Foraminifera biozonation and morphogroups from Nimbolook section, east margin of Lut block, Iran

Abstract

One stratigraphic section named Nimbolook succession in the northwest of Qayen city was measured and sampled. Based on identified foraminifera Berthelina intermedia assemblage zone, Rotalipora appenninica and Biticinella subbreggiensis interval zones were proposed. These biozones coincide with global biozones. According to foraminifera fauna, an Early–Late Albian age was suggested for this study. Palaeoecological studies led to the recognition of three benthic foraminifera (MG1–3) and two planktonic morphogroups (MG4–5). In the lower and middle part of the section, the abundance of benthic and agglutinated foraminifera (MG1–3) is more than planktonic foraminifera (MG4–5), respectively. Calcareous benthic morphogroups could be attributed to aerobic, shallow to slightly deep water, and eutrophic to mesotrophic environment. Agglutinated benthic morphogroups suggested that aerobic, mesotrophic, to eutrophic environments are characteristic by a dominance of arenaceous shallow infaunal specimens which are active deposit feeders. Planktonic foraminifera morphogroups with trochospiral and smooth test have been seen near the surface water, aerobic to semi-aerobic environment. Increasing planktonic foraminifera and specially keeled species could be a suggested recovery in paleoenvironmental conditions.