Search

The article critiques the comments made by Landing et al. on their paper, emphasizing that their interpretation of Cambrian strata in the Caledonian Highlands is flawed and lacks scientific support. It also discusses the issues with forced lithostratigraphic frameworks, the inadequate correlation methods used by Landing et al., and the inaccuracies in their data and interpretations regarding the Cambrian geological record.

Copyright of Canadian Journal of Earth Sciences is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

MODerate resolution Imaging Spectroradiometer (MODIS) cryosphere products have been available since 2000 – following the 1999 launch of the Terra MODIS and the 2002 launch of the Aqua MODIS – and include global snow-cover extent (SCE) (swath, daily, and 8 d composites) at 500 m and ∼5 km spatial resolutions. These products are used extensively in hydrological modeling and climate studies. Reprocessing of the complete snow-cover data record, from Collection 5 (C5) to Collection 6 (C6) and Collection 6.1 (C6.1), has provided improvements in the MODIS product suite. Suomi National Polar-orbiting Partnership (S-NPP) Visible Infrared Imaging Radiometer Suite (VIIRS) Collection 1 (C1) snow-cover products at a 375 m spatial resolution have been available since 2011 and are currently being reprocessed for Collection 2 (C2). Both the MODIS C6.1 and the VIIRS C2 products will be available for download from the National Snow and Ice Data Center beginning in early 2020 with the complete time series available in 2020. To address the need for a cloud-reduced or cloud-free daily SCE product for both MODIS and VIIRS, a daily cloud-gap-filled (CGF) snow-cover algorithm was developed for MODIS C6.1 and VIIRS C2 processing. MOD10A1F (Terra) and MYD10A1F (Aqua) are daily, 500 m resolution CGF SCE map products from MODIS. VNP10A1F is the daily, 375 m resolution CGF SCE map product from VIIRS. These CGF products include quality-assurance data such as cloud-persistence statistics showing the age of the observation in each pixel. The objective of this paper is to introduce the new MODIS and VIIRS standard CGF daily SCE products and to provide a preliminary evaluation of uncertainties in the gap-filling methodology so that the products can be used as the basis for a moderate-resolution Earth science data record (ESDR) of SCE. Time series of the MODIS and VIIRS CGF products have been developed and evaluated at selected study sites in the US and southern Canada. Observed differences, although small, are largely attributed to cloud masking and differences in the time of day of image acquisition. A nearly 3-month time-series comparison of Terra MODIS and S-NPP VIIRS CGF snow-cover maps for a large study area covering all or parts of 11 states in the western US and part of southwestern Canada reveals excellent correspondence between the Terra MODIS and S-NPP VIIRS products, with a mean difference of 11 070 km 2 , which is ∼0.45 % of the study area. According to our preliminary validation of the Terra and Aqua MODIS CGF SCE products in the western US study area, we found higher accuracy of the Terra product compared with the Aqua product. The MODIS CGF SCE data record beginning in 2000 has been extended into the VIIRS era, which should last at least through the early 2030s. [ABSTRACT FROM AUTHOR]

Copyright of Canadian Journal of Earth Sciences is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Canadian Journal of Earth Sciences is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Floating Catchment Area (FCA) methods are a popular tool to investigate accessibility to public facilities, in particular health care services. FCA approaches are attractive because, unlike other accessibility measures, they take into account the potential for congestion of facilities. This is done by 1) considering the population within the catchment area of a facility to calculate a variable that measures level of service, and then 2) aggregating the level of service by population centers subject to catchment area constraints. In this paper we discuss an effect of FCA approaches, an artifact that we term demand and level of service inflation. These artifacts are present in previous implementations of FCA methods. We argue that inflation makes interpretation of estimates of accessibility difficult, which has possible deleterious consequences for decision making. Next, we propose a simple and intuitive approach to proportionally allocate demandand and level of service in FCA calculations. The approach is based on a standardization of the impedance matrix, similar to approaches popular in the spatial statistics and econometrics literature. The result is a more intiuitive measure of accessibility that 1) provides a local version of the provider-to-population ratio; and 2) preserves the level of demand and the level of supply in a system. We illustrate the relevant issues with some examples, and then empirically by means of a case study of accessibility to family physicians in the Hamilton Census Metropolitan Area (CMA), in Ontario, Canada. Results indicate that demand and supply inflation/deflation affect the interpretation of accessibility analysis using existing FCA methods, and that the proposed adjustment can lead to more intuitive results. [ABSTRACT FROM AUTHOR]

Freely-available satellite data streams and the ability to process these data on cloud-computing platforms such as Google Earth Engine have made frequent, large-scale landcover mapping at high resolution a real possibility. In this paper we apply these technologies, along with machine learning, to the mapping of peatlands–a landcover class that is critical for preserving biodiversity, helping to address climate change impacts, and providing ecosystem services, e.g., carbon storage–in the Boreal Forest Natural Region of Alberta, Canada. We outline a data-driven, scientific framework that: compiles large amounts of Earth observation data sets (radar, optical, and LiDAR); examines the extracted variables for suitability in peatland modelling; optimizes model parameterization; and finally, predicts peatland occurrence across a large boreal area (397, 958 km2) of Alberta at 10 m spatial resolution (equalling 3.9 billion pixels across Alberta). The resulting peatland occurrence model shows an accuracy of 87% and a kappa statistic of 0.57 when compared to our validation data set. Differentiating peatlands from mineral wetlands achieved an accuracy of 69% and kappa statistic of 0.37. This data-driven approach is applicable at large geopolitical scales (e.g., provincial, national) for wetland and landcover inventories that support long-term, responsible resource management. [ABSTRACT FROM AUTHOR]

The objective of this paper is to fill a gap in the literature on internationalization, in relation to the absence of objective and measurable performance indicators for the process of how firms sequentially enter external markets. To that end, this research develops a quantitative tool for use as a performance indicator of gradualness for firms entering external markets at a sectoral level. The performance indicator is based on firms’ export volumes, number of years operating in the export market, geographic areas targeted for export and when exports began to each area. The indicator is tested empirically in the wine sector. The main contribution of this study is the creation of a reliable international priority index, which can serve more widely as a valuable tool because of its potential use in other industry sectors and geographic areas, and which would allow the analysis of how geographically differentiated internationalization strategies develop. [ABSTRACT FROM AUTHOR]

Readers will be led down a random path from continental dynamics to paleoclimate. A key to understanding continental dynamics is recognizing that differences in gravitational potential energy per unit area between high and low terrain govern much of large-scale continental deformation. Removal of mantle lithosphere, not just crustal thickening, plays a crucial, but difficult-to-test, role in changes in surface elevation. Although measuring past surface heights remains a challenge, indications of such processes suggest that surface uplift associated with such removal can affect relative plate motion. Climate change, from a warmer to cooler climate, and associated changes in erosion and sedimentation introduce further complications to determining past elevations. The phenomena that led to such cooling include a number of possibilities, but I favor the emergence of islands in the Maritime continent, which transformed the Pacific Ocean from one with a warm eastern tropical Pacific, as during El Niño events, to the present-day La Niña–like background state. Teleconnections from the eastern tropical Pacific to Canada affect the duration of summers and the potential of high-latitude ice to accumulate. Lateral gradients in gravitational potential energy per unit area (GPE), a force per unit length, govern large-scale continental dynamics. Removal of mantle lithosphere and thickening of crust raise GPE; knowledge of mean surface elevations provides a test of these processes. Climate change from a warmer to cooler climate and from one with less to more erosion can give the false impression of elevation change. Emergence of Indonesian islands, more rain over them, a stronger Walker Circulation, and cooler eastern Pacific may have led to ice ages. [ABSTRACT FROM AUTHOR]

Copyright of Canadian Journal of Earth Sciences is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The question of what lies ahead is of particular concern for Latin Americanists. The last decade has witnessed a serious erosion of both the popularity of their specialty, and an equally troublesome reduction in employment opportunities. This paper uses Association of American Geographers (AAG) data bases to document the age-gender structure of contemporary Latin Americanist geographers, and projects likely compositional changes through the end of the century. [ABSTRACT FROM AUTHOR]

While climate scientists have developed high resolution data sets on the distribution of climate risks, we still lack comparable data on the local distribution of public climate change opinions. This paper provides the first effort to estimate local climate and energy opinion variability outside the United States. Using a multi-level regression and post-stratification (MRP) approach, we estimate opinion in federal electoral districts and provinces. We demonstrate that a majority of the Canadian public consistently believes that climate change is happening. Belief in climate change’s causes varies geographically, with more people attributing it to human activity in urban as opposed to rural areas. Most prominently, we find majority support for carbon cap and trade policy in every province and district. By contrast, support for carbon taxation is more heterogeneous. Compared to the distribution of US climate opinions, Canadians believe climate change is happening at higher levels. This new opinion data set will support climate policy analysis and climate policy decision making at national, provincial and local levels. [ABSTRACT FROM AUTHOR]

Presents a reply to the comment given by I. Brookes to the article "Late Wisconsinan stratigraphy and chronology of southern St. George's Bay, Newfoundland: a re-appraisal," by Trevor Bell, David G.E. Liverman, Martin J. Batterson and Kevin Sheppard, which appeared in the 2001 issue of the 'Canadian Journal of Earth Sciences." Disagreements in field observations and interpretations; Discussion of a complex sedimentary sequences of interbedded diamicton, gravel and mud above the basal till; Discounting the significance of a date given to a diamicton at Highlands.

This paper describes the development of cybercartography since the introduction of the term in 1997. Although the origins of cybercartography were largely conceptual in nature, the evolution of cybercartography to date has been an iterative process reflecting the creative interplay between theory and practice. A major step forward was made in 2002 when the Geomatics and Cartographic Research Centre at Carleton University received a $2.5 million grant from the Social Sciences and Humanities Research Council of Canada to explore the utility of cybercartography to what was described as the New Economy. By 2006, the interaction between theory and practice had led to considerable advances in cybercartography as a holistic, location-based concept and two new cybercartographic products, the Cybercartographic Atlas of Antarctica and the Cybercartographic Atlas of Canada's Trade with the World, were produced. Between 2006 and 2009, cybercartography was further developed as a result of interaction with indigenous communities, especially in Canada's north and new interactive atlases such as the Kitikmeot Place Names Atlas and the Community Atlas of Arctic Bay were created in cooperation with the communities involved. The Nunaliit Cybercartographic Atlas Framework, built using open source software and open specifications and standards, was developed to facilitate direct input to these atlases. Cybercartography is now entering a new phase in both theory and practice building on a recently completed prototype atlas of Indigenous Perspectives and Knowledge. [ABSTRACT FROM AUTHOR]

Copyright of Canadian Geographer is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Canadian Journal of Earth Sciences is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Introduces a series of articles featured in the special issue of the "Canadian Journal of Earth Sciences." Discussion of articles on the final compendium of papers on the Alberta Basement Transect of Lithoprobe.

Geological maps are powerful models for visualizing the complex distribution of rock types through space and time. However, the descriptive information that forms the basis for a preferred map interpretation is typically stored in geological map databases as unstructured text data that are difficult to use in practice. Herein we apply natural language processing (NLP) to geoscientific text data from Canada, the U.S., and Australia to address that knowledge gap. First, rock descriptions, geological ages, lithostratigraphic and lithodemic information, and other long-form text data are translated to numerical vectors, i.e., a word embedding, using a geoscience language model. Network analysis of word associations, nearest neighbors, and principal component analysis are then used to extract meaningful semantic relationships between rock types. We further demonstrate using simple Naive Bayes classifiers and the area under receiver operating characteristics plots (AUC) how word vectors can be used to: (1) predict the locations of "pegmatitic" (AUC = 0.962) and "alkalic" (AUC = 0.938) rocks; (2) predict mineral potential for Mississippi-Valley-type (AUC = 0.868) and clastic-dominated (AUC = 0.809) Zn-Pb deposits; and (3) search geoscientific text data for analogues of the giant Mount Isa clastic-dominated Zn-Pb deposit using the cosine similarities between word vectors. This form of semantic search is a promising NLP approach for assessing mineral potential with limited training data. Overall, the results highlight how geoscience language models and NLP can be used to extract new knowledge from unstructured text data and reduce the mineral exploration search space for critical raw materials. [ABSTRACT FROM AUTHOR]

There is a paucity of data on the reason for and the quantity of antimicrobials used in broiler chickens in Canada. To address this, the Canadian Integrated Program for Antimicrobial Resistance Surveillance (CIPARS) implemented surveillance of antimicrobial use (AMU) and antimicrobial resistance (AMR) in broiler chicken flocks in 2013. Shortly after this (2014), the poultry industry banned the preventive use of ceftiofur in broiler chickens. The objectives of this analysis were to describe antimicrobial use (AMU) in Canadian broiler chickens between 2013 and 2015 (n = 378 flocks), compare these results to other animal species in Canada, to highlight the utility of farm surveillance data to evaluate the impact of a policy change, and to explore how different antimicrobial use metrics might affect data interpretation and communication. The surveillance data indicated that the poultry industry policy resulted in lower antimicrobial use and resistance, and they successfully captured information on when, where, why, and how much antimicrobials were being used. The majority of antimicrobials were administered via the feed (95%). The relative frequency of antimicrobial classes used in broiler chickens differed from those used in swine or in food animal production in general. Coccidiostats were the most frequently used antimicrobial classes (53% of total kg). Excluding coccidiostats, the top three most frequently used antimicrobial classes were bacitracin (53% of flocks), virginiamycin (25%) and avilamycin (21%), mainly used for the prevention of necrotic enteritis. Depending on the AMU metric utilized, the relative rankings of the top antimicrobials changed; hence the choice of the AMU metric is an important consideration for any AMU reporting. When using milligrams/Population Correction Unit (mg/PCU) the top three antimicrobial classes used were bacitracins (76 mg/PCU), trimethoprim-sulfonamides (24 mg/PCU), and penicillins (15 mg/PCU), whereas when using a number of Defined Daily Doses in animals using Canadian standards /1,000 chicken-days at risk (nDDDvetCA/1,000 CD) the ranking was bacitracins (223 nDDDvetCA/1,000 CD), streptogramins (118 nDDDvetCA/1,000 CD), and trimethoprim-sulfonamides (87 nDDDvetCA/1,000 CD). The median animal treatment days in feed for one cycle (ATD/cycle) during the three-year study were 34 ATD/cycle; this was equal to the mean age of the flocks at pre-harvest sampling day (days at risk), indicating that the studied flocks except those that were raised without antibiotics and organic, were fed with medicated rations throughout the observation period. Overall, more than half (59%) of antimicrobials used in broiler chickens were in classes not used in human medicine, such as ionophores and chemical coccidiostats aimed to prevent coccidiosis. Compared to grower-finisher pigs and in production animal species (national sales data), the mg/PCU of antimicrobials used in broiler chickens was relatively lower. The findings of this paper highlighted the importance of farm-level AMU surveillance in measuring the impact of interventions to reduce antimicrobials in poultry. [ABSTRACT FROM AUTHOR]

John Tuzo Wilson (1908-1993) was one of the greatest Canadian scientists of the 20th century. His contributions to Earth Sciences, leading the formulation of the theory of plate tectonics, have revolutionized our understanding of how the planet Earth works and evolved over the past 4 billion years. This 50th anniversary special issue of the Canadian Journal of Earth Sciences is dedicated in honour of John Tuzo Wilson, who inspired tens of thousands of students all around the world to study the Earth. This special issue contains 12 papers dealing with various aspects of the 'Wilson Cycle' in the geologic record, plate tectonics, mantle plumes, and how John Tuzo Wilson accepted 'continental drift' and formulated the theory of plate tectonics. The contributions have mostly been made by geoscientists who directly or indirectly associated with John Tuzo Wilson and have contributed significantly to the plate tectonics paradigm. [ABSTRACT FROM AUTHOR]

Copyright of Canadian Journal of Earth Sciences is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Canadian Journal of Earth Sciences is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Many rock avalanches entrain and liquefy saturated soil from their paths. Evidence for this includes mud displaced from the margins of rock avalanche deposits, substrate material smeared along the base of deposits, extrusion of liquefied soil upward through the deposits, and increases of volume. A hypothesis first suggested in 1881 and since reinforced by several authors suggests that entrainment of substrate material increases mobility. Although the process has been discussed in the literature for more than 100 years, few detailed and quantitative descriptions exist. The main purpose of this paper is to describe two recent cases from British Columbia, Canada, where rockslides entrained substrate on a very large scale, influencing the character of the events. Estimated volume balance curves, based on detailed field mapping, are provided for both cases. Dynamic analyses are carried out using a numerical model and using the same set of rheological parameters. The mechanism of material entrainment and displacement is discussed. The data suggest that rapid rock failures entraining very large quantities of saturated substrate material represent a special type of landslide, transitional between rock avalanche and debris avalanche. Many rock avalanches can thus be seen as end members of a continuum of phenomena involving rock failure followed by interaction with saturated substrate. [ABSTRACT FROM AUTHOR]

The Marron Volcanics of South-Central British Columbia are host to a suite of zeolites and other minerals, the most significant of which are brewsterite-Sr and wakefieldite-(Ce). Tschernich ([28]) states that according to the nomenclature established by the IMA in Coombs et al. ([10]), and analysis information given to Tschernich in conversations with Wise, heulandite from "Yellow Lake" should be labeled heulandite-Ca. Tschernich ([26]) describes one exceptional vein 50 meters long and 0.5-2 cm wide in which one side was primarily covered with colorless brewsterite with calcite crystals and brown, acicular goethite; on the opposite side were grown proportionally equal amounts of "Sr-bearing heulandite", brewsterite, and calcite crystals. The Yellow Lake occurrence is the third recorded for the wakefieldite subgroup of minerals, after Wakefield, Quebec [wakefieldite-(Y)] and the Kusu mine, Democratic Republic of Congo [Pb-bearing wakefieldite-(Ce), formerly I kusuite i ]. [Extracted from the article]

Utilizing a combination of conodont-based biostratigraphy and geochemistry, the Frasnian–Famennian (F/F, mid-Late Devonian) boundary was located in the Long Rapids Formation, northern Ontario. It is present in a black shale sequence, 21.46 m above the base of the Long Rapids Formation, just above a carbonate bed that has similarities to the Upper Kellwasser Limestone, recognized as a lithological marker for the F/F boundary in Germany, Belgium, and France. There is no evidence of an impact event, and sedimentation across the boundary is continuous, although there is a discontinuity layer just below the boundary and the early part of the linguiformis Zone (of the standard Late Devonian conodont zonation) is missing. Strong positive δ [sup 13] C (organic and carbonate) values were identified and are interpreted as evidence of mass mortality in anoxic waters at the F/F extinction; positive δ[sup 18] O values suggest the extinction was also accompanied by a temperature drop. Negative δ[sup 34] S values also indicate anoxia, and negative δ[sup 15] N values provide evidence of reduced surface-water productivity. No iridium anomaly was found at the boundary, although higher than usual values were found about 85 cm below the F/F boundary. Sedimentological and biological evidence in the Long Rapids Formation indicates that the F/F extinction was coincident with major sea-level fluctuations in the late Frasnian, including a transgression beginning at the end of the linguiformis Zone and continuing through the Early triangularis Zone and beyond. Marine oscillations were accompanied by anoxia, which appears to be the killing mechanism for the conodont and other end Frasnian extinctions.La limite Frasnien–Famennien (F/F, Dévonien tardif moyen) a été localisée dans la Formation de Long Rapids, au nord de l'Ontario, en utilisant une combinaison de géochimie et de biostratigraphie basée sur les conodontes. Elle se trouve dans une séquence de shale noir, environ 21,46 m au-dessus de la base de la Formation de Long Rapids, juste au-dessus d'un lit de calcaire qui ressemble en bien des points au calcaire Kellwasser supérieur, lequel est reconnu comme un horizon repère lithologique pour la limite F/F en Allemagne, en Belgique et en France. Il n'y a pas d'évidence d'un événement d'impact et la sédimentation est continue à travers la limite, bien qu'il y ait une couche de discontinuité tout juste en dessous de la limite et que la partie précoce de la Zone à linguiformis (de la zonation standard pour les conodontes au Dévonien tardif) soit absente. Des valeurs fortement positives δ[sup 13] C (matières organiques et carbonates) ont été identifiées et elles sont interprétées comme évidence d'une mortalité de masse dans des eaux anoxiques à l'extinction F/F; des valeurs δ[sup 18] O positives portent à croire que l'extinction était accompagnée d'une chute de température. Des valeurs δ[sup 34] S négatives indiquent aussi l'anoxie et des valeurs δ[sup 15] N négatives fournissent des évidences de productivité réduite à la surface de l'eau. Aucune anomalie d'iridium n'a été trouvée à la limite, bien que des valeurs plus élevées que d'habitude aient été trouvées à environ 85 cm sous la limite F/F. Des évidences sédimentologiques et biologiques dans la Formation de Long Rapids indiquent que l'extinction F/F a coïncidé avec de grandes fluctuations du niveau de la mer au Frasnien tardif, incluant une transgression qui a débuté à la fin de la Zone à linguiformis et qui s'est poursuivie à travers et au-delà de la Zone à triangularis précoce. Les oscillations marines étaient accompagnées d'anoxie ce qui semble être le mécanisme qui ait tué les conodontes et celui responsable d'autres extinctions à la fin du Frasnien. [Traduit par la Rédaction] [ABSTRACT FROM AUTHOR]

The presence of Watinoceras reesidei Warren, Watinoceras coloradoense (Henderson), Watinoceras thompsonense Cobban, and Mytiloides mytiloides (Mantell) within the Tuskoola sandstone beds of the Vimy Member of the Kaskapau (Blackstone) Formation, places these strata within the lower Turonian stage of the Upper Cretaceous, within the Watinoceras reesidei Zone. International discoveries of Watinoceras in the United States, the Arctic, west Africa, northern Africa, Europe, and Asia, in the past fifty years has allowed the authors, while updating the stratigraphy and taxonomy, to refine correlation of the Tuskoola sandstone, a sandy facies of the "Second White Specks" horizon of Western Canada.La présence de Watinoceras reesidei Warren, Watinoceras coloradoense (Henderson), Watinoceras thompsonense Cobban et Mytiloides mytiloides (Mantell) dans les lits de grès de Tuskoola du membre Vimy de la Formation de Kaskapau (Blackstone), place ces strates à l'étage Turonien inférieur du Crétacé supérieur, à l'intérieur de la zone à Watinoceras reesidei. Des découvertes internationales de Watinoceras aux États-Unis, dans l'Arctique, en Afrique occidentale, en Afrique du Nord, en Europe et en Asie au cours des cinquante dernières années ont permis aux auteurs, tout en mettant à jour la stratigraphie et la taxonomie, de préciser la corrélation du grès de Tuskoola, un faciès gréseux de l'horizon « Second White Specks » de l'Ouest du Canada.[Traduit par la Rédaction] [ABSTRACT FROM AUTHOR]

A new model for evolution of the Archean Hopedale Block, based on mapping and supporting U–Pb geochronological and geochemical studies, is highlighted by (i) ca. 3.25 Ga emplacement of igneous precursors of Maggo Gneiss; (ii) &gt3.1 Ga, high-grade Hopedalian metamorphism and attendant deformation; (iii) emplacement of the Hopedale mafic dykes; (iv) 3.1 Ga deposition of Hunt River volcanic rocks; (v) ca. 3.0 Ga deposition of Florence Lake volcanic rocks; (vi) 2.88–2.96 Ga, greenschist- to amphibolite-facies Fiordian metamorphism and formation of penetrative, northeast-striking Fiordian structures; and (vii) emplacement of a suite of 2.89–2.83 Ga tonalite to granite intrusions, which partially overlap and locally postdate Fiordian metamorphism and deformation. The Hunt River and Florence Lake volcanic sequences are different in age but similar in most other respects. The former consists mainly of amphibolite-facies mafic metavolcanic rocks and lesser amounts of komatiite flows and metasedimentary and 3105 ± 3 Ma felsic volcanic rocks. The Florence Lake volcanic belt consists mainly of greenschist- to amphibolite-facies mafic metavolcanic rocks, lesser amounts of felsic metavolcanic rocks, dated at 2979 ± 1 and 2990 ± 2 Ma, komatiite flows, and rare metasedimentary rocks. The similarity of rock types, field relationships between different rock types, such as the common association of ultramafic and felsic metavolcanic rocks, and the chemistry of volcanic rocks in both belts suggest a common tectonic setting for each belt. A model involving episodic volcanism, separated by 100 Ma, in ensialic basins is consistent with the dominance of tholeiitic basalt and an abundance of pre-volcanic basement.Un nouveau modèle pour l'évolution du bloc Hopedale (Archéen), basé sur la cartographie et supportant les études sur la géochronologie et la géochimie U–Pb, est mis en évidence par (i) la mise en place vers 3,25 Ga des précurseurs ignés du gneiss Maggo, (ii) le métamorphisme élevé de Hopedale, vers 3,1 Ga, et la déformation qui l'accompagne (iii) la mise en place des dykes mafiques Hopedale, (iv) la déposition à 3,1 Ga des roches volcaniques de Hunt River, (v) la déposition vers 3,0 Ga des roches volcaniques de Florence Lake, (vi) le métamorphisme fiordien, du faciès de schistes verts au faciès des amphibolites, et la formation de structures fiordiennes pénétrantes et de direction nord-est, de 2,88 à 2,96 Ga et (vii) la mise en place d'une suite d'intrusions de tonalite à granite, 2,89 à 2,83 Ga; ces intrusions recouvrent en partie le métamorphisme et la déformation fioridiens et, par endroits, elles leur sont plus tardives. Les séquences volcaniques de Hunt River et de Florence Lake sont d'âges différents mais elles sont similaires selon la plupart des autres aspects. La séquence de Hunt River consiste surtout en roches volcaniques mafiques au faciès des amphibolites avec moins de coulées komatiitiques, des roches métasédimentaires et des roches volcaniques âgées de 3105 ± 3 Ma. La ceinture volcanique de Florence Lake comprend surtout des roches métavolcaniques mafiques du faciès des schistes verts au faciès des amphibolites et des quantités moindres de roches métavolcaniques felsiques âgées de 2979 ± 1 et 2990 ± 2 Ma, des coulées komatiitiques et de rares roches métasédimentaires. La similitude des types de roches, les relations de terrain entre les divers types de roches, telles que l'association fréquente des roches métavolcaniques ultramafiques et felsiques, ainsi que la chimie des roches volcaniques dans les deux ceintures suggèrent un contexte tectonique commun. Un modèle impliquant des épisodes de volcanisme, séparés par 100 Ma, dans des bassins ensialiques concorde avec la dominance de basalte tholéiitique et une abondance de socle prévolcanique.[Traduit par la Rédaction] [ABSTRACT FROM AUTHOR]

The Paleoproterozoic southeastern Churchill Province (SECP) is located in the northeastern Canadian Shield of Labrador and Quebec. The SECP formed through the oblique collisions of the Archean Nain and Superior cratons with a third intervening Archean block, the core zone. The belt has a tripartite structure, comprising the Torngat Orogen (TO) formed by Nain craton – core zone collision in the east, the core zone in the centre, and the New Quebec Orogen (NQO) formed by Superior craton – core zone collision in the west. The SECP thus records transpressional development on the flanks of the Superior and Nain cratons as they indented northwards to form the larger Trans-Hudson – Nagssugtoqidian orogenic belt to the north. Principal stages of tectonic development were (1) 2.2–2.1 Ga crustal rifting of Nain and Superior cratons; (2) ca. 1.9 Ga subduction under eastern Nain craton; (3) ca. 1.87–1.85 Ga collision of Nain craton and core zone to form the TO; (4) 1.845–1.820 Ga sinistral transpression in the TO, and subduction under the western core zone; and (5) 1.82–1.77 Ga collision of Superior craton and core zone to form the NQO, in association with dextral transpression. Crustal-scale cross sections of the SECP have been developed from reflection and refraction seismic data. The western part of the NQO is dominantly west-vergent and associated with an imbricate thick-skinned thrust stack that ramps from the base of the crust. The core zone is characterized by a 35–40 km thick crust and pervasive east-dipping fabrics related to westerly thrusting. The TO is a narrow, doubly vergent belt, associated with a 48 km thick crust that forms a crustal root with a Moho relief of 12 km. The root is interpreted to result from attempted subduction of the core zone under the Nain craton, possibly as a result of mid-crustal wedging by the Nain craton. The TO was the site of intense convergence that resulted in excision of juvenile crust, possibly including tectonic removal of the axial magmatic arc. As a result, the middle to lower levels of the SECP consist largely of refractory Archean lithosphere. This may account for the lack of widespread post-collisional plutonism in the SECP and the preservation of the TO root.Le sud-est de la Province de Churchill (SECP, Southeastern Churchill Province; Paléoprotérozoïque) est situé dans le nord-est du Bouclier canadien, au Labrador et au Québec. Le SECP a été formé par des collisions obliques entre les cratons archéens de Nain et du Supérieur et un troisième bloc archéen intermédiaire, la zone noyau. La ceinture a une structure tripartite, comprenant l'orogène Torngat (TO), formé par la collision entre la zone noyau et le craton de Nain, à l'est, la zone noyau au centre et l'orogène du Nouveau-Québec (NQO), formé par la collision entre la zone noyau et le craton du Supérieur, à l'ouest. Le SECP enregistre donc le développement de transpressions sur les flancs des cratons de Nain et du Supérieur alors que ces derniers se déplaçaient vers le nord pour former la grande ceinture orogénique trans-hudsonienne – nagssugtoqidienne au nord. Les principaux stages de développement tectonique ont été : (1) la dérive crustale des cratons de Nain et du Supérieur, 2,2–2,1 Ga; (2) la subduction sous le craton de Nain oriental, vers 1,9 Ga; (3) la collision entre le craton de Nain et la zone noyau pour former l'orogène Torngat, vers 1,87–1,85 Ga; (4) la transpression senestre dans TO, 1,845–1,82 Ga; la subduction sous la zone noyau occidentale; (5) la collision entre le craton du Supérieur et la zone noyau pour former l'orogène du Nouveau-Québec, associée à de la transpression dextre, 1,82–1,77 Ga. Des coupes à l'échelle crustale du SECP ont été produites à partir de données de sismique réflexion et réfraction. La partie ouest de l'orogène du Nouveau-Québec est déversée surtout vers l'ouest et associée à une épaisse structure imbriquée de chevauchement qui remonte à partir de la base de la croûte. La zone noyau est caractérisée par une croûte dont l'épaisseur est de 35–40 km et des textures pénétrantes à pendage vers l'est qui sont reliées à du chevauchement vers l'ouest. L'orogène Torngat est une ceinture étroite à double vergence, associée à une croûte épaisse de 48 km qui forme une racine crustale avec un relief du Moho de 12 km. On interprète la racine comme une tentative de subduction de la zone noyau sous le craton de Nain, possiblement à la suite d'un coincement mi-crustal par le craton de Nain. L'orogène Torngat a été le site d'une intense convergence qui a eu comme résultat d'exciser la croûte juvénile, possiblement avec le retrait tectonique de l'arc magmatique axial. Il en a résulté que les niveaux mi-inférieurs du SECP consistent surtout de lithosphère archéenne réfractaire. Cela pourrait expliquer le manque de plutonisme post-collisionnel étendu dans le SECP et la préservation de la racine de l'orogène Torngat.[Traduit par la Rédaction] [ABSTRACT FROM AUTHOR]

The character of the Paleozoic basement of Quesnel Terrane and the position of the terrane accretion surface that separates Quesnel and Kootenay terranes from rocks of the ancient North American margin are subjects of debate. To address these problems, detailed mapping and U–Pb geochronologic studies were carried out in the Christina Lake area to define the relationship of the Mollie Creek assemblage, Josh Creek diorite, and Fife diorite to similar lithologies in the Greenwood – Grand Forks and Rossland regions, and to place limits on the ages of regional deformation and local position of the terrane accretion surface. Deformed metasedimentary rocks of the Mollie Creek assemblage may correlate with sedimentary rocks of the Pennsylvanian to Early Triassic Mount Roberts Formation in the Rossland area. The Mollie Creek assemblage is intruded by the foliated Late Triassic Josh Creek diorite. The Josh Creek diorite and Mollie Creek assemblage have been deformed together as a result of phase two deformation, following the intrusion of the Josh Creek diorite in the Late Triassic and prior to the intrusion of the Fife diorite and deposition of the overlying Rossland Group in the Early Jurassic. Based on relative age, structural position, and lithological similarities to other units within Quesnel Terrane, the Mollie Creek assemblage, Josh Creek diorite, and Fife diorite are a part of Quesnel Terrane and lie above the terrane accretion surface in the Christina Lake area. Therefore, Quesnel Terrane does not unconformably overlie basement rocks of known North American affinity in this region.Le caractère du socle paléozoïque du terrane de Quesnel et la position de la surface d'accrétion du terrane qui sépare les terranes de Quesnel et de Kootenay des roches de l'ancienne marge nord-américaine sont sujets à discussion. Afin d'aborder ces problèmes, de la cartographie de détail et des études géochronologiques U–Pb ont été entreprises dans la région du lac Christina afin de définir la relation entre l'assemblage de Mollie Creek, la diorite de Josh Creek, la diorite de Fife et des lithologies similaires dans les régions de Greenwood–Grand Forks et de Rossland et de circonscrire les âges de la déformation régionale ainsi que la position locale de la surface d'accrétion du terrane. Des roches métasédimentaires déformées de l'assemblage de Mollie Creek correspondent peut-être à des roches sédimentaires de la Formation de Mount Roberts (Pennsylvanien à Trias précoce) dans la région de Rossland. La diorite foliée de Josh Creek (Trias tardif) pénètre dans l'assemblage de Mollie Creek. La diorite de Josh Creek et l'assemblage de Mollie Creek ont été déformés ensemble à la suite d'une déformation de phase deux, après l'intrusion de la diorite de Josh Creek au Trias tardif et avant l'intrusion de la diorite de Fife et la déposition du Groupe de Rossland sus-jacent, au Jurassique précoce. Selon les âges relatifs, la position structurale et les similitudes lithologiques aux autres unités à l'intérieur du terrane de Quesnel, l'assemblage de Mollie Creek, la diorite de Josh Creek et la diorite de Fife font partie du terrane de Quesnel et reposent au-dessus de la surface d'accrétion du terrane dans la région du lac Christina. Le terrane de Quesnel ne repose donc pas en discordance sur les roches du socle d'affinité nord-américaine connue dans cette région.[Traduit par la Rédaction] [ABSTRACT FROM AUTHOR]

New U–Pb ages and K–Ar dates, primarily for rocks proximal to mineral occurrences in the Fawnie Range of central British Columbia, document latest Cretaceous (ca. 74–66 Ma) continental-arc igneous activity and date associated base and precious metal mineralization. U–Pb ages of ca. 73–69 Ma for the Capoose pluton and hypabyssal to extrusive garnet rhyolites at the Capoose prospect demonstrate a latest Cretaceous age for mineralization and a likely plutonic source for mineralizing fluids. A U–Pb age of ca. 67 Ma for a late mineralized felsic dyke and two K–Ar dates (ca. 70 and 68 Ma) for hornfelsed Jurassic volcanic rocks at the Blackwater–Davidson prospect constrain a latest Cretaceous age for mineralization. A U–Pb age of ca. 74 Ma for a fine grained diorite sill that cuts a significant epithermal gold vein at the Tsacha prospect places a minimum age on mineralization at this probable Jura-Cretaceous deposit and documents latest Cretaceous magmatism. Latest Cretaceous K–Ar dates are reported for an andesite flow adjacent to the Eocene Holy Cross deposit (ca. 66 Ma), about 35 km north of the Fawnie Range, and a Kasalka Group rhyolite (ca. 68 Ma) exposed near the western margin of the Nechako Plateau. Latest Cretaceous magmatism and mineralization in the Fawnie Range represent the waning stages of Bulkley suite magmatism and porphyry-style mineralization, which was concentrated along the western margin of the Nechako Plateau at circa 88–70 Ma. The distribution of latest Cretaceous arc igneous rocks along the North American Cordilleran is reviewed and tectonic implications discussed.De nouveaux âges U–Pb et de nouvelles datations K–Ar, surtout pour des roches à proximité d'occurrences minérales dans la chaîne Fawnie du centre de la Colombie-Britannique documentent la plus récente activité ignée d'arc continental au Crétacé (ca. 74–66 Ma) et datent la minéralisation associée de métaux précieux et de métaux de base. Des âges U–Pb d'environ 73–69 Ma pour le pluton de Capoose et les rhyolites grenatifères hypabyssales à extrusives dans la zone d'intérêt Capoose démontrent un âge Crétacé terminal pour la minéralisation et une source plutonique probable pour les fluides minéralisateurs. Un âge U–Pb d'environ 67 Ma pour un dyke felsique à minéralisation tardive et deux datations K–Ar (ca. 70 et 68 Ma) pour des roches volcaniques au faciès des cornéennes, datant du Jurassique, à la zone d'intérêt Blackwater–Davidson limitent l'âge de la minéralisation au Crétacé terminal. Un âge U–Pb d'environ 74 Ma pour un filon-couche de diorite à grains fins qui recoupe une importante veine d'or épithermale à la zone d'intérêt Tsacha donne un âge minimum pour la minéralisation de ce dépôt, probablement au Jurassique–Crétacé, et documente le magmatisme au Crétacé terminal. Des datations K–Ar de Crétacé terminal sont rapportées pour un écoulement d'andésite adjacent au gisement de Holy Cross, datant de l'Éocène (ca. 66 MA), situé à environ 35 km au nord de la chaîne Fawnie et pour une rhyolite du Groupe de Kasalka (ca. 68 Ma) affleurant près de la bordure ouest du plateau Nechako. Du magmatisme et de la minéralisation dans la chaîne Fawnie, au Crétacé terminal, représentent les dernières phases du magmatisme de la suite Bulkley et de la minéralisation de type porphyrique, qui a été concentrée le long de la bordure ouest du plateau Nechako il y a environ 88–70 Ma. On passe en revue la distribution des roches ignées d'arc au Crétacé terminal le long de la Cordillère nord-américaine et on discute des implications tectoniques.[Traduit par la Rédaction] [ABSTRACT FROM AUTHOR]

Copyright of Canadian Journal of Earth Sciences is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Residential segregation into spatial neighborhoods and boroughs is a well-known spatial dynamic process that characterise complex urban environments. Existing models of segregation, including the pioneering Schelling ones, often do not consider all the factors that can contribute to this process. Segregation as well as aggregation emerges from local interactions among individuals, and is rooted in the complexity of social, economic and environmental interactions. The main objective of this study is to develop and implement a geospatial agent-based model to simulate the decision-making process of location of new household for incoming immigrant populations. Particularly this study aims to simulate and analyse the dynamics of the new immigrant populations arriving in the bilingual cities and boroughs of the island of Montreal. The model was implemented in NetLogo software, using real geospatial datasets. The obtained simulation results indicate realistic spatial patterns of spatial composition of the ethnographic fabric on the island of Montreal. The proposed model has the potential to be used as part of the city planning purposes. [ABSTRACT FROM AUTHOR]

The article focuses on the mineral poudretteite which was first collected from the Poudrette quarry on Mont Saint-Hilaire, Canada but superior quality was harvested from Myanmar. It talks about the geological description of the area in Myanmar being responsible for the quality of the mineral which was superior than the ones found in Canada.

Seafloor mapping can offer important insights for marine management, spatial planning, and research in marine geology, ecology, and oceanography. Here, we present a method for generating regional bathymetry and geomorphometry maps from crowd-sourced depth soundings (Olex AS) for a small fraction of the cost of multibeam data collection over the same area. Empirical Bayesian Kriging was used to generate a continuous bathymetric surface from incomplete and, in some areas, sparse Olex coverage on the Newfoundland and Labrador shelves of eastern Canada. The result is a 75m bathymetric grid that provides over 100x finer spatial resolution than previously available for the majority of the 672,900 km2 study area. The interpolated bathymetry was tested for accuracy against independent depth data provided by Fisheries and Oceans Canada (Spearman correlation = 0.99, p<0.001). Quantitative terrain attributes were generated to better understand seascape characteristics at multiple spatial scales, including slope, rugosity, aspect, and bathymetric position index. Landform classification was carried out using the geomorphons algorithm and a novel method for the identification of previously unmapped tributary canyons at the continental shelf edge are also presented to illustrate some of many potential benefits of crowd-sourced regional seafloor mapping. [ABSTRACT FROM AUTHOR]

While there is no denying that oil sands development in the Athabasca Oil Sands Region (AOSR) has large impacts upon the habitat it disturbs, developers are legally required to return this land to “an equivalent land capability.” While still early in the process of reclamation, land undergoing reclamation offers an opportunity to study factors influencing reclamation success, as well as how reclaimed ecosystems function. As such, an Early Successional Wildlife Dynamics (ESWD) program was created to study how wildlife return to and use reclaimed upland boreal habitat in the AOSR. Wildlife data comprising 182 taxa of mammals, birds, and amphibians, collected between 2011 and 2017 and from five oil sands leases, were compared from multiple habitat types (burned [BRN], cleared [CLR], compensation lakes [COMP], logged [LOG], mature forest [MF], and reclaimed sites [REC]). Overall, similarity of wildlife communities in REC and MF plots varied greatly, even at 33 years since reclamation (31–62% with an average of 52%). However, an average community similarity of 52% so early in the successional process suggests that current reclamation efforts are progressing towards increased similarity compared to mature forest plots. Conversely, our data suggest that REC plots are recovering differently than plots impacted by natural (BRN) or other anthropogenic disturbances (LOG), which is likely due to differences associated with soil reconstruction and development on reclaimed plots. Regardless of the developmental trajectory of reclaimed habitats, progression towards increased wildlife community similarity at REC and MF plots is apparent in our data. While there is no expectation that reclaimed upland habitats will resemble or function identically to naturally occurring boreal forest, the degree of similarity observed in our study suggests that comparable ecological functionality is possible, increasing the probability that oil sands operators will be able to fulfill their regulatory requirements and duty to reclaim regarding wildlife and wildlife habitat. [ABSTRACT FROM AUTHOR]

Copyright of Canadian Journal of Earth Sciences is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Emerald Basin on the Scotian Shelf off Nova Scotia, Canada, is home to a globally unique aggregation of the glass sponge Vazella pourtalesi, first documented in the region in 1889. In 2009, Fisheries and Oceans Canada (DFO) implemented two Sponge Conservation Areas to protect these sponge grounds from bottom fishing activities. Together, the two conservation areas encompass 259 km2. In order to ascertain the degree to which the sponge grounds remain unprotected, we modelled the presence probability and predicted range distribution of V. pourtalesi on the Scotian Shelf using random forest modelling on presence-absence records. With a high degree of accuracy the random forest model predicted the highest probability of occurrence of V. pourtalesi in the inner basins on the central Scotian Shelf, with lower probabilities at the shelf break and in the Fundian and Northeast Channels. Bottom temperature was the most important determinant of its distribution in the model. Although the two DFO Sponge Conservation Areas protect some of the more significant concentrations of V. pourtalesi, much of its predicted distribution remains unprotected (over 99%). Examination of the hydrographic conditions in Emerald Basin revealed that the V. pourtalesi sponge grounds are associated with a warmer and more saline water mass compared to the surrounding shelf. Reconstruction of historical bottom temperature and salinity in Emerald Basin revealed strong multi-decadal variability, with average bottom temperatures varying by 8°C. We show that this species has persisted in the face of this climatic variability, possibly indicating how it will respond to future climate change. [ABSTRACT FROM AUTHOR]

Salt marshes are highly effective carbon (C) sinks and have higher rates of soil C burial (per square meter) than terrestrial ecosystems. Marsh reclamation and anthropogenic impacts, however, have resulted in extensive losses of salt marshes. Restoration of marshes drained and “reclaimed” for agriculture (referred to in Canada as dykelands) and degraded marshes can generate C credits, but only if C burial is reliably quantified. To date, studies reporting on C burial rates have been limited primarily to restored marshes which are more than 10 years old. Here we report on a study which assessed C burial six years after the return of tidal flooding to a section of dykeland in Aulac, New Brunswick on Canada’s Bay of Fundy. The C burial rate in the restored marsh averaged 1 329 g C m-2 yr-1, more than five times the rate reported for a nearby mature marsh. Carbon density in the recovering marsh was relatively consistent with depth and although salt marsh cordgrass (Spartina alterniflora) became established in 2012, the bulk of the C in the new marsh deposit is assumed to be allochthonous. Financial constraints are a barrier to marsh restoration projects and C markets could provide a considerable source of funding for restoration work in the future. For marsh restoration projects to be recognized in C crediting systems, however, it must also be demonstrated that the allochthonous C would not otherwise have been sequestered; the potential for this is discussed. [ABSTRACT FROM AUTHOR]

This study examined the influence of walkability on walking behaviour and assessed whether associations varied according to life-stage and population center (PC) size. Walkability scores were obtained for the six-digit postal codes of residential neighbourhoods of 11,200 Canadians, who participated in biennial assessments of the National Population Health Survey from 1994 to 2010. Participants were stratified by age-group. Mixed-effects logistic regression models were used to estimate the influence of cumulative exposure to neighborhood walkability on utilitarian and exercise walking by PC size and life-stage. Associations of neighbourhood walkability with utilitarian and exercise walking varied according to age-group and PC size. Exposure to high walkable neighborhoods was associated with utilitarian walking in younger and older adults in all PC sizes, except for older adults living in a medium PC. Living in a highly walkable neighborhood in a large PC was associated with walking for exercise in younger (OR: 1.42; 95%CI: 1.20–1.67) and older adults (OR: 2.09; 95%CI: 1.51–2.89). Living in highly walkable neighbourhood in a medium PC was associated with walking for exercise in older adults (OR: 1.62; 95%CI: 1.15–2.29). These results emphasize the need to consider the size and nature of every community, and the age-group of a population when implementing strategies to promote walking. [ABSTRACT FROM AUTHOR]

Produce has become a major source of foodborne illness, and may become contaminated through surface water irrigation. The objectives of this study were to (i) determine the frequency of verotoxigenic E. coli (VTEC), Listeria monocytogenes, and Salmonella in surface waters used for irrigation in the Lower Mainland of British Columbia, (ii) assess the suitability of fecal coliforms and generic E. coli as hygiene indicators, and (iii) investigate the correlations of environmental factors with pathogen occurrence. Water samples were collected semi-monthly for 18 months from seven irrigation ditches across the Serpentine and Sumas watersheds. VTEC colonies on water filters were detected using a verotoxin colony immunoblot, and the presence of virulence genes vt1 and vt2 was ascertained via multiplex PCR. Detection of L. monocytogenes and Salmonella was completed using standard, Health Canada Compendium of Analytical Methods. Fecal coliforms and generic E. coli were enumerated by 3M™ Petrifilm™ and filtration methods, and meteorological and geographic data were collected from government records. VTEC, L. monocytogenes, and Salmonella were detected in 4.93%, 10.3%, and 2.69% of 223 samples, respectively. L. monocytogenes occurrence was greatest in the Serpentine watershed (χ2; p < 0.05), and was most common during the winter and fall (Fisher exact test; p < 0.05). Site dependence of VTEC and Salmonella occurrence was observed within watersheds (Fisher’s exact test; p < 0.10). Pathogen occurrence correlated with fecal coliform counts (r = 0.448), while VTEC occurrence also correlated with precipitation over the five days before sampling (r = 0.239). The density of upstream livestock correlated with VTEC (rs = 0.812), and L. monocytogenes (rs = 0.841) detection. These data show that foodborne pathogens are present in the waters used for irrigation in the Lower Mainland of British Columbia, but their frequency may depend on spatial and temporal factors. [ABSTRACT FROM AUTHOR]

Coiled tubing corrosion was investigated for 16 field water samples (S5 to S20) from a Canadian shale gas field. Weight loss corrosion rates of carbon steel beads incubated with these field water samples averaged 0.2 mm/yr, but injection water sample S19 had 1.25±0.07 mm/yr. S19 had a most probable number of zero acid-producing bacteria and incubation of S19 with carbon steel beads or coupons did not lead to big changes in microbial community composition. In contrast other field water samples had most probable numbers of APB of 102/mL to 107/mL and incubation of these field water samples with carbon steel beads or coupons often gave large changes in microbial community composition. HPLC analysis indicated that all field water samples had elevated concentrations of bromide (average 1.6 mM), which may be derived from bronopol, which was used as a biocide. S19 had the highest bromide concentration (4.2 mM) and was the only water sample with a high concentration of active bronopol (13.8 mM, 2760 ppm). Corrosion rates increased linearly with bronopol concentration, as determined by weight loss of carbon steel beads, for experiments with S19, with filtered S19 and with bronopol dissolved in defined medium. This indicated that the high corrosion rate found for S19 was due to its high bronopol concentration. The corrosion rate of coiled tubing coupons also increased linearly with bronopol concentration as determined by electrochemical methods. Profilometry measurements also showed formation of multiple pits on the surface of coiled tubing coupon with an average pit depth of 60 μm after 1 week of incubation with 1 mM bronopol. At the recommended dosage of 100 ppm the corrosiveness of bronopol towards carbon steel beads was modest (0.011 mm/yr). Higher concentrations, resulting if biocide is added repeatedly as commonly done in shale gas operations, are more corrosive and should be avoided. Overdosing may be avoided by assaying the presence of residual biocide by HPLC, rather than by assaying the presence of residual surviving bacteria. [ABSTRACT FROM AUTHOR]

Background: Urban environments can influence many aspects of health and well-being and access to health care is one of them. Access to primary health care (PHC) in urban settings is a pressing research and policy issue in Canada. Most research on access to healthcare is focused on national and provincial levels in Canada; there is a need to advance current understanding to local scales such as neighbourhoods. Methods: This study examines spatial accessibility to family physicians using the Three-Step Floating Catchment Area (3SFCA) method to identify neighbourhoods with poor geographical access to PHC services and their spatial patterning across 14 Canadian urban settings. An index of spatial access to PHC services, representing an accessibility score (physicians-per-1000 population), was calculated for neighborhoods using a 3km road network distance. Information about primary health care providers (this definition does not include mobile services such as health buses or nurse practitioners or less distributed services such as emergency rooms) used in this research was gathered from publicly available and routinely updated sources (i.e. provincial colleges of physicians and surgeons). An integrated geocoding approach was used to establish PHC locations. Results: The results found that the three methods, Simple Ratio, Neighbourhood Simple Ratio, and 3SFCA that produce City level access scores are positively correlated with each other. Comparative analyses were performed both within and across urban settings to examine disparities in distributions of PHC services. It is found that neighbourhoods with poor accessibility scores in the main urban settings across Canada have further disadvantages in relation to population high health care needs. Conclusions: The results of this study show substantial variations in geographical accessibility to PHC services both within and among urban areas. This research enhances our understanding of spatial accessibility to health care services at the neighbourhood level. In particular, the results show that the low access neighbourhoods tend to be clustered in the neighbourhoods at the urban periphery and immediately surrounding the downtown area. [ABSTRACT FROM AUTHOR]

Climate-influenced changes in fire regimes in northern temperate and boreal regions will have both ecological and economic ramifications. We examine possible future wildfire area burned and suppression costs using a recently compiled historical (i.e., 1980–2009) fire management cost database for Canada and several Intergovernmental Panel on Climate Change (IPCC) climate projections. Area burned was modelled as a function of a climate moisture index (CMI), and fire suppression costs then estimated as a function of area burned. Future estimates of area burned were generated from projections of the CMI under two emissions pathways for four General Circulation Models (GCMs); these estimates were constrained to ecologically reasonable values by incorporating a minimum fire return interval of 20 years. Total average annual national fire management costs are projected to increase to just under $1 billion (a 60% real increase from the 1980–2009 period) under the low greenhouse gas emissions pathway and $1.4 billion (119% real increase from the base period) under the high emissions pathway by the end of the century. For many provinces, annual costs that are currently considered extreme (i.e., occur once every ten years) are projected to become commonplace (i.e., occur once every two years or more often) as the century progresses. It is highly likely that evaluations of current wildland fire management paradigms will be necessary to avoid drastic and untenable cost increases as the century progresses. [ABSTRACT FROM AUTHOR]

Understanding the development of landscape patterns over broad spatial and temporal scales is a major contribution to ecological sciences and is a critical area of research for forested land management. Boreal forests represent an excellent case study for such research because these forests have undergone significant changes over recent decades. We analyzed the temporal trends of four widely-used landscape pattern indices for boreal forests of Canada: forest cover, largest forest patch index, forest edge density, and core (interior) forest cover. The indices were computed over landscape extents ranging from 5,000 ha (n = 18,185) to 50,000 ha (n = 1,662) and across nine major ecozones of Canada. We used 26 years of Landsat satellite imagery to derive annualized trends of the landscape pattern indices. The largest declines in forest cover, largest forest patch index, and core forest cover were observed in the Boreal Shield, Boreal Plain, and Boreal Cordillera ecozones. Forest edge density increased at all landscape extents for all ecozones. Rapidly changing landscapes, defined as the 90th percentile of forest cover change, were among the most forested initially and were characterized by four times greater decrease in largest forest patch index, three times greater increase in forest edge density, and four times greater decrease in core forest cover compared with all 50,000 ha landscapes. Moreover, approximately 18% of all 50,000 ha landscapes did not change due to a lack of disturbance. The pattern database results provide important context for forest management agencies committed to implementing ecosystem-based management strategies. [ABSTRACT FROM AUTHOR]

Seasonal distribution of adult Atlantic sturgeon was examined using pop-up satellite archival tags (PSATs) and ultrasonic transmitters deployed in the Saint John River, New Brunswick, Canada. Seven MK10 PSATs programmed for release in June 2012 and seven MiniPAT PSATs programmed for release in February and April 2013 were deployed in August 2011 and 2012, respectively. Eleven of 14 PSATs surfaced and transmitted depth and temperature data archived for the duration of their deployment (121–302 days). Among these eleven PSATs, five were recovered and 15-sec archival data was downloaded. Following exit from the Saint John River in the fall, tagged fish occupied a mean monthly depth of 76.3–81.6 m at temperatures as low as 4.9˚C throughout the winter before returning to shallower areas in the spring. The majority of ultrasonic detections occurred in the Bay of Fundy, but fish were detected as far as Riviere Saint-Jean, Quebec, approximately 1500 km from the Bay of Fundy (representing long-distance migratory rates of up to 44 km/day). All PSATs were first detected in the Bay of Fundy. Tags that released in February and April were found 5–21 km offshore of the Saint John Harbour, while tags that released in June were first detected in near shore areas throughout the Bay of Fundy. The substrate at winter tag release locations (estimated from backward numerical particle-tracking experiments) consisted primarily of moraines and postglacial mud substrate with low backscatter strength, indicative of soft or smooth seabed. Based on the proximity of winter tag release locations, the consistent depths observed between fish, and previous research, it is suspected that a winter aggregation exists in the Bay of Fundy. This study expands the understanding of the marine distribution and range of Atlantic sturgeon on the east coast of Canada. [ABSTRACT FROM AUTHOR]

Objective: The adoption of pro-environmental behaviours reduces anthropogenic environmental impacts and subsequent human health effects. This study developed composite indices measuring adoption of pro-environmental behaviours at the household level in Canada. Methods: The 2007 Households and the Environment Survey conducted by Statistics Canada collected data on Canadian environmental behaviours at households' level. A subset of 55 retained questions from this survey was analyzed by Multiple Correspondence Analysis (MCA) to develop the index. Weights attributed by MCA were used to compute scores for each Canadian province as well as for socio-demographic strata. Scores were classified into four categories reflecting different levels of adoption of pro-environmental behaviours. Results: Two indices were finally created: one based on 23 questions related to behaviours done inside the dwelling and a second based on 16 questions measuring behaviours done outside of the dwelling. British Columbia, Quebec, Prince-Edward-Island and Nova-Scotia appeared in one of the two top categories of adoption of pro-environmental behaviours for both indices. Alberta, Saskatchewan, Manitoba and Newfoundland-and-Labrador were classified in one of the two last categories of pro-environmental behaviours adoption for both indices. Households with a higher income, educational attainment, or greater number of persons adopted more indoor pro-environmental behaviours, while on the outdoor index, they adopted fewer such behaviours. Households with low-income fared better on the adoption of outdoors pro-environmental behaviours. Conclusion: MCA was successfully applied in creating Indoor and Outdoor composite Indices of pro-environmental behaviours. The Indices cover a good range of environmental themes and the analysis could be applied to similar surveys worldwide (as baseline weights) enabling temporal trend comparison for recurring themes. Much more than voluntary measures, the study shows that existing regulations, dwelling type, households composition and income as well as climate are the major factors determining pro-environmental behaviours. [ABSTRACT FROM AUTHOR]

Objective: Reported associations between socioeconomic status (SES) and obesity are inconsistent depending on gender and geographic location. Globally, these inconsistent observations may hide a variation in the contextual effect on individuals' risk of obesity for subgroups of the population. This study explored the regional variability in the association between SES and BMI in the USA and in Canada, and describes the geographical variance patterns by SES category. Methods: The 2009–2010 samples of the Behavioral Risk Factor Surveillance System (BRFSS) and the Canadian Community Health Survey (CCHS) were used for this comparison study. Three-level random intercept and differential variance multilevel models were built separately for women and men to assess region-specific BMI by SES category and their variance bounds. Results: Associations between individual SES and BMI differed importantly by gender and countries. At the regional-level, the mean BMI variation was significantly different between SES categories in the USA, but not in Canada. In the USA, whereas the county-specific mean BMI of higher SES individuals remained close to the mean, its variation grown as SES decreased. At the county level, variation of mean BMI around the regional mean was 5 kg/m2 in the high SES group, and reached 8.8 kg/m2 in the low SES group. Conclusions: This study underlines how BMI varies by country, region, gender and SES. Lower socioeconomic groups within some regions show a much higher variation in BMI than in other regions. Above the BMI regional mean, important variation patterns of BMI by SES and place of residence were found in the USA. No such pattern was found in Canada. This study suggests that a change in the mean does not necessarily reflect the change in the variance. Analyzing the variance by SES may be a good way to detect subtle influences of social forces underlying social inequalities. [ABSTRACT FROM AUTHOR]

Copyright of Canadian Journal of Earth Sciences is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Background: Up to 150 million North Americans currently use a groundwater system as their principal drinking water source. These systems are a potential source of exposure to enteric pathogens, contributing to the burden of waterborne disease. Waterborne disease outbreaks have been associated with US and Canadian groundwater systems over the past two decades. However, to date, this literature has not been reviewed in a comprehensive manner. Methods and Principal Findings: A combined review and pooled-analysis approach was used to investigate groundwater contamination in Canada and the US from 1990 to 2013; fifty-five studies met eligibility criteria. Four study types were identified. It was found that study location affects study design, sample rate and studied pathogen category. Approximately 15% (316/2210) of samples from Canadian and US groundwater sources were positive for enteric pathogens, with no difference observed based on system type. Knowledge gaps exist, particularly in exposure assessment for attributing disease to groundwater supplies. Furthermore, there is a lack of consistency in risk factor reporting (local hydrogeology, well type, well use, etc). The widespread use of fecal indicator organisms in reported studies does not inform the assessment of human health risks associated with groundwater supplies. Conclusions: This review illustrates how groundwater study design and location are critical for subsequent data interpretation and use. Knowledge gaps exist related to data on bacterial, viral and protozoan pathogen prevalence in Canadian and US groundwater systems, as well as a need for standardized approaches for reporting study design and results. Fecal indicators are examined as a surrogate for health risk assessments; caution is advised in their widespread use. Study findings may be useful during suspected waterborne outbreaks linked with a groundwater supply to identify the likely etiological agent and potential transport pathway. [ABSTRACT FROM AUTHOR]

The inshore, continental shelf waters of British Columbia (BC), Canada are busy with ship traffic. South coast waters are heavily trafficked by ships using the ports of Vancouver and Seattle. North coast waters are less busy, but expected to get busier based on proposals for container port and liquefied natural gas development and expansion. Abundance estimates and density surface maps are available for 10 commonly seen marine mammals, including northern resident killer whales, fin whales, humpback whales, and other species with at-risk status under Canadian legislation. Ship noise is the dominant anthropogenic contributor to the marine soundscape of BC, and it is chronic. Underwater noise is now being considered in habitat quality assessments in some countries and in marine spatial planning. We modeled the propagation of underwater noise from ships and weighted the received levels by species-specific audiograms. We overlaid the audiogram-weighted maps of ship audibility with animal density maps. The result is a series of so-called “hotspot” maps of ship noise for all 10 marine mammal species, based on cumulative ship noise energy and average distribution in the boreal summer. South coast waters (Juan de Fuca and Haro Straits) are hotspots for all species that use the area, irrespective of their hearing sensitivity, simply due to ubiquitous ship traffic. Secondary hotspots were found on the central and north coasts (Johnstone Strait and the region around Prince Rupert). These maps can identify where anthropogenic noise is predicted to have above-average impact on species-specific habitat, and where mitigation measures may be most effective. This approach can guide effective mitigation without requiring fleet-wide modification in sites where no animals are present or where the area is used by species that are relatively insensitive to ship noise. [ABSTRACT FROM AUTHOR]