Litho- and biostratigraphy of the early Eocenelarger benthic foraminifera-dominated carbonates of the central Tethys domain, Zagros Foreland Basin, SW Iran

The Early Paleogene Tethyan domain saw the development of large platform carbonates rich in large benthic foraminifera (LBF), of which the Taleh Zang Formation in Lurestan Basin, SW Iran, represents an excellent example. The LBF assemblage is dominated by alveolinids, together with a variety of foraminiferal genera such as Nummulites, Rotalia, Sackesaria, Assilina, Operculina, and Glomalveolina. Smaller benthic foraminifera, calcareous algae, gastropods, echinoids, and bivalves constitute minor components of the carbonate. Biostratigraphy analysis of the LBF is conducted on two distinct sections of the Taleh Zang Fm. The sections referred to as TZ-1 and TZ-2 have respective thicknesses of 87 m and 132 m. This analysis has constrained the formation age to the early Ypresian within Shallow Benthic Zones (SBZs) 5-7. Facies analysis supports the major accumulation of these successions in a shallow water environment within the euphotic zone. We recognize 9 distinct facies and microfacies representing four main depositional environments including tidal flat, lagoon, bioclastic shoal, and shallow open marine. These environments are distributed along a low-angle homoclinal ramp and form the foundation of a stratigraphic interpretation characterized by intervals displaying shallowing and deepening trends. Three shallowing-upward intervals have been identified within the Taleh Zang succession. The determined intervals cannot be solely attributed to global sea level fluctuations and support a significant impact of the regional structural context resulting from collision-induced uplift and variable subsidence rates. The identified intervals exhibit local and regional correlation and compatibility on the Arabian Plate, providing robust confirmation of the significant roles played by both tectonics and eustasy at a regional scale.& COPY; 2023 The Author(s). Published by Elsevier B.V. This is an open access article under the CC BY license(http:// creativecommons.org/licenses/by/4.0/).

Automated summary

The Taleh Zang Formation in the Lurestan Basin, SW Iran, contains large platform carbonates rich in large benthic foraminifera. The formation is dominated by alveolinids and various other genera of foraminifera, along with minor components such as calcareous algae, gastropods, echinoids, and bivalves. Biostratigraphy analysis indicates that the formation is of early Ypresian age and was deposited in a shallow water environment within the euphotic zone. The presence of intervals displaying shallowing and deepening trends suggests that regional tectonics and eustasy played significant roles in the formation of these deposits.