Dilek Peninsula-Büyük Menderes Delta National Park Aegean Region in general. The peninsula was shaped into its current form over several geological eras with the tectonic merging of Paleozoic schist formations, Mesozoic limestone and marble deposits, and finally the accretion of large clays and other sediments during the Neogene period. This is partly because of Turkey's unstable fault block terrain, and because of the close proximity of the Anatolian-Aegean plate boundary, which generates massifs of mountains all across western Turkey. This includes the peninsula and the mountains surrounding the Büyük Menderes River, known collectively as the Menderes Massif. The peninsula is highly mountainous, with most of its
Anatolian languages as languages such as Mysian, Cilician, and Pamphylian, which are too poorly attested to construe a relationship with Anatolian. The Anatolian branch is generally considered the earliest to split from the Proto-Indo-European language, from a stage referred to either as Indo-Hittite or "Middle PIE"; typically a date in the mid-4th millennium BC is assumed. Under the Kurgan hypothesis, there are two possibilities for how the early Anatolian speakers could have reached Anatolia: from the north via the Caucasus, and from the west, via the Balkans, the latter of which is considered somewhat more likely by Mallory (1989), Steiner (1990) and