Pliocene surface and high Quaternary terraces in the Batova River valley, Northeast Bulgaria

During the engineering geological explorations, carried out in the Batova River valley, two high terraces and a Pliocene surface above them have been established. They are modeled in the Miocene sediments of the Karvuna, Topola and Evxinograd Formations. The Pliocene surface shapes the heights of the Frangen plateau, with absolute elevations from 220 to 250 m. This surface is inclined towards the Batova River valley. The high terraces are incised in the sediments of the Topola and Evxinograd Formations or in delapsium at absolute heights 120-130 m and 84-92 m. Events and processes referring to the formation of the two high terraces are dated on the basis of paleogeographic analysis, stratigraphic data for the shelf sediments and comparative investigations with the terraces of the Dacian lacustrinefluvial basin. The age of the 120-130-meter terrace is determined as Late Kujalnik-Gurian (Late Romanian-Early Pleistocene) and of the 84-92-meter terrace - as Chaudian (Middle Pleistocene). The slope in the region to the south of the Rogachevo village had been repeatedly deformed by subaqueous slidings, occurring during the Late Kujalnik-Gurian (Late Romanian-Early Pleistocene), when the 120-130-meter marine terrace was formed. The slope in the Bakalaka locality was also deformed by subaqueous slidings occurring during the Chaudian transgression (Middle Pleistocene), when the 84-92-meter terrace was formed.