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During the late Miocene, the Guadalquivir Basin and its satellite basin, the Ronda Basin, were under Atlantic cool-water influence. The aim of our study is to develop a sequence stratigraphic subdivision of the Ronda Basin fill and to provide models for the cool-water carbonates. The Upper Miocene of the Ronda Basin can be divided into three depositional sequences. Sequence 1 is early Tortonian, Sequence 2 late Tortonian to earliest Messinian, and Sequence 3 Messinian in age. The sediments were deposited in a ramp depositional system. Sequence 1 is dominated by conglomerates and marls. In Sequence 2 and Sequence 3, carbonate deposits dominate in the inner ramp whereas siliciclastics preferentially occur in the middle and outer ramp. Bryomol carbonate sediments occur in all sequences whereas rhodalgal carbonates are restricted to Sequence 3. In bays protected from siliciclastic influx, rhodalgal deposits formed under transgressive conditions. A bryomol factory occurs in zones of continuous siliciclastic supply. This distribution results from facies partitioning during the flooding of the Ronda Basin, which has a rugged and irregular relief. Embayments were protected from siliciclastic influx and provided regions with less hydraulic energy. 相似文献
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Christian Götze András Jung Ines Merbach Rainer Wennrich Cornelia Gläßer 《Central European Journal of Geosciences》2010,2(2):132-137
Floodplain ecosystems are affected by flood dynamics, nutrient supply as well as anthropogenic activities. Heavy metal pollution poses a serious environmental challenge. Pollution transfer from the soil to vegetation is still present at the central location of Elbe River, Germany. The goal of this study was to assess and separate the current heavy metal contamination of the floodplain ecosystem, using spectrometric field and laboratory measurements. A standardized pot experiment with floodplain vegetation in differently contaminated soils provided the basis for the measurements. The dominant plant types of the floodplains are: Urtica dioica, Phalaris arundinacea and Alopecurus pratensis, these were also chemically analysed. Various vegetation indices and methods were used to estimate the red edge position, to normalise the spectral curve of the vegetation and to investigate the potential of different methods for separating plant stress in floodplain vegetation. The main task was to compare spectral bands during phenological phases to find a method to detect heavy metal stress in plants. A multi-level algorithm for the curve parameterisation was developed. Chemo-analytical and ecophysiological parameters of plants were considered in the results and correlated with spectral data. The results of this study show the influence of heavy metals on the spectral characteristics of the focal plants. The developed method (depth CR1730) showed significant relationship between the plants and the contamination. 相似文献
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Luísa D.V.Carvalho Tiago Jalowitzki Ricardo Scholz Guilherme O.Gonalves Marcelo Peres Rocha Rogério Silvestre Pereir Cristiano Lana Marco Paulo de Castro Gláucia Queiroga Reinhardt A.Fuck 《地学前缘(英文版)》2022,(1):182-203
We present major and trace element compositions of mineral concentrates comprising garnet xenocrysts,ilmenite,phlogopite,spinel,zircon,and uncommon minerals (ti... 相似文献
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Motivated by consideration of the solar tachocline, we derive, via an asymptotic procedure, a new set of equations incorporating velocity shear and magnetic buoyancy into the Boussinesq approximation. We demonstrate, by increasing the magnetic field scale height, how these equations are linked to the magneto-Boussinesq equations of Spiegel and Weiss (Magnetic buoyancy and the Boussinesq approximation. Geophys. Astrophys. Fluid Dyn. 1982, 22, 219–234). 相似文献
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We report on biomarker responses conducted as part of a multi-level assessment of the chronic toxicity of estuarine sediments to the amphipod Gammarus locusta. A companion article accounts for organism and population-level effects. Five moderately contaminated sediments from two Portuguese estuaries, Sado and Tagus, were assessed. Three of them were muddy and two were sandy sediments. The objective was to assess sediments that were not acutely toxic. Three of the sediments met this criterion, the other two were diluted (50% and 75%) with clean sediment until acute toxicity was absent. Following 28-d exposures, the amphipods were analysed for whole-body metal bioaccumulation, metallothionein induction (MT), DNA strand breakage (SB) and lipid peroxidation (LP). Two of the muddy sediments did not cause chronic toxicity. These findings were consistent with responses at organism and population levels that showed higher growth rates and improvement of reproductive traits for amphipods exposed to these two sediments. Two other sediments, one muddy and one sandy, exhibited pronounced chronic toxicity, affecting SB, MT induction (in muddy sediment), survival and reproduction. Potential toxicants involved in these effects were identified. The last sandy sediment exhibited some loss of DNA integrity, however growth was also enhanced. Present results, together with the organism/population-level data, and also benthic communities information, were analysed under a weight-of-evidence approach. By providing evidence of exposure (or lack of it) to contaminants in sediments, the biomarkers here applied assisted in distinguishing toxicants' impacts in test organisms from the confounding influence of other geochemical features of the sediments. 相似文献
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Berta Biescas François Dufour Glória Furdada Giorgi Khazaradze Emma Suriñach 《Surveys in Geophysics》2003,24(5-6):447-464
Seismic signals generated by avalanches have been recorded by theavalanche team of the Universitat de Barcelona at theVallée de la Sionne experimental site (Switzerland) since 1998. During these years avalanches of varying size and flowwere recorded by two sensors located at different positions.In the present paper we show the general features of the running spectra of the seismicsignals for the different type of recorded avalanches. Using this method we are able not only to detect avalanches with low amplitude signals but also to distinguishbetween avalanches and other seismic sources (i.e., local earthquakes) which have thesame frequency content but a different frequency evolution. 相似文献
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Triassic seismic sequence stratigraphy and paleogeography of the western Barents Sea area 总被引：2，自引：0，他引：2
Evy Glørstad-Clark Jan Inge Faleide Bjørn Anders Lundschien Johan Petter Nystuen 《Marine and Petroleum Geology》2010
A sequence stratigraphic framework of the Triassic on the Norwegian Barents shelf is presented. The Triassic succession was subdivided into five second-order sequences based on facies analysis of 2D seismic data constrained by well data. The sequences were separated by maximum flooding surfaces that correlate seismically for hundreds of kilometers. 相似文献
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High environmental salinity reduces the reproductive potential of the spider crab Maja brachydactyla (Decapoda,Majidae) 
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下载免费PDF全文 The spider crab Maja brachydactyla is an important fisheries species in Europe. Adults were sampled in Ría de A Coruña (NW Spain) and transported to IRTA rearing facilities. Salinity and photoperiod changes and their effect on reproduction were tested in the laboratory. The number of newly hatched larvae per batch (presence of actively swimming newly hatched larvae in a broodstock tank) was counted and sampled to estimate dry weight and proximal composition. Keeping spider crab broodstock in a high salinity environment (38 ppt) significantly reduced the number of newly hatched larvae, reaching up to fivefold difference in winter. The number of newly hatched larvae produced under a natural photoperiod was 10‐fold higher than those produced using a fixed photoperiod at 34 ppt salinity during winter. No clear pattern of changes in larval dry weight, protein, lipid or carbohydrate composition was observed under the environmental conditions tested. The results show that the salinity used for broodstock maintenance, especially during the embryonic development, is an important factor causing changes in larval production of M. brachydactyla and with potential implications for recruitment success. 相似文献