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11.
Modeling of wind gap formation and development of sedimentary basins during fold growth: application to the Zagros Fold Belt,Iran 
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下载免费PDF全文 Marine Collignon Philippe Yamato Sébastien Castelltort Boris J. P. Kaus 《地球表面变化过程与地形》2016,41(11):1521-1535
Mountain building and landscape evolution are controlled by interactions between river dynamics and tectonic forces. Such interactions have been extensively studied, however a quantitative evaluation of tectonic/geomorphic feedbacks, which is imperative for understanding sediments routing within orogens and fold‐and‐thrust belts, remains to be undertaken. Here, we employ numerical simulations to assess the conditions of uplift and river incision necessary to deflect an antecedent drainage network during the growth of one, or several, folds. We propose that a partitioning of the river network into internal (endorheic) and longitudinal drainage arises as a result of lithological differences within the deforming crustal sedimentary cover. Using examples from the Zagros Fold Belt (ZFB), we show that drainage patterns can be linked to the non‐dimensional incision ratio R between successive lithological layers, corresponding to the ratio between their relative erodibilities or incision coefficients. Transverse drainage networks develop for uplift rates smaller than 0.8 mm yr?1 and low incision ratios (?10 < R < 10). Intermediate drainage networks are obtained for uplift rates up to 2 mm yr?1 and large incision ratios (R > 20). Parallel drainage networks and the formation of sedimentary basins occur for large values of incision ratio (R > 20) and uplift rates between 1 and 2 mm yr?1. These results have implications for predicting the distribution of sediment depocenters in fold‐and‐thrust belts, which can be of direct economic interest for hydrocarbon exploration. They also put better constraints on the fluvial and geomorphic responses to fold growth induced by crustal‐scale tectonics. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献
12.
Amandine Bordon Odile Peyron Anne-Marie Lzine Simon Brewer Eric Fouache 《Quaternary International》2009,200(1-2):19
High-temporal resolution analysis of pollen records from Lake Maliq (Albania) provides quantitative estimates of monthly temperature and precipitation changes since the last deglaciation. The climate parameters were estimated using the best modern analogue technique with an updated modern pollen-climate database composed of 2748 surface samples. The record shows two main cooling phases in the Maliq area (the Oldest and Younger Dryas) and a cooling event around 8200 years, which suggests that the forcing factors driving climate variations in the North Atlantic area since the Last Glacial period also extended their influence into the Mediterranean area. The Oldest and Younger Dryas are also characterized by an arid climate and a change in the seasonality of precipitation: the summer precipitation tends to be greater during the cooling phases than during the temperate periods. The Holocene climate is relatively stable and the values of each parameter reach their modern levels, except for an arid event between 8300 and 8100 cal BP. 相似文献
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Jessica R. Lacy Steve Gladding Andreas Brand Audric Collignon Mark Stacey 《Estuaries and Coasts》2014,37(5):1058-1077
We investigate the dynamics governing exchange of sediment between estuarine shallows and the channel based on field measurements at eight stations spanning the interface between the channel and the extensive eastern shoals of South San Francisco Bay. The study site is characterized by longitudinally homogeneous bathymetry and a straight channel, with friction more important than the Coriolis forcing. Data were collected for 3 weeks in the winter and 4 weeks in the late summer of 2009, to capture a range of hydrologic and meteorologic conditions. The greatest sediment transport from shallows to channel occurred during a pair of strong, late-summer wind events, with westerly winds exceeding 10 m/s for more than 24 h. A combination of wind-driven barotropic return flow and lateral baroclinic circulation caused the transport. The lateral density gradient was produced by differences in temperature and suspended sediment concentration (SSC). During the wind events, SSC-induced vertical density stratification limited turbulent mixing at slack tides in the shallows, increasing the potential for two-layer exchange. The temperature- and SSC-induced lateral density gradient was comparable in strength to salinity-induced gradients in South Bay produced by seasonal freshwater inflows, but shorter in duration. In the absence of a lateral density gradient, suspended sediment flux at the channel slope was directed towards the shallows, both in winter and during summer sea breeze conditions, indicating the importance of baroclinically driven exchange to supply of sediment from the shallows to the channel in South San Francisco Bay and systems with similar bathymetry. 相似文献
15.
Modelling for anchovy recruitment studies in the Gulf of Lions (Western Mediterranean Sea) 总被引：4，自引：4，他引：0
Anchovy (Engraulis encrasicolus) is an important commercial species and one of the most abundant pelagic fish in the Gulf of Lions and the Catalan Sea. The
factors influencing its recruitment are crucial to fisheries and ecological research. Among those factors transport of larvae
by hydrodynamics (currents) is important because it determines whether the organisms can reach areas favourable to recruitment
or are dispersed. Therefore, the first step in anchovy recruitment modelling is to simulate North-western Mediterranean Sea
circulation. Several years (2001–2008) of hydrodynamics were simulated with the MARS-3D code. The resulting simulated currents
and salinity are used by Lagrangian tool, Ichthyop, to transport anchovy eggs and larvae to the Western Mediterranean Sea.
The aim of this study is to understand the main hydrodynamic processes that control anchovy transport and the effects of diel
vertical migration on the transport and final distribution of anchovy. 相似文献
16.
Marine Collignon Negar Haghipour Maarten Lupker Ali Mohammadi Marcus Christl Jean‐Pierre Burg 《地学学报》2019,31(2):111-119
Coupling between tectonics and surface processes is usually ill‐quantified as other factors such as climate and lithology affect the later. We provide catchment‐wide 10Be denudation rates of the Mand catchment in the Zagros Fold Belt (Iran) to infer correlations between these rates and ongoing tectonic shortening in the region. Denudation rates are generally low (~0.05–0.1 mm/a) but increase to ~1 mm/a near the Halikan anticline, where changes in precipitation, lithology or hillslope gradient are insignificant. The denudation rates upstream and downstream of the Halikan anticline are consistent with the GPS convergence rates in these areas. The sharp increase in denudation rates over the Halikan anticline denotes its growth as previously detected from terrace incision. It also reveals small wavelength coupling between crustal deformation and erosion. Denudation rates are therefore a useful and sensitive tool that helps constraining non‐brittle active tectonics such as folding of a sedimentary cover. 相似文献
17.
Pascal Bonnefond Pierre Exertier Olivier Laurain Amandine Guillot Nicolas Picot Mathilde Cancet 《Marine Geodesy》2015,38(3):171-192
The geodetic Corsica site was set up in 1998 in order to perform altimeter calibration of the TOPEX/Poseidon (T/P) mission and subsequently, Jason-1 and OSTM/Jason-2. The scope of the site was widened in 2005 in order to undertake the calibration of the Envisat mission and most recently of SARAL/AltiKa. Here we present the first results from the latter mission using both indirect and direct calibration/validation approaches. The indirect approach utilizes a coastal tide gauge and, as a consequence, the altimeter derived sea surface height (SSH) needs to be corrected for the geoid slope. The direct approach utilizes a novel GPS-based system deployed offshore under the satellite ground track that permits a direct comparison with the altimeter derived SSH. The advantages and disadvantages of both systems (GPS-based and tide gauges) and methods (direct or indirect) will be described and discussed. Our results for O/IGD-R data show a very good consistency for these three kinds of products: their derived absolute SSH biases are consistent within 17 mm and their associated standard deviation ranges from 31 to 35 mm. The AltiKa absolute SSH bias derived from GPS-zodiac measurement using the direct method is ?54 ±10 mm based on the first 13 cycles. 相似文献
18.
Emissions from the production of iron and steel could constitute a significant share of a 2°C global emissions budget (around 19% under the IEA 2DS scenario). They need to be reduced, and this could be difficult under nationally based climate policy approaches. We compare a new set of nationally based modelling (the Deep Decarbonization Pathways Project) with best practice and technical limit benchmarks for iron and steel and cement emissions. We find that 2050 emissions from iron and steel and cement production represent an average 0.28?tCO2 per capita in nationally based modelling results, very close to the technical limit benchmark of 0.21?tCO2 per capita, and over 2.5 times lower than the best practice benchmark of 0.72?tCO2 per capita. This suggests that national projections may be overly optimistic about achievable emissions reductions in the absence of global carbon pricing and an international research and development effort to develop low emissions technologies for emissions-intensive products. We also find that equal per capita emissions targets, often the basis of proposals for how global emissions budgets should be allocated, would be inadequate without global emissions trading. These results show that a nationally based global climate policy framework, as has been confirmed in the Paris Agreement, could lead to risks of overshooting global emissions targets for some countries and carbon leakage. Tailored approaches such as border taxes, sectoral emissions trading or carbon taxes, and consumption-based carbon pricing can help, but each faces difficulties. Ultimately, global efforts are needed to improve technology and material efficiency in emissions-intensive commodities manufacturing and use. Those efforts could be supported by technology standards and a globally coordinated R&D effort, and strengthened by the adoption of global emissions budgets for emissions-intensive traded goods.Policy relevanceThis article presents new empirical findings on global iron and steel and cement production in a low-carbon world economy, demonstrates the risks associated with a nationally based global climate policy framework as has been confirmed in the Paris Agreement, and analyses policy options to deal with those risks. 相似文献
19.
Marrel Amandine Perot Nadia Mottet Clémentine 《Stochastic Environmental Research and Risk Assessment (SERRA)》2015,29(3):959-974
Stochastic Environmental Research and Risk Assessment - To evaluate the consequences on human health of radionuclide releases in the environment, numerical simulators are used to model the... 相似文献
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Spatial variability in organic material sinking export in the Hudson Bay system,Canada, during fall 总被引：1，自引：0，他引：1
Amandine Lapoussière Christine Michel Michel Gosselin Michel Poulin 《Continental Shelf Research》2009
Spatial variations in the sinking export of organic material were assessed within the Hudson Bay system (i.e., Hudson Bay, Hudson Strait and Foxe Basin) during the second oceanographic expedition of ArcticNet, on board the CCGS Amundsen in early fall 2005. Sinking fluxes of particulate organic material were measured using short-term free-drifting particle interceptor traps deployed at 50, 100 and 150 m for 8–20 h at eight stations. Measurements of chlorophyll a (chl a), pheopigments (pheo), particulate organic carbon (POC), biogenic silica (BioSi), protists, fecal pellets and bacteria were performed on the collected material. In parallel, sea surface salinity and temperature were determined at 121 stations in the Hudson Bay system. Three hydrographic regions presenting different sedimentation patterns were identified based on average surface salinity and temperature. Hudson Strait was characterized by a marine signature, with high salinity (average=32.3) and low temperature (average=2.1 °C). Eastern Hudson Bay was strongly influenced by river runoff and showed the lowest average salinity (26.6) and highest average temperature (7.6 °C) of the three regions. Western Hudson Bay showed intermediate salinity (average=29.4) and temperature (average=4.4 °C). Sinking fluxes of total pigments (chl a+pheo: 3.37 mg m−2 d−1), diatom-associated carbon (19.8 mg m−2 d−1) and BioSi (50.2 mg m−2 d−1) at 50 m were highest in Hudson Strait. Eastern Hudson Bay showed higher sinking fluxes of total pigments (0.52 mg m−2 d−1), diatom-associated carbon (3.29 mg m−2 d−1) and BioSi (36.6 mg m−2 d−1) compared to western Hudson Bay (0.19, 0.05 and 7.76 mg m−2 d−1, respectively). POC sinking fluxes at 50 m were low and relatively uniform throughout the Hudson Bay system (50.0–76.8 mg C m−2 d−1), but spatial variations in the composition of the sinking organic material were observed. A large part (37–78%) of the total sinking POC was unidentifiable by microscopic observation and was qualified as amorphous detritus. Considering only the identifiable material, the major contributors to the POC sinking flux were intact protist cells in Hudson Strait (28%), fecal pellets in eastern Hudson Bay (52%) and bacteria in western Hudson Bay (17%). A significant depth-related attenuation of the POC sinking fluxes (average loss between 50 and 150 m=32%) and a significant increase in the BioSi:POC ratio (average increase between 50 and 150 m=76%) were observed in Hudson Strait and eastern Hudson Bay. For all other sinking fluxes and composition ratios, we found no statistically significant difference with depth. These results show that during fall, the sinking export of total POC from the euphotic zone remained fairly constant throughout the Hudson Bay system, whereas other components of the organic sinking material (e.g., chl a, BioSi, fecal pellets, protist cells) showed strong spatial variations. 相似文献