TITLE:
Biozonation and Paleobathymetry on Foraminifera Upper Cretaceous Deposites of Central Iran Basins (Isfahan, Baharestan Section)
AUTHORS:
Bita Ghasem Shirazi, Lida Bakhshandeh, Abdollah Yazdi
KEYWORDS:
Biozonation, Foraminifera, Central Iran, Paleobathymetry, Turonian, Late Campanian
JOURNAL NAME:
Open Journal of Geology,
Vol.4 No.8,
August
6,
2014
ABSTRACT: In this study Late
Cretaceous stratum in central Iran, Baharestan section in Isfahan area, was
evaluated by biozonation and paleobathymetry.These sediments have 89 meters thick, and strata
have been formed of marl and marl limestone. In order to indicate the ancient
depth of Upper Cretaceous at this time, planktonic and benthic foraminifera
were studied. The percentage of the total planktonic foraminifera to the whole
sample of foraminifera after the removal of indwell benthic foraminifera (%P*)
using the formulaD=e(3.58718 + (0.03534×%P*))was identified and depth of 200 - 450
meters was achieved for them. In the present investigation, 30 planktonic
species of 11 genus have been identified. The Upper Cretaceous deposit was
divided to 6 biozones on the basis of planktonic foraminifera which are
cosmopolitan and consist of: Biozone 1—Marginotruncana sigali-Dicarinella
primitivapartial range zone;Biozone 2—Dicarinella
concavatainterval zone;Biozone 3—Dicarinella asymetricatotal range zone; Biozone 4—Globotruncanita
elevatapartial range zone;
Biozone 5—Globotruncana ventricosainterval
zone; Biozone 6—Radotruncana calcaratainterval
zone.Based on planktonic
foraminifera, the Upper Cretaceous sediments in the study area are of the
Turonian-Late Campanian ages.