نتایج جستجو برای: fluvial environment
تعداد نتایج: 521898 فیلتر نتایج به سال:
Abstract Continental depositional environments preserve the majority of the macrofloral record since the advent of land-plant colonization in the mid-Paleozoic, and wetland representatives are encountered more commonly than those that grew under more seasonal conditions. It has been assumed that preservation potential and future recovery of plant debris are high once detritus is introduced into...
River basin management is becoming increasingly complex in the United States since watershed managers are required to take into consideration the threatened and endangered (T&E) species that inhabit aquatic and riparian ecosystems. Unfortunately, too many fallacies and political agendas have crept into the picture. Suppositions and hypotheses fly everywhere in the political-legal environment un...
[1] Using a stereo pair of HiRISE images of a pole‐facing crater slope at 38°S, 218°E, we measure topographic profiles along nine gullies. Typical slopes of the interior channel region (above the depositional apron) are ∼20°. We test the hypothesis that sediment transport on gully slopes occurs via fluvial transport processes by developing a numerical sediment transport model based on steep flu...
Coupling between erosion and tectonics are thought to play a determinant role in mountains evolution. Here, we investigate the interplay in this coupling between the assumed erosion law and the crustal rhe-ology at the margin of a collisional plateau, like the Himalaya of central Nepal. Lithospheric deformation is calculated over a time scale of 100 kyr by a two-dimensional finite elements mode...
We report a new synthesis of best estimates of the inputs of fixed nitrogen to the world ocean via atmospheric deposition and compare this to fluvial inputs and dinitrogen fixation. We evaluate the scale of human perturbation of these fluxes. Fluvial inputs dominate inputs to the continental shelf, and we estimate that about 75% of this fluvial nitrogen escapes from the shelf to the open ocean....
Fluvial landscapes are a result of lithospheric tectonic movement, climate evolution and surface processes. Existing evidence proves that regional deformation can be reflected by the fluvial landforms. The southern Alashan Block lies closest to northeastern Tibetan Plateau has become latest plateau outward expansion boundary. Yabrai Shan is located at intersection Plateau, Ordos Blocks, thereby...
The study of paleosols can be a vital tool in the paleoenvironmental interpretation of continental deposits because their physical and chemical characteristics are a reflection of variations in aspects of soil formation. Changes in paleosol characteristics can be used to determine the architecture and nature of parent material, paleosol maturity, topography, climate and soil-forming organisms (...
Erosion by glacial and fluvial processes shapes mountain landscapes in a long-recognized and characteristic way. Upland valleys incised by fluvial processes typically have a V-shaped cross-section with uniform and moderately steep slopes, whereas glacial valleys tend to have a U-shaped profile with a changing slope gradient. We present a novel regional approach to automatically differentiate be...
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