Writers : Behdani,Ensieh;supervisor:M. Najafi;advisor:R. Mussavi Harami
Refference : M.Sc.Thesis,Ferdowsi university,Mashhad
Publishing Year : 1383

Abstract :

Flysch deposits along with other rock types in Chahkand, Fanud and Ghasibe areas.274 are parts of eastern Iranian Flyschs basin, that their thickness are 301, 220 and meters, respectively. Lithostratigraphic analysis all show that divisions of Certaceous ) 1978( sequence(Kshcu,Kphu,Kshsu,Ksspu,Ksuu)for Flysch deposits that defined by Ohanian .in the geological map of Birjand (1/100000), have not been found in the studied sections in( Kshcu,Kphu,Kshsu,Ksspu,Ksuu ) in the Chahkand section and also 3 parts Kshcu, Ksuu,Kshsu ?parts K Faund section were identified. It should be mentioned that in Gasibe section only one part( Ksspu) was introduced by Ohanian (1978). however, this research shows that the Ohaniar ( In the other hand, tectonic events in this area . Ksspu units is older than what he purposed have broken as rock units, therefore the contact between rock units are mostly faulted Sedimentary rocks of study area mainly composed of sandstone, shale, siltstone ،and Radiolarian cherts. Igneous rocks consist of ulteramafic type such as pridotites and mafics rocks with pillow structure as well as mctamorphozcd spilites Among the altered rocks related to pridotits can refer to serpentinites and listvenitiezed ulteramafics. Metamorphic rocks are also consist of low grade metmorphozed sedimentary units including slate and Biostratigraphic study Radiolarians bearing redish cherts in top of South Birjand's phylite.
Ophiolitic sequence in lower boundary of Fanud section which owns Radiolariaris Fanud have been collected and then investigated led to identification of two Radiolariar ?assembelage .The ?assembelage I is late Baremian_ Early ?Aptian and the assemblage II is Albian_Cenomanian in age. Based on this study, no fossils have been reported with the ageof Late Baremian-Early Aptian, therefore the age of first opening (rifling) between the Lut and Afghan blocks, where the studied sediments have been deposited, can be suggested during the Late Barernian- Early Aptian. in the other hand, since the age of the youngest fossil is Albian-Cenomanian, therefore the age of ophiolite above this sequence can be suggested post Cenomanian. In conclusion, the age of flysch deposits within the ophiolite
assembelage is probably Late Upper Cretaceous and younger than Cenomanian-Torunian Within the Fanua of assemblag 11, a few foraminifera have been identified which indicat the Cenomanian age for these strata. At last, the present of shallow water silici_clastk sediment including Graywacke and Sublitharenite to litharenite Sandstones in accompan_with redish plagic sediment and also intercalation of mafic to ulteramafic rocks, a Arc Trench basins type can be consider For deposition of Melangc_Flysch sediments of South of Birjand.

Subject List : Lithostratigraphy