Neogene fluviolacustrine systems in the northern Peri-Aegean Region

Abstract

The complex fluviolacustrine systems in the northern Peri-Aegean Region were set on in Middle Miocene time, and fully developed in Late Miocene, Pliocene and Quaternary times. Their onset and evolution are closely related to the complex rifting along the Vardar/Axios and Strouma/Strymon fault belts. Pre-Miocene history Complex fluviolacustrine systems existed in Late Eocene and Early Oligocene times South of the newly-formed Stara-planina (Balkan) mountain range, and were draining towards two (Piyanets and East-Rhodope) large marine gulfs. During the Late Oligocene marine regression, a system of river-connected lakes formed in connection to the Pannonian Paratethys, and was dried out and closed during a compression phase in earliest Neogene time. The principal planation surface (peneplain) on the Balkan Peninsula has been formed during the following relative tectonic quiescence. The low-mountain relief had been drained by small rivers that left no recognizable sediments. Middle Miocene onset and evolution; First sedimentation cycle First evidence about the onset of peri-Aegean fluviolacustrine systems comes from the late Middle Miocene (Karpatian?-Badenian-Sarmatian: Palamarev et al., 1999; Vatsev, 1999). The start of the neotectonic stage is marked by beginning Late Badenian-Early Sarmatian disintegration of the peneplain. Several horsts (the Pirin horst included) renewed their uplift. The first sedimentation cycle recognized throughout the Strouma/Strymon fluviolacustrine system occurred in Badenian and Sarmatian times (Nedjalkov et al., 1988) within a river plain and local lakes. The lakes formed mostly in the Sarmatian, and often produced lignite coal seams (Kyustendil, Serres) and locally (Simitli) diatomites or diatom-bearing marls. The Vardar/Axios fluviolacustrine system (Psilovicos & Syrides, 1984) and parts (Rhodope, Razlog graben) of the Mesta/Nestos system have been also set on.