The evolution of the Intra-Pontide suture: Implications of the discovery of late Cretaceous–early Tertiary mélanges

Akbayram, Kenan; Şengör, A. M. Celâl; Özcan, Ercan

doi:10.1130/2016.2525(18)

Cited by 21 publications

(25 citation statements)

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“…The most recent description of the entire Sakarya Continent was given by Yılmaz et al (1997b) and Akbayram et al (2016a) and we largely follow their lead in this paper adding more data wherever appropriate. The Sakarya Continent has a polymetamorphic sialic basement that yielded zircon populations with age clusterings around 2 Ga (Eburnean), 1050-950 (early Pan-African) and 550-750 (late Pan-African).…”

Section: West Of Ankaramentioning

confidence: 77%

“…The entire Thrace Basin was a forearc basin between the late Cretaceous, when subduction began in that segment of the northern branch of the Neo-Tethys now represented by the Intra-Pontide Ocean, and the Bartonian when unconformable sediments began covering the suture. Görür and Okay (1996) thought the age of the forearc basin was Palaeocene to Oligocene, which is unlikely, because the arc to the north had already stopped its activity during the latest Cretaceous to earliest Palaeocene and the collision was complete by the later medial-Eocene (Akbayram et al 2016a). Şengör and Özgül (2010) assumed that the entire Thrace Basin is underlain by a subduction-accretion complex of mainly late Cretaceous age.…”

Section: Sutures Of the Northern Branch Of The Neo-tethysmentioning

confidence: 99%

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The phanerozoic palaeotectonics of Turkey. Part I: an inventory

Şengör¹,

Lom

Sunal³

et al. 2019

Med. Geosc. Rev.

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Section: West Of Ankaramentioning

confidence: 77%

Section: Sutures Of the Northern Branch Of The Neo-tethysmentioning

confidence: 99%

The phanerozoic palaeotectonics of Turkey. Part I: an inventory

Şengör¹,

Lom

Sunal³

et al. 2019

Med. Geosc. Rev.

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“…This seems consistent with the 52 km offset reported by Akbayram and Okay (2012) from the northern strand east of the Sea of Marmara. The timing of the offset reported by Akbayram and Okay (2012) is problematic, however, because some of it could have formed just after the medial Eocene collision along the Intra-Pontide suture in a completely different system of strike-slip faults (Akbayram et al 2013). It is clear, however, that at least the Marmara Fault family north of the South Marmara Shelf takes up a displacement which is concentrated farther east on the northern strand of the North Anatolian Fault, and that offset is an absolute maximum of 57 km.…”

Section: The Origin Of the Marmara Deepsmentioning

confidence: 92%

The geometry of the North Anatolian transform fault in the Sea of Marmara and its temporal evolution: implications for the development of intracontinental transform faults

et al. 2014

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The North Anatolian Fault is a 1200 km long strike-slip fault system connecting the East Anatolian convergent area with the Hellenic subduction zone and, as such, represents an intracontinental transform fault. It began forming some 13-11 Ma ago within a keirogen, called the North Anatolian Shear Zone, which becomes wider from east to west. Its width is maximum at the latitude of the Sea of Marmara, where it is 100 km. The Marmara Basin is unique in containing part of an active strike-slip fault system in a submarine environment in which there has been active sedimentation in a Paratethyan context where stratigraphic resolution is higher than elsewhere in the Mediterranean. It is also surrounded by a long-civilised rim where historical records reach well into the second half of the first millennium BCE (before common era). In this study, we have used 210 multichannel seismic reflexion profiles, adding up to 6210 km profile length and high-resolution bathymetry and chirp profiles reported in the literature to map all the faults that are younger than the Oligocene. Within these faults, we have distinguished those that cut the surface and those that do not. Among the ones that do not cut the surface, we have further created a timetable of fault generation based on seismic sequence recognition. The results are surprising in that faults of all orientations contain subsets that are active and others that are inactive. This suggests that as the shear zone evolves, faults of all orientations become activated and deactivated in a manner that now seems almost haphazard, but a tendency is noticed to confine the overall movement to a zone that becomes narrower with time since the inception of the shear zone, i.e., the whole keirogen, at its full width. In basins, basin margins move outward with time, whereas highs maintain their faults free of sediment cover, making their dating difficult, but small perched basins on top of them in places make relative dating possible. In addition, these basins permit comparison of geological history of the highs with those of the neighbouring basins. The two westerly deeps within the Sea of Marmara seem inherited structures from the earlier Rhodope-Pontide fragment/Sakarya continent collision, but were much accentuated by the rise of the intervening highs during the shear evolution. When it is assumed that below 10 km depth the faults that now constitute the Marmara fault family might have widths approaching 4 km, the resulting picture resembles a large version of an amphibolite-grade shear zone fabric, an inference in agreement with the scale-independent structure of shear zones. We think that the North Anatolian Fault at depth has such a fabric not only on a meso, but also on a macro scale. Detection of such broad, vertical shear zones in Precambrian terrains may be one way to get a handle on relative plate motion directions during those remote times.Résumé : La faille nord-anatolienne est constituée d'un système de failles décrochantes d'une longueur de 1200 km qui relie le secteur conve...

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“…3 and 6) show that Marmara Island dominantly exposes rocks of the upper crystalline crust. More precisely, geological surface observations in this area (Aksoy 1995(Aksoy , 1996Attanasio et al, 2008;Karacık et al, 2008;Ustaömer et al, 2009) differentiate three main rock types in outcrops: a Permian marble unit in the north, an Eocene granodiorite unit in the center, and a Permian metabasite in the south of Marmara Island. Considering the residual anomalies ( Fig.…”

Section: Model Limitationsmentioning

confidence: 94%

3-D crustal density model of the Sea of Marmara

et al. 2019

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Abstract. The Sea of Marmara, in northwestern Turkey, is a transition zone where the dextral North Anatolian Fault zone (NAFZ) propagates westward from the Anatolian Plate to the Aegean Sea Plate. The area is of interest in the context of seismic hazard of Istanbul, a metropolitan area with about 15 million inhabitants. Geophysical observations indicate that the crust is heterogeneous beneath the Marmara basin, but a detailed characterization of the crustal heterogeneities is still missing. To assess if and how crustal heterogeneities are related to the NAFZ segmentation below the Sea of Marmara, we develop new crustal-scale 3-D density models which integrate geological and seismological data and that are additionally constrained by 3-D gravity modeling. For the latter, we use two different gravity datasets including global satellite data and local marine gravity observation. Considering the two different datasets and the general non-uniqueness in potential field modeling, we suggest three possible “end-member” solutions that are all consistent with the observed gravity field and illustrate the spectrum of possible solutions. These models indicate that the observed gravitational anomalies originate from significant density heterogeneities within the crust. Two layers of sediments, one syn-kinematic and one pre-kinematic with respect to the Sea of Marmara formation are underlain by a heterogeneous crystalline crust. A felsic upper crystalline crust (average density of 2720 kg m−3) and an intermediate to mafic lower crystalline crust (average density of 2890 kg m−3) appear to be cross-cut by two large, dome-shaped mafic high-density bodies (density of 2890 to 3150 kg m−3) of considerable thickness above a rather uniform lithospheric mantle (3300 kg m−3). The spatial correlation between two major bends of the main Marmara fault and the location of the high-density bodies suggests that the distribution of lithological heterogeneities within the crust controls the rheological behavior along the NAFZ and, consequently, maybe influences fault segmentation and thus the seismic hazard assessment in the region.

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The evolution of the Intra-Pontide suture: Implications of the discovery of late Cretaceous–early Tertiary mélanges

Cited by 21 publications

References 0 publications

The phanerozoic palaeotectonics of Turkey. Part I: an inventory

The phanerozoic palaeotectonics of Turkey. Part I: an inventory

The geometry of the North Anatolian transform fault in the Sea of Marmara and its temporal evolution: implications for the development of intracontinental transform faults

3-D crustal density model of the Sea of Marmara

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