Göllü Polye and Lake Van: Geomorphological and Hydrological Connections

Abstract

The Göllü Polje holds a significant position for seeking answers to research problems due to its geomorphological features and its proximity to the level of Lake Van. Particularly, the elevation studies of the polje floor are among the reasons for the concentration of research in this area. The studies conducted in the Göllü Polje area aim to determine the geomorphological roles played by the polje in reaching the highest level of Lake Van in past periods and how and to what extent it was affected by these level changes. Additionally, it has been addressed which findings could be used to explain the changes in the level of Lake Van and to understand what kind of connection the lake has with other open basins, how the hydrological balance within the Polje area is established, and what effects it was subjected to in later periods. It has been decided to conduct core drilling studies and investigate the validity of this hypothesis that Lake Van might have overflowed into the polje and lake sediments might have accumulated within the polje. A total of 84 samples were taken for the determination of the mineralogical contents of the sediments obtained from the cores, and carbonate (calcite, aragonite, and dolomite) and quartz contents were examined and analyzed. When the core analyses together with all clay, quartz carbonate, and organic carbon mineral data and graphs are evaluated, it is understood that slope erosion intensified and there was an increase in the deposition of minerals such as kaolinite and illite in certain periods within the polje. It is also understood that during periods when slope erosion slowed down and the polje took the form of a lake, disrupting river drainage, montmorillonite mineral precipitated, and these periods followed each other in phases.