A stratigraphic section from the Tirgan Formation was selected in Arkan village nearby Bojnourd city in order to study echinoderm fauna systematically. Many specimens of echinoderms, especially toxasteridae which is associated with brachiopods were collected and studied systematically in this paper. Microscopie slides were also prepared and studied. All slides contain benthic foraminifers and c...

We investigate the evolutionary history of the wide-ranging Nearctic treefrog Hyla arenicolor through the integration of extensive range-wide sampling, phylogenetic analyses of multilocus genetic data, and divergence dating. Previous phylogeographic studies of this frog documented a potential signature of introgressive hybridization from an ecologically and morphologically divergent sister spec...

abtalkh formation is a part of late cretaceous sedimentary unit in the kopet- dagh basin, ne iran. this study deals with the study of this formation in the eastern parts of the basin in padeha village. it thickness is about 991m, and lithologically consists of grey, greyish to blue shale and marl. the lower contact with abderaz formation is conformable and transitional, but the upper boundary w...

This study shows that ichonology can be used to refine sequence stratigraphy as well as to interpret the depositional environment of the Kalat Formation (Upper Maastrichtian) in the Central Kopeh- Dagh Basin (NE Iran), Dareh-Gaz section. Field studies and petrography of these deposits led to recognize four lithofacies and nine subfacies that formed in the tidal flat (lithofacies A), lagoon (lit...

this study shows that ichonology can be used to refine sequence stratigraphy as well as to interpret the depositional environment of the kalat formation (upper maastrichtian) in the central kopeh- dagh basin (ne iran), dareh-gaz section. field studies and petrography of these deposits led to recognize four lithofacies and nine subfacies that formed in the tidal flat (lithofacies a), lagoon (lit...

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