The influence of halokinesis on prograding clinoforms: Insights from the Tiddlybanken Basin,Norwegian Barents Sea     

Luis Alberto Rojo  Dora Marín  Nestor Cardozo  Alejandro Escalona  Hemin Koyi 《Basin Research》2020,32(5):979-1004

Although the trajectory and geometry of clinoforms in different types of basins have been described in many studies, few studies discuss the influence of halokinesis on clinoforms in salt-related basins. In this study, we analyse the Lower Cretaceous clinoforms in the Tiddlybanken Basin, Norwegian Barents Sea to evaluate the impact of salt mobilization on the geometry and trajectory of clinoforms as well as its implications on sediment partitioning. To accomplish this objective, we use a multidisciplinary approach consisting of seismic and well-interpretation, 3D structural restoration, and forward stratigraphic modelling. The results show that salt mobilization affects prograding clinoforms by: (a) causing lateral variations in progradation rates, resulting in complex palaeogeography, (b) increasing slope angles, which affect the equilibrium of the clinoform profile and can trigger slope-readjustment processes and (c) producing lateral and temporal variations in accommodation space, leading to different clinoform trajectories, stacking patterns and reservoir distribution along the basin. Forward stratigraphic modelling shows that in salt-related basins and other tectonically active basins, the isolated use of conventional methods for clinoform analysis might lead to potential interpretation pitfalls such as misinterpretation of trajectories and overestimation of foreset angles, which can have negative consequences for exploration models.  相似文献   

基于AHP_熵权法的孟印缅地区洪水灾害风险评估   总被引：2，自引：1，他引：1  

刘媛媛  王绍强  王小博  江东  N H Ravindranath  Atiq Rahman  Nyo Mar Htwe  Tartirose Vijitpan 《地理研究》2020,39(8):1892-1906

孟印缅三国地处亚热带与热带季风气候区,因自然条件制约,洪涝灾害频繁发生,对“孟中印缅经济走廊”建设将会带来重大影响。开展孟印缅地区的洪水风险评估可为“孟中印缅经济走廊”的建设安全提供必要的信息和科技支撑。利用1980—2016年的降水数据,结合河网、数字高程和土地利用等数据,选取雨季降雨量、暴雨天数、高程、坡度、河网密度、植被覆盖度、土壤可蚀性、人口密度、地均GDP和土地利用10个指标,采用层次分析法和AHP_熵权法对孟印缅地区的洪水灾害风险分布进行了比较研究。研究表明：孟印缅地区高风险区和较高风险区分别占总面积的1.05%和28.76%,高风险区主要分布在印度北部的恒河平原、印度东北部的阿萨姆邦、孟加拉国大部分地区和缅甸南部。受自然、人口和经济条件的制约,孟加拉国是孟印缅三国中洪水风险最高的国家,高风险区和较高风险区分别占总面积的10.61%和65.87%。层次分析法和AHP_熵权法结果间的比较表明,后者比前者识别出更大范围的洪水高风险区。本研究为中国开展周边国家自然灾害的风险评估提供了有效的方法,有助于推进国家孟中印缅经济走廊的建设。  相似文献   

Diagenesis of Organic Matter in Eelgrass (Zostera marina L.) Vegetated Sediments     

Tishchenko  P. Ya.  Khodorenko  N. D.  Barabanshchikov  Yu. A.  Volkova  T. I.  Mar’yash  A. A.  Mikhailik  T. A.  Pavlova  G. Yu.  Sagalaev  S. G.  Semkin  P. Yu.  Tishchenko  P. P.  Shvetsova  M. G.  Shkirnikova  E. M. 《Oceanology》2020,60(3):341-352

Oceanology - In February and July 2014, multidisciplinary geochemical studies of the sediments were carried out at two stations. One of them was located in Voevoda Bight, which has a bottom depth...  相似文献   

Physicochemical modeling of the behavior of microelements (As,V, Cr,Co, and Hg) under the mixing of riverine and marine waters (the Razdol’naya River-Amur Bay System)   总被引：1，自引：0，他引：1  

A. V. Savchenko  L. M. Gramm-Osipov  A. A. Mar’yash 《Oceanology》2009,49(1):39-46

By means of physicochemical modeling with the Selector software package, a model for the mixing of riverine water (pH = 7.02) and seawater was compiled and calculated. The Razdol’naya River-Amur Bay (Sea of Japan) system was assessed as an example. By means of the MINTEQA2/PRODEFA2 software package, the role of the sorption processes in riverine and marine waters, as well as in the zone of their mixing, was ascertained. The physicochemical migration forms of microelements (arsenic, vanadium, chromium, cobalt, and mercury) in the waters of the geochemical system considered and their behavior in passing through the geochemical barrier were established.  相似文献   

Particle fluxes dynamics in Blanes submarine canyon (Northwestern Mediterranean)     

Diana Zúñiga  M. Mar Flexas  Anna Sanchez-Vidal  Johan Coenjaerts  Antoni Calafat  Gabriel Jordà  Jordi García-Orellana  Joan Puigdefàbregas  Miquel Canals  Manuel Espino  Francesc Sardà  Joan B. Company 《Progress in Oceanography》2009,82(4):239-251

Within the framework of the multidisciplinary RECS project and with the aim of describing the particle flux transfer from the continental shelf to the deep basin, an array of five mooring lines equipped with a total of five pairs of PPS3/3 sequential-sampling sediment traps and RCM-7/8 current meters were deployed 30 m above the bottom from March 2003 to March 2004 inside and outside the Blanes Canyon. One mooring line was located in the upper canyon at 600 m depth, one in the canyon axis at 1700 m depth and other two close to the canyon walls at 900 m depth. A fifth mooring line was deployed in the continental open slope at 1500 m water depth.The highest near-bottom downward particle flux (14.50 g m⁻² d⁻¹) was recorded at the trap located in the upper canyon (M1), where continental inputs associated with the presence of the Tordera River are most relevant. On the other hand, the downward fluxes (4.35 g m⁻² d⁻¹) in the canyon axis (M2) were of the same order as those found in the western flank (M3) of the canyon. Both values were clearly higher than the value (1.95 g m⁻² d⁻¹) recorded at the eastern canyon wall (M4). The open slope (M5) mass flux (5.42 mg m⁻² d⁻¹) recorded by the sediment trap located outside the canyon system was three orders of magnitude lower than the other values registered by the inner canyon stations. The relevance of our data is that it explains how the transport pathway in the canyon occurs through its western flank, where a more active and persistent current toward the open ocean was recorded over the entire year of the experiment.Off-shelf sediment transport along the canyon axis showed clear differences during the period of the study, with some important events leading to strong intensifications of the current coupled with large transport of particle fluxes to the deepest parts of the canyon. Such events are primarily related to increases in river discharge and the occurrence of strong storms and cascading events during the winter.In summary, in this study it is shown that the dynamics of the water masses and the currents in the study area convert the sharp western flank of the Blanes Canyon in a more active region that favors erosion processes than the eastern flank, which has a smoother topography and where the absence of erosional conditions yields to steadier sedimentary processes.  相似文献   

Spatial distribution of chaetognaths off the northern Bicol Shelf, Philippines (Pacific coast)     

Noblezada  Mary Mar P.; Campos  Wilfredo L. 《ICES Journal of Marine Science》2008,65(3):484-494

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Relational places of ethnic Burman women migrants in the borderland town of Tachilek, Myanmar     

Kyoko Kusakabe  Zin Mar Oo 《Singapore journal of tropical geography》2007,28(3):300-313

This paper presents an investigation based on the testimonies of ethnic Bamar or Burman women migrant workers in the ethnically diverse 'borderland' town of Tachilek, Myanmar and interviews with their relatives in the home village in the central Burman heartlands. We examine how the concept of relational places, here involving a village in the central Mandalay Division and a town in the Myanmar–Thailand borderland, is related to differential power relations affecting the women migrants. We focus on the ways that gender identity and social position are limited by the relational places of community elders and the migrant women themselves, and suggest that the relational places of migrants in Myanmar are constructed through the nexus of varied forms of state control in both the central Burman heartlands and the multiethnic borderlands of the country.  相似文献   

Testing the predictive power of seagrass depth limit models     

Carlos M. Duarte  Núria Marbà  Dorte Krause-Jensen  María Sánchez-Camacho 《Estuaries and Coasts》2007,30(4):652-656

The power of equations predicting seagrass depth limit (Z_c) from light extinction (K _z) was tested on data on seagrass depth limits collected from the literature. The test data set comprised 424 reports of seagrass colonization depth and water transparency, including data for 10 seagrass species. This data set confirmed the strong negative relationship betweenZ _c andK _z. The regression equation in Duarte (1991) overestimated the realized seagrass colonization depths at colonization depths < 5 m, while there was no prediction bias above this threshold. These results indicated that seagrass colonizing turbid waters (K _z 0.27 m^-1) have higher apparent light requirements than those growing in clearer waters. The relationship between seagrass colonization depth and light attenuation shifts at a threshold of light attenuation of 0.27 m^-1, requiring separate equations to predictZ _c for seagrass growing in more turbid waters and clearer waters, and to set targets for seagrass restoration and conservation efforts.  相似文献   

Recent changes in flood risk in the Gran La Plata,Buenos Aires province,Argentina: causes and management strategy     

María Isabel Andrade  Olga Eugenia Scarpati 《GeoJournal》2007,70(4):245-250

The paper analyses the causes of flood occurrence in the Gran La Plata, Buenos Aires Province, Argentina, and the changes that have occurred since the 1970s. The area is characterized by serious deficiencies in the use and management of water resources. The main factors are: (1) flood risk information is not updated; (2) urban building organization does not consider the flood risk; (3) the topography and other physical features are not taken into account in urban development. This research considers some specific problems, especially in data availability, and suggests ways to solve them, including improved analytical methodology. One of the main objectives is to analyse flood risk in social terms, producing a map of flood risk from the “human social vulnerability” point of view. The results suggest that flood risk has increased since the 1980s and that this is associated with changes in precipitation patterns that have also been aggravated by lack of controls on urban development. The poorer areas with the lowest level of infrastructure and public services, many of them developed over the last quarter-century, are especially vulnerable.  相似文献   

Mountain Front Development by Folding and Crustal Thickening in the Internal Zone of the Betic Cordillera-Alboran Sea Boundary     

Carlos Marín-Lechado  Jesús Galindo-Zaldívar  Luís Roberto Rodríguez-Fernández  Antonio Pedrera 《Pure and Applied Geophysics》2007,164(1):1-21

The boundary between the Alboran Sea and Betic Cordillera is a good example of a fold related mountain front in the Internal Zone of an alpine mountain range. Since the late Miocene, NNW-SSE convergence between the Eurasian and African plates has produced shortening and related orthogonal extension. To improve the characterisation of the geometry of the deep structure in the region and to establish the recent tectonic evolution of the mountain front, well logs and newly acquired geophysical data (multichannel reflection seismic and gravimetric surveys) have been interpreted and integrated with available surface data. The most marked tectonic structure corresponds to large antiforms and synforms of ENE-WSW trend which are related to mountain ranges and basins, respectively. The fold belt continues toward the northern continental shelf of the Alboran Sea. The fold vergence is generally northwards and its amplitude decreases progressively towards SSE, until disappearring in a sharp boundary where the reflectors are undeformed. The deep geometry suggests that fold growth started during upper Tortonian times and continued its activity up to Pliocene or even Quaternary times. The NNW-SSE compression produces crustal thickening and a regional and progressive southwards emersion. The location of main present-day deformation fronts in the Internal Zones contrasts with classical models where the deformation progresses towards the frontal part of External Zones of cordilleras. In addition, this fold-related deformation mountain front has features different from fault related fronts, as it does not show a sharp boundary, and folds that determine rectilinear mountain boundaries decrease progressively in amplitude or in wavelength up to undeformed areas.  相似文献