Thermohaline modelling of hot geothermal fluid systems in coastal environment: the Seferihisar- Balçova Area example (Turkey)
German Science Foundation (DFG; Ma 4450/1-2).
The worldwide concern about the consequences of global warming is increasing interest in developing geothermal resources, both for power generation and direct use. This is providing new field data for geochemical and numerical investigations of extensional geothermal systems. The numerical models should explore the role of faults and fractures on the different forces driving hot fluid flows as well as the impact of anthropogenic activities and seawater intrusions on thermal fluid circulation. To date, however, there has been limited effort made to systematically determine the basic relationships between system configuration (e.g., hydraulic permeability, inherited geological structures) and the resulting thermally induced flow behavior of geothermal systems.
An exceptional example to investigate the mentioned issues is the hot Seferihisar-Balçova Geothermal system (SBG) which is part of the Cesme Peninsula, Western Anatolia, Turkey. In the SBG, geothermal processes are extremely vigorous and hot waters close to boiling temperature can be observed at the surface. The driving mechanisms of fluid flow and their interrelationships with faults are poorly understood. Furthermore, the fluid transport processes are characterized by complex temperature and hydrochemical anomalies. Their causes remain still unclear. Not at least, the geothermal energy extraction in the coastal aquifers of this area induces seawater intrusion which pollutes freshwater resources.
In the last years, the SBG, has been thoroughly investigated for its geothermal resources. As a result, an extensive database has been gathered. Owing to a pre-established collaboration between the FU Berlin and the Dokuz Eylül University, Izmir, the database is now available for scientific research. Thus, it will be possible to apply numerical modelling, water chemistry, hydrogeology approaches to study the dynamics of geothermal fluid migration. The final objective is to understand the basic processes driving the thermal waters within the SBG, the role of different driving forces as well as their interactions in controlling geothermal processes. The results will shed new light on the links between the migration of subsurface energy, active transport processes and tectonic structures.
Dr. F. Magri (FUB), Prof. Dr. Pekdeger (FUB), Prof Ü. Gemici and Dipl. T. Akar (DEU, Izmir, Turkey)