Basin progress: active deformation analysis by tectonostratigraphic elements and geophysical methods on North Anatolian Fault System (Eastern Marmara Region, Turkey)

Bülent Doğan,Mohammad Alahmad,Ertan Pekşen,Selin Yavuzyilmaz,Fadime Sertçelik,İbrahim Sertçelik,Metin Aşci,Ahmet Karakaş,Murat Selim Çepni,Cengiz Kurtuluş,Arzu Erener

doi:10.1007/s11069-021-04894-4

Abstract

The Northern Branch of the North Anatolian Fault System controls and deforms the Izmit Basin and the Sapanca Lake Basin in the study area. Unlike the Sapanca Lake Basin, the oblique normal faults with WNW–ESE trending with maximum length of 5 km in the south of the basin have contributed to the deformation process in the formation of Izmit Basin. The fault sets mainly incline to the north. The N-S width of the dextral strike-slip active deformation was determined as 9 km at Izmit basin and 3.8 km at Sapanca Lake basin. Further, the minimum principal stress axes (σ3) vary in the trending ranges of N11°–74°E, which are caused by the transtensional stresses associated with strike-slip faulting in the Izmit Basin by a different tectonic source than the Sapanca Lake Basin. Besides, the crust depth of main strand of NAFS-NB was determined up to 1112 m by magnetic method. The secondary faults were determined by both magnetic and resistivity methods up to a depth of 110 m. The depression area between Izmit bay and Sapanca Lake on the northern Anatolian fault is an integrated basin with two dextral strike-slip tectonic origins. Thus, the Izmit Basin, along with the main strike-slip faulting, has been developed in the asymmetric negative flower structure, where only the southern boundary has become a fault. The Sapanca Lake Basin is a lazy-Z-shaped pull-apart system formed by the E–W trending fault as a releasing bend. A simple shear deformation ellipsoid with a long axis of approximately 35 km on the Northern Branch of the North Anatolian Fault System is defined for the Izmit–Sapanca integrated basin. Therefore, intra-basin deposits have different depths estimated from the gravity data in the Izmit–Sapanca integrated basin, and the maximum sediment thickness estimated is 2200 m in the middle of the Izmit Basin.

Highlights

The North Anatolian Fault System (NAFS) is a right-lateral strike-slip fault with approximate 1200 km length (Fig. 1a), (Barka 1992)
The escape of the Central Anatolian plate to the west occurred along the strike-slip NAFS and East Anatolian Fault System (EAFS) (Şengör et al 1985; Bozkurt 2001)
Paleotectonic structures developed associated with collision tectonic (Yılmaz et al 19Lo9a5d;inOgk[MayatahJnadx]/Tjaüxy/osuützpu. t1/C9o9m9m).oTnHhTeMliLt/hjaoxl.ojsgical and structural features of the bedrock units in the southern uplift of the study area have been explained in the Armutlu-Ovacık Zone and the northern uplift in the İstanbul - Zonguldak Zone (Yiğitbaş et al 1999)

Summary

Introduction

The North Anatolian Fault System (NAFS) is a right-lateral strike-slip fault with approximate 1200 km length (Fig. 1a), (Barka 1992) It has opened many basins of different lengths and widths and has deformed these basins until the present. This study explains the development of an integrated basin-like ISIB consisting of Izmit basin and Sapanca Lake basin with different basin morphology, located on a right-lateral strike-slip fault (NAFS). In this sense, the deformation geometry of the active structural elements, which are associated with lithofacies features, the sedimentary processes of the basin-filling formations, and which are different from each other in each basin, are formed from the surface to a certain depth of the upper crust. The fault types were detailed in three dimensions and it was determined that IB and SB are integrated basins in two different geometries with different deformation areas, and NAFS-NB was the main tectonic source for these basins to take their present shape

Study Area

Stratigraphic setting

Geophysical Data And Methods

Electrical Resistivity

Discussion

Conclusions