Geostatistical mapping of leakance in a regional aquitard, Oak Ridges Moraine area, Ontario, Canada     

A. Desbarats  M. Hinton  C. Logan  D. Sharpe 《Hydrogeology Journal》2001,9(1):79-96

The Newmarket Till forms a regionally extensive aquitard separating two major aquifer systems in the Greater Toronto area, Canada. The till is incised, and sometimes eroded entirely, by a network of sand- and gravel-filled channels forming productive aquifers and, locally, high-conductivity windows between aquifer systems. Leakage through the till may also be substantial in places. This study investigates the spatial variability of aquitard leakance in order to assess the relative importance of recharge processes to the lower aquifers. With a large database derived from water-well records and containing both hard and soft information, the Sequential Indicator Simulation method is used to generate maps of aquitard thickness and window probability. These can be used for targeting channel aquifers and for identifying potential areas of recharge to the lower aquifers. Conductivities are modeled from sparse data assuming that their correlation range is much smaller than the grid spacing. Block-scale leakances are obtained by upscaling nodal values based on simulated conductivity and thickness fields. Under the "aquifer-flow' assumption, upscaling is performed by arithmetic spatial averaging. Histograms and maps of upscaled leakances show that heterogeneities associated with aquitard windows have the largest effect on regional groundwater flow patterns. Electronic Publication  相似文献   

Modeling an Exhumed Basin: A Method for Estimating Eroded Overburden     

Poelchau  Harald S. 《Natural Resources Research》2001,10(1):73-84

The Alberta Deep Basin in western Canada has undergone a large amount of erosion following deep burial in the Eocene. Basin modeling and simulation of burial and temperature history require estimates of maximum overburden for each gridpoint in the basin model. Erosion can be estimated using shale compaction trends. For instance, the widely used Magara method attempts to establish a sonic log gradient for shales and uses the extrapolation to a theoretical uncompacted shale value as a first indication of overcompaction and estimation of the amount of erosion. Because such gradients are difficult to establish in many wells, an extension of this method was devised to help map erosion over a large area. Sonic t values of one suitable shale formation are calibrated with maximum depth of burial estimates from sonic log extrapolation for several wells. This resulting regression equation then can be used to estimate andmap maximum depth of burial or amount of erosion for all wells in which this formation has been logged. The example from the Alberta Deep Basin shows that the magnitude of erosion calculated by this method is conservative and comparable to independent estimates using vitrinite reflectance gradient methods.  相似文献   

Petroleum Distribution Characteristics of the Americas and the Exploration Prospect Analysis     

HAO Qingqing  LI Lintao  ZUO Yinhui  CHEN Weijun  WU Lei  YI Junjie 《《地质学报》英文版》2018,92(1):378-393

The world’s present demand for oil and gas is still in a rapid growth period, and traditional oil and gas resources account for more than 60% of the global oil and gas supply. The Americas is the world’s second largest production and consumption center of liquid fuel, and is also the world’s largest natural gas producer. In 2016, the Americas had 85.3 billion tons of proven oil reserves and 18.7 trillion m3 of proven natural gas reserves, which account for 35.4% and 10.0% of world’s total reserves, respectively. It produced 1267.1 Mt of oil and 1125.4 billion m3 of natural gas, which account for 28.9% and 31.7% of the world’s total production, respectively. The crude oil and natural gas reserves are mainly distributed in the U.S., Canada and Venezuela. The U.S. is the earliest and most successful country in shale gas exploration and development, and its shale gas is concentrated in the southern, central and eastern U.S., including the Marcellcus shale, Barnett shale, EagleFord shale, Bakken shale, Fayettevis shale, Haynsvill shale, Woodford shale and Monterey/Santos shale. The potential oil and gas resources in the Americas are mainly concentrated in the anticline and stratigraphic traps in the Middle-Upper Jurassic slope deposition of the North Slope Basin, the Paleozoic Madsion group dolomite and limestone in the Williston Basin, dominant stratigraphic traps and few structural traps in the Western Canada Sedimentary Basin, the Eocene structural-stratigraphic hydrocarbon combination, structural-unconformity traps and structural hydrocarbon combination, and the Upper Miocene stratigraphic-structural hydrocarbon combination in the Maracaibo Basin of Venezuela, the stratigraphic-structural traps and fault horst, tilting faulted blocks and anticlines related to subsalt structure and basement activity in the Campos Basin, the subsalt central low-uplift belt and supra-salt central low-uplift belt in the Santos Basin of Brazil, and the structural-stratigraphic traps in the Neuquen Basin of Argentina. In addition, the breakthrough of seismic subsalt imaging technology makes the subsalt deepwater sea area of eastern Barzil an important oil and gas potential area.  相似文献   

The Influence of Culture on Wildfire Mitigation at Peavine Métis Settlement,Alberta, Canada     

Amy Christianson  Tara K. Mcgee  Lorne L'Hirondelle 《社会与自然资源》2014,27(9):931-947

This article presents findings of a study that explored how culture influenced support for wildfire mitigation in Peavine Métis Settlement, an Aboriginal community located in Alberta, Canada. Community-based research was completed using interviews, focus groups, and participant observation. The results show that cultural factors appeared to influence wildfire mitigation preferences. Participants indicated the current state of the forest was not natural, and that mitigation activities would likely improve forest health. Participants supported Settlement Council-led wildfire mitigation activities at both the residential and community level due to a preference for communal action and collective problem solving. Participants also were found to distrust “outsiders” and preferred programs developed by members of their own community. The results of this study show that wildfire mitigation programs based on local culture can be well supported in an Aboriginal community.  相似文献   

Whose Norms Prevail? Policy Networks,International Organizations and “Sustainable Forest Management”     

Fred Gale  Timothy Cadman 《社会与自然资源》2014,27(2):170-184

This article investigates the origin of international norms, arguing that one pathway is via the strategic action of sector-specific policy networks. Evidence is adduced from an examination of the contested norm of sustainable forest management (SFM). It is argued that a Canadian forestry policy network, under pressure internally and externally to demonstrate its environmental and social credentials, promoted an “economistic” SFM norm in regional negotiations known as the Montreal Process. The article outlines the policy network approach, applies it to the Canadian forest sector, and analyzes how a policy network centered in the Canadian Forest Service and the Canadian Council of Forest Ministers worked to have the network's preferred conception of SFM internationally endorsed. The article highlights the importance of investigating which social actors champion which international norms and encourages reflexive policymaking by calling into question the degree to which international norms actually reflect a genuine global consensus.  相似文献   

太平洋夏季水对加拿大海盆海冰的影响   总被引：1，自引：0，他引：1  

宋雪珑  周生启 《海洋学报》2014,36(11):38-45

近年来,北极海冰发生了大面积减少,减少的原因仍存在着争议。基于2003-2011年的水文和遥感卫星数据,对北冰洋加拿大海盆的太平洋水和海冰进行研究。通过对比2006年和2007年太平洋水位温与海冰密集度的空间分布,发现太平洋水暖异常于2007年1-3月进入加拿大海盆的中部,并可能导致了2007年夏季海冰大面积的融化。2003-2011年,在加拿大海盆的中部,太平洋水位温与海冰密集度存在着时间上的负相关。选取2007年8月,发现两者在空间上也存在着负相关。这很可能说明太平洋水暖异常在流动的过程中,向上输送了热量,在一定程度上,融化了海冰,从而触发海冰-反照率正反馈,导致海冰的减少。因此,通过白令海峡进入北冰洋的太平洋夏季水,对北极海冰面积的减少有着重要影响。  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   

加拿大纽芬兰-拉布拉多省镍矿勘查潜力          下载免费PDF全文

王永春  张熹鹏  孙东宾  王龙 《地质找矿论丛》2016,31(2):289-294

纽芬兰-拉布拉多省地处加拿大地盾东缘,成矿条件十分优越,是加拿大重要的镍矿成矿区,矿化类型多样。文章基于前人对该区镍矿床和矿化的研究,从区域成矿地质背景、矿化类型及地质特征、地球物理特征、勘探潜力、勘查态势等等方面进行了系统分析。拉布拉多地区的镍矿资源主要分布于辉长质—橄长质镁铁质岩石分布区,主要与中元古代侵入的辉长岩、斜长岩、橄长岩、辉石岩有关,或与太古宙超镁铁质变火山岩有关,矿化类型有橄长岩和辉长岩型、辉石岩型、斜长岩型、铁闪长岩型、火山岩(科马提岩)型;Voisey′s Bay Ni-Cu-Co硫化物矿床是拉布拉多地区已发现的大型镍矿床。纽芬兰地区的镍矿资源主要与古生代辉长-闪长质侵入岩、前寒武系镁铁质片麻岩有关,矿化类型主要有辉长岩型、镁铁质片麻岩型、火山热液型。纽芬兰-拉布拉多省的镍矿勘查前景乐观。  相似文献   

白令海、楚科奇海、加拿大海盆沉积物重金属潜在生态风险评价          下载免费PDF全文

宋冬梅冯文强  刘焱光刘春晓 吴会胜 《极地研究》2016,28(3):346-352

利用电感耦合等离子体质谱仪(ICP-MS仪)测定北极亚北极海区的白令海、楚科奇海、加拿大海盆海区沉积物中8种重金属元素的浓度,并对8种重金属元素的地球化学特征、空间分布特征、可能来源进行了研究。研究发现,Cr、Zn、Co、Ni、Cu、Pb、Bi有很强的相关性,说明其具有相似的来源,且空间分布的特征相似,均为沉积物底质中的浓度在研究区内呈现出在白令海和楚科奇海较低,在加拿大海较高的特征;而Cd与其他重金属空间分布差异明显。应用Hakanson潜在生态危害指数法与内梅罗综合污染指数法对各重金属的潜在风险进行了评价,其中,用Hakanson潜在生态危害指数法求得北极整体生态风险性指数值达到43.01,处于轻微生态风险状态,Co重金属元素风险最大。研究结果表明,两种评价结果得出类似规律,白令海生态安全性最高,楚科奇海大部分地区生态安全性较高,加拿大海盆的生态安全性最差。在研究区内整体上呈现出由高纬度向低纬度生态安全逐渐增高,西部生态风险性大于东部的趋势。  相似文献   

Indicators of abundance and spatial distribution of lobsters (Homarus americanus) from standard traps     

M. John Tremblay  Carl Macdonald  Ross R. Claytor 《新西兰海洋与淡水研究杂志》2013,47(1):387-399

Indicators of abundance for American lobster (Homarus americanus) based on 8 years of trap catch rates (catch‐per‐unit‐effort, CPUE) were evaluated. Volunteer harvesters recorded count, sex and size of lobsters captured in standard traps on a daily basis during the fishing season in coastal Nova Scotia, Canada. We examined the extent to which standardised CPUEs of prerecruits predict the future catches of legal sizes and explored spatial patterns in the abundance of lobsters of different size and reproductive status. The standardised CPUE of prerecruits was correlated with legal size catches in only one of five areas examined. This area had a strong signal of incoming recruitment. Improving the capacity of prerecruit CPUE for predicting legal size catches several years later most likely lies with model incorporation of variables associated with catchability. The spatial distribution of catch rates showed that the area with the highest historical landings per unit area also had the highest relative abundance of prerecruits. The spatial distribution data point to further areas of research related to recruitment processes in lobster in coastal Nova Scotia.  相似文献