Paleomagnetic constraints on the timing and distribution of Cenozoic rotations in Central and Eastern Anatolia

Abstract

Abstract. To quantitatively reconstruct the kinematic evolution of Central and Eastern Anatolia within the framework of Neotethyan subduction accommodating Africa-Eurasia convergence, we paleomagnetically assess the timing and amount of vertical axis rotations across the Ulukışla and Sivas regions. We show paleomagnetic results from ∼ 30 localities identifying a coherent rotation of a SE Anatolian rotating block comprised of the southern Kırşehir Block, the Ulukışla Basin, the Central and Eastern Taurides, and the southern part of the Sivas Basin. Using our new and published results, we compute an apparent polar wander path (APWP) for this block since the Late Cretaceous, showing that it experienced a ∼ 30-35 • counterclockwise vertical axis rotation since the Oligocene time relative to Eurasia. Sediments in the northern Sivas region show clockwise rotations. We use the rotation patterns together with known fault zones to argue that the counterclockwise-rotating domain of south-central Anatolia was bounded by the Savcılı Thrust Zone and Deliler-Tecer Fault Zone in the north and by the African-Arabian trench in the south, the western boundary of which is poorly constrained and requires future study. Our new paleomagnetic constraints provide a key ingredient for future kinematic restorations of the Anatolian tectonic collage.

Multiple Exhumation Phases in the Central Pontides (N Turkey): New Temporal Constraints on Major Geodynamic Changes Associated With the Closure of the Neo‐Tethys Ocean

“…As an alternative, the occurrence of Early Oligocene AFT cooling ages in the Kösedağ batholith to the east of the Kırşehir Block (Figure ; Boztuğ & Jonckheere, ) and along the southern margin of the Anatolides and Taurides (e.g., Doğanşehir and Essence granitoids, Figure ; Karaoğlan et al, ) has been interpreted to record the onset of continental collision between the Eurasian and Arabian plates (see also Rolland, , and references therein). The occurrence of a regional compressional event that triggered an acceleration in fault‐related exhumation from ~40 Ma, in association with syndepositional deformation, surface uplift, and oroclinal bending processes in the Kırşehir and Tauride‐Anatolide microcontinental domains, is also documented by cross‐cutting relationships, paleomagnetic, stratigraphic, and structural data (Figure ; e.g., Advokaat et al, ; Aktaş & Robertson, ; Çetinkaplan et al, ; Clark & Robertson, , ; Elmas & Yilmaz, ; Gürer et al, , ; Jaffey & Robertson, ; Karaoğlan et al, ; Lefebvre et al, ; Nairn et al, ; Önal & Kaya, ; Pourteau et al, ; Robertson et al, , ; Rolland, ). For example, stratigraphic data from the Kırşehir Block document compressional deformation from ~40 Ma after a phase of tectonic quiescence marked by a regional marine transgression associated with the deposition of nummulitic limestones (Figure ; ~55–50 to 40–38 Ma; e.g., Advokaat et al, ; Clark & Robertson, , ; Dinçer, ; Gürer et al, , ; Jaffey & Robertson, ; Lefebvre et al, ; Licht et al, 2017; Özcan et al, ; Pourteau et al, ).…”

Palaeogene stratigraphy and chronology of the western Sivas Basin, central Anatolia (Turkey): Tectono‐sedimentary evolution of a well‐preserved basin along the northern Neotethys suture zone

“…Restoration of ca. 30–45° of palaeomagnetically derived counterclockwise vertical‐axis rotation in the Kangal sub‐basin and in the SSFTB (Gürer, van Hinsbergen, et al., 2018; Gürsoy et al., 1997; Krijgsman et al., 1996) suggests that they likely had a more E or ESE initial orientation, yet the sediment transport system would have still been oriented parallel or subparallel to the basin margins and structural trends in the adjacent fold‐thrust belts. Sediment was sourced primarily from the Tauride thrust belt to the south, likely from the eastern edge of the Kırşehir block to the west, and from exhumed TS‐1 strata in the SSFTB.…”

The Pre‐Obduction to Post‐Obduction Evolution of the Sivas Ophiolite (Turkey) and Implications for the Precollisional History of Eastern Anatolia

“…This ophiolitic mélange is probably thinner to the north, or locally absent, such as in the Sivas area. In central Anatolia to the east of the EKFZ (see Gürer & van Hinsbergen, ; Gürer, Plunder, et al, ; Gürer, van Hinsbergen, et al, ), the northernmost part of the Tauride and the whole Kırşehir block were subducted during the Late Cretaceous. Subduction of the Kırşehir block is supported by the HT/LP metamorphism estimated at 800 °C/8 kbar at ∼85–90 Ma (Whitney & Hamilton, ), prior to its exhumation at ~80–75 Ma (Lefebvre et al, , and references therein).…”