Kalecik (Ankara) güneydoğusu alt Maastrichtiyen-Paleosen biyostratigrafisi ve paleoekolojisi
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Date
2000
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info:eu-repo/semantics/closedAccess
Abstract
Kalecik (Ankara) güneydoğusunda fliş fasiyesinde çökelmiş, yörede Alt Maastrihtiyen ve Paleosen' i temsil eden Samanlık formasyonunun üst seviyeleri ile Dizilitaşlar formasyonunun tamamından derlenen örneklerden Gansserina gansseri (Alt Maastrihtiyen), Morozovella pseudobulloides, Morozovella trinidadensis (Daniyen), Morozovella angulata (Daniyen-Tanesiyen), Planorotalites pseudomenardii, Morozovella velascoensis (Tanesiyen) planktik foraminifer zonları ile Arkhangelskiella cymbiformis (CC-25) (Alt Maastrihtiyen), Markalius inversus (NP-1), Cruciplacolithus tenuis (NP-2), Chiasmolithus danicus (NP-3) (Daniyen), Ellipsolithus macellus (NP-4), Fasciculithus tympaniformis (NP-5), Heliolithus kleinpellii (NP-6) (Tanesiyen) kalkerli nannoplankton zonları tanımlanmıştır, iz fosil çalışmaları ile Samanlık formasyonunun üst seviyelerinde Thalassinoides isp. (sığ deniz), Dizilitaşlar formasyonunun taban ve orta seviyelerinde ise Helminthopsis isp. (derin deniz), Ophiomorpha isp. (sığ deniz) türleri gözlenmiştir. iz fosil toplulukları, sediman kompozisyon analizi sonuçları, planktik, bentik foraminifer ve kalkerli nannoplankton sayısal bolluk dağılımları birlikte değerlendirilerek, Erken Maastrihtiyen-Paleosen boyunca yörede deniz seviyesinin sabit olmadığı belirlenmiştir. Elde edilen verilere göre, Samanlık formasyonunun üst seviyeleri Erken Maastrihtiyen' de denizaltı yelpazesinin yakınsak kesimlerinde çökelmiştir. Dizilitaşlar formasyonunun taban ve orta seviyeleri Alt-Orta Daniyen' de denizaltı yelpazesinin ortaç ve yakınsak kesimlerinde, üst seviyeleri ise Üst Daniyen-Tanesiyen boyunca yakınsak kesimlerinde depolanmıştır. Planktik foraminifer kavkılarından elde edilen ?18O0/? ve ?13O0/?(PDB) izotop değerleri ile hesaplanan paleosıcaklık ve paleotuzluluk miktarları, ısıya karşı duyarlı olan kalkerli nannoplankton gruplarının yüzde bolluk dağılımları ile karşılaştırıldığında Erken Maastrihtiyen boyunca deniz yüzey suyu sıcaklığı ve tuzluluğunun Paleosen' e oranla düşük olduğu, Paleosen' de ise Daniyen' in başından itibaren arttığı belirlenmiştir.
In this study, the Gansserina gansseri (Lower Maastrichtian), Morozovella pseudobulloides, Morozovella trinidadensis (Danian), Morozovella angulata (Danian-Thanetian), Planorotalites pseudomenardii, Morozovella velascoensis (Thanetian) planktic foraminiferal zones and Arkhangelskiella cymbiformis (CC-25) (Lower Maastrichtian), Markalius inversus (NP-1), Cruciplacolithus tenuis (NP-2), Chiasmolithus danicus (NP-3) (Danian), Ellipsolithus macellus (NP-4), Fasciculithus tympaniformis (NP-5), and Heliolithus kleinpellii (NP-6) (Thanetian) calcareous nannoplankton zones were recognised from the samples which collected from the upper level of the Samanlik formation and from the bottom to the top of the Dizilitaslar formation. These units represent early Maastichtian-Paleocene interval. They were deposited in the turbidite facies of the southeast Kalecik region. On the basis of trace fossil studies Thalassinoides isp., (shallow marine) was identified in the upper level of the Samanlik formation, and Helminthopsis isp., (deep marine), and Ophiomorpha isp., (shallow marine) were recognized in the bottom and the middle levels of the Dizilitaslar formation. The results from the studies of trace fossils, analysis of sedimentary composition, distribution of the numerical abundance of planktic, benthic foraminifera, and calcareous nannoplankton show that the upper levels of the Samanlik and Dizilitaslar formations were deposited with the characteristic proximal facies, whereas the lower and middle levels of Dizilitaslar formation represent the proximal and intermediate facieses of a submarine fan. Lower Maastrichtian, upper the Danian and Thanetian were developed during a regressive period while the lower and middle Danian reflect alternating transgressive and regressive events. When the palaeotemperature and palaeosalinity values, calculated from ?18O‰ and ?13C‰ (PDB), are compared from planktic foraminifera tests and percentage abundance as well as the diversity of temperature-sensitive calcareous nannoplankton groups, indicate that during the early Maastrichtian, the palaeotemperature and palaeosalinity of sea-surface water was relatively lower than during the Paleocene. Palaeotemperature and palaeosalinity values started to increase from the early Danian onwards.
In this study, the Gansserina gansseri (Lower Maastrichtian), Morozovella pseudobulloides, Morozovella trinidadensis (Danian), Morozovella angulata (Danian-Thanetian), Planorotalites pseudomenardii, Morozovella velascoensis (Thanetian) planktic foraminiferal zones and Arkhangelskiella cymbiformis (CC-25) (Lower Maastrichtian), Markalius inversus (NP-1), Cruciplacolithus tenuis (NP-2), Chiasmolithus danicus (NP-3) (Danian), Ellipsolithus macellus (NP-4), Fasciculithus tympaniformis (NP-5), and Heliolithus kleinpellii (NP-6) (Thanetian) calcareous nannoplankton zones were recognised from the samples which collected from the upper level of the Samanlik formation and from the bottom to the top of the Dizilitaslar formation. These units represent early Maastichtian-Paleocene interval. They were deposited in the turbidite facies of the southeast Kalecik region. On the basis of trace fossil studies Thalassinoides isp., (shallow marine) was identified in the upper level of the Samanlik formation, and Helminthopsis isp., (deep marine), and Ophiomorpha isp., (shallow marine) were recognized in the bottom and the middle levels of the Dizilitaslar formation. The results from the studies of trace fossils, analysis of sedimentary composition, distribution of the numerical abundance of planktic, benthic foraminifera, and calcareous nannoplankton show that the upper levels of the Samanlik and Dizilitaslar formations were deposited with the characteristic proximal facies, whereas the lower and middle levels of Dizilitaslar formation represent the proximal and intermediate facieses of a submarine fan. Lower Maastrichtian, upper the Danian and Thanetian were developed during a regressive period while the lower and middle Danian reflect alternating transgressive and regressive events. When the palaeotemperature and palaeosalinity values, calculated from ?18O‰ and ?13C‰ (PDB), are compared from planktic foraminifera tests and percentage abundance as well as the diversity of temperature-sensitive calcareous nannoplankton groups, indicate that during the early Maastrichtian, the palaeotemperature and palaeosalinity of sea-surface water was relatively lower than during the Paleocene. Palaeotemperature and palaeosalinity values started to increase from the early Danian onwards.
Description
Keywords
Alt Maastrihtiyen, Biyostratigrafi, Kalecik Güneydoğusu, Paleoekoloji, Paleosen, Biostratigraphy, Lower Maastrichtian, Palaeoecology, Paleocene, Southeast Kalecik
Journal or Series
Yerbilimleri
WoS Q Value
Scopus Q Value
Q4
Volume
Issue
22
