Geologica Carpathica, Volume (67), No (5), Year (2016-10) , Pages (451-462)

Title : ( Planktonic foraminiferal turnover across the Cenomanian –Turonian boundary (OAE2) in the northeast of the Tethys realm, Kopet-Dagh Basin )

Authors: behnaz kalanat , Mohammad Vahidinia , HOSSEIN VAZIRI MOGHADDAM , Mohamad Hosein Mahmudy Gharaie ,

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Abstract

Two Late Cenomanian – Early Turonian (C–T) intervals of the eastern part of the Kopet-Dagh basin, NE Iran have been investigated to evaluate the response of planktonic foraminifera to the geological event OAE2. The Gharesu and Taherabad sections with the thicknesses of 30m and 22.5m are composed of shale and marl interbedded with glauconitic sandstone. Three biozones Rotalipora cushmani, Whiteinella archaeocretacea and Helvetoglobotruncana helvetica were recognized based on study of planktonic foraminifera, in these sections. We observed the patterns of planktonic foraminiferal assemblage changes around the C–T boundary and divided this succession into several successive intervals. This study confirms that OAE2 was a long term event. A gradual perturbation in the study successions starts in the interval 1 with low abundance and diversity of planktonic foraminifera. An enhanced oxygen minimum zone (OMZ) occurs in the interval 3 which coincides with a temporary absence of planktonic foraminifera and sedimentation of framboidal pyrite. High diversity of planktonic foraminifera and appearance of new genera in the interval 5 indicate return of normal conditions to the basin. A significant short-term sea surface temperature cooling is also indicated by planktonic foraminiferal turnover and carbonate contents in the interval 2 which is comparable with other parts of the Tethys Ocean, Boreal sea and Atlantic region.

Keywords

, biostratigraphy, palaeoecology, planktonic foraminifera, Cenomanian – Turonian boundary, OAE2, Tethyan realm, Kopet-Dagh basin.
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@article{paperid:1059888,
author = {Kalanat, Behnaz and Vahidinia, Mohammad and HOSSEIN VAZIRI MOGHADDAM and Mahmudy Gharaie, Mohamad Hosein},
title = {Planktonic foraminiferal turnover across the Cenomanian –Turonian boundary (OAE2) in the northeast of the Tethys realm, Kopet-Dagh Basin},
journal = {Geologica Carpathica},
year = {2016},
volume = {67},
number = {5},
month = {October},
issn = {1335-0552},
pages = {451--462},
numpages = {11},
keywords = {biostratigraphy; palaeoecology; planktonic foraminifera; Cenomanian – Turonian boundary; OAE2; Tethyan realm; Kopet-Dagh basin.},
}

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%0 Journal Article
%T Planktonic foraminiferal turnover across the Cenomanian –Turonian boundary (OAE2) in the northeast of the Tethys realm, Kopet-Dagh Basin
%A Kalanat, Behnaz
%A Vahidinia, Mohammad
%A HOSSEIN VAZIRI MOGHADDAM
%A Mahmudy Gharaie, Mohamad Hosein
%J Geologica Carpathica
%@ 1335-0552
%D 2016

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