Biostratigraphy of the Kazhdumi Formation (Albian), northeast of Shiraz, Zagros Basin (SW of Iran)
- PDF / 2,936,478 Bytes
- 11 Pages / 595.276 x 790.866 pts Page_size
- 88 Downloads / 230 Views
ORIGINAL ARTICLE
Biostratigraphy of the Kazhdumi Formation (Albian), northeast of Shiraz, Zagros Basin (SW of Iran) Massih Afghah1 · Mahnaz Parvaneh Nejad Shirazi2 · Mojtaba Keshavarzi2 Accepted: 7 September 2020 © The Author(s) 2020
Abstract The Kazhdumi Formation is one of the most significant rock units in the Bangestan Group in Zagros Basin. In this study, one section of the Kazhdumi Formation (Kuh-e-Rahmat) was selected for research. The section is extended approximately 89 m thick. The lower lithostratigraphic limit of the Kazhdumi Formation is marked by an oxidized zone, while the upper boundary is described as gradational type. The stratigraphic distribution of foraminifer taxa confirms two biozones in the studied section: Hemicyclammina sigali and Mesorbitolina subconcava in the Assemblage Zone and Mesorbitolina aperta in the range zone. Based on the investigated calcareous algae, Trinocladus tripolitanus, Range Zone is described. The identified calcareous algae are well distributed along Kazhdumi Formation. According to the received data of the established biozones, the age of the Kazhdumi Formation is Albian. Keywords Albian · Foraminifer · Calcareous algae · Zagros · Iran
Introduction The Zagros area is one of the most well-known oil producing regions in the world. Many geologists have studied the stratigraphy of the mentioned area (e.g., James and Wynd 1965; Kalantari 1976). Previous oil exploration was conducted by the Anglo-Persian Oil Company in 1909 (Afghah and Farhoudi 2012). Because of the oilfield development in southwestern Iran, studies of the Zagros rock units are required by the National Iranian Oil Company (Motiei 1992). Among rock units studied in the Zagros basin, the Kazhdumi Formation (Albian) is significant for Iranian geologists because of its characteristics as a petroleum source rock. Thus, the stratigraphic position and the biostratigraphic characteristics of Kazhdumi Formation are valuable for National Iranian Oil Company geologists. James and Wynd (1965) studied the Kazhdumi Formation for the first time, which is a part of the Bangestan Group. This group consists of the * Massih Afghah [email protected] 1
Department of Geology, Shiraz Branch, Islamic Azad University, Shiraz, Iran
Geology Department, Payame Noor University, PO Box: 19395‑3697, Tehran, Iran
2
Kazhdumi, Sarvak, Surgah, and Ilam formations. In general, the lithological aspect of the Kazhdumi Formation is comprised of dark bituminous shale (Soleimani 2009). The surrounding strata, Dariyan (Aptian) is the underlying formation, while Sarvak is known as the overlying formation (Cenomanian). These strata are well exposed in many parts of the Zagros mountain ranges. Both rock units are composed of carbonates that extend along the Zagros Basin. James and Wynd (1965) divided the Zagros Basin into four zones: Khouzestan, Lurestan, Coastal, and Interior Fars (Fig. 1). The Kazhdumi Formation changes laterally to carbonate facies from the type section (Khuzestan area) to the Interior Fars region, which consis
Data Loading...
