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Basal gravel and sand mantling the bedrock floors of buried valleys throughout the Canadian Interior Plains, and conformably overlying proglacial lacustrine sediment, comprise the Empress Group. While previously conceptualized as stratigraphically equivalent deposits of preglacial rivers prior to the first and most extensive continental and montane glaciations, subsequent stratigraphic studies indicated that buried valley basal gravel must have been deposited between, or during, progressively more extensive continental glaciations and could not be stratigraphically equivalent throughout the buried valley network. However, in the general absence of formation-rank stratigraphic description of basal gravel units that might better inform the geologic history of the deposits, most workers simply consider Empress Group sediments time-transgressive. In this paper, we examine basal gravel at provincial and regional scales to understand its genesis and geologic history. At the provincial scale, we map basal gravel in three dimensions using a novel machine learning approach. At the regional scale, we formally define basal gravel formations at either end of the largest buried valley system in Alberta, which informs its glacial history and physiographic development and shows the importance of formation-rank stratigraphic description. Our results indicate that the buried valley network across Alberta is palimpsest in genesis and basal gravel units within it are chronostratigraphically intercalated between tills. We advocate that the Empress Group definition be extended across Alberta with modifications to improve its clarity and utility, and formally define the Old Fort, Unchaga, Ipiatik, and Winefred formations as part of the Empress Group. [ABSTRACT FROM AUTHOR]

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This special issue reports on some of the results of a multi-disciplinary research program conducted in the Boreal Plains of northwest Alberta and northeast British Columbia. Several innovative approaches to conducting geoscientific research in this remote drift-covered region are presented, including geochemical analysis of bentonites for evaluating kimberlite potential, the use of electromagnetic surveys for mapping buried aggregate deposits, and paleo-topographic mapping techniques to define buried channels. Results of the program include the discovery of several large aggregate deposits, the first kimberlite indicator minerals in northeast British Columbia, a significant sphalerite dispersal train in northwest Alberta, the first documented report of kimberlite-sourced bentonites, and numerous previously unknown interglacial sites. Together these papers provide a greatly enhanced understanding of the glacial history, Quaternary stratigraphy, and kimberlite geology of northwest Alberta and northeast British Columbia and provide an improved framework for resource exploration in the region. Ce numéro spécial fait le point sur quelques résultats d’un programme de recherche multidisciplinaire effectué dans les plaines boréales du nord-ouest de l’Alberta et du nord-est de la Colombie-Britannique. Plusieurs approches innovatrices de recherche géoscientifique dans cette région éloignée recouverte de sédiments glaciaires sont présentées, incluant l’analyse géochimique des bentonites pour l’évaluation du potentiel kimberlitique, l’utilisation de relevés électromagnétiques pour cartographier des dépôts enfouis d’agrégats et des techniques de cartographie paléotopographique dans le but de définir des chenaux enfouis. Les résultats du programme comprennent la découverte de plusieurs grands dépôts d’agrégats, des premiers minéraux indicateurs de kimberlite dans le nord-est de la Colombie-Britannique, une traînée importante de dispersion glaciaire de sphalérite dans le nord-ouest de l’Alberta, la première documentation de bentonites dont la source est une kimberlite et de nombreux sites interglaciaires inconnus à ce jour. Ensemble, ces articles fournissent une bien meilleure compréhension de l’historique glaciaire, de la stratigraphie du Quaternaire et de la géologie des kimberlites dans le nord-ouest de l’Alberta et le nord-est de la Colombie-Britannique; ils fournissent aussi un meilleur encadrement d’exploration pour les ressources dans cette région. [ABSTRACT FROM AUTHOR]

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Dinosaur skeletal material from the mid-Cretaceous of Canada is rare; however, the Cenomanian-aged Dunvegan Formation of northeastern British Columbia and northwestern Alberta is rich with ichnofossils attributed to nodosaurid ankylosaurs. A long bone (Hudson's Hope Museum specimen HH 2017.010.002) collected in 1993 from the Murray River of northeastern British Columbia is identified here as an ankylosaur femur. Femoral measurements of the bone plotted against femoral measurements of major dinosaur clades, combined with observations on femoral features, indicate that the bone belongs to an ankylosaur. The specimen is too damaged to assign to Nodosauridae or Ankylosauridae. HH 2017.010.002 represents the first limb bone material recovered from the Dunvegan Formation; previous ankylosaur material described from the Dunvegan Formation includes associated vertebrae and ribs from British Columbia and osteoderms from Alberta, as well as the presumed nodosaurid footprints Tetrapodosaurus borealis Sternberg, 1932. The Cenomanian is a time of great ecological change in North America, including the possible extirpation of ankylosaurid ankylosaurs. Fossils from the Dunvegan Formation can thus yield important insight into the responses of fauna to this major transition. [ABSTRACT FROM AUTHOR]

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For sheer complexity, braincases are generally considered anatomically conservative. However, recent research on the braincases of tyrannosaurids have revealed extensive morphological variations. This line of inquiry has its root in Dale Russell's review of tyrannosaurids in which he established Daspletosaurus torosus — a large tyrannosaurine from the Campanian of southern Alberta. In the wake of systematic revisions to tyrannosaurines previously assigned to Daspletosaurus, one potentially distinct species remains undescribed. This paper describes and compares a braincase referable to this species with that of the holotype for Daspletosaurustorosus using computerized-tomography-based reconstructions. The two braincases have numerous differences externally and internally. The specimen of Daspletosaurus sp. has a bottlenecked olfactory tract, short and vertical lagena, and a developed ascending column of the anterior tympanic recess. The holotype of Daspletosaurus torosus has many unusual traits, including an anteriorly positioned trochlear root, elongate common carotid canal, distinct chamber of the basisphenoid recess, asymmetry in the internal basipterygoid aperture, and laterally reduced but medially expanded subcondylar recess. This comparison also identified characters that potentially unite the two species of Daspletosaurus, including deep midbrain flexures in the endocasts. However, many character variations in the braincases are known in other tyrannosaurids to correlate with body size and maturity, or represent individual variations. Therefore, taxonomic and phylogenetic signals can be isolated from background variations in a more comprehensive approach by using additional specimens. New information on the two braincases of Daspletosaurus is consistent with the emerging view of tyrannosaurid braincases as highly variable, ontogenetically dynamic character complexes. [ABSTRACT FROM AUTHOR]

The 100 m thick stratigraphic section exposed at Dinosaur Provincial Park (DPP; southern Alberta) contains bentonites that have been used for more than 30 years to date DPP's rocks and fossils using the K–Ar decay scheme. Limited reproducibility among different vintages of K–Ar and 40Ar/39Ar ages inhibited the development of a high-resolution chronostratigraphy. Here, we employ and further test a recently completed U–Pb geochronology and associated age-stratigraphy model to update temporal constraints on the Park's bentonites, formational contacts, and other markers. In turn, we document rock accumulation rates and calibrate ages and durations of informal megaherbivore dinosaur assemblage zones and other biozones. Weighted mean 206 Pb/238 U ages from five bentonites range from 76.718 ± 0.020 to 74.289 ± 0.014 Ma (2σ internal uncertainties) through an interval of 88.75 m, indicating a duration of ∼2.43 Myr and an overall rock accumulation rate of 3.65 ± 0.04 cm/ka. An increase in rate above the Oldman–Dinosaur Park formational contact conforms to a regionally expressed pattern of increased accommodation at ∼76.3 Ma across Alberta and Montana. Palynological biozone data suggest a condensed section/hiatus in the uppermost portion of the Oldman Formation. Dinosaur assemblage zones exhibit durations of ∼700–600 kyr and are significantly shorter than those in the overlying Horseshoe Canyon Formation. A decreased rate in dinosaur assemblage turnovers in the last eight million years of the Mesozoic in western Canada may be explained by withdrawal of the Western Interior Seaway and the expansion of ecologically homogenous lowlands in its wake. [ABSTRACT FROM AUTHOR]

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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 overall palynology of the upper Horseshoe Canyon Formation to lower Scollard Formation within the Edmonton Group is reviewed providing new insights into biostratigraphic relationships for the interval, including the recognition of unconformities in the stratigraphic package. The palynomorph recovery from the Horseshoe Canyon Formation and overlying units documents a number of significant events that allow the subdivision of the section. The Albertosaurus bonebed occurs within the lower Maastrichtian portion of the Edmonton Group. The bonebed is situated just below the base of the Scollardia trapaformis Palynomorph Zone, an important marker assemblage that has been documented from areas of the Yukon, Northwest Territories, Alberta, and Saskatchewan. This indicates that the bonebed lies at the top of the Mancicorpus vancampoi Zone. The transition between the zones is marked by a colour change in the sediments, the appearance of coals and organic-rich sediments above the transition, a decrease in numbers of vertebrate fossils, and the appearance of new pollen species. It is inferred that the observed changes reflect a climatic switch from dry to wetter conditions. At a large scale, palynomorph assemblages across this transition do not clearly indicate marked differences that can be attributed to the climatic change, with the exception of the appearance of Scollardia trapaformis and Mancicorpus gibbus in the assemblages. On a microscale of a few metres, there are changes in relative abundance of plant groups. Un examen de la palynologie globale de la partie supérieure de la Formation de Horseshoe Canyon à la partie inférieure de la Formation de Scollard, du Groupe d'Edmonton, jette un nouvel éclairage sur les relations biostratigraphiques dans cet intervalle, dont la reconnaissance de discordances stratigraphiques. Les palynomorphes trouvés dans la Formation de Horseshoe Canyon et les unités sus-jacentes documentent un certain nombre d'évènements importants qui permettent de subdiviser cet intervalle. Le lit à ossements d'Albertosaurus se trouve dans la partie maastrichtienne inférieure du Groupe d'Edmonton, juste en dessous de la zone de palynomorphe à Scollardia trapaformis, un important assemblage repère qui a été documenté dans diverses régions du Yukon, des Territoires du Nord-ouest, de l'Alberta et de la Saskatchewan. Cela indique que le lit à ossements se situe au sommet de la zone à Mancicorpus vancampoi. La transition d'une zone à l'autre est marquée par un changement de couleur des sédiments, l'apparition de charbons et de sédiments riches en matière organique au-dessus de la transition, la diminution du nombre de fossiles de vertébrés et l'apparition de nouvelles espèces de pollen. Les changements observés refléteraient le passage d'un climat sec à un climat plus humide. À grande échelle, les assemblages de palynomorphes qui caractérisent cette transition ne révèlent clairement aucune différence marquée pouvant être attribuée à des changements climatiques, à l'exception de l'apparition de Scollardia trapaformis et Mancicorpus gibbus au sein de l'assemblage. À l'échelle de quelques mètres, l'abondance relative de certains groupes de plantes varie. [ABSTRACT FROM AUTHOR]

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Discusses nonmarine fossil turtles preserved from the Late Cretaceous epoch of Alberta. Materials and methods; Turtle assemblages; Discussion.

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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.)

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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.)

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.)

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.)