Late Cretaceous to Early Paleogene global sea level fluctuations and the sedimentary environment in central Alborz (Northern Iran)

Abstract

The Cretaceous-Paleogene sequence, including K-Pg transition, located 45 km from the South of Sari in the North of Iran was analyzed in regards to lithology, lithofacies, foraminifera, and palynology evaluation. The main aim of this study was the reconstruction of sedimentary environmental condition including relative sea level changes during the K-Pg transition. Seventy rock samples were collected from 133 m of sedimentary rocks, mainly comprising limestone, sandstone, siltstone, and evaporate. Two species of foraminifera, ten species of spore, and seven species of pollen grains have been identified. K/Pg boundary has been determined based on the first occurrence of Tricolpites phillipsii in the 133 m above the base of the studied section. Two palynofacies have been identified based on statistical analysis of palynofacies factors (SOM, MP, Ph). Palynofacies analysis suggests nearshore (inner ramp) as a sedimentary environment for these sequences. Our palynofacies data indicate sea-level regression near K/P which can be correlated to the global sea level trend.