The Mesopotamian Geomorphology researches..

Sedimentological and Geomorphological Study of Sand Dunes

in Najaf, Samawa, And Nasiriya Area

 Ra'ad Abdul-Albaqi Al-Ani

Abstract

   There are many sand dunes belts distributed in south and southwestern parts of the Western Desert ; Najaf, Samawa, and Nasiriya fields. One hundred samples were collected from the three field, 40 from  Najaf,  and 60 samples from Samawa and from Nasiryia.

   Geomorphological study shows there are two types of dunes; the barchan dune in Nasiriya area from by the action of uni-directional wind and fixed dune in Samawa area, that contains the domed- shape and elongated type of dunes that form due to variation in the prevailing wind direction.

   Mechanical analysis showed that sand grains in Najaf field to be well-moderately sorted ( 0.38-1.2), strongly coarse to strongly fine skewed (- 0.81- to 0.39) and very –laty to leptokurtic ( 0.1-1.3). Samawa dunes are well to poorly sorted (0.04 – 1.44 ), strongly coarse to strongly fine slewed (- 0.48 to 1.120, very platy to very leptokurtic (0.49 – 1.69). In Najaf dune sands are very well sorted near symmetrical to stongly fine skewed (-0.1 to 0.5), and meso to very leptokurtic (0.9-2.3), the distribution of these sediments is unimodal in Najaf and Nasiriya  and bimodal in Samawa area.

   The identification of heavy and light minerals, clay minerals analysis, and the morphology test by SEM suggest that the sediments under study were transported from geological formations and alluvial deposits of Euphrates River.

   The average value of roundness are 0.49 and sphericity 0.85 that include, the texture of the dune sand are immaturity and transported few distance.

   Generally, the topography, geology, wind direction and the vegetation cover affected the shape and arrangement of dunes and their extention in a NW-SE orientation in the three studied dune fields.

 MSc. Thesis submitted by Ra'ad Abdul-Albaqi Al-Ani, Dept. Geology. College of Science, Baghdad University, 1979.

 Supervisedby; Dr. Ali Jawad Ali

  Dr. Mudafer Ahmed Mahmmod