oa Late Campanian to Paleocene Planktic Foraminiferal Biozonation for Izeh, the Zagros Basin, Iran

Planktonic foraminiferal biostratigraphic study of the Gurpi Formation at Danial section in northeast<br>Izeh, the Zagros Basin, Iran, provides improved age resolution and good biostratigraphic control for<br>late Cretaceous to Paleocene strata. Late Cretaceous to Paleocene assemblages are open marine<br>faunas, and most of the standard tropical/subtropical planktonic foraminiferal zones are represented in<br>the section. The late Cretaceous proposed biostratigraphic zones include one Late Campanian zone,<br>Radotruncana calcarata, and five Maastrichtian zones, Globotruncanella havanensis, Globotruncana<br>aegyptiaca, Gansserina gansseri, Contusotruncana contusa and Abathomphalus mayaroensis (four<br>subzones; CF1, CF2, CF3, and CF4). On the other hand, eight Paleocene proposed biostratigraphic<br>zones and subzones are P0-P (P. eugubina-G. cretacea), P1a (P. eugubina), P1b (S.trilocolinoides), P1c<br>(G.compressa/P.inconstans), P2 (P. uncinata/P. praeangulata), P3a (M. angulata), P3b (M.<br>velascoensis), and P4a (P. pseudomenardii).<br>The turning point of the study is relatively complete succession across the Cretaceous-Tertiary (K/T)<br>transition which is presented by four subzones (R. fructicosa, P. hariaensis, P. palpebra, and P.<br>hantkeninoides) within the late Maastrichtian and eight zone and subzones within the Paleocene. The<br>K/T boundary is marked continuously by using the zones CF1 and P0-P at the latest part of the<br>Maastrichtian and early Danian respectively. This considerably higher resolution in biostratigraphic<br>zonation is a result of good foraminiferal preservation that may reflects larger, more rapid sea-level<br>changes, consistent with increasing ice volume during the time interval.