西加拿大盆地油砂储层中的泥夹层特征   总被引：3，自引：0，他引：3  

胡元现  M.Chan  S.Bharatha  G.Gurba  D.Lee  S.Papadimitrio 《地球科学》2004,29(5):550-554

西加拿大盆地含有丰富的油砂资源,主要产于阿尔伯达省东北部的下白垩统马克马里组(McMurray Formation)．该组含有不等的砂泥斜互层．这些砂泥斜互层(IHS)在局部很发育．描述其中的泥夹层为建立客观的储层模型提供了的重要数据．试图从6个方面对泥夹层进行描述并简要讨论如何利用这些描述结果去建立客观有效的储层模型．  相似文献   

Repeated glacial-lake outburst floods in Patagonia: an increasing hazard?     

Alejandro Dussaillant  Wouter Buytaert  Paul Carling  Claudio Meier  Fabián Espinoza 《Natural Hazards》2010,54(2):469-481

Five similar glacial-lake outburst floods (GLOFs) occurred in April, October, December 2008, March and September 2009 in the Northern Patagonia Icefield. On each occasion, Cachet 2 Lake, dammed by the Colonia Glacier, released circa 200-million m³ water into the Colonia River. Refilling has occurred rapidly, such that further outbreak floods can be expected. Pipeflow calculations of the subglacial tunnel drainage and 1D hydraulic models of the river flood give consistent results, with an estimated peak discharge surpassing 3,000 m³ s^?1. These floods were larger in magnitude than any flood on record, according to gauged data since 1963. However, geomorphological analysis of the Colonia valley shows physical evidence of former catastrophic outburst floods from a larger glacial-lake, with flood discharges possibly as high as 16,000 m³ s^?1. Due to potential impacts of climate change on glacier dynamics in the area, jökulhlaups may increase future flood risks for infrastructure and population. This is particularly relevant in view of the current development of hydropower projects in Chilean Patagonia.  相似文献   

Miocene Tectonic Evolution from Dextral-Slip Thrusting to Extension in the Nyainqentanglha Region of the Tibetan Plateau   总被引：4，自引：0，他引：4       下载免费PDF全文

WU Zhenhan Patrick J. BAROSH ZHAO Xun WU Zhonghai HU Daogong LIU Qisheng 《《地质学报》英文版》2007,81(3):365-384

Dextral-slip in the Nyainqentangiha region of Tibet resulted in oblique underthrusting and granite generation in the Early to Middle Miocene, but by the end of the epoch uplift and extensional faulting dominated. The east-west dextral-slip Gangdise fault system merges eastward into the northeast-trending, southeast-dipping Nyainqentangiha thrust system that swings eastward farther north into the dextral-slip North Damxung shear zone and Jiali faults. These faults were took shape by the Early Miocene, and the large Nyainqentangiha granitic batholith formed along the thrust system in 18.3-11.0 Ma as the western block drove under the eastern one. The dextral-slip movement ended at -11 Ma and the batholith rose, as marked by gravitational shearing at 8.6-8.3 Ma, and a new fault system developed. Northwest-trending dextral-slip faults formed to the northwest of the raisen batholith, whereas the northeast-trending South Damxung thrust faults with some sinistral-slip formed to the southeast. The latter are replaced farther to the east by the west-northwest-trending Lhunzhub thrust faults with dextral-slip. This relatively local uplift that left adjacent Eocene and Miocene deposits preserved was followed by a regional uplift and the initiation of a system of generally north-south grabens in the Late Miocene at -6.5 Ma. The regional uplift of the southern Tibetan Plateau thus appears to have occurred between 8.3 Ma and 6.5 Ma. The Gulu, Damxung-Yangbajain and Angan graben systems that pass east of the Nyainqentangiha Mountains are locally controlled by the earlier northeast-trending faults. These grabens dominate the subsequent tectonic movement and are still very active as northwest-trending dextral-slip faults northwest of the mountains. The Miocene is a time of great tectonic change that ushered in the modern tectonic regime.  相似文献   

CALIBRATION:REGRESSION MODELS FOR CONCENTRATION PROBLEMS     

H.J.RUSKIN 《地理学报(英文版)》1989,(2)

A brief review of the literature on point estimators in linear calibration problems is undertaken,Supportive evidence for the relative merits of the classical and inverse regression models,drawn in generalfrom the classical inferential and Bayesian approaches,is considered and the criteria for comparison ofthe estimators are discussed with respect to their suitability for certain classes of problems.Theperformance of the estimators is assessed with respect to determining the current value of ‘x’,thepercentage concentration of administered drug levels in blood in this example.No single‘best’methodof estimation appears to hold for all values of the unknown concentration when performance is assessedby criteria based on the mean square error (MSE).However,the inverse estimator would appear to besuperior to the classical for those values of unknown X close to x.  相似文献   

Indirect estimation of ungauged peak discharges in a bedrock channel with reference to design discharge selection     

Paul A. Carling  Tamir Grodek 《水文研究》1994,8(6):497-511

Geomorphological evidence and recent trash lines were used as stage indicators in a step-backwater computer model of high discharges through an ungauged bedrock channel. The simulation indicated that the peak discharge from the 26.7 m² catchment was close to 150m³s^?1 during the passage of Hurricane Charlie in August 1986. This estimate can be compared with an estimate of 130–160 m³s^?1 obtained using the Flood Studies Report (FSR) unit hydrograph methodology. Other palaeostage marks indicate that higher stages have occurred at an earlier time associated with a discharge of 200 m³s^?1. However, consideration of both the geometry of a plunge pool and transport criteria for bedrock blocks in the channel indicates that floods since 1986 have not exceeded 150 m³s^?1. Given that the estimated probable maximum flood (PMF) calculated from revised FSR procedure is at least 240 m³s^?1, it is concluded that compelling evidence for floods equal to the PMF is lacking. Taking into consideration the uncertainty of the discharge estimation, the 1986 flood computed using field evidence has a minimum return period of 100 years using the FSR procedure. This may be compared with a return period for the same event in the neighbouring gauged River Greta of > 100 years and a rainfall return period of 190 years. In as much as discharges of similar order to FSR estimates are indicated, it is concluded (a) that regional geomorphological evidence and flood simulation within ungauged catchments may be useful as a verification for hydrological estimates of recent widespread flood magnitude and (b) that palaeohydraulic computation can be useful in determining the magnitude of the local maximum [historic] flood when determining design discharges for hydraulic structures within specific catchments.  相似文献   

Threshold of coarse sediment transport in broad and narrow natural streams     

P. A. Carling 《地球表面变化过程与地形》1983,8(1):1-18

The threshold of coarse sediment transport has been examined in natural streambeds in an upland Pennine (U.K.) area. Threshold values of the total boundary shear stress (T₀) (for a given grain size), in a narrow natural stream (W/D < 11) are considerably higher than values of T₀ in a broad stream (W/D > 11). Efficiency in the entrainment process is related not only to the overall channel geometry, but also varies as a function of discharge in channels characterized by compound roughness. Empirical curves relating T₀ and a mean grain size (d ₅) are presented, but are limited in application to streams of similar physical and hydraulic characteristics as the ones examined in this investigation. Considerable divergence is noted between these empirical functions and a summary empirical function for general application obtained from a published source. The reasons for this divergence are discussed. The influence of grain shape was found not to be important in the initiation of motion criterion. This conclusion may reflect the limited range of natural grain shapes in the study streams, but might reasonably apply to other field investigations of similar streams. Modifications of the Shields' and Yalin diagrams are suggested for practical applications in shallow streams with poorly-graded bed material. The Shields' parameter may be regarded as an inverse function of the relative protrusion of individual grains in the shallow flow depth (d ₅/D). The increased importance of augmented drag forces, in the entrainment process in shallow flows, is suggested as the physical explanation for the reduced values of the Shields' parameter. However, the relationships presented should not be applied to laboratory experiments concerned with well-graded sediments (therefore beds with little deviation in level), in which the Shields' parameter may be regarded as constant at high Reynolds' grain numbers. Consistent estimated field values of ?, a threshold sediment transport parameter, might be used to compare field data to threshold values derived from statistical arguments and laboratory experiments reported in the literature.  相似文献   

EXPERIMENTAL STUDY OF BEDLOAD TRANSPORT IN UNSTEADY OPEN-CHANNEL FLOW     

T.SONG Post-Doctoral Fellow  School of Civil  Structural Engineering  Nanyang Technological University  Nanyang Avenue  Singapore . Presently  Civil Engineer  Engineering Depatment  Technology Division  Maritime  Port Authority of Singapore. 《国际泥沙研究》1997,(3)

I.INTRODUCTIONBedloadtransportinsteadyuniformopenchannelflowhasbeenextensiVelystudied.Manyoftheformulasdevelopedforthepredictionofbedloadtransportinuniformopen-channelflowcanbebroughtinthefollowingform(ChienandWan,1983);ac=f(O)(l)xvhereacisthedimensionlessparameterofbedloadtranSPortandOisthedimensionlessparameterofflowintensity.TheseparametersaredefinedasfwheregsisthebedloadtranspoftratePerunitwidthindryweight;disthesedimentdiameter,Sisthebedslopeofthechannel;Rbisthehydraulicradiusdue…  相似文献   

Editorial: Citations and other musings     

Peter Swart  Paul Carling 《Sedimentology》2008,55(5):1115-1116

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Flow reversal over a natural pool–riffle sequence: a computational study     

Zhixian Cao  Paul Carling  Rob Oakey 《地球表面变化过程与地形》2003,28(7):689-705

A computational study is presented on the hydraulics of a natural pool–rif?e sequence composed of mixed cobbles, pebbles and sand in the River Lune, northern England. A depth‐averaged two‐dimensional numerical model is employed, calibrated with observed data at the ?eld site. From the computational outputs, the occurrence of longitudinally double peak zones of bed shear stress and velocity is found. In particular, at low discharge there exists a primary peak zone of bed shear stress and velocity at the rif?e tail in line with the local maximum energy slope, in addition to a secondary peak at the pool head. As discharge increases, the primary peak at the rif?e tail at low ?ow moves toward the upstream side of the rif?e along with the maximum energy slope, showing progressive equalization to the surrounding hydraulic pro?les. Concurrently, the secondary peak, due to channel constriction, appears to stand at the pool head, with its value increasing with discharge and approaching or exceeding the primary peak over the rif?e. The existence of ?ow reversal is demonstrated for this speci?c case, which is attributable to channel constriction at the pool head. A dynamic equilibrium model is presented to reconstruct the pool–rif?e morphology. A series of numerical modelling exercises demonstrates that the pool–rif?e morphology is more likely produced by shallow ?ows concentrated with coarse sediments than deep ?ows laden with low concentrations of ?ne sediments. It is concluded that channel constriction can, but may not necessarily, lead to competence reversal, depending on channel geometry, ?ow discharge and sediment properties. Copyright © 2003 John Wiley & Sons, Ltd.  相似文献   

On evolution of bed material waves in alluvial rivers     

Zhixian Cao  Paul A. Carling 《地球表面变化过程与地形》2003,28(4):437-441

Field and laboratory measurements have shown distinct characteristics of bed sediment waves under differing conditions, whilst their theoretical interpretation has emerged to be equivocal. This note aims to clarify the interpretation of evolution of bed material waves. The complete set of governing equations for the flow–sediment–morphology system is deduced to demonstrate its universally hyperbolic nature, irrespective of the sediment transport functions implemented to close the equations. The hyperbolic nature can admit not only attenuating bed material waves, but also shock‐like waves that are not unusual in the real world. It is suggested that the theory of dispersion/diffusion is not universally appropriate for evolution of bed material waves. Copyright © 2003 John Wiley & Sons, Ltd.  相似文献