نتایج جستجو برای: fluvial systems
تعداد نتایج: 1187088 فیلتر نتایج به سال:
Fluvial strata dominated internally by sedimentary structures of interpreted upper flow regime origin are moderately common in the rock record, yet their abundance is not appreciated and many examples may go unnoticed. A spectrum of sedimentary structures is recognised, all of which occur over a wide range of scale: 1. cross-bedding with humpback, sigmoidal and ultimately low-angle cross-sectio...
The relative rates of erosion by rivers and glaciers, and the topographic effects of these two different styles of erosion, remain outstanding problems in geomorphology. We use a quantitative description of local fluvial landscapes to estimate how glaciated landscapes might look now had glaciers not developed. This indicates the landscape modification attributable to glacial erosion. We present...
The Goto Islands are located at the westernmost tip of Japan archipelago, and preserve a lower–middle Miocene sedimentary sequence deposited during rifting continental margin opening Sea Japan. stratigraphy Group new K–Ar, fission-track, U–Pb age data were used to determine initial conditions in southwest thickness is 2000–3000 m. lower unit (ca. 22–17.6 Ma) consists thick, greenish, volcanicla...
Whether or not steady-state topography and denudation are probable states depends on the timescale of system response to tectonic and climatic perturbations relative to the frequency of those perturbations. This paper presents analytical derivations of algebraic relations for the response time of detachment-limited fluvial bedrock channel systems both to tectonic and climatic perturbations. Det...
Gently sloping surfaces for settlement are scarce in high mountains ranges and they are commonly related to distal parts of alluvial fans where floods hazards can be expected. To understanding the influence of external factors, such as climatic variability and land uses, on the alluvial fan accretion and flooding processes, sedimentology and pollen analysis from local site provide valuable data...
The Copper Harbor Conglomerate is a Mesoproterozoic (1.09 Ga) freshwater sedimentary sequence that outcrops in the Upper Peninsula of Michigan. The formation was deposited during infilling of the failed Midcontinent Rift and contains fluvial, lacustrine, and alluvial fan facies. This study describes and analyzes the formation of small domal structures preserved in fluvial sandstone facies withi...
Improved techniques are needed to characterize complex fluvial systems and monitor ecologically important, yet highly vulnerable riverine environments. This paper explores potential alternatives to traditional mapping of in-stream habitat and presents fuzzy set theory as a means of departing from the rigid, Boolean, object-based framework. We utilize hydrodynamic modeling, remotely sensed data,...
Although fossil fluvial travertines have been described, factors controlling their formation are poorly understood because of the paucity modern counterparts. To disclose processes affecting deposition, a travertine system at Bagni San Filippo (Siena, central Italy) was studied here and compared with other cases. The occur in valley an ephemeral stream, but continuous water influx from hot spri...
نمودار تعداد نتایج جستجو در هر سال
با کلیک روی نمودار نتایج را به سال انتشار فیلتر کنید