Investigation of lithological units portion in sediment yield using mineralogical and lithological method, case study: Hassan Abdal watershed basin, Zanjan

The purpose of this study is to determine the contribution of each lithological units in sediment generation of watershed. In this study, samples were collected primarily from sediments of small dams and sediments of waterways. Grading was performed for all samples by wet sieving. Then, 600 micron and 4 mm sieves were selected as indicators and by choosing 100 grains of sediment from each sample, mineralogical analysis was performed using a binocular and considering mineral and rock fragments the results were compared and adapted with the lithological units and the share percentage of each stone, each mineral deposits were determined by counting the number of minerals and rock fragments. According to the results, Єz lithological unit has the highest share in erosion and sediment yield with a 44.62 percent. This unit consists of pink to red Micaceous shale. PMl lithological unit with 22.88 percent is in the second place consisting limestone. The third lithological unit that has the largest share in sediment yield is Ev unit, which consists of andesite and andesitic breccia with layers of tuff and tuffite. Pl-Qc, Єl, Qt, Js, Et, Ek1, Pd, Єbt and Ef units with 4.25, 3.22, 2.09, 2.05, 2.01, 1.83, 1.33, 1.32 and 1.23 percent are in the next order and have the highest share in the erosion and sediment yield of watershed.