Sedimentary facies assemblages of the Selendi Supradetachment Basin (Western Turkey): Implications for balancing subsidence and sedimentation in a Neogene lacustrine basin

Abstract

The Selendi Basin developed as a supradetachment basin on the Simav detachment fault in response to the continental extension in western Turkey (Türkiye) and the associated Menderes Massif uplift. Process-based facies analyses were used to define and interpret the depositional evolution of the lacustrine Selendi Basin. The Early-Middle Miocene deposits are composed of stream-dominated alluvial fans, foreshore, shoreface, shoal-water delta and offshore transition facies assemblages, which are laterally and vertically transitional throughout the succession. The alluvial fan and nearshore deposits reveal that the topography of the basin floor and the coastal plain was gently inclined. Shoal-water deltas, 70–250 cm thick, in the delta complex reflect comparable water depths and a relative rise in lake level, ultimately attributable to basin subsidence. Shallow environmental conditions prevailed during the basin's evolution, as evidenced by widespread nearshore deposits along its southern margin. The facies assemblages forming the basin's southern part show a predominantly aggradational stacking pattern, recording a balance between the sediment supply and a steadily growing basin accommodation. The balanced fill deposition and aggradational stacking pattern of the sedimentary facies associations indicate that the rate of basin subsidence and the uplift of the Menderes Massif was relatively consistent. This study shows that the intensity of a synsedimentary fault system, especially one leading to basin opening, plays a crucial role in controlling the architecture and sedimentary facies of the basin succession, both by creating accommodation and by filling it.