16 research outputs found

    Late Quaternary Landscape Evolution in a Region of Stable Postglacial Relative Sea Levels, British Columbia Central Coast, Canada

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    After retreat of the Cordilleran Ice Sheet (CIS) and subsequent glacio-isostatic adjustment of the central coast of British Columbia (BC), Canada, a complex coastline emerged as relative sea level rapidly reached equilibrium and maintained stability over the end of the Late Pleistocene and Holocene. This study provides a late Quaternary reconstruction of the landscape evolution of a geographically distinct location on the central BC coast, northwest Calvert Island, which experienced a re-advance of the CIS near the end of the Late Pleistocene and minimal subsequent relative sea-level change. Geomorphological observations from LiDAR imagery, sedimentological and palaeoecological evidence from exposures, cores and shovel pits, and a robust luminescence and 14C-based chronology spanning the last 15 000 years are used to reconstruct the landscape of northwest Calvert Island following CIS retreat. A single-aliquot regenerative dose protocol that was developed specifically for luminescence dating of the sediments on Calvert Island was utilized in this study. Localized proglacial sedimentation was linked to the glacial re-advance experienced at the end of the Late Pleistocene. Extensive coastal reconfiguration (e.g. rapid shoreline progradation of \u3e1 m a−1) occurred in the absence of extensive RSL change, which was the main driver of coastal change elsewhere along the BC coast. Changes in climate, small magnitude changes in RSL, and fire all probably played a role in isolated aeolian landform development and stabilization in the study area. An important contribution of this study is the documentation of the multi-disciplinary approach for reconstructing palaeogeography, using multiple geochronological methods, micro- and macro-sedimentology, the palaeoecology inferred from both macro and microfossils (e.g. diatoms and foraminifers), stratigraphy, field mapping and remote sensing. In addition, these findings inform our understanding of the drivers of coastal sedimentary processes, particularly in the temperate coastal rainforest region of BC, and the role that fire may play in those processes. Coastal palaeogeography studies in the region will become increasingly important as discoveries of Late Pleistocene human habitation along the coastal migration route continue to be documented. © 2017 Collegium Boreas. Published by John Wiley & Sons Lt

    The inner shelf geology of Atlantic Canada compared with the North Sea and Atlantic United States: Insights for Atlantic Canadian offshore wind energy

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    The Quaternary history of the Atlantic Canadian inner shelf shares some similarities with the North Sea and northern United States of America (US) Atlantic coast, with the influence of large-scale glaciation and subsequent sea level transgression being the main drivers of seafloor morphology, sedimentology, and uppermost stratigraphy. The geology of the inner shelf, generally confined to 100 m water depth for this study, is an important constraint on the development of offshore renewables, in particular wind energy. Offshore wind has seen rapid growth, particularly in Europe and Asia, where the industry has now experienced decades of production. In the US, one small-scale production farm and many hundreds of MW are in the production pipeline. In contrast, offshore wind in Canada, despite onshore installed wind capacity that ranks highly globally, lacks any operating turbines and there are no plans for development in the wind resource-rich Atlantic Canadian region. In this study, the geological constraints on offshore wind in Atlantic Canada are explored. Generally, the available offshore wind resource is high, and thus the main geophysical constraint on the development of offshore wind energy converters is the inner shelf geology. Several sites with available high-resolution geophysical data are selected for in-depth analysis and comparison with production and planned offshore wind farm sites found elsewhere. In general, a lack of sufficiently thick Quaternary sedimentation—necessary for the most common bottom-fixed foundations for wind turbines—will make developing offshore wind in Atlantic Canada challenging when compared with North Sea and US Atlantic Coast locations. A few locations may be suitable geologically, such as Sable Island Bank in Nova Scotia (thick package of sands), Northumberland Strait between Prince Edward Island and Nova Scotia (shallow firm seabed and sandbanks), Baie des Chaleurs in New Brunswick/Québec (thick, low relief fine sediments), and St. George's Bay, Newfoundland (shallow, postglacially modified moraine). Highlights • Glaciated shelves in Atlantic Canada present distinct challenges for offshore wind foundations. • Few analogies exist between Atlantic Canadian shelf sites and offshore wind sites elsewhere. • Piles—typical offshore wind foundations—require thick sediments, rare in Atlantic Canada. • Thin sand/cobble blankets over bedrock are ubiquitous but thick sand banks/mud basins exist. • The inner shelf seabed geology is variable and historically data collection has focused elsewhere

    Spatial and temporal trends of contaminants in Canadian Arctic freshwater and terrestrial ecosystems: A review

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    The state of knowledge of contaminants in Canadian Arctic biota of the freshwater and terrestrial ecosystems has advanced enormously since the publication of the first major reviews by Lockhart et al. and Thomas et al. in The Science of the Total Environment in 1992. The most significant gains are new knowledge of spatial trends of organochlorines and heavy metal contaminants in terrestrial animals, such as caribou and mink, and in waterfowl, where no information was previously available. Spatial trends in freshwater fish have been broadened, especially in the Yukon, where contaminant measurements of, for example, organochlorines were previously non-existent. A review of contaminants data for fish from the Northwest Territories, Yukon and northern Quebec showed mercury as the one contaminant which consistently exceeds guideline limits for subsistence consumption or commercial sale. Lake trout and northern pike in the Canadian Sh
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