کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
4685884 | 1635514 | 2010 | 10 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
Quantifying erosion over timescales of one million years: A photogrammetric approach on the amount of Rhenish erosion in southwestern Germany
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کلمات کلیدی
موضوعات مرتبط
مهندسی و علوم پایه
علوم زمین و سیارات
فرآیندهای سطح زمین
پیش نمایش صفحه اول مقاله
چکیده انگلیسی
The Lein valley in southwestern Germany possesses well-preserved Pliocene to mid Pleistocene land surfaces featuring a gentle relief and sediments accumulated by former tributaries of the Danube. This ancient Danubian land surface was captured and incised by mid Pleistocene to Holocene tributaries of the River Rhine. In a photogrammetric approach we calculated the volume of material extracted by Rhenish erosion providing a first quantification of the effects of stream piracy on timescales of about 1Â Ma. Using stereoscopic surface modelling software a DEM was generated with a resolution of 5Â m. From borehole data, literature, geological maps, and own field observations we determined the morphometric parameters of the ancient Danubian Ur-Lein valley. The gradient was imported as a 3D-breakline into the model where it controls the reinterpolation of surrounding data points. The result is a high-resolution DEM of the valley of the Ur-Lein. Subtraction of the DEM of the actual landscape from the DEM of the ancient Ur-Lein valley yields a model representing the rock volume eroded by the Rhenish Lein which totals 1.39Â km3 and converts into a rate of erosion between 63 and 74Â mm/ka over a period of 700 to 600Â ka, respectively, in accordance with figures obtained elsewhere in Central Europe through cosmogenic nuclides. It reflects the dominance of frequent fluctuations in climate and is considered to be mainly a product of strong changes in temperature and related processes during the transitional times between mid to late Pleistocene warm and cold states. A filtering procedure applied to cold and transitional state erosion rates of the Middle and Late Pleistocene yielded peak values between 66 and 77 mm/ka, up to three times higher than the modern rate or the rate of warm-state episodes. An assessment of the contribution of Rhenish stream piracy on long-term mid Pleistocene denudation under changing climate conditions resulted in a maximum 4.9-fold acceleration.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Geomorphology - Volume 122, Issues 3â4, 15 October 2010, Pages 244-253
Journal: Geomorphology - Volume 122, Issues 3â4, 15 October 2010, Pages 244-253
نویسندگان
Annette Strasser, Marcel Strasser, Hartmut Seyfried,