ORIGIN OF THE CONCRETIONARY LIMESTONES IN THE ISTANBUL DEVONIAN SUCCESSION

The study area is located near the apex of the north-facing and V-shaped Konya-Niğde Graben. Its south-southeast margin is defined and controlled by the NE-trending Karaman-Niğde Fault Zone. It also forms the geographic boundary between the central Tauride in the south and central Anatolia in the north. This study aimed to determine the Latest Pliocene-Quaternary uplift rate of the central Tauride and the evolutionary history of the Kızıllar Canyon located on the uplifting southern footwall block of the Karaman Niğde Fault Zone. Both the geological and geomorphological field data, which were obtained within the framework of this study, revealed the following: (1) the Kızıllar River drainage system developed as a result of several capture events; (2) Lithological and hydrological characteristics of the valley reveal the reason for the lack of gradation in the river’s longitudinal profile; (3) the Kızıllar Canyon reflects the incision process of the Kızıllar River; (4) the Kızıllar River cut vertically into its bed up to 230 m, which corresponds to the minimum Latest Pliocene- Quaternary uplift rate of the central Tauride (~0.06 mm/yr); and (5) the Kızıllar Canyon developed as a natural response of the river to the uplift of the Konya-Niğde Fault Zone footwall block.

The Dodurga Fault is an active right-lateral strike-slip fault, approximately 63 km long, striking NW-SE in northwestern Anatolia. Based on 1:25,000-scale active fault mapping, the fault is subdivided into two principal geometric segments. Segment 1 is approximately 16 km long and extends from Sulhiye in the west to Erikli in the east, whereas Segment 2 is 47 km long and is characterized by a right-stepping geometry and a 10°-15° southeastern deflection. Geological and geomorphological observations, together with kinematic analyses, indicate that the fault is dominantly right-lateral strike-slip in character. Stream channels offset by up to several kilometers along the fault trace support its long-term activity, and fault-plane kinematic indicators independently confirm dextral motion. Paleostress analyses of the kinematic data indicate that the recent deformation phase along the Dodurga Fault is governed by approximately N-S contraction and E-W extension. Empirical scaling relationships suggest that Segment 1 and Segment 2 are capable of generating earthquakes of Mw 6.47 and Mw 6.97, respectively. If both segmentsrupture together, the Dodurga Fault could potentially generate an earthquake of Mw 7.16.

Kapuzbaşı karst spring is located between Kayseri and Adana, one of the most important and wellstudied mountainous karst regions, Aladağlar, Central Taurus, Türkiye. Previous scientific studies revealed the hydrogeological setup, perceptual model including groundwater residence time and potential recharge-discharge relationship; however, there has not been any process-based conceptual modeling experiment on the karst spring aiming to parameterize the karst system hydrodynamics. In the present study, we aimed to develop a numerical model of the karst groundwater system to parameterize the system hydrodynamics, which was built based on the conceptual understanding of the karst hydrogeology. We selected the lumped-conceptual hydrological model of KarstMod to quantify the discharge of the Kapuzbaşı spring. The modeling experiment showed that the recharge area of the karst spring is covering approximately 350 km2, and the approximate annual discharge exceeds 250 hm3. The preferential flow mechanism triggered after the water level in epikarst exceeding 92 mm, and the melt factor is approximated as 9.91 mm/°C/day. The response time of conduit reservoir is approximately 1 day, and the loss flux triggered when the water level in conduit reservoir exceeding 4 mm. The hydraulic conductivity of the matrix reservoir is found approx. 0.012 mm/day. The model performance based on the daily discharge was obtained as Nash Sutcliffe Efficiency (NSE) = 0.77, and Kling-Gupta Efficiency (KGE) = 0.87 in the calibration, and NSE = 0.76, and KGE = 0.77 for the validation periods, respectively. Eliminating the less sensitive model parameters in the calibration leads to more robust and less uncertain discharge simulations.