newfoundland
Authors: Pajari G. E. , Pickerill R. K. , Currie K. L.
Published: April 2011

The Carmanville ophiolitic mélange of northeastern Newfoundland forms an olistostrome within a thick succession of Middle to Upper Ordovician flyschoid shale, siltstone, and grey-wacke. The olistostrome consists of sedimentary, volcanic, and ultramafic olistoliths ranging in size from granules to several kilometres. The matrix appears to have been derived entirely by disaggregation and disintegration of hydroplastic and thixotropic sediments. The matrix was sufficiently fluid for turbulent motion to occur in the lower parts of the olistostrome, yet viscous enough to produce alignment of fragments and a pervasive cleavage, as well as drag folds in the surrounding hydroplastic sediments. The olistoliths have been drawn from a stratigraphic column hundreds, if not thousands, of metres thick, and an area many kilometres across. A small proportion of the olistoliths were deformed and metamorphosed prior to incorporation in the olistostrome.The Carmanville ophiolitic mélange is tentatively correlated with the Dunnage mélange to define the northern margin of a sheet of ocean floor and island arc obducted toward the southeast onto an accreting continental rise in Llanvirnian–Llandeilian time. Olistostrome formation within this unstable pile commenced in post-Arenigian time, and may have continued intermittently until Llandoverian time. The olistostrome and surrounding rocks were further deformed, metamorphosed, and intruded by granitoid plutons during Silurian and Devonian time.
An occurrence of Lower Carboniferous fish remains from Alberta, Canada
Authors: McKenzie M. A. , Bamber E. W.
Published: April 2011

Late Tournaisian? teeth and spines of the chondrichthyan genera Orodus, Helodus, Deltodus, Leiodus, Petalorhynchus, and ?Polyrhizodus are illustrated. The nature of the assemblage and the host limestone (Livingstone Formation, southwestern Alberta) indicates a predominance of durophagous, bottom living chondrichthyans, feeding on hard-shelled invertebrates in a shallow marine, high energy, carbonate bank environment.
Storm-dominated shallow marine deposits: the Fernie–Kootenay (Jurassic) transition, southern Rocky Mountains
Authors: Hamblin Anthony P. , Walker Roger G.
Published: April 2011

The transition from the Passage Beds of the Fernie into the lowermost part of the Kootenay Formation is exposed in 11 sections in the Crowsnest Pass to Banff area. Six distinct facies can be defined. Facies A (thin bedded turbidites) and facies B (thicker bedded turbidites) both have sole marks indicating north-northwestward flow. Facies C is the most important and consists of interbedded sandstones and shales, with sole marks indicating north-northwestward flow, and "hummocky cross stratification" as the characteristic internal sedimentary structure. It is interpreted to be formed by storm waves in depths below fair-weather wave base. Facies D contains low angle intersecting sets of parallel lamination (beach) and facies E is characterized by trough cross bedding (fluvial). Facies F consists of lenticular sandstones and shales, with coals. The facies occur in the sequence listed and indicate a northward prograding beach complex. Following intense storms, water driven toward the beach surges back seaward, entraining sand and developing into a density current. If deposition from the density current takes place in depths stirred by the storm waves, hummocky cross stratification is formed. In slightly deeper, quieter water the density current deposits a classical turbidite. Thus, the eastward-prograding Kootenay "delta" of previous interpretations now appears to be a northward-prograding beach complex fed by rivers, but with sand transported alongshore by waves. There is no evidence of tidal current activity, and shallow marine deposition is dominated by storms.
Defining a paleomagnetic polarity pattern in the Monteregian intrusives
Authors: Foster J. , Symons D. T. A.
Published: April 2011

Oka and nearby small plutons on the western end of the Monteregian Hills were sampled for paleomagnetic study at 43 sites (569 specimens). Every specimen was AF step demagnetized in 4 kA/m increments to 20 or 24 kA/m. Consistent remanence directions were found for 36 sites (452 specimens). Use of a stability index to select only those specimens with the best defined end points does not improve the site statistics. The Oka, Brilund, Carillon, and Ile Cadieux plutons have statistically similar mean remanence direction populations which are different from the Ste. Dorothée sill direction. Except for one Carillon site, all site mean directions are normally polarized, whereas all nine plutons, except for Mt. Johnson, from the middle and eastern end of the Monteregian Hills are reversely polarized. Normally and reversely polarized plutons give statistically similar but antiparallel pole positions, giving a combined pole position of 169.0°W, 72.4°N (δp = 2.8°, δm = 3.7°), which is consistent with the 120 ± 4 Ma radiometric age. The polarity pattern evidence suggests that Oka and adjacent plutons were emplaced rapidly during one normal polarity interval, and that the Monteregian Hills plutons were emplaced progressively from west to east during two normal and two reversed polarity intervals lasting ~ 2 Ma. This leads to some speculations on the plume and rift modes of emplacement.
Shock-diminished paleomagnetic remanence at the Charlevoix impact structure, Quebec
Authors: Robertson P. Blyth , Roy J. L.
Published: April 2011

The magnetic characteristics of shocked and unshocked anorthosites of the Charlevoix impact structure have been reexamined to assess the effects of high thermal and alternating field (af) cleaning treatments, and to evaluate any shock-induced features of the remanence in terms of mineralogy of the shocked rocks.From 16 sites, 197 specimens were subjected to stepwise thermal treatments to 710 °C, and a further 46 to incremental af cleaning to 290 mT. The 10 sites from the unshocked St-Urbain anorthosite carry a magnetization with unblocking temperatures (TUB) generally between 600–625 °C, with a significant fraction of remanence with TUB > 670 °C. Similarly, most of the remanence has a resistive coercive force (rcf) of 100–175 mT, with a significant fraction exceeding 290 mT. The remanence is carried by two exsolution phases of titano-hematite, with the later and more hematite-rich lamellae having the higher TUB and rcf. Although only one direction exists, at two sites where intensities are somewhat lower and some natural remanent magnetization (NRM) directions scattered, treatment reveals a dual polarity remanence. The pole (154°E, 02°S) obtained from these unshocked St-Urbain anorthosite sites falls on a well established segment of the late Precambrian apparent polar path of suitable age (≈950 Ma). Significant results could not be obtained from three additional sites in the marginal zone due to their ready acquisition of a viscous magnetization following thermal treatments.Data from two sites which display no shock effects and lie near the margin of the central uplift, and from one highly shocked sample from the crater centre show some possible effects of the shock event. All three have intensities substantially lower than in the St-Urbain sites, which is interpreted in the case of at least one of these sites as a shock-diminished remanence. A puzzling feature of the highly shocked samples is that the phase with a texture reminiscent of the ilmenite–hematite exsolution in the unshocked anorthosites, contains no iron. The remaining remanence, whose direction is parallel with that of the unshocked sites, is interpreted as pre-crater rather than shock-produced. Although many instances have been reported of a new shock-induced remanence imparted to rocks of equivalent and even lesser shock grade than those examined at Charlevoix, in all cases the magnetic carrier seems to have been magnetite. The lack of a shock-induced remanence at Charlevoix is attributed to the high TUB and rcf of hematite in these rocks.
The dynamothermal aureole of the Bay of Islands ophiolite suite
Authors: Malpas John
Published: April 2011

The Bay of Islands ophiolite suite was displaced from an oceanic environment and emplaced upon the continental margin of Eastern North America during Early to Middle Ordovician times. The displacement tectonics produced a dynamothermal aureole that is found at the stratigraphic base of each ophiolite thrust slice. Structural and chemical studies of the aureole rocks indicate that they were produced by polyphase deformation of tuffaceous sediments and volcanic rocks under conditions of relatively high heat flux. Calculations show that this heat could not all have been produced by friction, but that the overriding ophiolite slab must have been hot. High geothermal gradients necessary to satisfy such a model are to be expected only in certain oceanic environments.
New geophysical evidence for sea-floor spreading in central Baffin Bay
Authors: Jackson H. R. , Keen C. E. , Falconer R. K. H. , Appleton K. P.
Published: April 2011

Geophysical data collected during a detailed survey in Baffin Bay have shown that lineated magnetic anomalies trending north-northwest occupy the deep central region. These anomalies exhibit maximum amplitudes of about 300 nT and can be modelled by a 1-km thick magnetic source layer divided into blocks of normal and reversed polarity. The magnetizations required are comparable with those of oceanic basalts. A striking feature of the gravity field is a 20 mGal gravity low, about 20 km wide, which runs through the centre of the bay with approximately the same trend as the magnetic lineations. The gravity low is associated with a change in crustal structure measured from seismic refraction data and sometimes with a deepening of the sediment-basement interface, reminiscent of a median valley. These results suggest that the magnetic anomalies were produced by sea-floor spreading and that the gravity low marks an extinct spreading centre in Baffin Bay. Comparisons of the magnetic anomaly profiles with a model profile computed for magnetic anomalies 13–24 (38 to 60 Ma), show good correlation between the observed and computed anomalies in the time period represented by anomalies 13–21, with slow spreading rates of about 0.3–0.4 cm yr−1 perpendicular to the spreading axis. These results are in reasonable agreement with magnetic anomaly identifications and spreading rates deduced from geophysical data in the Labrador Sea. The direction of plate motion in Baffin Bay is not well defined from the data, but the Labrador Sea data require plate motions at a highly oblique angle to the spreading centre in the bay. Peculiarities of the postulated spreading centre, including the change in crustal structure beneath the gravity low along its strike from south to north, and the decrease in coherence and amplitude of the magnetic anomalies immediately north of the survey area, may be the result of these very low spreading rates, oblique spreading and changes in spreading direction, or the proximity of this area to the junction with a possible major transform fault through the Nares Strait.
Trace metal speciation in the Yamaska and St. François Rivers (Quebec)
Authors: Tessier A. , Campbell P. G. C. , Bisson M.
Published: April 2011

Water and suspended sediment samples were collected at 12 stations on the Yamaska and St. François Rivers, located in southeastern Quebec, and were analyzed for the trace metals Cd, Co, Cu, Ni, Pb, Zn, Fe, and Mn. The suspended sediment samples were subjected to a sequential extraction procedure designed to partition the particulate trace metals into five fractions: (1) exchangeable; (2) bound to carbonates; (3) bound to Fe–Mn oxides; (4) bound to organic matter; and (5) residual.Although suspended sediment levels as well as total soluble and particulate trace metal concentrations were highly variable in time and space, speciation patterns for each metal proved reasonably constant. Very small proportions of all metals, except Cd and Mn, were found in the exchangeable fraction, whereas high levels of all metals were present in the residual fraction; Fe–Mn oxides and organic matter constituted important transport phases for most metals. Deviations from this general behaviour were occasioned by man-induced perturbations (e.g., inputs of municipal sewage or mine waste water). At stations influenced by such factors, total particulate metal concentrations increased and the relative contribution of the residual fraction decreased. The trace metal content of fraction 3 proved to be particularly sensitive to anthropogenic inputs; other phases acting as trace metal sinks included those liberated in fractions 1 (Cd, Cu, Ni, Zn), 2(Cu, Ni, Zn), and 4(Cu, Ni).
Interprétation géodynamique du domaine pan-africain (Précambrien terminal) de l'Anti-Atlas (Maroc) à partir de données géologiques et géochronologiques
Authors: Leblanc M. , Lancelot J. R.
Published: April 2011

U–Pb and Rb–Sr ages performed in the Anti-Atlas (Morocco), especially in Bou Azzer area, demonstrate a Pan-African orogeny (680–570 Ma), along the northern margin of the West African craton (2000 Ma). Geological and geochronological data allow the reconstitution of a coherent succession of events of Pan-African ages. The geodynamic evolution of this domain comprises a stage of oceanic opening (ophiolites) followed with a stage of closure: obduction of the ophiolites on the craton, then subduction under an active continental margin. This segment of the Pan-African belt can be correlated with the other parts of the belt, located on the eastern margin of the West African craton.
Possible Early Paleozoic coral, Intermontane Belt, south-central British Columbia
Authors: Nelson Samuel J.
Published: April 2011

A possible organic structure resembling a halysitid coral was found in the Chapperon Group of south-central British Columbia, a unit generally considered of Late Paleozoic age. If it is such a coral, then it would be the oldest fossil so far found in the eugeosynclinal rocks of the Canadian Western Cordillera and could imply an Early Paleozoic eugeosyncline.
Upper Triassic salt deposits of the western North Atlantic
Authors: Jansa L. F. , Bujak J. P. , Williams G. L.
Published: April 2011

The Amoco–Imp–Skelly Osprey H-84 well, located in the Carson Subbasin on the eastern Grand Banks of Newfoundland, penetrated 2054 m of evaporites consisting almost exclusively of halite. These are dated palynologically as Carnian–Norian to Hettangian–Sinemurian and establish the occurrence of Upper Triassic evaporites on the western side of the North Atlantic. A lateral-fractionation model is proposed to explain the progressive decrease in less soluble evaporitic minerals west of the western periphery of Tethys. According to this model, slow and intermittent encroachment of the sea into the developing intracontinental graben system occurred after initial rifting. This encroachment took place in a hot and arid climatic zone and led to the brines becoming progressively depleted in less soluble salts towards the distal margins of the basin system. The similarity in composition of the Upper Triassic evaporitic sequences on the Grand Banks and in the Lusitanian Basin indicates that the two areas were close at this time. This would preclude major rotation of the Iberian Peninsula and the presence of a cratonic arch between the Iberian Peninsula and Grand Banks.
Devonian corals of late Eifelian age from the Ogilvie Formation of Yukon Territory
Authors: Pedder A. E. H.
Published: April 2011

Coral faunas from 254.9–345.4 m above the base of the type section of the Ogilvie Formation on Mount Burgess, and from parts of other Ogilvie sections, are shown to be equivalent to late Eifelian coral faunas of the Hume Formation of western District of Mackenzie, and its correlatives in southwestern District of Mackenzie and northeastern British Columbia. Although older faunas from lower beds and younger faunas from higher beds of the Ogilvie Formation have been described previously, this is the first description of Hume faunas from the formation.The Redstoneainae, a new subfamily of the Spongophyllidae, is proposed. Two new genera, Tawuphyllum and Gaynaphyllum, and a new species, Radiastraea norrisi, are also established.Photographic illustrations of interiors of Iteophyllum virgatum Crickmay, Endophyllum barbatum Crickmay, the lectotype of Smithia verrilli Meek, and neotype of Spongophyllum sedgwicki Edwards and Haime are published for the first time.
Trondhjemitic basement enclave near the Archean Favourable Lake volcanic complex, northwestern Ontario, Canada
Authors: Hillary E. M. , Ayres L. D.
Published: April 2011

A 15 km2 foliated to gneissic trondhjemite enclave (2.91 Ga) in the Archean North Trout Lake batholith is a metamorphosed remnant of prevolcanism sialic basement. The basement is separated from the nearby Archean Favourable Lake volcanic complex by younger plutons, but was a source of detritus for some of the sedimentary formations in the volcanic complex. The trondhjemite is only a small remnant of an originally more extensive basement.Primary plutonic features can be readily recognized in the trondhjemite in spite of amphibolite facies metamorphism. The basement underwent at least two deformational events: (1) syn-emplacement deformation that produced foliation and gneissosity, and brecciated and deformed early dikes and xenoliths and (2) later recrystallization. The recrystallization was caused by strain and heat produced by emplacement of the North Trout Lake batholith. Emplacement of successive batholith phases progressively heated the basement and elevated it from its originally deeper level. Metamorphism culminated with emplacement of the youngest major phase of the batholith. The intensity of recrystallization and the habit and abundance of late leucocratic quartz monzonite sills and dikes are zoned with respect to this youngest phase.The high Al2O3 trondhjemitic magma probably formed by partial melting of amphibolite at relatively shallow depths. The parent amphibolite probably represents a still earlier volcanic event.
Polycylindrichnus: possible Silurian tunicate burrows from southern Ontario
Authors: Fournier Judith A. , Pemberton S. George , Risk Michael J.
Published: April 2011

Several specimens of a new trace fossil, Polycylindrichnus prolifer, n. gen., n. sp., have been collected from the Middle Silurian Thorold Formation in Hamilton, Ontario. Traces are multiple burrows, originating from a common source at depth, budding into several cylindrical to conical, subhorizontal burrows. Burrow openings lie on a common bedding plane. Traces are tentatively attributed to the activities of infaunal tunicates.
The Rb/Sr geochronology of the Archean Chibougamau pluton, Quebec
Authors: Brooks C.
Published: April 2011

The U–Pb zircon age for the Chibougamau pluton is some 200 Ma older than the published Rb–Sr total-rock age. However, application of sample rejection techniques based on petrography, volatile content, and major-element chemistry to published and new Rb–Sr data, permits a selection of less altered total-rock samples which define an age in close agreement with the zircon age. These data suggest that the Chibougamau pluton crystallized with a uniform initial-Sr ratio equivalent to values for the surrounding metavolcanics and by inference Earth's mantle at 2.7 Ga.
Labrador Sea bio-, tephro-, oxygen isotopic stratigraphy and Late Quaternary paleoceanographic trends
Authors: Fillon R. H. , Duplessy J. C.
Published: April 2011

A stratigraphic framework for eastern Labrador Sea cores has been developed for the interval 0–90 000 years BP through analysis of oxygen isotopes, volcanic ash, benthonic foraminifera, and the radiolarian Diplocyclas davisiana. Benthonic and planktonic foraminiferal isotope stratigraphy and the time scale of Shackleton and Opdyke provide a basis for the approximate dating of a series of marker events which include ash zones at ca. 59 000 and ≤ 21 000 years BP; benthonic foraminiferal abundance maxima at ca. 83 000, 75 000, 60 000, 19 000, and 3000 years BP; and D. davisiana percentage maxima at ca. 90 000, 73 000, 64 000, 54 000, 45 000 – 32 000, and 10 000 years BP. Incursions of subpolar planktonic foraminifera into the area during parts of isotopic stage 2 (between about 13 000 and 25 000 years BP but probably excluding the 15 000–18 000 years BP glacial maximum interval) and during the isotopic stage 4/5a transition (around 75 000 years BP) suggest that the eastern Labrador Sea was free of sea ice, at least in summer during periods of rapid continental ice sheet growth which lead to the isotopic stage 4 and stage 2 glacial maxima. A larger than normal stage 1/stage 2 difference in the isotopic composition of benthonic foraminifera (1.8‰) implies that this open water and attendant surface cooling was a potential source for colder than modern deep water. In contrast the Norwegian Sea was a reservoir of warmer than modern deep water during the last glacial.
Comportement de quelques elements en traces au cours de l'anatexie: exemple du Massif de Saint-Malo (Bretagne, France)
Authors: Martin Hervé
Published: April 2011

The Saint Malo massif presents a continuous metamorphic series from gneiss to greenschist facies to anatectic granites; in addition, it shows evidence of all stages of progressive melting. A modal and geochemical study shows that incongruent melting of biotite according to the reaction[Formula: see text]plays a major role during anatexis. The distribution of trace elements between the liquid and residual solid states is closely bound to the melting of this mineral phase.Analytical results are compared to the results forecast from a theoretical model of sequential melting at equilibrium. With the exception of strontium, there is good agreement between the theory and the analytical data, which confirms the fundamental role played by the biotite.Rb proceeds normally in the liquid during the melting of biotite; Cr, Ni, and V, on the other hand, take refuge in the cordierite, whereas Co, which is not plentiful in the biotite, is not influenced by the destruction of the latter. In contrast, Sr shows a different behavior from that predicted from the mathematical models. This seems to be due to a mass separation of the liquid during the initial stages of the anatectic process. The liquid, which is injected into the adjacent nonmobilized gneiss, is rich in Sr and Co and poor in Rb, Cr, Ni, and V. This results in a relative impoverishment of the residual solid, in Sr and a little in Co (not predicted from the theoretical models). [Translated by the Journal]
Phillipsite altered to analcime in basal Windsor [shallow-water marine] carbonates of Mississippian age in Nova Scotia
Authors: Bitter Peter H. von , Plint-Geberl Hilary A.
Published: April 2011

Phillipsite crystals altered to analcime are reported for the first time in ancient shallow-water marine carbonates (Lower Windsor Group, Cape Breton Island, Nova Scotia, Canada).
Eolian coastal dune deposits and surrounding marine sandstones, Rocky Mountain Supergroup (Lower Pennsylvanian), southeastern British Columbia
Authors: Stewart W. Douglas , Walker Roger G.
Published: April 2011

The Pennsylvanian Rocky Mountain Supergroup, in the Elk Range, B.C., includes three sandstone formations: Tyrwhitt (about 100 m thick), Storelk (about 95 m), and Tobermory (about 75). The Tyrwhitt consists mostly of structureless sandstones which prove to be bioturbated in X radiographs. There is an abundant trace fauna, as well as brachiopods. The second most abundant facies consists of medium scale (up to about 1 m) cross-bedded sandstones. The Tobermory is essentially similar to the Tyrwhitt but contains fewer structureless sandstones, and more beds with ripple cross-lamination and horizontal lamination. Both formations were probably deposited slowly in water deeper than fair-weather wave base (deeper than 10–15 m).The Storelk, sandwiched between Tyrwhitt and Tobermory, is dominated by large scale (up to 10.5 m) sets of cross-bedding. These occur in three members, separated by two structureless members. The Storelk structureless members are not mottled in X radiographs, and no trace fauna was found in the field. There is only one 1 m thick fossiliferous bed within the Storelk, which is otherwise barren of trace or body fossils. We reject fluvial and marine sandwave interpretations of the large scale cross-bedding, and suggest that the Storelk represents a coastal eolian dune complex. Paleoflow directions are dominantly toward south-southwest, similar to Pennsylvanian paleowind directions in the western United States. The Storelk structureless members possibly represent sand blown into standing bodies of water, one of which was connected to the open sea (the fossiliferous bed).
Phanerozoic flysch trace fossil diversity—observations based on an Ordovician flysch ichnofauna from the Aroostook–Matapedia Carbonate Belt of northern New Brunswick
Authors: Pickerill R. K.
Published: April 2011

An Ordovician flysch trace fossil assemblage from the Aroostook–Matapedia Carbonate Belt, northern New Brunswick, consists of the following identifiable ichnogenera: Alcyonidiopsis, Asteriacites, Asterosoma, Belorhaphe, Bifasciculus, Buthotrephis, Chondrites, Cochlichnus, Cosmorhaphe, Diplichnites, Fucusopsis, Glockeria, Gyrochorte, Helminthoida, Helminthopsis, Neonereites, Paleodictyon, Planolites, Protopaleodictyon, Scalarituba, Spirodesmos, Spirorhaphe, and Taenidium. The stratigraphic range of six ichnogenera, viz. Glockeria, Gyrochorte, Helminthoida, Spirodesmos, Spirorhaphe, and Taenidium, is, therefore, now extended to rocks of Ordovician age.The diversity exhibited by the assemblage is inconsistent with currently proposed models of Phanerozoic flysch trace fossil diversity. It is suggested that existing models suffer from an inadequacy of sampling and systematic effort per period of geological time, as reflected by the limited number of post-Cambrian/pre-Cretaceous, particularly post-Carboniferous/pre-Cretaceous, adequately documented flysch ichnoassemblages. The assemblage described here clearly illustrates a significant radiation of deep-sea behavioural diversity in the Ordovician. This is possibly related to the development during the Ordovician of a sufficient oxygen concentration and supply of organic detritus in the deep sea or colonization of deeper-water habitats concomitant with the significant diversification of Ordovician shelf benthic communities.
Heavy minerals and sedimentological studies on the glaciogenic Late Precambrian Gaskiers Formation of Newfoundland
Authors: Gravenor C. P.
Published: April 2011

The heavy minerals found in diamictites and intrastratal sandstone and siltstone rhythmites of the Late Precambrian Gaskiers Formation of Newfoundland are dominated by altered pyroxenes and amphiboles with lesser amounts of garnet and zircon and trace amounts of tourmaline and rutile. The garnets are angular, fresh in appearance, and about 9% of the garnets have glacially derived chattermark trails. This observation, along with the presence of striated and facetted clasts, suggest that at some time prior to final deposition, the diamictites underwent transport in glaciers which were of ice cap or ice sheet dimensions.
An inverted Archean succession at Rainy Lake, Ontario
Authors: Poulsen K. Howard , Borradaile Graham J. , Kehlenbeck Manfred M.
Published: April 2011

Interpretation of new structural data, particularly application of the concept of structural facing, demonstrates that part of the Archean sequence at Rainy Lake was structurally over-turned prior to the development of dominant (F2) folds. This structural revision indicates that, here, Coutchiching metasediments are younger than Keewatin volcanic rocks. Fold-nappe or thrust-nappe tectonics may have been responsible for the pre-F2 inversion of the stratigraphic sequence.
Mammals from the Upper Cretaceous Oldman Formation, Alberta. IV. Meniscoessus Cope (Multituberculata)
Authors: Fox Richard C.
Published: April 2011

New fossils of Meniscoessus major (Cimolomyidae: Multituberculata) are described from the Upper Cretaceous Oldman Formation, Alberta. Associations of P3–4, M1–2, and P4M1 are documented for the first time for this species. M. major, one of the largest known multituberculates in rocks of Judithian age, was probably a direct descendant of M. intermedius, known from the lowermost parts of the Oldman Formation, Alberta. The relationships of M. major to other species of Meniscoessus probably do not include descent from an M. ferox-like ancestor or ancestry of M. robustus-like descendants.
Upper Ordovician (Richmondian) cavity-dwelling (coelobiontic) organisms from southern Ontario
Authors: Kobluk David R.
Published: April 2011

Upper Ordovician (Richmondian) patch reefs in exposures of the Meaford Formation (Streetsville Member) in Mullett Creek, Mississauga, Ontario contain a preserved coelobiontic (cavity-dwelling) biota. This is the first report of Upper Ordovician reef coelobionts.The cavity biota is dominated by algae that grew attached to the roof and walls of cavities. The fauna and flora consist of: (1) algae (including Girvanella, mammillary and laminated algae, micrite pendants, and a Renalcis-like alga); (2) calcareous vermiform tubes; (3) endolithic metazoa (Trypanites); (4) bryozoans; and (5) hemispherical worm tubes. In addition, thin micrite sheets, of possible organic origin, also line the roofs of some cavities.An infauna of burrowing worms, and coelobiontic sponges, which are common in Lower Cambrian and Middle Ordovician reef cavities, is absent from these Upper Ordovician cavities. In comparison, therefore, with older and also modern reef cavity biotas this Upper Ordovician coelobiontic biota is unusual.
Late Quaternary sediments and geomorphic history of north-central Vancouver Island
Authors: Howes D. E.
Published: April 2011

Materials from two glacial and two nonglacial intervals are identified on north-central Vancouver Island, British Columbia. The oldest Pleistocene unit, Muchalat River drift, consists of till and overlying glaciolacustrine silt. It has been tentatively correlated with Dashwood drift of the Semiahmoo Glaciation. An overlying single exposure of mudflow sediment in the Gold River valley contains wood dated at 40 900 ± 2000 years BP within the time span of the Olympia nonglacial interval. The Olympia nonglacial interval was characterized by a period of degradation in which Olympia-age sediments were deposited in transient sedimentary environments and subsequently eroded. Gold River drift includes Gold River advance deposits, Gold River till, and Gold River late glacial deposits, and was deposited during the Fraser Glaciation. The Fraser Glaciation was well underway on north-central Vancouver Island by 25 200 ± 330 years BP. During the Fraser Glaciation maximum, which occurred after 20 600 ± 330 years BP, Coast Mountain ice flowed in a southwesterly direction across north-central Vancouver Island overtopping all but the highest peaks of the Vancouver Island Mountains. Deglaciation commenced prior to 12 930 ± 160 years BP and the ice had probably disappeared before 9500 years ago. During postglacial times rivers have dissected older Quaternary sediments and bedrock up to at least 40 m. Macroflora data recorded in postglacial lacustrine sediments suggest that the Hypsithermal Interval commenced before 8300 ± 70 years BP.
Tectonic significance of the northeastern Gander Zone, Newfoundland: an Acadian ductile shear zone
Authors: Hanmer Simon
Published: April 2011

Penetrative deformation and granite intrusion in the northeastern Gander Zone, Newfoundland, represent a progressive Acadian event. Interference between ductile, strike–slip shearing along the southeastern margin of the Appalachian orogen and the emplacement of syntectonic granite diapirs results in the formation of a vertical, northeast–southwest strike–slip ductile shear zone where granites come to outcrop and a ductile strike–slip thrust zone where granites are absent at the surface. Sinistral movement along the vertical shear zone is compatible with recent palaeomagnetic models for the Appalachians and the British Caledonides. The constraints that the geologic model places on the symmetry of the Appalachian orogen in Newfoundland and the definition and extrapolation of the Gander tectonostratigraphic zone are discussed.
Palynology and paleotemperature analysis of the Whidbey Formation, Puget Lowland, Washington
Authors: Heusser Calvin J. , Heusser Linda E.
Published: April 2011

A series of pollen assemblages and the environments of deposition are shown by samples from 143 levels of interbedded sand, silt, clay, and peaty and woody sediments in sections from the Pleistocene Whidbey Formation at Useless Bay (the type locality), West Beach, Point Wilson, and Foulweather Bluff. Deposition of the formation is interpreted to have taken place over a broad floodplain under fluvial conditions where drainage shifted between and into tracts of paludified ground. Of the four sections studied, only Useless Bay and Point Wilson contain assemblages with analogs found in the modern pollen rain on the floodplains of the Nisqually, Skokomish, and Chehalis Rivers in western Washington, Q-mode factor analysis of pollen percentages in the Whidbey samples extracted Douglas-fir, pine, alder, grass, and sedge as the principals for 93% of the data. Stepwise regression relating modern pollen rain and temperature resulted in a transfer function that, when applied to the principals for the Whidbey, produced mean July temperatures for the intervals represented by the sections. Temperature curves for Useless Bay and Point Wilson show maxima comparable with the modern average of 15.8 °C; maximum values at West Beach and Foulweather Bluff are approximately 2° lower. These curves, when compared with curves from late Quaternary deposits and the "interglacial" Puyallup and Alderton Formations, indicate that sediments belonging to the Whidbey are largely from an interglacial age, comparable to the Holocene or present interglaciation, but also from cooler episodes similar to the late Fraser Glaciation.
Modeling of zero-offset reflection profiles with asymptotic ray theory
Authors: McMechan George A.
Published: April 2011

Synthetic reflection profiles computed by asymptotic ray theory can be used in the interpretation of laterally varying tectonic structures. The algorithm is implemented for normally incident (zero-offset) rays in two-dimensional models that are specified in terms of constant velocity layers separated by piecewise cubic boundaries. Applications include modeling of profiles containing lenses, interbedded high- and low-velocity layers, and oceanic ridges. The method is practical and flexible in the sense that structural, lithologic, drill core, and seismic refraction constraints can be directly combined with the seismic reflection data.
A positive fold test from Nipissing diabase
Authors: Morris W. A.
Published: April 2011

Positive fold tests are reported on two remanence components resolved from the same Nipissing diabase sills. These tests conclusively indicate that the region south of the Sudbury Basin in the Southern Structural Province has been subjected to two distinct deformational episodes subsequent to the intrusion of the Nipissing diabase. One event precedes (1850–2150 Ma) and one event postdates (1250–1850 Ma) intrusion of the Sudbury irruptive. Some evidence also exists for a third event that may be related to the development of the Sudbury structure, around 1850 Ma. Evidence that the Nipissing was intruded into already folded Huronian sediments confirms previous suggestions of four separate orogenic pulses in the period 2300–1250 Ma.
Evidence from lead isotopes regarding the genesis of ore deposits in the Chibougamau region, Quebec
Authors: Thorpe R. I. , Guha Jayanta , Cimon Jules
Published: April 2011

Twenty-three lead isotope analyses are reported for massive sulfide deposits, the main copper–gold shear zone deposits in anorthosite of the Doré Lake complex, and two gold deposits, all in Archean terrane, in the Chibougamau district. Five analyses were also obtained for lead occurrences in Proterozoic carbonate sediments in the Mistassini Basin.Galenas from the Coniagas and Lemoine deposits of volcanogenic massive sulfide type, from the Taché Lake deposit of possibly the same type, from the Norbeau and Ayrhart gold properties, and one from within the Opemiska mine, have Archean compositions. Of these, the Lemoine, Norbeau, and Opemiska mine galenas are slightly younger than the others or were contaminated during later deformation and (or) metamorphism.Analyses for the main Cu–Au deposits generally form a cluster, although the spread in 206Pb/204Pb ratios is significant and three analyses for the Copper Rand deposit, in particular, are distinct from data for the other deposits. One interpretation is that the data, in combination with the Archean analyses, define a secondary isochron reflecting a primary age of Archean deposits and rocks at 2735–2800 Ma and a secondary event, including genesis of the Cu–Au ores, at 2240–2160 Ma. Additional evidence for a metamorphic–plutonic(?) event at about 2200 Ma has been provided by previous paleomagnetic studies. One galena from the Opemiska deposit appears to have had uranogenic lead added at 1735–2075 Ma. Three analyses of galena from the Campbell (Merrill) pit are anomalous or indicate they were formed at 162–300 Ma, and it is suggested they may have resulted from multiple episodic additions of ambient rock lead to galena originally deposited at about 2200 Ma.Two new analyses, together with four older values, for Mistassini Basin lead occurrences define a possible secondary isochron that may indicate an integrated source age of 2655 or 2940 Ma at mineralization ages of 2100 and 1700 Ma, respectively. This secondary isochron is very poorly defined because three other new analyses plot above the line.This study suggests that further geochronological investigation of the Cu–Au orebodies, and of felsic dykes that occur in many cases in close spatial association with them, should be undertaken.
Pleistocene muskox (Ovibos moschatus) from near Saskatoon, Saskatchewan
Authors: Skwarawoolf T. , Millar J. F. V.
Published: April 2011

A partial cranium of Ovibos moschatus, the tundra muskox, was recovered near Saskatoon, Saskatchewan from sand and gravel tentatively identified as part of the Floral Formation. Both lithological and paleontological evidence suggest that the sands and gravels were deposited in a periglacial environment. This occurrence is the first report of tundra muskox from Pleistocene deposits on the Canadian Prairies.