The Role of Mineralogical and Statistical Analyses of Sediments In Source Studies of Shandan-Saravan Sand Dunes, Baloo chestan

Samples taken from lithological units and sand dunes in point grid, were analyzed through
morphoscopic and mineralogical studies. The same-sized maps of sand dunes were then drawn by
using statistical parameters of grains. Maps and distribution of statistical parameters show that grain
size decreases from 0.37 mm in west to 0.18 min. in east through Erg. Also there is an increase in the
degree of sorting and roundness in this direction. The coarsest particles are found in ripple marks as
well as in sand sheets whereas nebkas contain the finest ones. According to the relationship between
grain size and their transportation distances by winds, the first accumulation phase (D1) is 3 km far
from the erg. Based on microscopical results, rock fragments make up 85%, whereas minerals make up
15% of grains including quartz, feldspar and calcite. According to X-ray diffraction and Electron
Microscope Scanning, quartz frequency relates to quartzose-sandstones, calcite frequency is relatedto
flishe limestene with clay minerals haveing originated from shale sources. In the second sedimentation
phase (D2) or erg, 98.54% of sands have been transported through saltation, while only 1.2 %, and.
0.26% through suspension and creep processes respectively. According to morphscopic analyses by
using binocular and SEM photos of quartz and results from Friedman's Diagram, 80% of sands were
shown to be transported by collaboration of water and wind, while only 20% by water alone. This
indicats that water is an important agent in semi-arid bioclimatical zones. Finally, based on
mineralogical studies, the most important sources of Shandan sand .dunes are recognized as Saravan
lithological units (ES 3, ES 4) as well as Zaboli lithological unit (EZ)with other units having little effect
in'sand production for the erg.