When Did the Western Anatolian Grabens Begin to Develop?

Abstract

To solve a long-lasting controversy on the timing and mechanism of generation of the western Anatolian graben system, new data have been collected from a mapping project in western Anatolia, which reveal that initially north-south trending graben basins were formed under an east-west extensional regime during Early Miocene times. The extensional openings associated with approximately north-south trending oblique slip faults provided access for calc-alkaline, hybrid magmas to reach the surface. A northsouth extensional regime began during Late Miocene time. During this period a major breakaway fault was formed. Part of the lower plate was uplifted and cropped out later in the Bozda~ Horst, and above the upper plate approximately north-south trending crossgrabens were developed. Along these fault systems, alkaline basalt lavas were extruded. The north-south extension was interrupted at the end of Late Miocene or Early Pliocene times, as evidenced by a regional horizontal erosional surface which developed across Neogene rocks, including Upper Miocene-Lower Pliocene strata. This erosion nearly obliterated the previously formed topographic irregularities, including the Bozda~ elevation. Later, the erosional surface was disrupted and the structures which controlled development of the Lower-Upper Miocene rocks were cut by approximately east-west trending normal faults formed by rejuvenated north-south extension. This has led to development of the present-day east-west trending grabens during Plio-Quaternary time.cene ($eng6r et al. 1985; GOrt~r et al. 1995).

Exhumation with a twist: Paleomagnetic constraints on the evolution of the Menderes metamorphic core complex, western Turkey

“…[15] Finally, the northern Menderes Massif is overlain by a series of NE-SW trending, early Miocene basins [Yilmaz et al, 2000;Bozkurt, 2001aBozkurt, , 2003. From east to west, these include the Uşak, Güre, Selendi, Demirci, and Gördes basins, which hereafter will be referred to as the NMM basins.…”

High-K volcanism in the Afyon region, western Turkey: from Si-oversaturated to Si-undersaturated volcanism

“…These events resulted in the internal imbrication of the Menderes Massif block and the southward overthrusting of the Lycian nappes ( Fig. 1), eventually leading to late Miocene extensional tectonics and Menderes Massif uplift (Ş engör et al 1984;Yılmaz et al 2000;Işık et al 2004;Ring and Collins 2005;Ç emen et al 2006;Westaway 2006;Glodny and Hetzel 2007;Prelević et al 2012). During the postcollisional period, potassic and ultrapotassic magmas were produced along with calc-alkaline and crust-derived magmas in the western Anatolia (Bozkurt 2001(Bozkurt , 2003Bozkurt and Mittwede 2005;Ş engör and Yılmaz 1981;Ş engör et al 1985).…”

The Gediz River fluvial archive: A benchmark for Quaternary research in Western Anatolia

“…The Basin fill sediments are subsequently deformed during the Late Miocene as a result of tectonic extension evidenced by the formation of large numbers of NNE-SSW trending normal faults (Yilmaz et al, 2000). The throws on these faults are reported by Bunbury et al (2001) to be generally less than 100m based upon the offset of the Ulubey Formation.…”

“…Purvis and Robertson (2004) report that these faults, which individually typically have <20 m offsets, cut all sedimentary units and therefore cannot be dated accurately. They also state, however, based upon the work of Seyitoğlu et al (1997), Yilmaz et al, (2000, 2001 and Westaway (pers. comm.…”