Biostratigraphy and assigning the paleosalinity by using Echinocorys and Planktonic foraminifera at Upper Maastrichtian, in Jorband section, Central Alborz, Iran

Jorband section is located in the north slope of central Alborz, and 28 Km south of Noor. It has been sampled and index fossilic groups of planktonic foraminifera and echinoids were studied in order to assign the paleosalinity and biozonation in central Alborz. The planktonic foraminiferal biozones identified within the Upper maastrichtian sequence of the Jorband section are three zones of Contustruncana contusa, Planoglobulina brazoensis, and Racemiguembelina fructicosa. The salinity changes were also searched in this section. In three layers in Jorband section examination echinocorys genus and is drawn as a diagram which in middle of the section, the salinity mounts is fewer than the beginning and top of the section.