A simple model of radiocaesium transport from Windscale to the Clyde Sea area     

I.G. McKinley  M.S. Baxter  W. Jack 《Estuarine, Coastal and Shelf Science》1981,13(1):59-67

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A Tsunami Generated by a Possible Submarine Slide: Evidence for Slope Failure Triggered by the North Anatolian Fault Movement     

K.?MinouraEmail author  F.?Imamura  U.?Kuran  T.?Nakamura  G. A.?Papadopoulos  D.?Sugawara  T.?Takahashi  A. C.?Yalciner 《Natural Hazards》2005,36(3):297-306

A tsunamigenic sediment layer has been discovered in fluvio-alluvial sequences on the northern coast of the Marmara Sea, northwestern Turkey. The layer consists of unsorted silty coarse sand including terrestrial molluscs and charcoal fragments. The AMS radiometric ages of the shells have been estimated at around BC 400, AD 300, AD 400, and AD 1000. We propose that a tsunami occurred in the Marmara Sea in the middle of 11th century and invaded the fluvial plains. The older fossils were derived from the underlying horizons, and it is probable that buoyant materials such as terrestrial molluscs and charcoals were isolated from liquefied sediments during submarine sliding. Slope failure of coastal blocks triggered by fault movement generated tsunamis, which might have transported floating materials to the backshore.  相似文献   

Diagenetic signatures of stratal surfaces in the Upper Jurassic Fulmar Formation, Central North Sea, UKCS   总被引：2，自引：0，他引：2  

FIONA E. BURNS  STUART D. BURLEY  ROB L. GAWTHORPE  JOHN E. POLLARD 《Sedimentology》2005,52(6):1155-1185

Sedimentation rate and changes in relative sea level affect early diagenetic cementation along key stratal surfaces within the deeply buried Upper Jurassic Fulmar Formation, South Central Graben, UKCS. As a result of the bioturbated nature of the shallow marine strata, variations in ichnofabrics and cross-cutting relationships between trace fossils are important in identifying and correlating stratal surfaces. Two transgressive and two regressive surfaces/sequence boundaries were studied, using petrographical, mineralogical and geochemical techniques. Cements, including early diagenetic pyrite framboids, grain-rimming apatite, microcrystalline dolomite and ankerite, occur at, above and immediately below both transgressive and forced regressive surfaces/sequence boundaries. Breaks or subdued rates of sedimentation associated with both types of surfaces meant that the sediment package resided within early diagenetic zones for prolonged periods of time, enhancing diagenetic reactions at and below the surfaces. The distribution of ankerite, despite being a deep-burial cement, was primarily controlled by concentrations of bioclasts that are particularly abundant at transgressive surfaces. The diagenetic character of the forced regressive surfaces/sequence boundaries is more complex than that of the transgressive surfaces, both in terms of mineralogy and paragenesis. This is attributed to the superimposition of diagenetic assemblages as a result of erosion, re-sedimentation and sediment by-passing. Although the diagenetic signature of the surfaces has been modified by dissolution/replacement reactions during deep burial, early diagenetic signatures can still be distinguished.  相似文献   

Development and the Household: Missing the point?     

Edward?R.?CarrEmail author 《GeoJournal》2005,62(1-2):71-83

Over the past two decades development has been shifting its focus toward smaller scales and particular problems. As a result, the household has become an increasingly important institution for development, and has come under increased scrunity as development practitioners and scholars seek to better understand this institution’s functions and foundations, trying to ‘get the household right’. These efforts, rather than clarifying the character and the function of the household, have contributed to its indeterminacy by reifying the very institution they seek to analyse. Arguing that these efforts fundamentally miss the point of examining the household, this paper introduces a different framework of analysis that addresses the household not as a fixed object of research, but as a local construction that embodies flows of power and knowledge both within and transcending the local. Using the example of varying constructions of the household in two villages in Ghana’s Central Region, this article illustrates how such an approach allows us to address the various functions of the household as particular embodiments of these flows, an approach that better explains the endurance or ephemerality of these functions. Such an approach provides a stronger foundation for the consideration of how particular constructions of this institution may have troubling implications for issues like gender equity and sustainability.  相似文献   

南海北部海区海底沉积物中孔隙水的Cl~-和SO_4~(2-)浓度异常特征及其对天然气水合物的指示意义   总被引：41，自引：9，他引：32  

蒋少涌  杨涛  薛紫晨  杨竞红  凌洪飞  吴能友  黄永样  刘坚  陈道华 《现代地质》2005,19(1):45-54

报道了中国南海北部海区海底沉积物中孔隙水的Cl-和SO42-质量浓度的变化特征, 圈定了孔隙水中Cl-质量浓度的高值异常区。由于水合物形成过程中的排盐效应, 会使其上覆浅表层沉积物中孔隙水的盐度增高, 因此这些氯离子的高值异常区值得进一步的勘查。对孔隙水中SO42-的质量浓度分析表明, 研究区的一些站位表现出随深度增加SO42-的质量浓度梯度发生明显的变化, 计算的硫酸盐甲烷交接带SMI界面深度均在 10m左右, 与ODP164航次和ODP204航次有天然气水合物的钻孔的SMI界面深度基本吻合, 说明这些站位深部有天然气水合物存在的可能性。  相似文献   

‘Surface Drag in the Arctic Marginal Sea-ice Zone: A Comparison of Different Parameterisation Concepts’   总被引：1，自引：0，他引：1  

Christof?LüpkesEmail author  Gerit?Birnbaum 《Boundary-Layer Meteorology》2005,117(2):179-211

Two parameterisation schemes for the turbulent surface fluxes and drag coefficients over the Arctic marginal sea-ice zone (MIZ) are (further) developed, and their results are compared with each other. Although the schemes are based on different principles (flux averaging and parameter averaging), the resulting drag coefficients differ only slightly in the case of neutral and stable stratification. For unstable stratification and sea-ice conditions being typical for the north-eastern Fram Strait, the drag coefficients resulting from the parameter-averaging concept are 5–10% larger than those of the flux-averaging concept. At a sea-ice concentration of 45%, the parameter-averaging method overestimates the heat fluxes by a factor of 1.2. An inclusion in the schemes of form drag caused by floe edges and ridges has a much larger effect on the drag coefficient, and on the momentum fluxes, than the choice between the parameter-averaging or flux-averaging methods. Based on sensitivity studies with the flux-averaging scheme, a simple formula for the effective drag coefficient above the Arctic MIZ is derived. It reduces the computational costs of the more complex parameterisations and could also be used in larger scale models. With this simple formula, the effective drag coefficient can be calculated as a function of the sea-ice concentration and skin drag coefficients for water and ice floes. The results obtained with this parameterisation differ only slightly from those using the more complex schemes. Finally, it is shown that in the MIZ, drag coefficients for sea-ice models may differ significantly from the effective drag coefficients used in atmospheric models.  相似文献   

Clay mineral records of East Asian monsoon evolution during late Quaternary in the southern South China Sea   总被引：3，自引：2，他引：1  

C.Colin  A.Trentesaux  D.Blamart 《中国科学D辑(英文版)》2005,48(1):84-92

High-resolution clay mineral records combined with oxygen isotopic stratigraphy over the past 190 ka during late Quaternary from core MD01-2393 off the Mekong River in the southern South China Sea are reported to reconstruct a history of East Asian monsoon evolution. The dominating clay mineral components indicate a strong glacial-interglacial cyclicity, with high glacial illite, chlorite, and kaolinite contents and high interglacial smectites content. The provenance analysis indicates the direct input of clay minerals via the Mekong River drainage basin. Illite and chlorite derived mainly from the upper reach of the Mekong River, where physical erosion of meta-sedimentary rocks is dominant. Kaolinite derived mainly from active erosion of inhered clays from reworked sediments in the middle reaches. Smectites originated mainly through bisiallitic soils in the middle to lower reaches of the Mekong River. The smectites/(illite+chlorite) and smectites/kaolinite ratios are determined as mineralogical indicato  相似文献   

Wavelet Analysis of Earthquake Activity in the West of the Chinese Mainland and Its Adjacent Area     

Shao Huicheng 《中国地震研究》2005,19(1):22-28

INTRODUCTIONWiththedevelopmentofsocietyandquickurbanizationfeaturedbyacentralizationofpopulationsandeconomies ,itisverylikelythatastrongearthquakewillcausethedeathofhundredsandthousandsofpeopleandhugelossofproperty .Forexample ,intheepicenterareaoftheBame…  相似文献   

Indonesia's archipelagic regime: Implications for Malaysia     

B.A. Hamzah 《Marine Policy》1984,8(1):30-43

This article examines Indonesian-Malaysian relations in the light of Indonesia's new archipelagic regime. Archipelagos are defined and the rights and duties of archipelagic states under the Law of the Sea Convention are outlined. Indonesian-Malaysian relations from the 1974 Memorandum of Understanding to the 1982 bilateral treaty are described. The author examines the implications of an Indonesian suspension of passage on Malaysian transport, submarine cables and pipelines, fishing, oil and gas, and search and rescue. The author concludes by indicating how the two countries should adjust to the regime.  相似文献   

Food supply and dispersal in the determination of wintering population levels of oystercatchers, Haematopus ostralegus     

William J. Sutherland 《Estuarine, Coastal and Shelf Science》1982,14(2):223-229

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