Türkiye Jeoloji Bülteni

Abstract: The Gölpazarı basin is a pull-apart basin, that located in the northwestern Turkey, is not well-advertisedin literature against its ideal geometric features. The basin floor is located at an altitude of 500 m with asize of 12 km in length and 4.5 km in width in ENE-WSW direction. The basin which has developed relatedto the right-lateral Gölpazarı fault, is bounded by strike-slip faults in the NW and SE edges and by normalfaults in the NE and SW margins. The basin floor has tilted towards west as a result of the relative activitiesof these faults. As represented by the basin fill deposits and geomorphology, the Gölpazarı basin was a closed depression and then by the opening of a strait in the south of the basin by the Akçay stream, the basinwas opened to external drainage in the early Quaternary. The existence of a thick Quaternary sequenceindicates that the capturing of the drainage basin by the external drinage has occured relatively young.Because of the close position of the basin to other pull-apart basins that developed under the control of thenorthern and middle strands of North Anatolian Fault Zone and origination by the right-lateral strike-slipregime have call to mind a genetic origination within the shear zone of the North Anatolian Fault Zone.  

Abstract: The stratigraphically lowest part of the investigated area consists of metapelites, metapsammites andmetarudites of Middle-Upper Triassic age, and is named as İkibaşlı Formation. Çiçeklikaya Formationwhich comprises of dolomitic limestones of Jura age conformably overlies İkibaşlı Formation. All  these Mesozoic aged units are tectonically overthrusted by the Muratdağı Melange with a low-angle.Muratdağı Melange composed of Neotethyan ophiolitic rocks is represented by ultramafic rocks and amelange (volcanic-sedimantary rocks) in the study area. Sub-ophiolite metamorphic rocks are tectonicallylocated between the ultramafics and melange of ophiolites of Western Anatolia in Alp-Himalaya belt.Sub-ophiolite metamorphic rocks which form under the ophiolitic rocks and have a maximum 100 meterthicknes are represented by amphibolitic rocks in the Northwestern Anatolia. Sub-ophiolite metamorphicrocks form in the period of subduction of an oceanic litosphere in the subduction zone. The ages obtainedfrom these rocks enable us to determine the age of a subduction of an oceanic litosphere and consequentlyto determine the closure age of Neotethyan Ocean. For this aim, 40Ar/39Ar age analysis was performed onhornblendes of metamorphic rocks and the plateau age of 100.7±1.3ma was determined.

Abstract: The last century earthquakes produced more than 1000 km surface rupture on the North Anatolian FaultZone (NAFZ), which is one of the most active deformation belts in the World. Paleoseismic data fromdifferent parts of the NAFZ exposes critical information about the earthquake history of the fault zone. Toresearch paleoseismicity of the Ilıpınar Segment and relationship between the segment and last centuryearthquakes, two paleoseismologic trench studies performed on the Yoncalık basin, where positioned ateastern section of the Ilıpınar segment. We identified two paleo-earthquakes, which correspond to BC8500-6150 and BC 5960-4300 time intervals in the Yoncalık-1 trench. On the other hand the analyses ofstratigraphy and structural features of the Yoncalık-2 trench similarly yield two events, from which theolder happened before BC 6325 and the younger was between BC 6325-2105. Despite of the wide rangeof these intervals, both trench results are coincide within their uncertainty limits. We interpret that eventsin both trenches reflects the same surface ruptures. By the joint analysis of both trenches, we conclude thatthe most recent and penultimate events should have occurred between BC 5960-4300 and BC 8500-6325,respectively. The results from paleoseismology of the Ilıpınar Segment, which constitute the easternmostpart of the NAFZ, indicate that the seismic behaviour of the segment is not in accord with the generalcharacteristic of the NAFZ. The reasons behind the disparity are considered to be related with complexfault geometry in the vicinity of Karlıova triple junction and partitioning of accumulated strain on thesestructures.

Abstract: Ancient mines and mining slag’s around Ulukışla (Niğde) and Pozantı (Adana) region were investigated interms of ancient mining point of view. Samples were collected for chemical and radiometric (14C) analysisfrom ancient ores and slag’s. According to the chemical analysis, Madenköy slags includes 0.8 g/t Au and142.1 g/t Ag; Alihoca-Karagöl slag’s includes 1.3 g/t Au and 34.7 g/t Ag; Gümüşköy slag’s includes 0.9 g/tAu and 67.9 g/t Ag, and Madenköy-Karagümüş slag’s are includes 1.3 g/t Au and 92.8 g/t Ag.Different size vessels, wooden fortifications and shovels and firewood’s were discovered around Madenköyü,Yeşelli-Büyük Toyislam ancient mines. 14C analysis of big vessel gives 1000±30 years (11th Century A.C.);small vessel gives 155±30 (19th Century A.C.); wooden fortification gives 105±30 (19th Century A.C.)radiometric ages. Two wooden shovel discovered around Maden köyü-Büyük Toyislam gives 125±30(20th Century A.C.) and 1000±30 (11th Century A.C.); wooden fortification gives 600±30 (15th CenturyA.C.); firewood gives 385±30 (17th Century A.C.) radiometric ages. Firewood of the ancient mine aroundHorozköy-Gavurun Damı region gives 270±25 (18th Century A.C.); ancient wooden fortification gives205±25 (18th-19th Century A.C.) and wooden staircase gives 135±30 (19th Century A.C.) radiometricages.Wooden charcoals were also analysed according to 14C ages of slag mounds around Karagümüş andMadenköy; 835±30 (12th Century A.C.) and 860±30 (12th Century A.C.) radiometric ages were observedrespectively. According to these radiometric ages, mining works is active starting from Byzantian era tothe Republic of Turkey with some interruptions in the region.Bolkar Mountains is called as “Muti Mountains” in the tablet of Neo-Hatti period in 800 BC, located ineastern part of Alihoca Village. This tablet could be accepted as the “first mining licence” according to itscontent, thus, mining in the region is active, with some interruptions, since Neo-Hatti Period.