Petrology of Nile River sands (Ethiopia and Sudan): Sediment budgets and erosion patterns

Autor: Eduardo Garzanti, Sergio Andò, Giovanni Vezzoli, Ahmed El Kammar, Ada Ali Abdel Megid
Přispěvatelé: Garzanti, E, Ando', S, Vezzoli, G, Megid, A, El Kammar, A
Rok vydání: 2006
Předmět:
Zdroj: Earth and Planetary Science Letters. 252:327-341
ISSN: 0012-821X
DOI: 10.1016/j.epsl.2006.10.001
Popis: Detrital modes of modem Nile sands, together with estimates of sediment volumes trapped in Sudanese reservoirs, allow us to calculate sediment loads of major tributaries (Blue Nile, White Nile, Atbara) and erosion rates in the Nile catchment. A tridimensional array of high-resolution bulk-petrography and heavy-mineral data was obtained on both levee (suspended load) and bar (bedload) deposits, analysed separately for each grain-size subclass at 0.5 Phi intervals. From available information on sediments stored in the Roseires, Khashm el Girba and Lake Nasser reservoirs between 1964 and 1990, the total Nile load is reassessed at 230 20 10(6) t/a, an estimate two to four times higher than figures reported so far, on which previous estimates of sediment yields and erosion rates were based. Of such huge amount of detritus, 82110 10 6 t/a are contributed by River Atbara, which carries more volcanic rock fragments, brown augite and olivine from basaltic rocks, and 140 20 10(6) t/a by the Blue Nile, which carries more K-feldspar and hornblende from amphibolite-facies basement rocks. The additional
Databáze: OpenAIRE
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