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301.
Robert W Risebrough Brock W De Lappe Wayman Walker Bernd R.T Simoneit Joan Grimalt Joan Albaiges Jose Antonio Garcia Regueiro Antoni Ballester Inolla Manuel Mariño Fernandez 《Marine pollution bulletin》1983,14(5):181-187
The Mussel Watch concept was applied in a study of man-induced chemical changes in the Ebro Delta on the Catalonian coast to obtain a preliminary assessment of the distribution of synthetic organic compounds, petroleum and biogenic hydrocarbons in the local coastal zone. Mussels, oysters and clams were selected as the indicator organisms. Levels of petroleum accumulated by mussels were generally high, in the order of 100–800 μg?1 dry weight, equivalent to those in mussels in the most polluted harbours and bays of California. The relative distributions of the steranes and pentacyclic triterpanes in the mussels were significantly different from those found in petroleum from a local field, indicating that local petroleum was not contributing to the present contamination. The composition of biogenic compounds was variable, probably reflecting differences in the composition of local plankton communities, PCB levels were high in relation to current levels in mussels from US sites, reflecting continuing PCB use in Spain. The Delta appears to be a point source of a number of organochlorine compounds, including HCB, the DDT compounds, endrin and γ-chlordane. Levels of the DDT compound o,p′-DDD, a pharmacologically active substance, were unexpectedly high; identification was confirmed by GS/MS. Many unidentified peaks were present on EC chromatograms, indicating a more complex pattern of contamination than might be suggested by printed summaries of data. 相似文献
302.
Tectono-stratigraphic evolution of an inverted extensional basin: the Cameros Basin (north of Spain)
Silvia Omodeo Salè Joan Guimerà Ramón Mas José Arribas 《International Journal of Earth Sciences》2014,103(6):1597-1620
The Cameros Basin is a part of the Mesozoic Iberian Rift. It is an extensional basin formed during the late Jurassic and early Cretaceous, in the Mesozoic Iberian Rift context, and it was inverted in the Cenozoic as a result of the Alpine contraction. This work aims to reconstruct the tectono-stratigraphic evolution of the basin during the Mesozoic, using new and revised field, geophysical and subsurface data. The construction of a basin-wide balanced section with partial restorations herein offers new insights into the geometry of the syn-rift deposits. Field data, seismic lines and oil well data were used to identify the main structures of the basin and the basin-forming mechanisms. Mapping and cross-sectional data indicate the marked thickness variation of the depositional sequences across the basin, suggesting that the extension of the depositional area varied during the syn-rift stage and that the depocentres migrated towards the north. From field observation and seismic line interpretation, an onlap of the depositional sequences to the north, over the marine Jurassic substratum, can be deduced. In the last few decades, the structure and geometry of the basin have been strongly debated. The structure and geometry of the basin infill reconstructed herein strongly support the interpretation of the Cameros Basin as an extensional-ramp synclinal basin formed on a blind south-dipping extensional ramp. The gradual hanging-wall displacement to the south shifted the depocentres to the north over time, thus increasing the basin in size northwards, with onlap geometry on the pre-rift substratum. The basin was inverted by means of a main thrust located in a detachment located in the Upper Triassic beds (Keuper), which branched in depth with the Mesozoic extensional fault flat. The reconstruction of the tectono-stratigraphic evolution of the Cameros Basin proposed herein represents a synthesis and an integration of previous studies of the structure and geometry of the basin. This study can be used as the basis for future basin-scale research and for modelling the ancient petroleum system of the basin. 相似文献
303.
Corts Maria Llasat Maria Carmen Gilabert Joan Llasat-Botija Montserrat Turco Marco Marcos Ral Martn Vide Juan Pedro Falcn Llus 《Natural Hazards》2017,85(1):39-57
Dam failure constitutes a grave threat to human life. However, there is still a lack of systematic and comprehensive research on the loss of life (L) caused by dam break in China. From the perspective of protecting human life, a new calculation method for L occurred in dam break floods is put forward. Fourteen dam failure cases in China are selected as the basic data by three-dimensional stratified sampling, balancing spatial, vertical elevation and temporal representations, as well as considering various conditions of the dam collapse. The method includes three progressive steps: Firstly, some impact factors of loss of life (IFL) are selected by literature survey, i.e., severity of dam break flood (S F), population at risk (P R), understanding of dam break (U B), warning time (T W) and evacuation condition (E C). And the other IFL of weather during dam break (W B), dam break mode (M B), water storage (S W), building vulnerability (V B), dam break time (T B) and average distance from affected area to dam (D D) are also taken into account to get a more comprehensive consideration. According to disaster system and disaster risk, these eleven IFL are divided into four categories. Through the improved entropy method, eight key IFL are further selected out of the eleven. Secondly, four L modules are built based on four categories, which are L-causing factor module (M 1), L-prone environment module (M 2), affected body module (M 3) and rescue condition module (M 4). Eventually, by using two methods of multivariate nonlinear regression and leave-one-out cross-validation in combination with coupled four modules, the calculation method for L is established. Compared with the results of Graham method and D&M method, the result of the proposed one is much closer to the actual value and performs better in fitting effect and regional applicability. In the application, L calculation and consequence assessment are carried out in the example of Hengjiang reservoir that has already broken down. At the same time, L calculation and risk prediction are used in the analysis of Yunshan reservoir, which is under planning. The proposed method can not only be applied to estimate L and its rate (f L ) under various types of dam break conditions in China, but also provide a reliable consequence assessment and prediction approach to reduce the risk of L. 相似文献
304.
Van Lichtervelde Marieke Grand’Homme Alexis de Saint-Blanquat Michel Olivier Philippe Gerdes Axel Paquette Jean-Louis Melgarejo Joan Carles Druguet Elena Alfonso Pura 《Mineralogy and Petrology》2017,111(1):1-21
Mineralogy and Petrology - The Cap de Creus granitic pegmatites in the eastern Catalan Pyrenees were dated using in situ U-Pb geochronology by laser ablation ICP-MS on zircon and columbite-group... 相似文献
305.
The Aegean island of Thera (Santorini) was covered by tephra from its cataclysmic Late Bronze Age (ca. 3600 yr B.P.) eruption. Vertical exposures of the eruptive sequence show secondary, nonvolcanic, circular (in cross section) features composed of stratified sediment. Many are inaccessible from the floors of modern quarries and appear to be caves filled with younger sediment, but show no connection to the land surface. A filled cave was found in the wall of a modern gully outside the modern quarries, and a filled cave was found in a terrace scarp, well above the modern gully. Natural (and probably rapid) incision by gullies into the thick tephra deposit left many locations with lateral access to tephra. Inhabitants from post‐Minoan to recent times excavated tephra for materials and buildings, and caves were subsequently filled by sporadic (possibly seasonal) flood events that deposited sediment. These gullies may have provided access for modern tephra removal that isolated the filled caves high on the modern quarry walls. © 2003 Wiley Periodicals, Inc. 相似文献