sedimentological study of motr-abad and solh-abad rivers, no-bahar watershed, central iran

no-bahar watershed is located, south of khorasan razavi province. geologically, the study area is a part of central iran zone. the rock units are late mesozoic and cenozoic in age in this watershed. no-babhar watershed includes several channels, which among them, only two main channels, motr-abad and solh-abad, have been studied. these rivers are mostly, braided channel in style, with high gradient and power flow, and short time flash flooding. totally, two sedimentary facies associated, includes four gravely facies (gmg, gmm, gci, gcm), two sandy facies (sh, sp) and three structural elements (sg, la, sb) have been identified. based on recognized sedimentary facies and structural elements, three sedimentary models which consist, gravel braided with sediment gravity flows, gravel bed meandering river and sandy meandering river are suggested.