Nile-Delta beach pebbles I. : grain size and origin

El-Fishawi Nabil M. and Molnár Béla: Nile-Delta beach pebbles I. : grain size and origin. In: Acta mineralogica-petrographica, (25) 1. pp. 25-39. (1981)

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This paper discusses roundness, sphericity, flatness.index, flatness ratio and elongation parameters of Nile Delta teach pebbles. Generally 1365 pebbles were analysed and a total of 12 285 measurements was done. Beach pebbles were measured for the main diameters, large inscribing circle and diameters of corners. Several indices was used to study the variations in the roundness and shape of pebbles. Three principal methods of evaluating roundness and two methods for sphericity are correlated in relation to their results. Flatness index is more close to being the inverse of the maximum projection sphericity of SNEED, E . D . and FOLK , R . L . [1958 ] than the KRUMBEIN, W . C . [1941 ] measure. Beach pebbles show a significant change with decreasing size, they become well rounded, more spherical, less elongate and more flattened in shape. On light of roundness, sphericity and other shape parameters, the relations to distance of transport along the coast are analysed. The increasing in roundness which accompanies the decreasing in sphericity and flatness paints to beach pebbles abrasion as a main cause for movement along the coast. The increasing in flatness index and decreasing in elongation index of beach pebbles from the points of supply towards the east was so marked. Geometrically, this modification should take place by abrasion chiefly of both short and long axes with slightly different rates.

Item Type: Article
Journal or Publication Title: Acta mineralogica-petrographica
Date: 1981
Volume: 25
Number: 1
ISSN: 0365-8066
Page Range: pp. 25-39
Language: English
Publisher: University of Szeged, Department of Mineralogy, Geochemistry and Petrology
Place of Publication: Szeged
Related URLs:
Uncontrolled Keywords: Kőzettan, Ásványtan, Földtan
Additional Information: Bibliogr.: p. 38-39. ; ill. ; összefoglalás angol nyelven
Subjects: 01. Natural sciences
01. Natural sciences > 01.05. Earth and related environmental sciences
Date Deposited: 2016. Oct. 17. 09:25
Last Modified: 2022. Jul. 25. 15:29

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