Tectonosedimentary evolution of the Karacasu and Bozdoğan basins in the Central Menderes Massif, W Anatolia

Abstract

IntroductionThe E-W-running Büyük Menderes and Gediz grabens, with their prominent morphologies, have attracted the attention of many researchers in the study of the Late Oligocene to Recent extension of West Anatolia. Being symmetric to each other, both zones in the Central Menderes Massif represent narrow intracontinental deformation belts with complex structural history and display multiple basin developments (Figure 1). The Büyük Menderes Graben (BMG) is limited by a regional detachment in the north. The basin is surrounded by the E-W-running Küçük Menderes Graben in the north and by the Muğla-Yatağan Basin and Kale-Tavas Molas Basin in the far south. Four Mio-Pliocene depressions (from west to east, the Çine, Bozdoğan, Karacasu, and Denizli basins) having overall N-S trends are situated just south of the BMG (Figure 1).Modes of development of variously oriented grabens in this region have received little attention. Although there is a hypothesis called the supradetachment transtensional mechanism (Yılmaz et al., 2000;Çemen et al., 2006;Çiftçi et al., 2011;Gessner et al., 2013), it is not substantiated by considerable structural or depositional field data from N-S running grabens. The previous studies in the BMG and in the vicinity of the BMG revealed a complicated and sometimes conflicting Neogene deformation history. For instance, formation of the Söke Basin in the west tip during the Early to Late Miocene was explained in terms of N-S extension (either detachment or high-angle faultrelated) (Sümer et al., 2013). On the other hand, both N-S compression- (Gürer et al., 2009) and N-S extension-related sedimentary basins (Emre and Sözbilir, 1987;Cohen et al., 1995;Bozkurt, 2000) were reported in the central part of the BMG in the Middle and Late Miocene. Further east in the Denizli Basin, the extension direction turns to NNW (or NE and NW) (Kaymakçı, 2005;Koçyiğit, 2005). This brief account suggests that further multidisciplinary detailed studies are still required in unexplored areas in order to reconcile or negate the existing conflicting views and provide more detailed structural history in the BMG and its vicinity.In this study we focused on the stratigraphic, sedimentological, and structural characteristics of the Karacasu and Bozdoğan (K&B) basins just south of the Abstract: The Karacasu and Bozdoğan basins, which trend obliquely to modern grabens in the Central Menderes Massif, are investigated in terms of morphology, basinfill architecture, and structure. Evaluation of the previous geophysical and new structural data indicates that the basins are symmetrical grabens mostly running in a N-S direction. Analysis of sedimentary facies of the basins' infill supports the simple graben model by revealing lateral alluvial/colluvial fans in basin margins and axial fluvial/lacustrine environments in a central trough. The long-term changes between fluvial and lacustrine conditions in the basins are attributed to paleoclimatic origin. Paleostress analysis of slickensides substantiates that the basins were deformed...

Stratigraphy of the Mio-Pleistocene sequence in the Göktepe region based on the fossil record (Muğla, SW Turkey)

“…The NW-SE striking Göktepe fault lies at the southeastern end of the graben and may therefore be related to this extension. Moreover, the fault appears to be extinct by ~364 ka (Middle Pleistocene), which is compatible with the direction change of the extension in the Early Pliocene to the NE-SW, and then to N-S extension in the Late Pliocene-Quaternary (Ocakoğlu et al, 2014).…”

“…Most of the previous studies in this area are related to the paleontology, stratigraphy, and/or structural features of the Kale-Tavas, Yatağan, and Ören basins (Becker-Platen 1970;Benda, 1971;Ünal, 1988;Seyitoğlu and Scott, 1991;Yılmaz et al, 2000;Akgün and Sözbilir, 2001; Okay (2001), Seyitoğlu et al (2004), and Ocakoğlu et al (2014). b) Geological map of the Göktepe area (red square shows the location of Figure 10).…”

“…a) Map showing the current geographical position of the Kale-Tavas (KTB), Yatağan (YB), Ören (ÖB), Bozdoğan (BB), and Karacasu (KB) basins. Faults are from Okay (2001), Seyitoğlu et al (2004), and Ocakoğlu et al (2014). b) Geological map of the Göktepe area (red square shows the location of Figure 10).…”

The Quaternary landforms of the Büyük Menderes Graben System: the southern Menderes Massif, western Anatolia, Turkey

“…This rapid extension at a rate of ∼20 mm/yr (Aktug et al, 2009) is accommodated by several normal and detachment faults that form horst-graben systems. The Menderes Massif is located at the center of this tectonic deformation where pervasive crustal extension in the Quaternary led to the development of extensional grabens delimited by faults trending E-W, NW-SE, and NE-SW (Bozkurt, 2000;Gürer et al, 2009;Kazanci et al, 2009;Ocakog  lu et al, 2014).…”

Structure of the Büyük Menderes Graben systems from gravity anomalies

“…This fault distinguishes high-grade metamorphic gneisses and a lower Miocene sedimentary rock sequence in its hanging wall from the marble-intercalated mylonitized schists in its footwall (Göğüs, 2004;Çemen et al, 2006;Çifçi et al, 2011). The basin is surrounded by the E-W trending Küçük Menderes Graben in the north and four Mio-Pliocene depressions (from west to east, the Çine, Bozdoğan, Karacasu, and Denizli basins) with approximate N-S trends located in the south of the BMG (Paton, 1992;Ocakoğlu et al, 2014). The BMG is about 140 km long and 2.5-14 km wide and forms an arc-shaped structural pattern.…”