Roman road pollution assessed by elemental and lead isotope geochemistry in East Belgium     

Virginie Renson  Nathalie Fagel  Nadine Mattielli  Serge Nekrassoff  Maurice Streel  Franois De Vleeschouwer 《Applied Geochemistry》2008,23(12):3253-3266

The ability of inorganic geochemistry to record environmental change and especially human impact has been evidenced by several studies across Europe, especially in peat, where it is possible to record the impact of agriculture, mining and other industries. However, despite the numerous investigations on the impact of ancient human activities such as ore mining and smelting, little attention has been paid to geochemistry as a tool to solve problems of palaeopollution in the surroundings of archaeological sites. This paper presents geochemical evidence of the impact of a possible early Roman road built in SE Belgian peatland. Increased Zn and Pb concentrations suggest that Pb–Zn ores were transported on the road. Lead isotope analyses suggest that these ores are locally derived, being compatible with those found in the nearby Pb–Zn ore deposits from East Belgium. Present results provide direct evidence that East Belgian Pb–Zn ores were already being mined during Roman times, i.e. earlier than previously suspected (i.e. 14th century) and that Zn appears to be relatively immobile here. On a broader scale, it also demonstrates that such an early road already had an impact on the environment in terms of metal pollution. This paper enlarges on the range of possibilities offered by geochemistry in the field of geoarchaeology.  相似文献   

Fracturing,Crushing, and Directional Concentration     

Serge Antoine Séguret 《Mathematical Geosciences》2016,48(6):663-685

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An inversion for fluid transport properties of three‐dimensionally heterogeneous rocks using induced microseismicity     

Serge A. Shapiro 《Geophysical Journal International》2000,143(3):931-936

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Chemical weathering studies in relation to geomorphological research in southeastern Canada   总被引：1，自引：0，他引：1  

Mireille Bouchard  Serge Jolicoeur 《Geomorphology》2000,32(3-4)

Although chemical weathering provides fundamental information relevant to geomorphology, the subject has been overlooked during the 20th century in Canada. This paper provides an overview of the current state of Canadian research on chemical weathering in southeastern Canada and takes into account three spatial and temporal contexts: (1) the formation of bedrock morphology by chemical weathering, (2) occurrences, characteristics and age of saprolites and (3) contemporary chemical denudation rates. Long-term geomorphological evolution of southeastern Canadian landscapes shows that chemical weathering has played an important role. An example is taken from the Laurentide region of the Canadian Shield north of Montréal (Québec). The present topography resulted from the stripping of the former weathering mantle and from the probable subsequent modification of the weathering front, first by the action of hillslope processes and rivers and then by glaciers, before and during Plio-Pleistocene times. The present landscape reflects the timing of the formation of erosion surfaces, and of the stripping of the Paleozoic cover rocks and exposure of the Shield. Since the late seventies, several isolated occurrences of saprolite-soil profiles have been discovered in eastern Canada and prompted a renewal of the study of these materials about the Cenozoic evolution of these regions. One of the problems in this field of research is the dating of saprolites and their inclusion in a chronostratigraphic framework, along with the other Cenozoic surficial deposits and landforms. Because of the multiple factors involved in the development of secondary minerals in saprolites during the course of weathering, it is preferable to distinguish the dating of saprolites from the study of their mineralogical and geochemical evolution. Fortunately, several new techniques are becoming available for the absolute dating of surficial deposits and saprolites, including the use of cosmogenic radionuclides. Saprolites provide a strong potential field of research for our understanding of the geological evolution of eastern Canada during the Cenozoic. Contemporary weathering and erosion rates are fields of research that have gained increasing interest recently, since modeling landscape geochemical response can be applied to various environmental stress situations, such as acidification by rain and forest harvesting. Rock-type may be the main factor explaining the large differences between watersheds. In fact, variability of cation removal in the temperate zone is probably most closely related to flow-paths of water. Investigations, at different scales, from entire watersheds to slopes to individual pedons, highlight the problem. In the Catamaran Brook watershed (New Brunswick), water chemistry is explained by a mix of groundwater and soil solution from the horizons at the base of the floodplain soils. Geochemical mass-balances based on net outputs give little information on the weathering reactions of primary minerals, the weathering products or on the nature of the weathering processes that provide the dissolved load of streams. Mineralogic and petrographic analysis of selected soil pedons are necessary to determine weathering reactions and their role as sources or sinks for bases, silica, aluminum and iron in the various compartments through which water percolates before it reaches the stream.  相似文献   

Abundance of fin whales (Balaenoptera physalus) in the north-western Mediterranean Sea,using photo-identification and microsatellite genotyping     

Céline Tardy  Denis Ody  Olivier Gimenez  Serge Planes 《Marine Ecology》2023,44(1):e12737

The Mediterranean fin whale population, Balaenoptera physalus, is resident, with almost no exchanges with the Atlantic population. The entire population was estimated at 1300 or 13,300 individuals by a recent project depending on the platform used. This disparity shows the importance of long-term monitoring with a unique protocol of survey. Capture-recapture approaches using dorsal photographs and genetic identity collections over a 10 years period were used to estimate the abundance of the north-western Mediterranean fin whale. We identified 332 individuals using photographs and 470 using genotypes, with a total of 546 individuals identified between 2008 and 2019, when some whales were double-marked. The inter-annual percentage of recapture varied between 15% and 17% respectively for genotypes and photographs methods. Using Cormack-Jolly-Seber models, the abundance of fin whales in the north-western Mediterranean is estimated at 1295 individuals (95% CI: 1116–1474) with a survival probability of 0.945 (95% CI: 0.690–0.993) from genotypes. Abundance estimates from combined collections (photographs and genotypes) and corrected photograph estimates were similar to the genetic ones. Future studies might prioritize the genetic approach which is the least biased and with a narrower confidence interval. The genetic abundance estimates show relative stability over time, when compared to 1990 estimates, and should be included in future conservation actions.  相似文献   

The missing Myopus: plugging the gaps in Late Pleistocene small mammal identification in western Europe with geometric morphometrics     

Louis Arbez  Aurelien Royer  Danielle Schreve  Remi Laffont  Serge David  Sophie Montuire 《第四纪科学杂志》2021,36(2):224-238

Lemmus and Myopus are two lemming species with distinct habitat requirements but which show very similar dental morphologies. They are thus extremely difficult to distinguish from one another in the fossil record on the basis of their dental remains, leading to poor understanding of the palaeobiogeographical evolution of Myopus as well as inaccurate palaeoenvrionmental reconstructions. Currently, the presence of Myopus in the fossil register from the Pleistocene is still debated and no firm occurrence of this lemming in western Europe has yet been confirmed for the Late Pleistocene. In this paper, we used geometric morphometrics on modern material to establish morphological differences between Lemmus and Myopus teeth (first lower and third upper molars). Morphological data were then used to build a robust linear discriminant model able to confidently classify isolated teeth of these two genera, and finally, linear discriminant models were used on fossil remains of Lemmus/Myopus from two Late Pleistocene archaeological/palaeontological sites (Grotte des Gorges and Gully Cave). This study demonstrates, for the first time, the presence of Myopus schisticolor in west European Late Pleistocene sites between the end of Marine Isotope Stage 3 and the beginning of the Holocene, during climatic events that favoured the development of taiga forest of birch and pine in these regions.  相似文献   

Regional climate modelling of the 2006 West African monsoon: sensitivity to convection and planetary boundary layer parameterisation using WRF   总被引：3，自引：3，他引：0  

Emmanouil Flaounas  Sophie Bastin  Serge Janicot 《Climate Dynamics》2011,36(5-6):1083-1105

Regional climate model (RCM) is a valuable scientific tool to address the mechanisms of regional atmospheric systems such as the West African monsoon (WAM). This study aims to improve our understanding of the impact of some physical schemes of RCM on the WAM representation. The weather research and forecasting model has been used by performing six simulations of the 2006 summer WAM season. These simulations use all combinations of three convective parameterization schemes (CPSs) and two planetary boundary layer schemes (PBLSs). By comparing the simulations to a large set of observations and analysis products, we have evaluated the ability of these RCM parameterizations to reproduce different aspects of the regional atmospheric circulation of the WAM. This study focuses in particular on the WAM onset and the rainfall variability simulated over this domain. According to the different parameterizations tested, the PBLSs seem to have the strongest effect on temperature, humidity vertical distribution and rainfall amount. On the other hand, dynamics and precipitation variability are strongly influenced by CPSs. In particular, the Mellor?CYamada?CJanjic PBLS attributes more realistic values of humidity and temperature. Combined with the Kain?CFritsch CPS, the WAM onset is well represented. The different schemes combination tested also reveal the role of different regional climate features on WAM dynamics, namely the low level circulation, the land?Catmosphere interactions and the meridional temperature gradient between the Guinean coast and the Sahel.  相似文献   

Sahel rainfall and decadal to multi-decadal sea surface temperature variability     

Elsa Mohino  Serge Janicot  Juergen Bader 《Climate Dynamics》2011,37(3-4):419-440

Decadal Sahelian rainfall variability was mainly driven by sea surface temperatures (SSTs) during the twentieth century. At the same time SSTs showed a marked long-term global warming (GW) trend. Superimposed on this long-term trend decadal and multi-decadal variability patterns are observed like the Atlantic Multidecadal Oscillation (AMO) and the inter-decadal Pacific Oscillation (IPO). Using an atmospheric general circulation model we investigate the relative contribution of each component to the Sahelian precipitation variability. To take into account the uncertainty related to the use of different SST data sets, we perform the experiments using HadISST1 and ERSSTv3 reconstructed sets. The simulations show that all three SST signals have a significant impact over West Africa: the positive phases of the GW and the IPO lead to drought over the Sahel, while a positive AMO enhances Sahel rainfall. The tropical SST warming is the main cause for the GW impact on Sahel rainfall. Regarding the AMO, the pattern of anomalous precipitation is established by the SSTs in the Atlantic and Mediterranean basins. In turn, the tropical SST anomalies control the impact of the IPO component on West Africa. Our results suggest that the low-frequency evolution of Sahel rainfall can be interpreted as the competition of three factors: the effect of the GW, the AMO and the IPO. Following this interpretation, our results show that 50% of the SST-driven Sahel drought in the 1980s is explained by the change to a negative phase of the AMO, and that the GW contribution was 10%. In addition, the partial recovery of Sahel rainfall in recent years was mainly driven by the AMO.  相似文献   

Application of regularised optimal fingerprinting to attribution. Part I: method, properties and idealised analysis   总被引：1，自引：0，他引：1  

Aurélien Ribes  Serge Planton  Laurent Terray 《Climate Dynamics》2013,41(11-12):2817-2836

Optimal fingerprinting has been the most widely used method for climate change detection and attribution over the last decade. The implementation of optimal fingerprinting often involves projecting onto k leading empirical orthogonal functions in order to decrease the dimension of the data and improve the estimate of internal climate variability. However, results may be sensitive to k, and the choice of k remains at least partly arbitrary. One alternative, known as regularised optimal fingerprinting (ROF), has been recently proposed for detection. This is an extension of the optimal fingerprinting detection method, which avoids the projection step. Here, we first extend ROF to the attribution problem. This is done using both ordinary and total least square approaches. Internal variability is estimated from long control simulations. The residual consistency test is also adapted to this new method. We then show, via Monte Carlo simulations, that ROF is more accurate than the standard method, in a mean squared error sense. This result holds for both ordinary and total least square statistical models, whatever the chosen truncation k. Finally, ROF is applied to global near-surface temperatures in a perfect model framework. Improvements provided by this new method are illustrated by a detailed comparison with the results from the standard method. Our results support the conclusion that ROF provides a much more objective and somewhat more accurate implementation of optimal fingerprinting in detection and attribution studies.  相似文献   

Oxygen isotope variability in calcite shells of the ostracod Cyprideis torosa in Akyatan Lagoon,Turkey     

Anne-Marie Bodergat  Christophe Lécuyer  François Martineau  Atike Nazik  Kemal Gürbüz  Serge Legendre 《Journal of Paleolimnology》2014,52(1-2):43-59

The euryhaline ostracod Cyprideis torosa lives in Akyatan Lagoon, Turkey, which is exposed to large spatial and seasonal variations in water salinity, δ¹⁸O, and temperature. Hydrogen and oxygen isotope measurements of waters reveal that the large range of salinity (15–80 g L^?1) in the lagoon results from a combination of evaporation and mixing between Mediterranean seawater and Seyhan River input. Round sieve-pore relative abundance in C. torosa provides a robust proxy for water salinity (S) from 15 to 80 g L^?1, according to the equation: S = 161.41 (±4.52) * log₁₀(% rounded pores) ? 94.04 (±3.44) (R² = 0.937; p = 10^?31). Seasonal sampling and isotope analysis of C. torosa in waters of known δ¹⁸O values (?4.7 to +6.9 ‰ V-PDB) and temperatures (15–35 °C) yielded a weak positive correlation (r = 0.71) between 1000 lnα_{(calcite–water)} ‰ V-SMOW) and 10³ * T^?1. Specimens of C. torosa collected during the mild and warm seasons have oxygen isotope compositions close to those of inorganic calcite precipitated in equilibrium with ambient water. The large oxygen-isotope variability observed during any season of the year most likely results from shell calcification in water bodies of highly variable salinity, alkalinity, Mg/Ca and water saturation relative to calcite. Indeed, distinct water bodies in the Akyatan Lagoon are generated by mixing of fresh and marine waters, which are exposed to different evaporation rates at the seasonal scale.  相似文献