Aquifer–peatland connectivity in southern Quebec (Canada)          下载免费PDF全文

Miryane Ferlatte  Anne Quillet  Marie Larocque  Vincent Cloutier  Stéphanie Pellerin  Claudio Paniconi 《水文研究》2015,29(11):2600-2612

In areas where peatlands are abundant, they are likely to play a significant role in the hydrological and hydrogeological dynamics of a watershed. Although individual case studies are reported in the literature, there is a large range of aquifer–peatland interactions and there is a need to understand the controls of these interactions. The objectives of this study were (1) to better understand aquifer–peatland connections and how these may be predicted by geology and geomorphic location and (2) to provide a variety of reference sites for glacial geological settings. Slope and depression peatlands were studied in the Abitibi‐Témiscamingue region and in the St. Lawrence Lowlands, two contrasting regions of southern Quebec. A total of 12 transects that span a shallow aquifer–peatland interface were instrumented with piezometers. Field investigations included peatland characterization, monthly water level monitoring, and continuous hydraulic head measurements with pressure transducers. The results indicate that 7 of the 12 transects receive groundwater from the surrounding shallow aquifer. At the peatland margin, four lateral flow patterns were identified and associated with slope peatlands (parallel inflow and divergent flow) and with depression peatlands (convergent flow and parallel outflow). Vertical hydraulic gradients suggest that water flows mainly downwards, i.e. from the peatland to the underlying mineral deposits. Vertical connectivity appears to decrease as the distance from the peatland margin increases. All of these exchanges are important components in the sustainability of peatland hydrogeological functions. The regional comparison of aquifer–peatland flow dynamics performed in this study provides a new set of referenced data for the assessment of aquifer–peatland connectivity. Copyright © 2014 John Wiley & Sons, Ltd.  相似文献   

Organic matter geochemistry and petrography of Late Cretaceous (Cenomanian-Turonian) organic-rich shales from the Belle Fourche and Second White Specks formations,west-central Alberta,Canada     

《Organic Geochemistry》2015

Organic-rich mudstones with up to 10 wt% TOC from the upper portion of the Belle Fourche Formation and the lower part of the Second White Specks Formation in the Western Canada Sedimentary Basin were evaluated as source rocks. Both geochemistry and organic petrography indicate an open marine paleoenvironment with deposition of Type II kerogen based on the predominance of marine alginite and amorphous organic matter (OM), limited amounts of terrigenous vitrinite and inertinite macerals, the presence of marine fossils, and the low ratio of TOC to total sulfur (∼1.26). The prevalence of short-chain n-alkanes (n-C₁₃ to n-C₁₉), a predominance of C₂₈ αββ(H)-20S steranes, and small concentrations of oleanane confirm the dominantly algal and planktonic origin of OM. Alternating oxic to anoxic paleoenvironmental sedimentary conditions are proposed based on common bioturbation, abundant inoceramid prisms, and good organic richness. Biomarker distributions are consistent with intermittent anoxia, without unequivocal evidence for water column stratification or hypersalinity. The thermal maturity measured in seven sediment cores by different methods consistently indicates a westward increase in maturity according to vitrinite reflectance, T_max, and hopane and sterane biomarkers. Two cores are thermally immature (∼0.42 %Ro), one is early mature (∼0.65 %Ro), and four cores are within the oil window (∼0.78 to 0.89 %Ro). All thermally mature cores retain good to very good hydrocarbon potential (248 mg HC/g rock) and are dominantly oil-prone and minor gas-prone based on their maceral compositions. The upper Belle Fourche and lower Second White Specks Formations represent potential targets for unconventional light shale oil production.  相似文献   

Transnationalism,emotion and second‐generation social mobility in the Filipino‐Canadian diaspora          下载免费PDF全文

Philip F. Kelly 《Singapore journal of tropical geography》2015,36(3):280-299

Through the case of Filipino‐Canadian youth experiences, this paper examines socio‐economic mobility among the children of immigrants in the context of transnational social fields and emotional engagements with the diasporic homeland. The Filipino‐Canadian experience is distinctive in terms of immigration patterns, settlement trajectories, policy frameworks and the historical and contemporary construction of ethno‐racial identities. Using educational attainment as a proxy for a wider process of social mobility, the paper shows that outcomes among Filipino youth have been anomalously poor. The explanations for this situation are multiple, but this paper draws particular attention to the ways in which negative emotional engagements with the Philippines as a diasporic homeland may shape self‐esteem and aspirations among Filipino youth in Canada and thereby play a role in social mobility.  相似文献   

华北克拉通与全球构造   总被引：6，自引：1，他引：5  

王荃 《地质通报》2011,30(1):1-18

华北克拉通是中国境内独具特色的大地构造单元,它既不同于新建立的华泰克拉通,又明显有别于扬子地台和塔里木地台。为追溯其形成和演化历史,将全球视为一个整体,在世界范围内寻找与其有宗谱关系的地体。经过认真的对比和鉴别,发现西伯利亚地台、加拿大地盾与中国的华北地台具有特殊的渊源关系。三者合计由14个太古宙原生陆壳块体,于古元古代末(1.79~2.2Ga)通过造山运动碰撞聚合在一起,形成了笔者所称的古劳亚大陆。后者最重要的地质标志就是统一的中元古代盖层,此即中国的长城系、蓟县系,俄罗斯西伯利亚的里菲系和北美洲的层群A、层群B。早寒武世,西伯利亚地台脱离了古劳亚大陆。中寒武世之初即536Ma,古劳亚大陆与形成于1000~1300Ma的Rodinia发生构造拼接,缔造了具有全球规模但命运短暂的超级大陆——Pannotia。这次构造拼接的意义不可低估,在时间上它恰好与骨骼化后生动物的快速发展(“生物大爆炸”)相吻合。过去长时间人们无法理解的,为什么远隔重洋的北美洲-澳大利亚-中国,寒武系中—上统的沉积类型和生物群具有高度一致性的问题,也随之迎刃而解。寒武纪末期510Ma,Pannotia解体并一分为二,在古劳亚大陆与古冈瓦纳大陆之间的地域形成了南太平洋。直到奥陶纪晚期即440Ma前后,古劳亚大陆才分裂,形成了北太平洋,中国北方包括华北和华泰2个克拉通在内,与北美洲的劳伦古陆和内陆地台,才各奔西东。回溯华北地台的渊源,作为一个整体它曾与西伯利亚地台共存了1.3Ga,而与北美的加拿大地盾至少共同度过1.4Ga之久。  相似文献   

Understanding and contextualizing social impacts from the privatization of fisheries: An overview     

Julia Olson 《Ocean & Coastal Management》2011,54(5):353-363

Fisheries management around the world has experimented with regulations to promote privatization, in order to reach such multifaceted goals as ending overfishing and reducing economic inefficiencies. This review surveys a wide range of empirical experiences in different contexts around the world to help provide a fuller picture of potential and sometimes disparate consequences from privatization in general and new ways of organizing around fishing that can follow in the wake of such measures. Looking at the many different participants in the fishing industry—from crew, small-boat owners, to households and communities—as well as the diverse sociocultural contexts in which fishing takes place, enables a better understanding of who and what is impacted, how they are impacted, why and with what further consequences, such that communities come to be seen less oppositional to economy, but rather constituted by multiple scalar processes and by economic relations comprising different motivations and behaviors.  相似文献   

加拿大地域间收入差异与国家财政补贴     

王鹏飞  Robert BAO  Catherine WONG 《地理研究》2011,30(7):1309-1318

运用基尼系数、变动系数、加重变动系数及锡尔系数对加拿大地域间收入差距变化进行实证分析后得出,自1950年代至1960年代加拿大地域差异的缩小比较缓慢,到了1970年代中期地域差异呈现出急剧缩小的倾向,随后地域差异缩小开始停滞,而进入1980年代后期地域差异又有扩大的倾向。同时加拿大政府的财政补贴对地域差异带来了很大的影...  相似文献   

Ten best practices to strengthen stewardship and sharing of water science data in Canada     

Bhaleka D. Persaud  Krysha A. Dukacz  Gopal C. Saha  Amber Peterson  Laleh Moradi  Stephen O'Hearn  Erin Clary  Juliane Mai  Michael Steeleworthy  Jason J. Venkiteswaran  Homa Kheyrollah Pour  Brent B. Wolfe  Sean K. Carey  John W. Pomeroy  Chris M. DeBeer  James M. Waddington  Philippe Van Cappellen  Jimmy Lin 《水文研究》2021,35(11):e14385

Water science data are a valuable asset that both underpins the original research project and bolsters new research questions, particularly in view of the increasingly complex water issues facing Canada and the world. Whilst there is general support for making data more broadly accessible, and a number of water science journals and funding agencies have adopted policies that require researchers to share data in accordance with the findable, accessible, interoperable, reusable (FAIR) principles, there are still questions about effective management of data to protect their usefulness over time. Incorporating data management practices and standards at the outset of a water science research project will enable researchers to efficiently locate, analyse and use data throughout the project lifecycle, and will ensure the data maintain their value after the project has ended. Here, some common misconceptions about data management are highlighted, along with insights and practical advice to assist established and early career water science researchers as they integrate data management best practices and tools into their research. Freely available tools and training opportunities made available in Canada through Global Water Futures, The Gordon Foundation DataStream, the Digital Research Alliance of Canada Portage Network, Compute Canada, and university libraries, among others are compiled. These include webinars, training videos, and individual support for the water science community that together enable researchers to protect their data assets and meet the expectations of journals and funders. The perspectives shared here have been developed as part of the Global Water Futures programme's efforts to improve data management and promote the use of common data practices and standards in the context of water science in Canada. Ten best practices are proposed that may be broadly applicable to other disciplines in the natural sciences and can be adopted and adapted globally.  相似文献   

Microstructural analyses of a Middle Pliocene till from the James Bay Lowlands,Canada—evidence of “potential” fast ice streaming     

John Menzies  Cunhai Gao  Charles Kodors 《Proceedings of the Geologists' Association. Geologists' Association》2013

Sediment from the Attawapiskat area near James Bay, Northern Ontario was sampled for micromorphological analyses. The sediment is a glacial diamicton (till) of subglacial origin. The till contains entrained and scavenged sediments of proglacial and/or subglacial glaciofluvial/glaciolacustrine origin from a subglacial deforming layer that was emplaced due to both stress reduction and/or porewater dissipation. Evidence of porewater escape, clay translocation and other microstructures all point to emplacement under active subglacial bed deformation. The limited number of edge to edge (ee) grain crushing events, however, point to lower stress levels than might anticipated under a thin fast ice lobe of the James Bay during the Middle Pliocene. Microstructures of Pleistocene tills were quantitatively compared with the Attawapiskat till and the limited number of ee events at Attawapiskat further highlighted that grain to grain contact was curtailed possibly due to high till porosity, high porewater pressures and low strain rates or alternatively due to a high clay matrix component reducing grain crushing contact events. It is suggested that this Middle Pliocene till may be indicative of sediments emplaced under ice lobe surging conditions or fast ice stream subglacial environments. This proposal has significant implications for the glaciodynamics of this part of the Middle Pliocene James Bay lobe. This research highlights a crucial link between subglacial conditions, till microstructural analyses and glaciodynamics.  相似文献   

DISCONTINUITY OF DISCHARGE OF UKRAINIAN RIVERS     

G. I. Shvets 《水文科学杂志》2013,58(1):53-57

Synopsis

The application of mathematical models for simulating the processes of the hydrological cycle is considered and the results of applying a translated version of the stanford watershed model to the River Clyde in Scotland are presented.  相似文献   

BEFOLKMNGS- OG ERHVERVSUDVIKLINGEN PÅ RØMØ 1950–70     

BODIL ENGELL M.Sc. 《Geografisk tidskrift / udgivet af Bestyrelsen for Det Kongelige danske geografiske selskab》2013,113(1):63-67

Engell. Bodil, 1977: Befolknings- og erhvervsudviklingen på Rømø 1950–70. Geografisk Tidsskrift 76: 63–67. København juni 1, 1977.

The general trend of unequal development between rural and urban intensifies on small islands. The development on the island of Rømø has further a special trend because of its intermediate position caused by the construction of the road-dam to Rømø, opened 1949. Furthermore, the recreational potential of the island and the special location close to the Danish-German border is of importance.  相似文献