Rotations of Normal Fault Blocks Quantify Extension in the Central Tauride Intramontane Basins, SW Turkey

Abstract

Quantifying the amount of stretching in extensional basin systems is often challenging in the absence of seismic profiles or boreholes. However, when fault spacing and orientation as well as vertical axis rotation patterns are known, map-view restoration may provide a good estimate of total extension. This integrated structural and paleomagnetic approach provides a relatively straightforward tool in extensional basin restoration and fault zone kinematic analysis. Here we provide results of an extensive paleomagnetic survey of the Neogene Central Tauride intramontane basins (SW Turkey), where previous work revealed a complex array of basin-bounding normal faults and relay ramps. In total, 437 oriented cores were sampled at 43 sites distributed within Miocene-Pliocene continental sedimentary rocks from the Ilgın, Altınapa, Yalvaç, and Beyşehir basins. Despite the more or less coherent overall strike of the mountain belt and basins, rotations vary from~42°clockwise (Yalvaç) to~10°(Beyşehir),~21°(Ilgın), and 30°(Altınapa) counterclockwise. We show that the rotation pattern is related to normal faults and lateral variations in fault displacement superimposed on regional rotation patterns. We restore these to estimate a minimum NE-SW horizontal extension of~30-35 km across the basin system. As a consequence of our reconstruction, it appears that the Sultandağları range that exposes low-grade metamorphic Paleozoic and Mesozoic rocks of the Geyikdağı and Bolkardağ nappes of the Taurides represents a Miocene extensional core complex.

Palinspastic Reconstruction Versus Cross‐Section Balancing: How Complete Is the Central Taurides Fold‐Thrust Belt (Turkey)?

“…After accretion of Beydağları to the upper plate at 35 Ma, the Taurides are restored as part of Central Anatolia (Gürer & van Hinsbergen, ). Finally, the Taurides are affected by Miocene rotations as documented by Koç et al ().…”

“…We used paleomagnetic and stratigraphic constraints on deformation and the modern dimensions of structural units to build a kinematic restoration of the Central Taurides using GPlates software. As a basis for our reconstruction, we used the restoration of Greece and western Turkey of van Hinsbergen and Schmid (), the restoration of central and eastern Turkey of Gürer and van Hinsbergen (), of McPhee (), and Maffione et al () and then we incorporated the restoration of Miocene oroclinal bending of the Central Taurides of Koç et al (). Our reconstruction is incorporated into the global plate circuit of Seton et al () with the updated Miocene Atlantic reconstruction of DeMets et al ().…”

“…Following an apparent period of tectonic quiescence in the northwestern Central Taurides, the Eocene fold‐thrust belt was partly refolded and thrusted by a western belt of thrusting that deformed the Geyikdağı and Beydağları platforms and the overlying Miocene to Pliocene Antalya basin. Miocene and younger thrusting in the belt was coeval with the formation of a regional system of extensional basins in the Tauride hinterland to the northeast of the range (Koç et al, , , ) and was associated with oroclinal bending of the Central Taurides (Koç, van Hinsbergen, et al, ; Figure ). Koç, van Hinsbergen, et al () found that the orocline formed by a 20°–30° CW rotation of the Köprüçay subbasin in the north, and a 25°–35° anticlockwise (ACW) rotation of the Manavgat subbasin to the south, which must have been accommodated by motion on the Miocene Bozburundağ and Aksu thrusts that are structurally below the orocline because the Aksu basin to the west did not rotate (Figure ).…”

“…The Miocene oroclinal bending therefore affected the Eocene rocks of the Taurides. Koç et al () recently made a kinematic restoration of the Miocene extension, shortening, and oroclinal bending, and we use their results as basis for our restoration of the pre‐Neogene deformation history of the Tauride belt.…”

Paleobathymetric evolution of the Miocene deposits of the Gömbe sector of the Lycian Foreland and Aksu basins in Antalya, Turkey

“…They were followed by İslamoğlu (2001), İslamoğlu andTaner (2002, 2003), Poisson et al (2003b), Şenel (2004), and Sagular (2009), and included planktonic foraminifera, nannoplanktons, molluscs, and corals. Tectonic evolution and paleoenvironmental characteristics of the region were addressed by Uysal (1988), Flecker et al (1998), Glover andRobertson (1998), Flecker et al (2005), Karabıyıkoğlu et al (2005), Poisson et al (2011Poisson et al ( ), Üner et al (2015, and Koç et al (2016). However, no published studies exist on the paleobathymetric evolution of these basins, in terms of changes in the accommodation space and vertical block movements in the region.…”