Türkiye Jeoloji Bülteni

Abstract: This paper proposes an alternative route for the southern branch of the NorthAnatolian Fault Zone (NAFZ)using evidence from morphotectonic features, seismology, GPS and recently published Magnetotelluricand Transient Electromagnetic (MT) data. In this new route, the southern branch connects with the mainbranch of the NAFZ in Bolu via the Gölpazarı pull-apart basin and Mudurnu. The slip distribution of theNAFZ as taken from GPS data indicates that the newly hypothesized route is the second most importantbranch of the NAFZ.

Abstract: Ophiolitic meta-gabbros are exposed on the Kazdağ Massif located in the southern part of the BigaPeninsula. Trace element composition of rutile and quartz was determined for metagabbros from theKazdağ Massif by LA-ICP-MS. The Zr content of both matrix rutiles and rutile inclusions in garnet rangefrom 176 to 428 ppm (average 335 ppm). Rutile grains usually have a homogeneous Zr distribution. Therutile grains from studied samples in the Kazdağ Massif are dominated by subchondritic Nb/Ta (11-23)and Zr/Hf ratios (20-33). Nb/Ta and Zr/Hf show positive correlation, which is probably produced bysilicate fractionation. The Nb/Ta and Zr/Hf ratios increase with a decrease in Ta and Hf contents. Thecore of rutile grains are generally characterized by low Nb/Ta ratios of 17-18 whereas the rims exhibitrelatively high Nb/Ta ratios of 19-23. Trace element analyses in rutile suggest that these rutile grains weregrown from metamorphic fluids.Ti-in-quartz can be used as a thermobarometer when used in combination with Zr-in-rutile thermometer.P-T conditions of ophiolitic meta-gabbros were calculated by Ti content of quartz and Zr content ofrutile, which are in equilibrium with each other. Ti contents of quartz are ranging between 28 and 42ppm (average 36 ppm). A P–T estimate can be obtained from the intersection of the Ti-in-quartz isoplethswith the Zr-in-rutile isopleths, which yield ~ 660 oC and 10 kbar. The P-T conditions of meta-ophioliticrocks suggest that they occur as a different separate higher-pressure tectonic slice in the Kazdağ Massif.Amphibolite-facies metamorphism resulted from northward subduction of the İzmir-Ankara branch of theNeo-Tethyan Ocean under the Sakarya Zone. Metamorphism was followed by internal imbrication of theKazdağ Massif resulting from southerly directed compression during the collision.

Abstract: An earthquake, a moment magnitude of 5.0 (Mw), occurred on 10 January 2016 at 19.40 local withits epicenter, Hacıduraklı, the village of Çiçekdağı, Kırşehir in Central Anatolia that was known as a seismically quiet region. Its focal mechanism solution showed a right-lateral strike-slip faulting. Thisindicated that the earthquake occurred in WNW-ESE trend segment of Manahözü Fault that was rightlateral strike-slip fault, consisted of two structural segments and complied with the focal mechanismof the earthquake. Manahözü Fault is active and one of the most important structures that play a rolein shaping the region. Seyfe Fault Zone NW-SE trend right-lateral strike-slip fault is one of the mostsignificant geological structures in Kırşehir and its near surroundings. The interaction between theseactive structures caused the occurrence of Seyfe pull-apart basin. Besides, it is thought that the rise inthe northern part of the Manahözü fault may occur due to the convergence between Manahözü Fault andYerköy Fault Zone. NW-SE trend segment of Manahözü Fault, an active structure, is also evaluated as astructure that has a potential to create earthquakes in future.

Abstract: Purpose of this study is to locate the landslides that can threaten the settlement areas around the Çetin damreservoir is situated in vicinities of Pervari town of Siirt city. The Çetin Dam is going to be constructed inBotan Çayı (Ulu Çay) valley. The Çetin dam crest, reservoir areas are all located on allochthonous units.The Maden Complex is situated between the slices of the metamorphic rocks. Very steep inclination of thevalley slopes are among the significant causes of the landslides. The frequency of the landslides increaseswhen this feature is combined with the presence of the Maden Complex. Another reason triggering thelandslides is the earthquakes.The reason why the slope inclination is steeper along Botan Çayı River is thetectonism which affected the region since the Middle Miocene. Among the most important numerous datathat shows that the region is uplifting continuously are elevated erosional surface of the old rivers and theterraces can be counted as evidence of uplifting. These features provide important evidences to understandthe relative ages of the landslides. The uplifting causes an increase in slope inclination. As the inclinationof the slopes increase, new and younger landslides occur in debris of the older landslides. It was observedin many places that the material sliding downslope following the occurrence of the landslide divertedthe river bed in the opposite direction. Most of the villages established on both banks along the valley ofBotan Çayı River are located on old landslide material, landslide debris and erosional surface. The wateremerging from the toe and foot of the older landslide material has promoted the horticultural activities. Inline with the increase in water saturation of the rock and soil beneath the reservoir after water holding inthe dam, new landslides can be expected around the active landslide areas. Based on their relative ages,the landslides mapped were classified in 7 groups. The symbol «1» was used for the oldest landslideand similarly, «7» was used for the youngest one. The landslides with the numbers «1,2,3,4 and 5» are theinactive, fossil landslides. The landslides indicated with 6 and 7 are active landslides. The landslides alsowere grouped based on flowing-sliding types and flowing-sliding materials except for dating.

Abstract: Global energy prospecting has significantly shown change with the development of technology that can beused in the production of energy sources which are unconventional such as tight reservoir and shale gasespecially within last several years. These sources which are economically seen as a great contributionand are predicted that it will be greater impact potential in the fields of economic, social and politics inthe future have been protested on the ground water, surface water and local air quality by millions ofpeople in many countries because of harmful and it has necessitated that these subjects are evaluated indetails with the economic benefits. Especially, natural disasters which have been encountered at global scale have drawn attention to the effect of the chemical composition of the atmosphere and compositionalchanges on humanity and echology in the 20th century. In this article, as well as it has been turn undereconomic prospecting, the formation of shale gas which becomes focus of interest especially of the last fewyears and also maybe causes to the configuration of global politics again, petrophysical features of shalesource rock, the role on the fulfillment of the energy need of the countries with searching and productiontechniques; and meanwhile the effects on ecology have been evaluated. It has been tried to be statedthat energy sources will not have a meaning as only fuel and energy source in the future just like in thehistorical process by being mentioned about their effects on the fields of economy and social.