Water–rock interaction is the focus of geothermal energy studies and can be documented by traditional geochemical methods such as ion ratio method and hydrogeochemical modelling etc. Statistical approaches are also vital for the quantitative models, and mainly combined with the traditional methods. In this study, we re-evaluate the published data, including water chemistry and volcanic and metamorphic whole-rock geochemistry from the Kavak geothermal field (Konya, Turkey) by using multivariate statistical analysis (e.g. factor analysis and clustering analysis) to research possible interaction between the thermal waters and surrounding rocks.The Kavak geothermal field (KGF) overlies a metamorphic basement composed of the Paleozoic metacarbonates and metaclastic rocks, yet is located near the Erenlerdağ–Alacadağ volcanic complex (ErAVC). An example of unimodal orogenic volcanism in an extensional geodynamic setting, the Neogene ErAVC is composed of widespread high-K calcalkaline andesite to rhyodacite lavas with enclaves and their pyroclastic counterparts. The Kavak geothermal field covers a small area (∼7.5 km 2 ) and lies along the Seydişehir fault zone in the southeast of the ErAVC. The Kavak thermal waters are meteoric in origin and peripheral waters (Ca–Na–HCO 3 ) in the geothermal system related to the orogenic volcanism. The Kavak thermal waters are characterised by high K + and Na + cations, and low pH (between 6.4–6.9 pH) values relative to the cold waters around the KGF. Two types of thermal waters were identified in the KGF based on the slight difference in their hydrochemistry and discharge temperature. The first type thermal water (∼22 °C) has higher TDS and Cl/Br ratio and lower dissolved silica and Br content relative to the second type of water (up to 45 °C). The chemical relationship between the KGF and high-K ErAVC is clearly seen in the cation-based diagrams. Multivariate statistical analysis confirms that first type and second type thermal waters identified based on their hydrochemistry formed two separate statistical groups, and suggests that the chemistry of the KGF waters was mainly controlled by the composition of the ErAVC rather than those of the basement metamorphic rocks as a result of water–rock interaction. L’interaction eau–roche est au centre des études sur l’énergie géothermique et peut être documentée par des méthodes géochimiques traditionnelles telles que la méthode du rapport d’ions et la modélisation hydrogéochimique, etc. Les approches statistiques sont également essentielles pour les modèles quantitatifs, et principalement combinées aux méthodes traditionnelles. Dans cette étude, nous réévaluons les données publiées, y compris la chimie de l’eau et la géochimie des roches volcaniques et métamorphiques du Champ géothermique de Kavak (Konya, Turquie) à l’aide d’une analyse statistique multivariée (telle que l’analyse factorielle, et l’analyse de regroupement) afin de rechercher des indices d’interaction possible entre les eaux thermales et les roches environnantes.Le champ géothermique de Kavak (KGF) repose sur un socle métamorphique composé de métacarbonates paléozoïques et de roches métaclastiques, situé près du complexe volcanique d’Erenlerdağ–Alacadağ (ErAVC). En tant qu’exemple de volcanisme orogénique unimodal dans un cadre géodynamique extensionnel, l’ErAVC du Néogène est majoritairement composé d’andésite calcoalcaline à haute teneur en potassium, ainsi que de rhyodacite à enclaves et leurs produits pyroclastiques associés. Le champ géothermique de Kavak (KGF) couvre une petite superficie (∼7,5 km 2 ) et se situe le long de la zone de faille de Seydişehir au sud-est de l’ErAVC. Dans ce système géothermique lié au volcanisme orogénique, les eaux thermales de Kavak (T∼22–45 °C) sont d’origine météorique et périphérique (Ca–Na–HCO 3 ). Ces eaux sont caractérisées par des teneurs en cations K + et Na + élevées et un pH bas (entre 6.4–6.9) relatif aux eaux froides autour du KGF. Deux types d’eaux thermales ont été identifiés dans le KGF, grâce à de légères différences hydrogéochimiques et de températures de sortie. Le premier type d’eau thermale (T∼22 °C) possède une TDS et un rapport Cl/Br relativement élevé ainsi que des teneurs plus faibles en silice dissoute et en Br (T>45 °C), ceci vis-à-vis du second type d’eau. La relation géochimique liant le KGF et les formations riches en potassium de l’ErAVC sont clairement mises en évidence par des diagrammes basés sur les cations. L’analyse statistique multivariée confirme que les deux types d’eaux thermales forment deux groupes séparés statistiquement. Ceci suggère que la chimie des eaux du KGF est principalement contrôlée par le biais de l’interaction eau-roche avec l’ErAVC plutôt qu’avec les roches métamorphiques du socle.
Subduction-related environments are complex geological sites where various magmas occur in close spatial and temporal association. To better understand geological processes led to the generation of compositionally distinct magmas, we need to know the origin and evolution of magmas formed in these settings. Our purpose here is to determine the genesis of the Sulutas Volcanic Complex (SVC), located near Konya (Central Anatolia, Turkey) and to understand its relation to the subduction-related processes. Based on a detailed field study of the SVC, we present here Ar-Ar geochronology, mineral chemistry, whole-rock major, trace element and Sr-Nd-Pb isotope data.The SVC can be subdivided into three distinct chemical groups. The oldest group (~16 Ma) characterized by bimodal association is composed of Na-alkaline basaltic rocks and adakitic dacite. The Na-alkaline basaltic rocks were derived from an OIB-like enriched asthenospheric mantle source, but the adakitic dacites from a mafic lower crust. Geochemistry of potassic lamprophyres (~13.5 to 12.5 Ma), the second group, can be best explained by melting of a depleted lithospheric mantle source that was metasomatized by slab-derived sediment melts. This metasomatic component generated phlogopite-rich veins in their source. The youngest group (~13 to 11 Ma), high-K calc-alkaline rocks (HKCA) is composed of basalt, andesite and mafic enclave-bearing dacite. Parental magmas to the HKCA are consistent with the derivation from a lithospheric mantle source metasomatized by fluid-like subduction components. Geochemical variations in the HKCA can be explained by magmatic processes (e.g. assimilation-fractional crystallization for basalt and dacite, fractional crystallization for andesite) from a common parental magma similar to the mafic enclave.The SVC composed of orogenic and anorogenic rocks occurred in a graben-like extensional basin in the Central Anatolia, and this extensional tectonics is related to the retreating subduction zone along the Cyprus arc within the convergence system of the African-Eurasian plates during Miocene.
