10 results
Search Results
2. Ecological controls on Devonian stromatoporoid-dominated and coral-dominated reef growth in the Mackenzie Basin, Northwest Territories, Canada.
- Author
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Corlett, Hilary, Jones, Brian, and Jin, Jisuo
- Subjects
STROMATOPOROIDEA ,REEFS ,GEOLOGICAL formations ,GEOLOGICAL basins ,SEDIMENTATION & deposition ,PALEOGEOGRAPHY - Abstract
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.)
- Published
- 2011
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3. Basin architecture and syndepositional fault activity during deposition of the Neoproterozoic Mackenzie Mountains supergroup, Northwest Territories, Canada.
- Author
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Turner, Elizabeth C. and Long, Darrel G.F.
- Subjects
INSTRUMENT landing systems ,ERHARD seminars training ,FLUID mechanics ,LITHOFACIES ,LANDFORMS ,GEOLOGICAL formations ,MOUNTAINS ,STRATIGRAPHIC geology - Abstract
The early Neoproterozoic Mackenzie Mountains supergroup (MMSG; ~4 km thick, <1083 Ma, >779 Ma) was deposited in a large but poorly understood basin. Analysis of new and existing stratigraphic data reveals unexpected, abrupt changes in thickness and lithofacies patterns in formation scale and smaller units over short distances parallel and perpendicular to depositional strike. These isopach and lithofacies patterns depict irregularly subsiding syndepositional sub-basins. These basins may have developed during basin extension in a lower-plate segment of an evolving passive margin, as the result of episodic, excessive subsidence along growth faults parallel to the basin margin, and crustal-scale (transfer) faults at a high angle to the margin. The extent of the lower-plate area is inferred to correspond to the distribution of the MMSG (~500 km strike length); upper-plate segments are inferred to flank the MMSG embayment to the northwest and southeast. A lower-plate model for the arcuate MMSG embayment has important implications for the Mackenzie Mountains zinc district. The present-day regional distribution of known carbonate-hosted base-metal showings suggests that the configuration of the thinned, faulted Neoproterozoic lower-plate segment, together with later reactivation of basement-rooted transfer faults during Neoproterozoic–Paleozoic rifting or Laramide compression, may have been important in focussing metalliferous fluids into overlying units. Le Supergroupe de Mackenzie Mountains, datant du Néoprotérozoïque (épaisseur ~4 km, <1083 Ma, >779 Ma) a été déposé dans un bassin vaste mais mal défini. L’analyse de données stratigraphiques, nouvelles et existantes, révèle des changements inattendus et brusques dans l’épaisseur et les patrons des lithofaciès à l’échelle de la formation et de plus petites unités sur de courtes distances parallèles et perpendiculaires à la direction de la déposition. Ces patrons d’isopaches et de lithofaciès décrivent des sous-bassins synsédimentaires à subsidence irrégulière. Ces bassins se sont possiblement développés durant une extension d’un bassin dans un segment de plaque inférieure d’une bordure passive en évolution et ils auraient été causés par une subsidence épisodique et excessive le long de failles de croissance parallèles à la bordure du bassin et le long de failles (de transfert) à l’échelle de la croûte à un angle élevé par rapport à la bordure. L’étendue du secteur de la plaque inférieure correspondrait à la distribution du Supergroupe de Mackenzie Mountains (sur une longueur ~500 km selon la direction) et les segments de la plaque supérieure longeraient l’enfoncement du Supergroupe de Mackenzie Mountains au nord-ouest et au sud-est. Un modèle de plaque inférieure pour l’enfoncement arqué du Supergroupe de Mackenzie Mountains a des implications importantes pour le district du zinc des monts Mackenzie. La distribution actuelle régionale connue d’indices de métaux de base dans des carbonates suggère que la configuration du segment inférieur néoprotérozoïque, aminci et faillé, et une réactivation postérieure des failles de transfert dans le socle au cours du Néoprotérozoïque – distension au Paléozoïque ou compression durant la compression laramienne, puissent avoir joué un rôle significatif dans la concentration des fluides métallifères dans les unités sus-jacentes. [ABSTRACT FROM AUTHOR]
- Published
- 2008
- Full Text
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4. Cessation of ice-wedge development during the 20th century in spruce forests of eastern Mackenzie Delta, Northwest Territories, Canada.
- Author
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Kokelj, S. V., Pisaric, M. F.J., and Burn, C. R.
- Subjects
WHITE spruce ,FROZEN ground forestry ,GLACIAL crevasses ,PERMAFROST ,PEATLAND forestry ,THERMAL properties - Abstract
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.)
- Published
- 2007
- Full Text
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5. Ovummuridae (calcareous microfossils) from a Late Devonian ramp: their distribution, preservation potential, and paleoecological significance.
- Author
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MacNeil, Alex J. and Jones, Brian
- Subjects
FOSSILS ,CARBONATES ,CEMENT ,STROMATOLITES ,PALEOZOIC stratigraphic geology ,RIVERS ,CRINOIDEA ,IGNEOUS rocks - Abstract
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.)
- Published
- 2006
- Full Text
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6. Late Holocene syngenetic ice-wedge polygons development, Bylot Island, Canadian Arctic Archipelago.
- Author
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Fortier, Daniel and Allard, Michel
- Subjects
HOLOCENE paleoceanography ,ICE-wedge polygons ,PATTERNED ground - Abstract
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.)
- Published
- 2004
- Full Text
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7. Geology, geochronology, and geochemistry of Archean rocks in the Eqe Bay area, north-central Baffin Island, Canada: constraints on the depositional and tectonic history of the Mary River Group of northeastern Rae Province.
- Author
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Bethune, K M and Scammell, R J
- Subjects
ARCHAEAN stratigraphic geology ,PLATE tectonics ,GEOLOGICAL time scales ,GEOCHEMISTRY - Abstract
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.)
- Published
- 2003
- Full Text
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8. Distinguishing between Archean and Paleoproterozoic tectonism, and evolution of the Isortoq fault zone, Eqe Bay area, north-central Baffin Island, Canada.
- Author
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Bethune, K M and Scammell, R J
- Subjects
ARCHAEAN stratigraphic geology ,FAULT zones ,GEOLOGICAL time scales - Abstract
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.)
- Published
- 2003
- Full Text
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9. A new Late Cretaceous (Turonian) basal euteleostean fish from Lac des Bois of the Northwest Territories of Canada.
- Author
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Fielitz, Christopher
- Subjects
FOSSIL fishes ,FOSSIL vertebrates ,MOLECULAR orbitals ,FINS (Anatomy) - Abstract
A new genus and species of Late Cretaceous euteleost, Avitosmerus canadensis, is described from an assemblage of fossil fishes found in a Late Cretaceous (Turonian) unnamed member (unit E) of the Great Bear Basin from Lac des Bois, Northwest Territories, Canada. It is a small fusiform fish characterized by a long slender supraorbital, the presence of a small suprapreopercle, branches of the preopercular sensory canal that reach the edge of the preopercle, and an anterior supraneural that is twice as large as those posterior to it. Additionally, elements of its caudal fin show a high degree of fusion. Avitosmerus is one of ten described Cretaceous basal euteleosts that are found worldwide (Avitosmerus, Barcarenichthys, Erichalcis, Gaudryella, Gharbouria, Humbertia, Kermichthys, Manchurichthys, Paravinciguerria, and Stompooria). Avitosmerus and Erichalcis are the only two basal euteleosts that have been described from the Cretaceous of North America. Placement of Avitosmerus into the Euteleostei is based on the presence of a free stegural, and the large first supraneural. Both of these characters are somewhat controversial and are in need of reexamination. Avitosmerus shares a number of characters with the other Cretaceous basal euteleosts, as well as Recent basal euteleosts, including a separate rostrodermethmoid and mesethmoid (Gaudryella, Erichalcis, Gharbouria, the Osmeridae, and the Coregonidae), lobate condyles of the hyomandibula (Avitosmerus, Gaudryella, and Gharbouria), leaf-shaped neural spine on the first preural centrum (Kermichthys), and the fusion of the parhypural, first, and second hypurals (Gaudryella).Un nouveau genre et une nouvelle espèce d'eutéléostéen du Crétacé supérieur, Avitosmerus canadensis, est décrit à partir d'un assemblage de poissons fossiles trouvé dans un membre sans nom (Unité E, Crétacé supérieur, Turonien) du Lac des Bois du bassin Great Bear, Territoires du Nord-Ouest, Canada. Il s'agit d'un petit poisson fusiforme caractérisé par un supraorbitaire long et mince, la présence d'un petit suprapréoperculaire, des branches du canal sensoriel préoperculaire qui atteignent l'extrémité du préopercule et un supraneural antérieur deux fois plus large que ceux qui lui sont postérieurs. De plus, des éléments de sa nageoire caudale montrent un degré de fusion élevé. Avitosmerus est l'un de dix eutéléostéens de base (Crétacé) qui sont retrouvés à travers le monde (Avitosmerus, Barcarenichthys, Erichalcis, Gaudryella, Gharbouria, Humbertia, Kermichthys, Manchurichthys, Paravinciguerria et Stompooria). Avitosmerus et Erichalcis sont les deux seuls eutéléostéens de base qui ont été décrits à partir du Crétacé de l'Amérique du Nord. Le placement d'Avitosmerus dans les Euteleostei est basé sur la présence d'un stegural séparé et d'un large premier supraneural. Ces deux caractères sont quelque peu controversés et devraient être réexaminés. Avitosmerus partage plusieurs caractères avec les autres eutéléostéens de base (Crétacé) aussi bien qu'avec les eutéléostéens de base récents comprenant : un dermethmoïde et un mésethmoïde séparés (Gaudryella, Erichalcis, Gharbouria, les Osmeridae, et les Coregonidae), des condyles lobés de l'hyomandibulaire (Avitosmerus, Gaudryella et Gharbouria), une nurépine en forme de feuille sur le premier centre préural (Kermichthys) et la fusion du parhypural, du premier et du second hypuraux (Gaudryella).[Traduit par la Rédaction] [ABSTRACT FROM AUTHOR]
- Published
- 2002
- Full Text
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10. An Early Devonian (Emsian) acanthodian from the Bear Rock Formation, Anderson River, Northwest Territories, Canada.
- Author
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Cumbaa, Stephen L and Schultze, Hans-Peter
- Subjects
GENES ,SPECIES ,BONES ,TAXONOMY - Abstract
A new genus and species of an Early Devonian (Emsian) mesacanthid acanthodiform from outcrops of the Bear Rock Formation along the Anderson River, Northwest Territories, Canada, is described. The new taxon is distinct from other mesacanthid genera and (or) species in having mesiolaterally expanded skull roof plates and paired nasal bones. Mesacanthids have fin-spines that are similar in size, number, position, and proportions. This new genus is the fourth in the family Mesacanthidae. The wider distribution and apparent taxonomic diversity represented by the discovery of the new genus are indications that the latest-surviving and arguably most advanced acanthodian group, the Acanthodiformes, was already well established in the Early Devonian.Une description est donnée d'un nouveau genre et d'une nouvelle espèce de poisson, un acanthodiforme mésacanthide du Dévonien inférieur (Emsian), provenant d' affleurements de la formation de Bear Rock et mis au jour le long de la rivière Anderson, dans les Territoires du Nord-Ouest, au Canada. Il se distingue des autres espèces et genres de Mesacanthidae par une expansion mésiolatérale des plaques de la voûte crânienne et une paire d'os nasaux. Les espèces et les genres de mésacanthes se ressemblent quant à la taille, au nombre, à la position et aux proportions des rayons épineux des nageoires. Le genre qui vient d' être découvert est le quatrième de la famille. La distribution plus étendue et la diversité taxonomique révélées par la découverte de ce nouveau genre semblent indiquer que, le dernier survivant et peut-être le plus évolué des acanthodiens, les Acanthodiformes, était déjà bien établi dans la période du Dévonien inférieur. [ABSTRACT FROM AUTHOR]
- Published
- 2002
- Full Text
- View/download PDF
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