Quantitative analysis, basin evolution and paleoecology of Early Miocene ostracods in the southwest of Kerman, Iran

This paper focuses on the quantitative analyses of Early Miocene ostracods in south and north of the Sirjan area, southwest of Kerman. Detailed studies resulted in identification of 23 species of ostracoda. The coexisting benthic foraminifera and comparing the identified microfauna assemblages with previous studies confirms the Early Miocene age for the strata. The quantitative analysis show a low diversity in the ostracoda assemblages, in compare with other areas. The ostracoda community is classified into seven morphogroups. Several communities are recorded in the ostracoda morphogroups, which reflects basic changes in the basin condition. The morphogroups analysis also reveals that the basal parts of the sections are deposited in shallow and poorly ventilated waters, while a normal condition prevailed through upward. A period of instability is predominant after the normal condition and final stages of deposition took place in the near shore environment, which reflects the end of sea life. The stratigraphical position and structural history of the basement suggest that syndepositional tectonic activities were responsible for the fluctuations in the environmental conditions. This suggestion is confirmed by comparing the studied area with adjacent areas, where similar deposits are deposited on different basements.