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   

夏季加拿大海盆海冰边缘区声体积后向散射强度研究   总被引：1，自引：1，他引：0  

刘洪宁  吕连港  刘娜  杨光兵  姜莹  杨春梅  刘宗伟  林丽娜 《海洋学报》2015,37(11):127-134

声信号的体积后向散射强度是声传播过程中一个关键的参数。海冰边缘区的声体积后向散射强度研究对深入认识北极声场环境有着十分重要的意义。本文利用中国第六次北极科学考察获取的数据资料研究了海冰边缘区声体积后向散射强度特性。结果表明:加拿大海盆海冰边缘区是声体积后向散射强度的明显过渡区。无冰海面(海冰密集度小于15%)海洋深层水的声体积后向散射强度明显大于密集海冰区域的海水(海冰密集度大于50%)。讨论了声体积后向散射强度与海冰融化之间的关系,造成融冰区声体积后向散射强度增大的原因是水下悬浮泥沙、浮游生物等悬浮物质增加。根据海冰密集海域的海水后向散射强度弱的特点,对北极下放式声学多普勒测流仪(LADCP)观测的设置提出建议。  相似文献   

The Beaufort Gyre variation and its impacts on the Canada Basin in 2003–2012   总被引：1，自引：1，他引：0  

钟文理  赵进平  史久新  曹勇 《海洋学报(英文版)》2015,34(7):19-31

The Beaufort Gyre (BG) was spun up in the last decade which is an important factor in regulating the variation of the upper ocean. The heat content and freshwater content of the upper ocean increased g...  相似文献   

加拿大海盆深层双扩散对流的观测分析   总被引：1，自引：0，他引：1  

谢玲玲  李明明  李敏 《海洋学报(英文版)》2015,34(11):71-79

The Canada Basin(CB) is the largest sub-basin in the Arctic, with the deepest abyssal plain of 3 850 m. The double-diffusive process is the possible passage through which the geothermal energy affects the above isolated deep waters. With the temperature-salinity-pressure observations in 2003, 500-m-thick transition layers and lower1 000-m-thick bottom homogenous layers were found below 2 400 m in the central deep CB. Staircases with downward-increasing temperature and salinity are prominent in the transition layers, suggesting the doublediffusive convection in deep CB. The interface of the stairs is about 10 m thick with 0.001–0.002°C temperature difference, while the thicknesses of the homogenous layers in the steps decrease upward from about 60 to 20 m.The density ratio in the deep central CB is generally smaller than 2, indicating stronger double-diffusive convection than that in the upper ocean of 200–400 m. The heat flux through the deepest staircases in the deep CB varies between 0.014 and 0.031 W/m2, which is one-two orders smaller than the upper double-diffusive heat flux,but comparable to the estimates of geothermal heat flux.  相似文献   

Review of shark legislation in Canada as a conservation tool     

《Marine Policy》2015

Sharks are threatened from overfishing due to their life cycle biology, and unsustainably high catch rates to supply fins for shark fin soup. Canada, a leader in shark conservation uses numerous legislative tools to help conserve sharks. These tools include international treaty obligations under the Northeastern Atlantic Fisheries Organization [NAFO] and the International Commission for the Conservation of Atlantic Tuna [ICCAT], as well as national and provincial legislation including the Fisheries Act, Pacific and Atlantic Fisheries Regulations, and Coastal Fisheries Protection Act. Through the use of these legislative tools Canada has successfully banned shark finning in its waters, and implemented closed seasons, gear restrictions, and species restrictions to help manage shark populations. However, Canada still allows the sale of shark fin products locally, and allows the exportation of shark fins internationally. In order for Canada to maintain its leadership status Canada must increase legislative protection of sharks by following international best practices, and ban the sale and exportation of shark fin products. This would ensure that Canada does not play a role in global supply or demand of shark fins. Doing so would strengthen Canada's position as a leader in shark conservation, and improve the legislation currently used as a conservation tool.  相似文献   

Mobile GIS技术在加拿大的应用与发展     

罗名海 《测绘科学》2007,32(5):134-135,57

本文介绍了Mobile GIS的组成要素、体系结构及在加拿大的应用情况,包括路面监测维护和交互式导航系统。Mobile GIS综合运用GPS、GIS和无线通讯技术,与Internet GIS一起构成分布式的移动计算环境,解决现场信息的实时获取和同步更新问题,使得GIS从办公室扩展到野外作业环境,是当今GIS发展的一个重要方向。  相似文献   

Magmatic and post-magmatic evolution of post-collisional rare-metal bearing granite: The Neoproterozoic Homrit Akarem Granitic Intrusion,south Eastern Desert of Egypt,Arabian-Nubian Shield     

Bassam A. Abuamarah  Mokhles K. Azer  Amany M.A. Seddik  Paul D. Asimow  Pedro Guzman  Brent T. Fultz  M.J. Wilner  Nathan Dalleska  Mahmoud H. Darwish 《Chemie der Erde / Geochemistry》2022,82(1):125840

The Homrit Akarem granitic intrusion (HAGI) outcrops near the western edge of the south Eastern Desert basement exposure in Egypt. It is a composite of two cogenetic intrusive bodies: an early albite granite phase shallowly emplaced at the apex of a magmatic cupola, and a later subjacent pink granite phase with a marginal zone of muscovite granite and better preservation of magmatic features. Mineral chemistry of primary biotite and garnet, together with whole-rock chemistry, identify the HAGI as a highly fractionated A-type peraluminous intrusion. The chemistry of F-dominant, Li-bearing, Fe³⁺-rich primary magmatic mica in the pink granite resembles that typically found in highly evolved Nb-Y-F pegmatites. The HAGI is the evolved product of a primary magma generated by partial melting of juvenile crust of the Arabian-Nubian Shield (ANS), emplaced along a regional strike-slip fault system that promoted its ascent. The main emplacement mechanism and evolutionary sequence of the HAGI was magmatic, although secondary minerals and textures resulting from hydrothermal fluid interactions are observed, especially at its margins. Primary columbite-(Mn) crystallized from melt and was partly replaced by secondary fluorcalciomicrolite. The high fluorine content of magmatic fluids exsolved from the intrusion is indicated by quartz-fluorite veins, greisenization, albitization, and F-bearing secondary oxide minerals. The magmatic derivation of this fluid is demonstrated by the F-dominant primary mica, a siderophyllite-polylithionite solid solution commonly known as zinnwaldite. The chemistry of zinnwaldite constrains the F/OH activity ratio and oxygen fugacity of its parental melt and thereby resolves the ambiguity between pressure and the effects of F in controlling the normative quartz content of rare-metal granites. The HAGI is less mineralized than the post-collisional rare-metal granites found further east in the south Eastern Desert, replicating a trend observed previously in the central Eastern Desert and suggesting that east-west zoning in rare metal enrichment is a persistent feature across latitudes at the western edge of the ANS.  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   

Hillslope hydrology and wetland response of two small zero‐order boreal catchments on the Precambrian Shield     

M. D. Frisbee  C. J. Allan  M. J. Thomasson  R. Mackereth 《水文研究》2007,21(22):2979-2997

Two Precambrian Shield zero‐order catchments were monitored from January 2003 to July 2004 to characterize their hydrological and biogeochemical characteristics prior to a forest management experiment. Hydrometric observations were used to examine temporal trends in hillslope‐wetland connectivity and the hillslope runoff processes that control wetland event response. The hillslope groundwater flux from the longer transect (E1) was continuous throughout the study period. Groundwater fluxes from a shorter and steeper hillslope (E0) were intermittent during the study period. Large depression storage elements (termed micro‐basins) located on the upper hillslope of the E1 catchment appeared to be at least partly responsible for the observed rapid wetland runoff responses. These micro‐basins were hydrologically connected to a downslope wetland by a subsurface channel of glacial cobbles that functioned as a macropore channel during episodic runoff events. The runoff response from the hilltop micro‐basins is controlled by antecedent water table position and water is quickly piped to the wetland fringe through the cobble channel during high water table conditions. During periods of low water table position, seepage along the bedrock–soil interface from the hilltop micro‐basin and other hillslopes maintained hillslope–wetland connectivity. The micro‐basins create a dynamic variable source‐area runoff system where the contributing area expands downslope during episodic runoff events. The micro‐basins occupied 30% of the E1 catchment and are a common feature on the Precambrian Shield. Copyright © 2007 John Wiley & Sons, Ltd.  相似文献   

Magnetotelluric Soundings In the Canadian Rocky Mountains     

V. R. S. Hutton  D. I. Gough†  G. J. K. Dawes  J. Travassos 《Geophysical Journal International》1987,90(1):245-263

Summary. Magnetotelluric soundings have been made at 25 stations in the Rocky Mountain Trench (RMT) and Main Ranges near 53° N, close to the centre of a major conductivity anomaly which had been mapped in a magnetovariation array study. Most stations covered the frequency range 0.01–500 Hz and three stations 0.0002–500 Hz. the resistivity tensor shows low to moderate anisotropy in the RMT, but is strongly 2-D or 3-D in the Rocky Mountains. Apparent resistivities as a function of frequency are displayed in pseudosections along the Trench and along a transverse profile across the RMT and into the Main Ranges. In preparation for 2-D modelling, 1-D inversions have been used to construct resistivity-depth sections satisfying both magnitudes and phases of the MT responses. These show very low resistivities, in the range 1—10Ωm, in the upper crust under the RMT and even lower values under the Main Ranges. the latter values give strong confirmation of the Northern Rockies conductor reported by Bingham, Cough & Ingham and are in agreement with models of the conductors fitted to long-period magnetovariation fields by Ingham, Gough & Parkinson. the MT results here reported add some essential depth and resistivity information. It is suggested that the conductors beneath the Rocky Mountains Main Ranges and Trench constitute a thickening at the edge of the Canadian Cordilleran Regional (CCR) conductor. Gough has argued that a wide variety of geophysical and geological parameters indicate high temperatures and partial melting in the mantle under the CCR conductor. At the upper crustal depths penetrated in this magnetotelluric study, it is considered more probable that the high conductivity is caused by hot, saline water of mantle origin rather than silicate melt. the CCR in general may have two layers of fluid producing its high conductivity, silicate melt below and saline hot water above.  相似文献