Quantitative palynostratigraphy and palaeoecology of Tethyan Paleocene-Eocene red beds in north of Zagros sedimentary basin, Iran

摘要

Biostratigraphic and quantitative characteristics of dinocyst assemblages and palynofacies have been used to interpret the paleoecology and sea level changes of Paleocene-Eocene red beds in north of Zagros sedimentary basin, Iran. One hundred forty-eight species and 69 genera of dinoflagellate cysts are recorded from 32 rock samples collected from the 153-m-thick outcrop section. Three dinocyst zones comparable to North Hemisphere midlatitude zonation are established and described. Three palynofacies differentiated-VI: proximal suboxic-anoxic shelf, VIII: distal dysoxic-anoxic shelf, and IX: distal suboxic-anoxic basin-suggest a suboxic-anoxic proximal-distal shelf and distal basin for the strata under investigation. The sequence stratigraphy events have been documented on the basis of palynological asset recorded such as palynofacies, SOM/MP ratio, dinocyst abundance and diversity, peridinioid/gonyaulacoid (P/G) ratio, proximochorate and cavate cysts ratio, and specific inner neritic, outer neritic, and oceanic taxa trends). The record of sea level changes for the Paleocene-Eocene red beds shows a third-order sequence with one sequence boundary (type II). The P/G ratio shows increasing upward trend of paleoproductivity in this sequence.