New Age and Paleogeographic History Redetermination of Sardar Conglomerate (Tabas, Eastern Iran) Based on Conodont Species, Comparison of New Chronological Framework to the Age of the Upper Paleozoic Sediments At the Praprotno, Slovenia

دسته چینه شناسی و فسیل شناسی
گروه سازمان زمین شناسی و اکتشافات معدنی کشور
مکان برگزاری پانزدهمین گردهمائی علوم زمین
نویسنده مهدی یزدی
تاريخ برگزاری ۲۷ بهمن ۱۳۷۵

The Conodonts Species collected from Sardar Conglomerate pebbles using acid leaching procedure have shown that the depositional time of Sardar Conglomerate is at least post- Namurian. The age of Sardar Conglomerate is Controversial e.g. Stocklin et al., ۱۹۶۵, ۱۹۹۱ (Early Carboniferous) Husseini, ۱۹۹۲ (Late Carboniferous). In order to have more precise age control over the time of its deposition, ۵ limestone clasts (Pebbles) from the Niaz section at kale Sardar were acid- Leached for conodonts, Faunas from the clasts give a ۴ different ages, late triangularis zone or Early crepida zone (Famennian), typious zone, anchoralis- Latus zone (Touraisian) and sinuatus- corrugatus sulcatus zone (Namurian). From this data alone, the Sardar Conglomerate must have been deposited some time after the sinuatus- corrugatus- sulcatus zone or at the end of Namurian (Early Westphalian).
Kolar-Jurkovsek and Jurkovsek (۱۹۹۴) concluded that, conodont species collected from acid - leached samples of the Upper Paleozoic sediments (pebbles) at Praprotno. Slovenia have different ages from Frasnien to Visean - Namurian. The similarity between conodont species and depositional history of Sardar Conglomerate (Shotori Range, Eastern Iran) and Upper Paleozoic sediments at Praprotno, Slovenia is very important for Paleogeographical evidence and Paleogeographical history of these two localities suggest that, the Sardar conglomerate and Upper Paleozoic sediments at Praprotno must have been deposited within the Westphalian or some time later.

The result of this investigation confirms that, the erosion rate in several parts of Iran was variable in different areas. Thus, the different ages of eroded zones, suggests that, erosion and redeposition of sediments was completed before transgression of Permian system. This Pre-Permian silicaclastic . erosion has been reported from different areas, for example in Jam (Semnan - Damghan) by Alavi -Naini (۱۹۷۲) Also Post - Namurian depositional reported, in Slovenia (Kolar – Jurhovesk and Jurkovesk, ۱۹۹۴) and in the Arabian Basin, Persian Gulf and adjacent area (Alsharhan and Narirn, ۱۹۹۵).

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