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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.)

Trilobites were recovered from four cores of the middle Cambrian Earlie Formation in southwestern Saskatchewan. Fossils occur in silty mudstone with interbedded siltstone and limestone, deposited in the inner detrital belt of the craton interior, under low-energy, subtidal conditions. Taxa identified include Kootenia dawsoni (Walcott 1889), Asaphiscus wheeleri Meek 1873, Blainia gregaria Walcott 1916b, Parehmania princeps Deiss 1939b, Ehmania weedi Resser 1935, Bolaspis labrosa (Walcott 1916a), and corynexochid gen. and sp. indet., indicating an age ranging from the lower to upper Altiocculus subzone of the Ehmaniella Zone, upper Wuliuan Stage. The upper Eldon and lower Pika formations located farther west in subsurface Alberta and the Rocky Mountains are considered to be age equivalent. Biostratigraphy confirms that strata overlying the Basal Sandstone Unit are diachronous and become progressively younger eastward. The trilobite fauna is lower in diversity relative to those in temporally equivalent units in the Rocky Mountains as well as the Great Basin, indicating that it may have experienced some environmental stressors, and that seafloor colonization was sporadic and opportunistic. [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.)

Lithoprobe's sponsorship has led to the acquisition of paleomagnetic data from ~20 units throughout the Paleoproterozoic Trans-Hudson Orogen (THO) of Saskatchewan and Manitoba, essentially the first such data for the region. Discussed summarily in this paper, they provide an initial framework for the THO's tectonic evolution. They show that the Archean Hearne and Superior cratons were at subtropical and subpolar paleolatitudes, respectively, at ~1875 Ma, with the Lynn Lake – LaRonge arc midway between them in the Manikewan Ocean. By ~1855 Ma, this ocean was still ~5500 ± 700 km wide, and its seafloor was subducting northwestward under the Hearne craton and pericratonic Peter Lake domain margin with the coeval development of an Andean-type continental magmatic arc, the Wathaman–Chipewyan batholith. Between ~1855 and ~1810 Ma, coalescing apparent polar wander path (APWP) segments record closing of the ocean at a rate of ~12 cm/a, trapping and accreting the several separate intervening terranes (Flin Flon, Hanson Lake, Lynn Lake – LaRonge, Rottenstone, and presumably also other THO terranes). From ~1815 to ~1775 Ma, the assembled terranes drifted as a coherent craton, yielding a stillstand and hairpin in the APWP. [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.)

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.)

Seismic-reflection techniques have been applied in several studies over the last 20 years as a uranium-exploration tool within the Athabasca Basin and have been utilized to provide the larger structural context for known uranium deposits within the basin. At the crustal scale, deposits within the eastern Athabasca Basin are shown to be associated with deep-seated shear zones that originated during Trans-Hudson orogeny and have subsequently been reactivated during and subsequent to deposition of the basin-fill sandstones. Seismic properties of the Athabasca sandstones and underlying basement have been determined through in situ borehole measurements. Reflectivity within the sandstones is generally weak. Seismically recognizable signatures are primarily associated with variations in fracture density, porosity, and degree of silicification. The basement unconformity and regolith, a prime target of exploration, is widely imaged as it is characterized by variable but generally distinct reflectivity. Results from the McArthur River mine site suggest that the spatial coincidence of seismically imaged high-velocity zones and deep-seated faults that offset the unconformity may be a more broadly applicable exploration targeting tool. Three-dimensional (3-D) seismic imaging near existing ore zones can define the local structural controls on the mineralization and point the way to new targets, thus leading to more efficient exploration drilling programs. Furthermore, seismically generated structural maps of the unconformity and rock competence properties may play a significant role at the outset of mine planning. La sismique réflexion a été utilisée dans plusieurs études au cours des 20 dernières années en tant qu’outil d’exploration pour l’uranium dans le bassin de l’Athabasca; elle a aussi été utilisée pour fournir le contexte structural à plus grande échelle pour les gisements connus d’uranium à l’intérieur du bassin. À l’échelle de la croûte, il est montré que des gisements dans le bassin Athabasca oriental sont associés à des zones de cisaillement à grande profondeur qui ont pris naissance durant l’orogène trans-hudsonien et qui ont par la suite été réactivées durant et après la déposition des grès remplissant les bassins. Les propriétés sismiques des grès de l’Athabasca et du socle sous-jacent ont été déterminées par des mesures in situ dans des forages. La réflectivité est généralement faible dans les grès. Des signatures sismiques identifiables sont surtout associées à des variations de densité des fractures, de la porosité et du degré de silicification. La discordance entre le socle et le régolite, une cible de choix en exploration, est bien imagée en raison de sa caractérisation par une réflectivité variable mais généralement distincte. Les résultats provenant du site minier McArthur River suggèrent que la coïncidence spatiale de zones de grandes vitesses imagées par sismicité et de failles à grande profondeur qui décalent la discordance puissent être un outil plus largement applicable comme cible d’exploration. De l’imagerie sismique 3D à proximité des zones minéralisées existantes peut définir les contrôles structuraux locaux sur la minéralisation et indiquer de nouvelles cibles, menant ainsi à des programmes de forages d’exploration plus efficaces. De plus, des cartes de structure, générées par sismicité, de la discordance et des propriétés de compétence du roc pourraient jouer un rôle important dès le début d’une planification minière. [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.)

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 recovery of identifiable plant remains intimately associated with a skeleton of Tyrannosaurus rex in southwestern Saskatchewan, Canada, provides the basis for interpreting the latest Maastrichtian (65.5–65 Ma) paleoenvironment of the region. Fossil plants from the site are described, and fruits formerly known as Aesculus antiquus Dawson or Ficus ceratops Knowlton are transferred to a new taxon, Spinifructus antiquus (Dawson) comb. nov. Study of the sediments of the Frenchman Formation that host the bones and plants, in combination with analysis of the plants, indicates that the regional climate was mesothermal and without winter frost, but with seasonal drought. The T. rex is believed to have roamed a broad river valley abundantly vegetated by a largely deciduous flora. The deciduous nature of the Saskatchewan paleovegetation, interpreted as a response to low winter light levels at high latitude, contrasts strongly with the contemporaneous vegetation of a few degrees latitude further south and leads to questions about how a dinosaur fauna survived in a region where the bulk of the vegetation entered an extended period of dormancy.La collecte de restes de plantes identifiables intimement associées à un squelette de Tyrannosaurus rex dans le sud-ouest de la Saskatchewan, au Canada, constitue la base pour interpréter le paléoenvironnement du Maastrichtien terminal (65,5 à 65 Ma) de la région. Des plantes fossiles du site sont décrites et des fruits antérieurement connus comme Aesculus antiquus Dawson ou Ficus ceratops Knowlton sont transférés à un nouveau taxon Spinifructus antiquus (Dawson) comb. nov. L'étude des sédiments de la Formation de Frenchman qui contient les os et les plantes, combinée à l'analyse des plantes, indique que le climat régional était mésothermique et sans gelée hivernale mais avec des sécheresses saisonnières. On croit que T. rex se déplaçait dans une large vallée de rivière où la végétation abondante était surtout à flore décidue. La nature décidue de la paléovégétation de la Saskatchewan, interprétée comme une réponse aux faibles niveaux de lumière en hiver à haute latitude, contraste fortement avec la végétation contemporaine présente à quelques degrés de latitude plus au sud et porte à remettre en question le fait qu'une faune de dinosaures ait survécu dans une région où la plus grande part de la végétation entrait dans une période de dormance étendue.[Traduit par la Rédaction] [ABSTRACT FROM AUTHOR]

An augened, strongly flasered, and multiply folded monzonitic gneiss occurs in a structural dome in the Black Bear Island Lake region of northern Saskatchewan, within the ca. 1850 Ma Paleoproterozoic southern Rottenstone Domain of the Trans-Hudson Orogen (THO). A sample of this rock has yielded thermal ionization mass spectrometry (TIMS) and sensitive high-resolution ion microprobe (SHRIMP) zircon data consistent with a formation age of at least 2500 Ma. Zircons also show somewhat younger, ca. 2380 Ma overgrowths, indicating a complex history. The Nd model age (T[sub DM] ) of 2726 Ma also confirms the late Archean age of the rock, as does the isotopic composition of common Pb from a K-feldspar sample. U–Pb analyses of titanites yield ages of ca. 1800 Ma, indicating recrystallization during terminal closure of the THO. It is unlikely that the Archean rocks are a part of the Archean Sask craton in the Glennie Domain, for Lithoprobe seismic sections indicate that the Sask craton dips westward beneath the La Ronge and Rottenstone domains. It is more likely that the rocks are part of a klippen of Hearne Province crust emplaced during closure of the THO, a large pendant in the ca. 1850 Ma Wathaman batholith, or a crustal fragment exotic to the orogen. Further study should shed light on the tectonic and paleogeographic history of the THO.Un gneiss à monzonite, œillé, fortement filandreux et à plis multiples se retrouve dans un dôme structural dans la région du lac Black Bear Island dans le nord de la Saskatchewan, à l'intérieur du domaine Rottenstone sud (Paléoprotérozoïque, ca. 1850 Ma) de l'orogène trans-hudsonien (THO). Un échantillon de cette roche a été soumis à la spectrométrie de masse à ionisation thermique (TIMS) et à la microsonde ionique à haute résolution et à haut niveau de sensibilité (SHRIMP); les données fournies sur du zircon concordent avec un âge de formation d'au moins 2500 Ma. Les zircons montrent aussi des accroissements secondaires un peu plus jeunes, ca. 2380 Ma, indiquant un historique complexe. L'âge modèle Nd (T[sub DM] ) de 2726 Ma confirme aussi l'âge de la roche comme Archéen tardif, ce qui est appuyé par la composition isotopique de la forme commune du Pb d'un échantillon de feldspath K. Des analyses U–Pb de titanites donnent des âges de ca. 1800 Ma, indiquant une recristallisation à la fin définitive de l'orogène trans-hudsonien. Il est peu probable que les roches archéennes forment une partie du craton archéen de Sask dans le domaine de Glennie, car les sections séismiques Lithoprobe indiquent que le craton Sask plonge vers l'ouest sous les domaines de La Ronge et de Rottenstone. Il est plus probable que les roches font partie d'un klippe de la croûte de la province de Hearne, mis en place à la fin de THO, ou d'un grand pendant dans le batholite de Wathaman, ca. 1850, ou encore d'un fragment de la croûte exotique à l'orogène. Des études ultérieures devraient aider à déterminer l'historique tectonique et paléogéographique de THO.[Traduit par la Rédaction] [ABSTRACT FROM AUTHOR]