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Copyright of Canadian Journal of Civil Engineering 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 Environmental Reviews 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.)

Similar to many freshwater ecosystems, the Laurentian Great Lakes of North America have undergone numerous anthropogenic stressors resulting in considerable loss of biodiversity and habitat. Among Great Lakes fishes, the coregonine sub-family has endured the most extensive declines, including extinction of several species (Coregonus johannae, C. alpenae, and C. kiyi orientalis) and at least 10 instances of local extirpations of other species (C. nigripinnis, C. reighardi, C. zenithicus, C. hoyi, and C. artedi) across all 5 lakes, much of which occurred prior to the 1960s owing to overfishing, interactions with non-indigenous species, and habitat loss. Despite these declines, no federal-, provincial-, or state-mandated actions were ever implemented to conserve coregonine diversity, potentially because so much of the coregonine declines occurred prior to the enactment of federal conservation legislation. Possible explanations for inaction since enactment of that legislation include insufficient data on biological vulnerability or threats, unresolved taxonomy, and limited support from the fishery management agencies and their stakeholders prior to the 2000s. In recent decades, however, several fishery management agencies have undertaken efforts to re-introduce coregonine diversity. These efforts helped lead to development of a science-based framework to restore coregonines that was universally endorsed by fishery managers representing eight U.S. states, four U.S. tribal organizations, and the province of ON, Canada, in May 2018. The basin-wide framework is based on principles of conservation biology and adaptive management. We describe details of its key steps, including planning, restoring, and evaluating, while also describing recent implementation efforts to develop methods, improve available resources, and enhance coordination across the basin. Although our paper describes a regional effort to restore native coregonines, our adaptive-management approach could be used by other multi-agency stakeholders seeking to conserve or restore native fishes. [ABSTRACT FROM AUTHOR]

Copyright of Environmental Reviews 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 Civil Engineering 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 Environmental Reviews 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 Civil Engineering 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.)

Copyright of Canadian Journal of Civil Engineering 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 Civil Engineering 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 Geotechnical Journal 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.)

Concrete pavements are well known for long structural life. The major challenge, however, is to provide a durable surface with adequate skid resistance for economy and safety. This paper examines the long-term frictional performance of eight different surface textures on 197 sections of concrete pavements within the long-term pavement performance (LTPP) program database. Analysis shows that tined and (or) grooved textures maintain consistently higher skid resistance over time and the surface friction of concrete pavements is less sensitive to ambient temperature. Cumulative traffic passes are more sensitive to longevity of friction than the cumulative axle loads. Five alternative models have also been successfully developed for prediction of the long-term skid resistance of concrete pavements as a function of texture type, cumulative traffic passes, speed, and concrete compressive strength. These models were shown to be statistically significant at 95% confidence levels with reasonable prediction accuracy. Les chaussées en béton sont reconnues pour leur longue durée de vie structurale. Le principal défi est toutefois de fournir une surface durable présentant une antidérapance adéquate pour la sécurité et l’économie. Le présent article examine le comportement au frottement de huit différentes textures de surface sur 197 sections de chaussées en béton dans la base de données du programme « long-term pavement performance (LTPP) ». L’analyse montre que des textures crantées et (ou) rainurées conservent de façon constante une meilleure antidérapance dans le temps et le frottement à la surface des chaussées en béton est moins sensible à la température ambiante. Le cumulatif des passages de la circulation est plus sensible à la longévité du frottement que le cumulatif des charges par essieu. Cinq autres modèles ont été développés avec succès pour prédire l’antidérapance à long terme des chaussées en béton en fonction du type de texture, du cumulatif des passages de la circulation, de la vitesse et de la résistance en compression du béton. Ces modèles se sont avérés statistiquement significatifs avec des coefficients de confiance de 95 % et une précision raisonnable de prévision. [ABSTRACT FROM AUTHOR]

Copyright of Canadian Journal of Civil Engineering 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.)

In North America, the rapid movement away from the direct discharge of water treatment plant (WTP) residual streams to receiving environments has resulted in considerable benefits to the drinking water industry in terms of enhancing environmental stewardship practices and supporting source water protection strategies. Over the past 20 years, application based research on appropriate technologies to treat residual streams such as filter backwash water (FBWW) has promoted the development of integrated process design that presents recycling as a viable residual management option. However, as utilities continue to develop and expand their main process lines to comply with more stringent government regulations encompassing both water quality and residual disposal practices, the development of sustainable residual management practices is expected to become a more prominent issue for this industry. The purpose of this paper is to present, from a critical point of view, the matrix of issues that currently exist regarding WTP residual streams and strategic pathways that would enhance future decision making processes for achieving long-term residual management solutions for the drinking water industry. En Amérique du Nord, l’abandon rapide de la décharge directe des effluents des usines de traitement des eaux dans les milieux récepteurs a grandement profité à l’industrie de l’eau potable en termes d’amélioration des pratiques de gérance environnementale et de soutien des stratégies de protection des sources d’eau. La recherche des 20 dernières années, appliquée aux technologies appropriées de traiter les effluents, tels que l’eau de lavage des filtres à contre-courant, a favorisé le développement d’une conception de procédé intégrée qui présente le recyclage comme une option viable de gestion des matières résiduelles. Toutefois, à mesure que les services publics continuent de développer et d’étendre leurs chaînes de procédé principales pour rencontrer les règlements gouvernementaux plus sévères touchant la qualité des eaux et les pratiques d’élimination des matières résiduelles, le développement de pratiques de gestion durable des matières résiduelles devrait revêtir plus d’importance pour cette industrie. L’objectif de cet article est de présenter de manière critique la matrice des enjeux existants dans les effluents des usines de traitement des eaux et les chemins stratégiques qui pourraient améliorer les prises de décisions futures pour arriver à des solutions de gestion des matières résiduelles à long terme pour l’industrie de l’eau potable. [ABSTRACT FROM AUTHOR]

Copyright of Canadian Journal of Civil Engineering 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 condition of sewer pipes in North America has severely deteriorated, over the last few decades, creating a need for rehabilitation. Sewer rehabilitation methods are numerous and are constantly being developed, benefiting from emerging technologies. The implementation of these methods is driven by the need to improve quality and to reduce cost and project duration. One of the rapidly expanding fields in the sewer rehabilitation industry is trenchless technology. Due to the large number of methods associated with emerging new technologies in this field, selecting the most suitable method can be a challenging task. Selection in this environment, without a computerized tool, may also suffer from the limited knowledge and (or) experience of the decision-maker and could result in overlooking some of the suitable methods that could do the job at less cost. This paper describes a recently developed system for rehabilitation of concrete and clay sewer pipes and focuses primarily on two of its components: (i) the database management system (DBMS) and (ii) the decision support system (DSS). The system can assist municipal engineers and contractors in selecting the most suitable trenchless rehabilitation technique that specifies job conditions and user requirements. An example application is presented to demonstrate the use and capabilities of the developed system.Key words: pipe defects, rehabilitation, sewer pipes, database management systems, decision support systems, multi-attribute utility theory.Les conditions des conduites d'égout en Amérique du Nord se sont déteriorées sévèrement durant les dernières décennies, créant un besoin pour une remise en état. Les méthodes de remise en état de systèmes d'égout sont nombreuses et en développement constant, bénéficiant de technologies émergentes. L'utilisation de ces méthodes est motivée par le besoin d'améliorer la qualité, la réduction des coûts et la durée du projet. Un des domaines en expansion rapide dans l'industrie de la remise en état de systèmes d'égout est la technologie sans tranchée. À cause du large nombre de méthodes associées aux nouvelles technologies émergentes dans ce domaine, la sélection de la méthode la plus appropriée peut être une tâche difficile. La sélection dans cet environnement, sans outil informatique, peut aussi souffrir des connaissances et/ou expériences limitées du preneur de décisions, et peut conduire à l'omission de méthodes appropriées qui pourraient accomplir le travail à moindre coût. Cet article décrit un système récemment développé pour la remise en état de conduites d'égout en béton et en argile, et se concentre principalement sur deux de ses composantes: (i) le système de gestion de bases de données « database management system (DBMS) » et (ii) le système d'aide à la décision « decision support system (DSS) ». Le système peut assister les ingénieurs municipaux et les contracteurs dans la sélection de la technique de remise en état sans tranchée la plus appropriée selon les conditions de travail et les exigences de l'usager. Un example d'application est présenté afin de démontrer l'usage et les capacités du système développé.Mots clés : défauts de conduites, remise en état, conduites d'égout, système de gestion de bases de données, système d'aide à la décision, theorie de services à attributs multiples.[Traduit par la Rédaction] [ABSTRACT FROM AUTHOR]

Freshwater mussels of the order Unionida are currently one of the most imperiled groups of organisms in the North American faunal region. Accurate risk assessments and development of effective management strategies for remaining populations require knowledge of thermal limits in the face of increasing surface water temperature due to climate change and various anthropogenic factors. We conducted a systematic literature review of unionid mussels (order Unionida, families Margaritiferidae and Unionidae) in the North American faunal region to (1) summarize lethal thermal tolerance data by life stage and taxonomy, (2) discuss ecological and climate change implications of existing lethal tolerance data, and (3) identify needs for future research. We identified lethal tolerance estimates for only 28 of 302 species in the families Unionidae and Margaritiferidae. The mean acute median lethal temperatures were 32.8 °C for glochidia (19 species), 35.0 °C for juveniles (13 species), and 36.3 °C for adults (4 species). Generally, glochidia were less tolerant than juveniles or adults of the same species—but there were several exceptions. Generally, Amblemini had the highest acute and chronic thermal tolerance of all tribes followed by Anodontini, Pleurobemini, Lampsilini, and Quadrilini. Acclimation temperature affected lethal tolerance endpoints in less than half (52 of 145) of comparisons within species. Lethal tolerance data for additional species, combined with a comprehensive database of in situ surface water temperatures, would be useful for modeling the frequency and duration of lethal limit exceedance in North America and identifying populations currently living at or near their upper lethal limits. [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.)

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 Grenville Orogen in North America is interpreted to have resulted from collision between Laurentia and another continent, probably Amazonia, at ca. 1100 Ma. The exposed segment of the orogen was derived largely from reworked Archean to Paleoproterozoic Laurentian crust, products of a long-lived Mesoproterozoic continental-margin arc and associated back arc, and remnants of one or more accreted mid-Mesoproterozoic island-arc terranes. A potential suture, preserved in Grenvillian inliers of the southeastern USA, may separate rocks of Laurentian and Amazonian affinities. The Grenvillian Orogeny lasted more than 100 million years. Much of the interior Grenville Province, with peak metamorphism at ca. 1090–1020 Ma, consists of uppermost amphibolite- to granulite-facies rocks metamorphosed at depths of ca. 30 km, but areas of lower crustal, eclogite-facies nappes metamorphosed at 50–60 km depth also occur and an orogenic lid that largely escaped Grenvillian metamorphism is preserved locally. Overall, deformation and regional metamorphism migrated sequentially to the northwest into the Laurentian craton, with the youngest contractional structures in the northwestern part of the orogen at ca. 1000–980 Ma. The North American lithospheric root extends across part of the Grenville Orogen, where it may have been produced by depletion of sub-continental lithospheric mantle beneath the long-lived Laurentian-margin Mesoproterozoic subduction zone. Both the Grenville Orogen and the Himalaya–Tibet Orogen have northern margins characterized by long-lived subduction before continental collision and protracted convergence following collision. Both exhibit cratonward-propagating thrusting. In the Himalaya–Tibet Orogen, however, the pre-collisional Eurasian-margin arc is high in the structural stack, whereas in the Grenville Orogen, the pre-collisional continental-margin arc is low in the structural stack. We interpret this difference as due to subduction reversal in the Grenville case shortly before collision, so that the continental-margin arc became the lower plate during the ensuing orogeny. The structurally low position of the warm, extended Laurentian crust probably contributed significantly to the ductility of lower and mid-crustal Grenvillian rocks. En Amérique du Nord, l’orogène de Grenville découlerait d’une collision entre la Laurentie et un autre continent, probablement l’Amazonie, il y a ~1100 Ma. Le segment affleurant de l’orogène provient en grande partie de la croûte laurentienne retravaillée entre l’Archéen et le Paléoprotérozoïque, soit les produits d’un arc de marge continentale de longue durée et d’un arrière-arc connexe, et les vestiges d’un ou de plusieurs terranes d’arcs insulaires accrétés au Mésoprotérozoïque moyen. Une suture potentielle, préservée dans les boutonnières du sud-est des tats-Unis, pourrait séparer les roches ayant des affinités laurentiennes ou amazoniennes. L’orogenèse grenvillienne a duré plus de 100 Ma. Une grande partie de l’intérieur de la Province du Grenville, avec une crête de métamorphisme vers 1090–1020 Ma, comprend des roches au faciès amphibolite à granulite supérieur métamorphisées à des profondeurs d’environ 30 km; cependant, des secteurs de nappes au faciès de l’éclogite, métamorphisées à des profondeurs de 50–60 km, se retrouvent aussi dans la croûte inférieure; de plus, un couvercle orogénique qui a échappé en grande partie au métamorphisme grenvillien est préservé localement. De manière générale, la déformation et le métamorphisme régional ont migré de manière séquentielle vers le nord-ouest dans le craton laurentien; les plus récentes structures de contraction dans la partie nord-ouest de l’orogène datant d’environ 1000–980 Ma. La racine lithosphérique nord-américaine s’étend à travers une partie de l’orogène de Grenville, où elle pourrait avoir été produite par un appauvrissement du manteau lithosphérique sous-continental en dessous de la zone de subduction de longue durée de la bordure laurentienne au Mésoprotérozoïque. L’orogène de Grenville et l’orogène Himalaya–Tibet ont des bordures septentrionales caractérisées par une subduction de longue durée avant la collision continentale et une convergence prolongée après [ABSTRACT FROM AUTHOR]

Three lithospheric cross sections provide a continental-scale synthesis of more than two decades of coordinated multidisciplinary research during the Canadian Lithoprobe project. The sections are based on seismic reflection and refraction data combined with a broad range of geological, geochemical, geochronological, and geophysical data. The dataset is derived from remnants of nearly every kind of tectonic regime, and the geologic history of the entrained rocks spans the Present to the Mesoarchean. The longest of the three cross sections is located within a 6000 km long Trans-Canada corridor traversing the North American continent at 45°N–55°N. From west to east, the profile crosses the Juan de Fuca ridge and active Cascadia subduction zone, the Cordilleran, Albertan, and Trans-Hudson orogens, the Superior Province, the Midcontinent rift, the Grenville and Appalachian orogens, and the Atlantic passive margin. The two northern cross sections include (i) a 2000 km long corridor in northwestern Canada (54°N–63°N) crossing the Cordilleran, Wopmay, and Slave orogens; and (ii) a 1600 km long corridor in northeastern Canada (52°N–61°N) crossing the New Quebec and Torngat orogens, the Nain craton, and the Makkovik and Grenville orogens. The unprecedented scale of the cross sections illuminates the assembly of the North American continent. Relationships between orogens are emphasized; plate collisions and accretions have sequentially stacked orogen upon orogen such that the older crust forms basement to the next younger. The large-scale perspective of these regional sections highlights the subhorizontal Moho that is indicative of either structural or thermal re-equilibration (or both), as few crustal roots beneath orogens are preserved. In contrast, heterogeneities in the lithospheric mantle suggest that, in certain situations, relict subducted or delaminated lithosphere can remain intact beneath and eventually within cratonic lithospheric mantle. Trois sections transversales lithographiques fournissent une synthèse à l’échelle continentale de plus de deux décennies de recherches multidisciplinaires coordonnées dans le cadre du projet canadien Lithoprobe. Les sections sont basées sur des données de sismique réflexion et réfraction combinées à une vaste gamme de données géologiques, géochimiques, géochronologiques et géophysiques. L’ensemble des données provient de lambeaux de presque tous les genres de régimes tectoniques et l’historique géologique des roches entraînées couvre une période allant du Présent au Mésoarchéen. La plus longue des trois sections transversales est située le long d’un corridor transcanadien d’une longueur de 6000 km traversant le continent nord-américain à une latitude de 45–55 °N. D’ouest en est, le profile traverse la crête de Juan de Fuca et la zone de subduction active Cascadia, les orogènes de la Cordillère, de l’Alberta et trans-hudsonien, la province du Supérieur, le rift mi-continental, les orogènes de Grenville et des Appalaches ainsi que la bordure passive de l’Atlantique. Les deux sections transversales au nord comprennent : (i) un corridor d’une longueur de 2000 km dans le nord-ouest du Canada (54–63 °N) traversant les orogènes de la Cordillère, de Wopmay et des Esclaves et (ii) un corridor d’une longueur de 1600 km dans le nord-est du Canada (52–61 °N) traversant les orogènes du Nouveau-Québec et de Torngat, le craton de Nain et les orogènes Makkovik et de Grenville. L’échelle sans précédent des sections transversales jette de la lumière sur l’assemblage du continent nord-américain. Les relations entre les orogènes sont soulignées; des collisions entre des plaques et des accrétions ont empilé orogène sur orogène de manière séquentielle de sorte que l’ancienne croûte forme le socle de l’orogène qui suit. La perspective à grande échelle de ces sections régionales souligne le Moho subhorizontal, indiquant un rééquilibrage structural ou thermique (ou les deux) puisque peu de racines de la croûte sont préservées sous les orogènes. Par ailleurs, les hétérogénéités dans le manteau lithosphérique suggèrent que, dans certaines situations, une lithosphère relique subduite ou de délamination puisse demeurer intacte sous, et éventuellement dans, le [ABSTRACT FROM AUTHOR]

The North American Central Plains (NACP) anomaly in enhanced electric conductivity and its relationship with the Paleoproterozoic Trans-Hudson orogen (THO) has been studied under the auspices of Lithoprobe for over a decade. The NACP anomaly was the first geophysical evidence of the existence of the THO beneath the Phanerozoic sediments of the Central Plains. This anomaly, detected geomagnetically in the late 1960s, has been the subject of a number magnetotelluric studies from the early 1980s. The PanCanadian and Geological Survey of Canada experiments in the 1980s and the Lithoprobe experiments in the 1990s together comprise four east–west and one north–south regional-scale profiles in Saskatchewan perpendicular to the strike of the orogen. In this paper, data from the northernmost line, coincident with seismic line S2B, are analysed and interpreted, and are shown to be key in determining the northern extension of the NACP anomaly. Dimensionality analysis confirms the rotation of deep crustal structures eastward to Hudson Bay, as earlier proposed on the basis of broad-scale geomagnetic studies. On this profile, as with the profile at the edge of the Paleozoic sediments, the NACP anomaly is imaged as lying within the La Ronge domain, in contact with the Rottenstone domain, and structurally above the Guncoat thrust, a late compressional feature. The location of the anomaly together with the surface geology suggests that the anomaly is caused either by sulphide mineralization concentrated in the hinges of folds, by graphite, or by a combination of both. Our interpretation of the data is consistent with that from other profiles, and suggests that the NACP anomaly was formed as a consequence of subduction and collisional processes involving northward subduction of the internides of the THO beneath the Hearne craton. On the southern part of this profile, a resistive structure is identified as the Sask craton, suggesting that Proterozoic rocks are above Archean rocks in the THO. [ABSTRACT FROM AUTHOR]

Copyright of Canadian Journal of Plant Science 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.)

The amaltheids are restricted temporally to the late Pliensbachian and geographically to the northern part of the northern hemisphere. Amaltheus stokesi is the only species that occurs in all areas of North America where amaltheids are found. The craton north of the Canada–U.S.A. border yields the most diverse amaltheid fauna, including six of the seven taxa known in North America. On Quesnellia and Stikinia, there are no endemic amaltheids, and diversity is low; A. stokesi increases in abundance northwards where, in Stikinia, A. margaritatus makes rare appearances. Wrangellia, with its rich Pliensbachian Tethyan and east Pacific faunas, is almost devoid of amaltheids, but its amaltheid fauna does include two specimens of A. viligaensis, an eastern Russian species that is unknown elsewhere in North America. Cratonal amaltheid faunas have more in common with those of northwest Europe than eastern Eurasia, suggesting that the Arctic and northern North Atlantic constituted the main dispersal route. Paleobiogeographic patterns on the major allochthonous terranes argue against terrane rotation and in support of post-Pliensbachian northward displacement relative to the North American craton. In addition, the presence of western Pacific faunal elements on Wrangellia suggests a more significant longitudinal displacement relative to the craton for this terrane compared to that for Quesnellia and Stikinia. The Chilliwack terrane of southwestern British Columbia is a Pliensbachian paleobiogeographic anomaly.Les Amaltheidés sont restreints dans le temps au Pliensbachien et géographiquement à la partie septentrionale de l'hémisphère Nord. Amaltheus stokesi est la seule espèce qui se trouve dans toutes les régions de l'Amérique du Nord où on retrouve des Amaltheidés. Le craton au nord de la frontière entre le Canada et les États-Unis fournit la faune Amaltheidé la plus diversifiée, incluant six des sept taxons connus en Amérique du Nord. À Quesnellia et Stikinia, il n'y a pas d'Amaltheidés endémiques et la diversité est faible; A. stokesi est de plus en plus abondant vers le nord où, à Stikinia, A. margaritatus apparaît rarement. Wrangellia, avec ses riches faunes tethysiennes et du Pacifique oriental (Pliensbachcien), ne contient presque pas d'Amaltheidés mais sa faune Amaltheidé comprend en effet deux spécimens de A. viligaensis, une espèce russe orientale inconnue ailleurs en Amérique du Nord. Les faunes cratonales Amaltheidés ont plus en commun avec celles de l'Europe du Nord-ouest que celles de l'Eurasie de l'Est, suggérant que l'Arctique et l'Atlantique du Nord septentrional étaient les principales voies de dispersion. Les patrons paléobiogéographiques sur les grands terranes allochtones plaident contre une rotation du terrane et en faveur d'un déplacement relatif vers le nord par rapport au craton, après le Pliensbachien. De plus, la présence d'éléments fauniques du Pacifique ouest sur Wrangellia suggère, pour ce terrane, un déplacement longitudinal plus important par rapport au craton que celui pour Quesnellia et Stikinia. Le terrane de Chilliwack du sud-ouest de la Colombie-Britannique est une anomalie paléobiogéographique du Pliensbachien.[Traduit par la Rédaction] [ABSTRACT FROM AUTHOR]

A combination of detailed, intermediate and large scale stratigraphic perspectives is necessary to understand the driving mechanisms for floral change across the Cretaceous-Tertiary (K–T) boundary, because short-term physical and biotic events occur within longer term trends. Most Maastrichtian palynofloral extinctions have been identified within the northern circumpolar, supra-continental, Aquilapollenites Province. In mid-continental North America, the presence of a physically defined K–T boundary provides opportunities to examine contemporaneous terrestrial palynofloras over a latitudinal (also approximately paleolatitudinal) distance of 3200 km. Seventy-five percent of last appearances occur before the K–T boundary at high latitudes and must have been caused by ongoing terrestrial processes. Palynofloral events directly associated with the K–T boundary include both local last appearances, and inferred extinctions, and synchronous and diachronous changes in relative abundances. Two different styles of factors are reflected in these events. The first, possibly attributable to chemical or other profound atmospheric perturbations associated with the worldwide distribution of the "fireball" layer of the K–T claystone, resulted in extinctions of angiosperm with a zoophilous pollination strategy. The second factor, possibly reflecting energy released during the deposition of ballistically transported impact debris or hackly (ejecta) layer of the boundary claystone, resulted in the selective, northward-attenuating removal of the canopy vegetation, best documented for southwestern Canada, which was succeeded by a fern-dominated vegetation in mid-continental North America. These consequences of the boundary event were mediated by independent, preexisting circumstances: climate (regional and through time), local depositional environment, and ongoing background extinctions and origins.Puisque des événements biotiques et physiques à court terme ont lieu à l'intérieur de tendances à plus long terme, il faut une combinaison de perspectives stratigraphiques à diverses échelles, détaillée, intermédiaire et grande, pour comprendre les mécanismes qui ont conduit à des changements dans la flore passant du Crétacé au Tertiaire (K–T). La plupart des extinctions palynoflorales maastrichtiennes ont été identifiées à l'intérieur de la province nordique Aquilapollenites, supra-continentale et circumpolaire. Au milieu du continent nord-américain, la présence d'une limite K–T physiquement délimitée fournit des opportunités d'examiner les palynoflores terrestres contemporaines sur une distance méridienne (et approximativement paléoméridienne) de 3200 km. Soixante-quinze pour cent des dernières apparitions ont eu lieu avant la limite K–T à de hautes latitudes et elles doivent avoir été causées par des procédés terrestres continus. Les événements palynofloraux directement associés à la limite K–T comprennent à la fois des dernières apparitions locales, des extinctions inférées, ainsi que des changements diachroniques et synchrones dans les abondances relatives. Deux différents styles de facteurs sont reflétés dans ces événements. Le premier, attribuable peut-être à des perturbations chimiques ou à d'autres perturbations atmosphériques profondes associées à la distribution mondiale de la couche « bolide » de l'argilite K–T, a eu comme résultat des extinctions d'angiospermes qui avaient une stratégie de pollinisation zoophile. Le second facteur, reflétant peut-être l'énergie libérée durant la déposition de débris d'impact à transport balistique ou la couche ébréchée (ejecta) de l'argilite limite, a eu comme résultat l'enlèvement, sélectif et s'atténuant vers le nord, de la végétation du couvert forestier, mieux documenté pour le sud-ouest du Canada, et suivi d'une végétation à dominance de fougères au milieu du continent nord-américain. Ces conséquences de l'événement limite ont été rehaussées par des circonstances indépendantes préexistantes : le climat (régional et à travers le temps), l'environnement local de déposition ainsi que des origines et des extinctions continuelles en fond de scène.[Traduit par la Rédaction] [ABSTRACT FROM AUTHOR]

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