This paper focuses on the correlation of two different marble units from an approximately 3,900 m deep geothermal exploration well (GP-1) in western Turkey by petrographical and geochemical data. Future geothermal exploration drilling in that area will benefit from a better (tectono) stratigraphic correlation and a better definition of the reservoir geometry in the basin. It is an innovative approximation in many settings to correctly correlate marble units without clear stratigraphic markers or fossil record, in particular, when sample material is restricted to cuttings. | Turkish Journal of Earth Sciences Turkish J Earth Sci 2021 30 1008-1031 http earth TÜBİTAK Research Article doi yer-2104-11 Geothermal reservoir rocks of the Büyük Menderes Graben Turkey stratigraphic correlation by a multiproxy approach 1 2 3 2 Dorothee SIEFERT Markus WOLFGRAMM Thomas KÖLBEL 4 1 1 Johannes GLODNY Jochen KOLB Elisabeth EICHE 1 Chair of Geochemistry and Economic Geology Institute of Applied Geosciences Karlsruhe Institute of Technology Karlsruhe Germany 2 EnBW Energie Baden-Württemberg AG Karlsruhe Germany 3 Geothermie Neubrandenburg GmbH Neubrandenburg Germany 4 GFZ German Research Centre for Geosciences Potsdam Germany Received Accepted Published Online Final Version Abstract This paper focuses on the correlation of two different marble units from an approximately 3 900 m deep geothermal exploration well GP-1 in western Turkey by petrographical and geochemical data. Future geothermal exploration drilling in that area will benefit from a better tectono stratigraphic correlation and a better definition of the reservoir geometry in the basin. It is an innovative approximation in many settings to correctly correlate marble units without clear stratigraphic markers or fossil record in particular when sample material is restricted to cuttings. The most distinctive petrographical and geochemical properties in this study are colour light transmission along with rare-earth element yttrium REY geochemistry and stable carbon and oxygen isotope data. Two stratigraphic correlations can be maintained for two different marble horizons of the GP-1 well to different stratigraphic horizons outcropping in the study area. Additional Rb-Sr geochronology yields an age of the last metamorphic overprint of the marbles of approximately 30 Ma. This study shows that a multiproxy approach is required to yield a reliable stratigraphic correlation as an important component of geothermal exploration which .
