Writers : Yazdi, M.
Refference : Geosciences Scientific Quarterly Journal,No.:19,P.:32
Publishing Year : 1375

Abstract :

The conodontsç!pecies collected from Sardar conglomerate pebbles using acid leaching procedure
have shown that the depositional time of Sardar conglomerate is at list post- Namurian. The age of Sardar conglomerate is controversial e.g. Stocklin et al., 1965, 1991 (Early Carboniferous) Husseini, 1992 (Late Carboniferous). In order to have more precise age control over the time of its deposition, 5 limestone clasts (pebbles) from the Niaz section at Kale Sardar were acid- leached for conodonts. Faunas from the clasts give a 4 different ages: Late tcA!ngu/an! zone or Early ccepIda zone (Famennian), typicus zone, anchoralis- latus zone (Tournaisian) and su,ua/us- corrugafus- su/ca/us zone (Namurian). From this data alone, the Sardar conglomerate must have been deposited some time after the sun/a/us- corcuga/us- au/ca/us zone or at the end of Namurian (Early Westphalian).
Kolar-Jurkovsek and Jurkovsek (1994) concluded that, conodont species collected from acid- leached samples of the Upper Paleozoic sediments (pebbles) at Praprotno, Slovenia have different ages from Frasnian to Visean- Namurian. The similarity between conodont 4pecies and depositional history of Sardar conglomerate (Shotori Range, Eastern Iran) and Upper Paleozoic sediments at Praprotno, Slovenia is very important for paleogeographical interpretation. Paleontological evidence and Paleogeographical history 01 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 ol 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 (1972). In this respect post- Namurian depositional also reported, in Slovenia (Kolar- Jurkovesk and Jurkovesk 1994) and in the Arabian Basin, Persian Gulf and adjacent areas (Aisharhan and Narirn, 1995).

Subject List : Paleogeography