Kalecik Castle is an important historical building. However, dacitic building stone sed is deteriorating mainly because of atmospheric conditions. The purpose of this tudy is to understand the deterioration mechanisms affecting the dacitic stones used n the castle&rsquo / s walls. To achieve this purpose various arhaeometrical methods such as etrography, X-ray diffraction analyses, analyses for determining physical poperties density, porosity, and water absorption capacities), ultrasonic velocity easurements and some mechanical tests are used. The results of this study show that the deterioration of Kalecik Castle results mostly rom physical factors such as frost action, wetting and drying and thermal shock. According to the study, chemical and biological factors that may also be an mportant cause of deterioration are negligible in Kalecik Castle&rsquo / s building stones.

In order to understand the tectonic evolution of the Kalecik region (Ankara, Turkey), a structural field study was performed in a selected area located in the east of Kalecik, where mostly imbricated thrust sheets of the Cretaceous Ophiolitic melange crop out. In the study area, the Cretaceous Ophiolitic melange, Cretaceous radiolaria-bearing sequences and the Paleocene units are all intruded by sub-vertical dykes. The attitudes of planar structures (dykes, beds and faults) and the kinematic data measured on faults were analyzed by using &ldquo / ROCKWORKS 2002&rdquo / and &ldquo / Angelier Direct Inversion Method (version 5.42)&rdquo / softwares, respectively. A major trend of NE-SW (045&deg / N) direction and relatively a post-Paleocene &ndash / pre-Miocene age was determined for the dykes indicating an extension in the NW-SE direction during post-Paleocene. The dykes cut bedded units displaying a dominant set trending in WNW-ESE (297&deg / N) direction and mostly dipping towards NE with moderate dip amounts. But at the same time, the Upper Cretaceous units were observed as intensely folded, faulted and thrusted due to the compressional regime that acted in Central Anatolia during Late Cretaceous. The angular difference between the major trend of dykes and the dominant trend of stratification was found as approximately 108&deg / ., which may also indicate that the dykes and beds were evolved during different deformation periods. The results of the kinematic analyses of different age faults revealed that the post-Paleocene &ndash / pre-Miocene Kalecik basaltic dykes are deformed under a continuous NW-SE-oriented post-Paleocene compressional to strike-slip tectonic regime which was followed by a NNW-SSE oriented post-Miocene extensional-transtensional regime.

The major purpose of this study is to evaluate the paleoenvironmental and paleoclimatological conditions during the Middle Miocene-Early Pliocene in Kalecik-Ankara by using mineralogical and geochemical proxies from Han&ccedil / ili Formation. To achieve a high-resolution paleoclimate data, 2 stratigraphic sectioning and 1 continous core drilling were examined. Field studies were followed by analytical techniques on the selected representative samples. The mineralogical compositions of the bulk samples and the minerals of the clay fractions were determined by X-ray diffractometer. Scanning electron microscopic analyses were also carried on the specific samples which have the potential to define the important microstructural units. The major and trace elemental compositions were determined by X-ray fluoresence spectrometer. Additionally, the stable isotope compositions of the samples selected from the continous core drilling on Han&ccedil / ili formation were among the major proxies to gather a paleoenvironmental and paleoclimatrological approach. All the proxies employed for this study clearly indicate that mineralogical and geochemical signatures are consistent with each other and can be used for paleoclimatic interpretations. The stable isotope values point that C4 plants were dominant during the deposition of Han&ccedil / ili Formation, while evaporation caused the development of alkaline environment which is seasonally dry with depositional temperature approximately between 25-30&deg / C. During deposition, lava flowand tuff were deposited due to the volcanic activity in the vicinity of the lake. Based on this volcanism, economical bentonite deposits were originated. The lake at which the Han&ccedil / ili formation was deposited, completed its development in a time to time silicate rich and salty-alkaline anvironment.