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The Cambrian pre-salt dolomite sequence in the Tarim Basin is a target zone of great strategic significance for hydrocarbon exploration in the basin. Using the results of the interpretation of 3D seismic data from Lunnan and 2D seismic data covering the whole basin, and based on a synthesis of outcrop data, drilling data, well logs, core data, and thin-section data, and the findings from previous studies, this paper studies the characteristics of the facies of the Middle–Lower Cambrian in the platform area in the Tarim Basin, the formation and evolution of platform margins, and the sedimentary characteristics, lithofacies, and paleogeographic characteristics of the Middle–Lower Cambrian series. Based on the types of lithofacies and the seismic facies analysis, the sedimentary facies of the Middle–Lower Cambrian strata can be classified into the five types. From bottom to top, the Middle–Lower Cambrian have experienced several development stages, including the deposition of continental shelf sediments of the Yuertusi Formation, gently sloping non-rimmed platform margin sediments of the Xiaoerbulake Formation, weakly rimmed platform margin sediments of the Wusongger and Shayilike formations, and strongly rimmed platform margin sediments of the Awatage Formation. In each stage, the platform margin shifted further east relative to its location in the previous stage. Based on these results and previous studies, the lithofacies and paleogeography maps of the Middle–Lower Cambrian in the Tarim Basin are modified, and the implications for hydrocarbon exploration in this area are discussed. [ABSTRACT FROM AUTHOR]

Canada ratified the United Nations Convention on the Law of the Sea (UNCLOS) in 2003. With that ratification is an obligation to submit data and information to the U.N. pertaining to the limits of the country's extended continental shelf (ECS); the portion of the juridical continental shelf that extends beyond 200 nautical miles. A team of Canadian scientists, managers, and legal experts that included representation from three Federal Departments (Natural Resources Canada, Fisheries and Oceans Canada, and Global Affairs Canada) with additional support from other departments, spent 13 years compiling and acquiring data to provide the scientific evidence to support delineation of Canada's seaward most maritime limit. The submission has the potential to provide Canada with 2.4 million km2 of additional submarine landmass in the Atlantic and the Arctic oceans over which Canada exercises sovereign rights for the purpose of exploring and exploiting its natural resources. Specific information such as the tectonic framework of the continental margin, the geomorphology of the margin and in particular the continental slope, the geologic nature of adjoined ridges, rises, and plateaux, and sediment thickness within adjacent basins are examples of fundamental pieces of geoscientific information needed to substantiate Canada's outermost maritime limits. This paper highlights a number of segments of Canada's continental margins to showcase this scientific evidence and how it is applied in the UNCLOS context. In doing so, the paper demonstrates the geologic complexity of Canada's margins as illustrated in scientific publications that have resulted from these new data collections, while at the same time presenting new scientific evidence and interpretations. This collection of data and information provides a wealth of new knowledge in Canada's offshore regions. The massive data compilation in the Atlantic led to conception of continental margins, in a source-to-sink scenario, as having an equilibrium base level or graded form, comparable to river systems. Departures from this shape relate to the interplay of sedimentary processes and in particular to those processes that do not fit the source-to-sink paradigm. For example, a significant part of the Atlantic margin is shown to be heavily influenced by along-slope geostrophic currents that generated massive contourite drift deposits. These deposits reflect lateral transport of sediment that had a significant impact on the morphology of the margin. The role of mass transport processes in shaping continental margins is also highlighted, and in particular the collapses of entire segments of the margin were observed. The prominent role mass failure processes play in delivering sediment to the adjacent abyssal plain is also critical in the ECS context. These observations challenge the entrenched notion of a continental margin comprising a shelf, slope, and rise and in particular the concept of the "continental rise". Prior to 2006, regions of the Arctic Ocean seaward of the Canadian landmass had fewer than 5000 km of seismic reflection data. The massive efforts of Arctic coastal States to map their margins for ECS purposes have led to a leap in technological advances to acquire data in ice-covered seas and have led to a wealth of new geoscientific knowledge. Perhaps foremost amongst this knowledge is demonstration that Canada Basin is indeed a fully developed ocean basin, albeit significantly infilled with sediment. Based on this knowledge and identification of related structures, new realistic tectonic scenarios for opening of the Amerasia Basin are proposed that include a significant component of transform or strike-slip motions. With seismic velocity and rock sample information, the continental nature of Alpha and Mendeleev ridges has been substantiated. Even bathymetric data were lacking in the Arctic and new editions of seafloor maps now support grids of 500 m spacing; although some regions remain sparse. Once thought to be relatively stagnant, sedimentary processes such as found in many ocean basins were discovered in the Arctic Ocean. Evidence of geostrophic currents, sediment mass failures, and deep-sea turbidity current channels were found to be ubiquitous, even in the deepest parts of the Arctic's basins. [ABSTRACT FROM AUTHOR]

Quaternary sediment in the Labrador Sea was derived from many proglacial sources in Greenland and eastern Canada. Understanding the spatial and temporal changes in sediment provenance provides information on ice extent and sediment dispersal patterns. Variations in mineral composition of sediment from late Quaternary cores has been determined by a whole pattern of quantitative X-ray diffraction procedure. Mineral facies were extracted statistically by a supervised analysis of 90 samples from bedrock and ice-rafted clasts, which were then used to predict the most probable mineral facies in 1443 marine sediment samples. We used a non-parametric Classification Decision Tree (CDT) to validate that decision. Only 26% of the samples were misclassified in the CDT. The six facies identified consisted of four facies reflecting differences in the composition of Canadian and Greenland Precambrian igneous and metamorphic bedrock, a set of samples dominated by high weight percentages of calcite and dolomite (detrital carbonate (DC) and Hudson Strait Heinrich (HS-H) events), and a "shale" facies. We isolated 284 sediments from the HS-H DC facies and determined that they could be divided into four categories based on differences in their mineral proportions. These categories vary geographically, based on non-carbonate sediment supply during these events from Greenland, the Canadian Shield, the Appalachians, and the outer continental shelf. In the Holocene of the Labrador Sea, dolomite is derived from Baffin Bay and abundance of calcite is influenced by both biogenic productivity and dissolution. [ABSTRACT FROM AUTHOR]

The Newfoundland and Labrador Shelves Bioregion, located on the glaciated continental shelf and adjacent continental slope of eastern Canada, is classified into units that reflect its great physiographic diversity. There are ten shelf units: bedrock zone, fjord systems, major inlet, shelf-crossing troughs, four types of offshore banks, basin, and disturbed (glaciotectonic) terrain. There are three units on the continental slope: channelized areas, trough-mouth areas, and large sedimentary drifts. A series of vignettes illustrates both the distinguishing characteristics of the principal geomorphic units and the morphologic diversity within them. A sediment mobility analysis reveals that wave- and current-generated disturbances are dominant and largely depth-controlled within the shelf units, while the south-flowing Labrador Current impacts sediment transport and mobility along the continental slope. [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.)

Kakanui volcaniclastic deposits on the South Island of New Zealand are the remnants of two late Eocene to early Oligocene Surtseyan-type cones. Eruptive-dominated material of the (i) stratified tuff and lapilli tuff, and (ii) lapilli tuff breccia lithofacies and post-eruptive debris of the (iii) shell-rich tuff and lapilli tuff, and (iv) chaotic and cross-bedded tuff and lapilli tuff lithofacies compose the deposits. The 9–250 m thick stratified tuff and lapilli tuff contains grain-flow deposits originating from low-volume tephra jets and local thinning and fining upward sequences that formed from density currents during sustained uprush. The lapilli tuff breccia, up to 4.5 m thick, contains inward-dipping beds deposited via debris flows along inner-cone walls. Burrows and articulated shells in the 2–4 m thick shell-rich tuff and lapilli tuff indicate volcanic quiescence and low sedimentation rates, whereas shell fragments upsection signal increased wave and current activity. Burrows, pyrite concretions, and mudstone in the lower part of the 26 m thick chaotic tuff and lapilli tuff indicate suspension deposition and cessation in pyroclastic volcanism. High-angle trough cross-beds and limestone rip-up fragments upsection are consistent with wave-induced current reworking. The depositional model involves a Surtseyan-type eruption on a continental shelf, followed by colonization of organisms on the tops of planed-off cones. The Kakanui deposits comprise a cluster of cones constituting part of a late Eocene – early Oligocene monogenetic volcanic field. The Kakanui succession provides an opportunity to study deposits that form from explosive subaqueous pyroclastic eruptions and wave-dominated deposition and erosion. Les dépôts volcanoclastiques Kakanui de l’Île du Sud de la Nouvelle-Zélande sont les lambeaux d’érosion de deux cônes de type surtseyen datant de l’Éocène tardif à l’Oligocène précoce. Les dépôts sont composés principalement de matériaux éruptifs composés (i) de tufs stratifiés et de tufs à lapilli et (ii) de lithofaciès de brèches de tuf à lapilli et de débris post-éruption composés (iii) de tufs coquilliers et de tufs à lapilli et (iv) de tufs chaotiques et à laminations croisées et de facies de tufs à lapilli. Le tuf stratifié et à lapilli d’une épaisseur de 9 à 250 mètres contient des dépôts d’écoulement de grains provenant de jets de tephra à faible volume et des séquences qui s’amincissent et dont les grains deviennent plus fins vers le sommet; ces séquences proviennent de courants de densité présents durant la montée soutenue de la lave. Les brèches de tuf à lapilli, atteignant des épaisseurs de 4,5 m contiennent des lits à pendage retourné déposés par des écoulements de débris le long des murs internes du cône. Des tunnels et des coquillages articulés dans le tuf riche en coquillages, d’une épaisseur de 2 à 4 m, combinés au tuf à lapilli, indiquent un volcan au repos et de faibles taux de sédimentation. Par contre, des fragments de coquillages dans le haut de la section sont un indice de plus de vagues et de courants. Les tunnels, les concrétions de pyrite et les mudstones dans la partie inférieure du tuf chaotique d’une épaisseur de 26 m et le tuf à lapilli indiquent une déposition de la matière en suspension et l’arrêt du volcanisme pyroclastique. Les lits à stratification entrecroisée dont l’angle est élevé et des fragments de calcaire arrachés concordent avec un remaniement par un courant induit par les vagues. Le modèle de déposition implique une éruption de type surtseyen sur un plateau continental, suivie d’une colonisation d’organismes sur les sommets des cônes tronqués. Les dépôts Kakanui comprennent une grappe de cônes qui font partie d’un champ volcanique monogénique datant de l’Éocène tardif – Oligocène précoce. La suite Kakanui fournit la possibilité d’étudier des dépôts qui se sont formés à partir d’éruptions explosives pyroclastiques subaquatiques et de déposition dominée par les vagues et par l’érosion. [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.)