Sequence Stratigraphy of Middle Albian to Cenomanian sediments (Sarvak Formation) in Tang-e-Chenarbashi (southeast Ilam) and role of fossil fauna for recognition and interpretation of the depositional sequences

• Main Authors: Jahanbakhsh Daneshian, S. Ali Moallemi, Kamyar Younesi
• Format: Article in Journal/Newspaper
• Language: English; Persian
• Published: University of Isfahan 2018
• Subjects: sequence stratigraphy; cretaceous; sarvak formation; fauna; Stratigraphy; QE640-699; Planktonic foraminifera
• Online Access: https://doi.org/10.22108/jssr.2019.108735.1033; https://doaj.org/article/e84fa04025644cadb285db4c41d32a1a

Abstract Middle Albian to Cenomanian strata of the Sarvak Formation indicate pelagic facies in Tang-e-Chenarbashi stratigraphic section. These strata deposited in five sequences of the third order and nine sequences of the fourth order. These sequences were determinated in a succession including six microfacies mudstone, sponge spicule packstone, peloidal packstone, radiolarian packstone, Oligosteginid, planktonic foraminifera wackestone - packstone, benthic foraminifera echinoidal wackestone - packstone. Study of the third order sequences show that in some of them exist paraconformity which related to sequence boundary of the fourth order sequences. Investigating these sequence boundaries and recognition the sequences were done based on planktonic foraminifera biozones. In this study, separating the fourth order sequences is generally based on fossil fauna. In the fourth order sequences, maximum flooding surfaces (mfs) were recognized based on maximum diversity and abundance of planktonic taxa and decreasing of benthic foraminifera. Introduction The Sarvak Formation, one of the four formations of the Bangestan Group in Zagros basin, generally includes two facies, deep facies in the Lurestan province and shallow facies in the Khuzestan and Fars provinces. The Sarvak Formation deposited during Middle Albian to Early Turonian which the two main orogenic phases, Austrian (Albian / Cenomanian) and Sub-Hercynian (Cenomanian / Turonian) occurred. The warmest climate and the highest sea level took place along the Earth history in Albian to Cenomanian, and this could be a good and unique objective to investigation the effects of many interesting phenomena due to the amazing and unrepeated events. In addition, depositions of this time span could be included interesting depositional sequences. The aim of this research is recognition of depositional sequences of the Sarvak sediments by using of fossils. Material and Methods One stratigraphic section with 712 meters thickness was selected for studying of deep facies of the ...