Investigating paleoecological changes in the Oman Sea (Sirik area) Holocene deposits based on calcareous nannoplanktons

In current study, some surface sediment samples of the Oman Sea (Sirik area) were prepared and photographed for study of calcareous nannoplanktons. For the first time, 17 genera and 29 species introduced from this area. Some nannoplanktons are the dominant taxa and some species are the rare taxa such as Florisphaera profunda, Gephyrocapsa ericsonii and Braarudosphaera bigelowii. In this study, we also observed many reworked species, and mostly of them belong to Neogene age. Relationship between 4 elements Zn, Cu, Ba and Si, distribution of nannoplankton and variational changes are investigated in this area. The Zn, Cu and Ba are directly related to productivity of nannoplankton and the ratio of them were high in the relatively nearshore of Sirik area. The Si prevents growth and distribution of nannoplankton, therefore the ratio of this elementt in relatively nearshore of Sirik area has negative relationship to abundances of nannoplankton. Thus, we can concluded that the Oman Sea floor, especially in areas close to the nearshore is a suitable environmental for growth and distribution of nannoplankton and the Oman Sea basin is a marginal sea.