Baghuk Mountain (Central Iran): high-resolution stratigraphy of a continuous Central Tethyan Permian–Triassic boundary section

• Main Authors: D. Korn, L. Leda, F. Heuer, H. Moradi Salimi, E. Farshid, A. Akbari, M. Schobben, A. Ghaderi, U. Struck, J. Gliwa, D. Ware, V. Hairapetian
• Format: Article
• Language: English
• Published: Copernicus Publications 2021-06-01
• Series: Fossil Record
• Online Access: https://fr.copernicus.org/articles/24/171/2021/fr-24-171-2021.pdf

<p>Permian–Triassic boundary sections at Baghuk Mountain (Central Iran) are investigated with respect to their lithological succession, biostratigraphy (particularly conodonts, nautiloids and ammonoids) as well as chemostratigraphy (carbon isotopes). The rock successions consist of the Late Permian Hambast Formation, the youngest Permian Baghuk Member (new name for the “Boundary Clay”) and the Early Triassic <i>Claraia</i> beds. Correlation of the data allows the establishment of a high-resolution stratigraphy based on conodonts with seven Changhsingian zones. Abundant ammonoids enable the separation of ammonoid assemblages with the successive Wuchiapingian genera <i>Prototoceras</i>, <i>Pseudotoceras</i> and <i>Vedioceras</i>, as well as the Changhsingian genera <i>Shevyrevites</i>, <i>Paratirolites</i>, <i>Alibashites</i>, <i>Abichites</i> and <i>Arasella</i>. Griesbachian and Dienerian ammonoids are usually poorly preserved. Nautiloids occur predominantly in the Wuchiapingian part of the section with two successive assemblages dominated by the Liroceratidae and Tainoceratidae, respectively. Numerous Early Triassic strata contain microbialites of various outer morphology and microstructure. The carbon isotope curve (<span class="inline-formula"><i>δ</i>¹³</span>C<span class="inline-formula">_carb</span>) shows a continuous late Changhsingian negative excursion continuing across the Baghuk Member with the lightest values at the base of the Triassic.</p>