Biostratigraphy and Studying the Hypothesis uses of Rugoglobigerina in Appointing the Paleosalinity in Central Alborz, Maastrichtian

In order to studying salinity and biostratigraphy in Central Alborz basin, two sections Jorband and Ziarat-kola are sampled and studied Planktonic foraminifera and Echinoids fossil. Studying of foraminifera In Ziarat-Kola section determining three biozone by planktonic foraminifera. 1: Racemiguembelina fructicosa Interval zone 2: Pseudoguembelina hariaensis Interval zone 3: Pseudoguembelina palpebra Interval zone.that showing late maastrichtian. As well, at Jorband section assigning three biozone by Planktonic foraminifera 1: Contusotruncana contusa Interval zone, 2: Planoglobulina brazoensis Partial range zone, 3- Racemiguembelina fructicosa Interval zone. That showing maastrichtian. Likewise, in order to determining Paleosalinity select two sections at Jorband and Ziarat-Kola. Main object assigning Paleosalinity confirm sensitive Rugoglobigerina to changes of salinity. At former section used from excessive changes of Echinocorys and in later one used from ratio of kinds Foraminifera tests (Porcelaneous, Agglutinate and Hyaline). In middle parts of Ziarat-Kola section, percentage of porcelaneous tests was more than basal and upper ones. In middle parts of Jorband section salinity was less than basal and upper ones that examined by abundancy of the genus of Echinocorys. Physiological changes of body in this echinoderm also justify salinity changes throughout Jorband section. According to Whitenella is ancestor of Rugoglobigerina and also sensitive to salinity, it is possible that Rugoglobigerina show characteristic of its ancestor that justify by studying of salinity changes in two section of Central Alborz.