TITLE:
Sequence Stratigraphy and Sea Level Fluctuations of the Ab-Deraz Formation, Based on Palynological Evidence and Magnetic Susceptibility Method “Kopet-Dagh Sedimentary Basin, Northeastern Iran”
AUTHORS:
Farshid Yousefimoghadam, Seyed Mahmood Hoseininezhad, Mohsen Allameh
KEYWORDS:
Sequence Stratigraphy, Magnetic Susceptibility, Ab-Deraz Formation, Kopeh-Dagh Basin
JOURNAL NAME:
Open Journal of Geology,
Vol.5 No.5,
May
11,
2015
ABSTRACT: Ab-deraz Formation is one
of the Lithostratigraphic units of upper cretaceous (Middle Touronian-Santonian)
in Kopet-Dagh sedimentary basin, located in northeastern Iran. The aims of this
study are separating sequence units and determining sea level Fluctuation by
using palynological factors and comparison via magnetic susceptibility which is
used for the first time in Ab-deraz Formation. Assuming the average MS
magnitude as the proxy for mean sea level changes, positive Magnetic
Susceptibility (MS) values were considered to present sea level falls and
negative values for sea level rises. Based on these data a curve showing water
level fluctuations throughout the stratigraphic column was prepared which shows
a general trend of regression from base to the top of the formation. To test
accuracy of this method, magnetic susceptibility results were compared with
those gained from palynology and palynofacies studies. Based on the changes in
palynological factors (the terrestrial/marine particles ratio, C/PPC ratio,
diversity and abundance of dinoflagellate), palynofacies, for separate
sequences, three sequences of the third type with four sequence boundaries, (3
boundaries of the type II and one boundary of the type I) were differentiated,
confirming the results gained from magnetic susceptibility method.