Türkiye Jeoloji Bülteni

Abstract: The Selçuk Graben is the name given to the young graben developed in the western tip of the Küçük Menderes graben. It was a part of the main graben until a strike-slip fault zone cut and displaced it to the southwest during late Quaternary. From this time onward, it has had a semi-independent evolution. In the horsts bordering the graben, metamorphic basement rocks crop out. The fill of the graben consists of alluvium from the Küçük Menderes River. The Selçuk Graben is an asymmetrical graben. The bordering southern horst is more prominent than the northern one, where the normal faults form clear fault steps. Morphologically, the less distinct northern faults maythus be interpreted as antithetic faults, which have developed on the hanging wall of the major listric normal faultsof the southern horst. The graben and the bordering horst were cut and displaced by several young strike-slip faults,which have made clear imprints in the morphology, including linear ridges, offset streams, etc. In the development sequence of Western Anatolian grabens, the Selçuk Graben is one of the latest ones. The Küçük Menderes Graben was opened earlier, during the Quaternary. It was located on the horst separating the Büyük Menderes and Gediz grabens in this period. The elevated horst then collapsed. The Selçuk Graben was situated at the western end of the Küçük Menderes Graben during this period. Later, with the development of NW trending left-lateral strike-slip faults,  together with conjugated faults along the coastal region of western Anatolia, the Selçuk Graben was separated from the Küçük Menderes Graben and has since evolved semi-independently.

Abstract: The İstanbul-Zonguldak Tectonic Unit is regarded as the eastern most fragment of Avalonia-Carolinaand designated as Far East Avalonia. Its stratigraphy is characterized by discontinuous sedimentation from Late Ediacaran to Late Carboniferous. In the western part of the block, known as İstanbul Terrane, the Gözdağ Formationis represented by lagoonal sedimentary rocks consisting of shale-sandstone with limestone of Middle Ordovician Lower Silurian age. Here, I report on stratigraphic positions and petrographical and geochemical data of fine- andcoarse-grained tuffs and lavas in the Late Ordovician strata of the Gözdağ Formation. The fine- and coarse-grainedtuffs have pyroclastic and the lavas have porphyritic, vitrophyric and aphanitic textures. The fine-and coarse-grained tuffs are of Sandbian and Katian ages, and the lavas have Hirnantian ages, according to the stratigraphic positionsof the Late Ordovician volcanic rocks. The fine-grained tuffs have high potassium calc-alkaline, and the coarsegrained tuffs and lavas have a calc-alkaline character. They are devoid of noticeable with-in plate components, as deduced by the presence of obvious negative Nb anomalies, and they have subduction signatures. In conjunction with data from the literature, the Sandbian fine-grained tuffs were deposited in a lagoonal depocenter in the İstanbul Zonguldak Tectonic Unit in the earliest Late Ordovician due to multiple Plinian-type eruptions during the last phaseof the Taconic orogeny, which formed between the Piedmont Terrane and Laurentia. The Katian coarse-grained tuffs were products of volcanic activities formed in the arc settings during the last stage of depletion of the TeisseyreTornquist Ocean, lying between Avalonia and Baltica. The Hirnantian lavas were formed by flowing in a lagoonaldepocenter of the İstanbul-Zonguldak Tectonic Unit during the soft-docking of Avalonia and Baltica, known as thepre-Caledonian orogeny

Abstract: Middle Miocene sedimentation in the sub-basins of Kösedere and Mordoğan, representing the western margin of the Foça Depression, is represented by the dominantly lacustrine of Hisarcık formation, which unconformably covers the calc-alkaline volcanics (Karaburun volcanics and Foça tuff) at the end of early Miocene.The Karaburun volcanics outcropping along the boundary faults of the Middle Miocene basins are of andesite composition. Foça tuff is represented by rhyolitic ignimbrites. The Kösedere member, which represents the basin margin alluvial fan deposits of the Hisarcık formation, was deposited in front of the boundary faults of the Kösedere sub-basin. The Karabağları member, which consists of a green claystone-siltstone assemblage deposited on the lacustrine shoreface, overlies the Kösedere member with lateral-vertical transition. The Ardıç member, whichis considered the lateral equivalent of the Karabağları member in the Mordoğan sub-basin, is represented by amudstone-sandstone succession reflecting the mudflat deposition, and has yielded large mammal fossils of the late MN5 biozone. The Mordoğan limestone member, reflecting the last period of Hisarcık lacustrine deposition, istransitive with the Karabağları and Ardıç members. The Esendere group deposits, which have yielded large mammal fossils of MN10-11 biozones, unconformably overlie the Hisarcık formation. The Hisarcık formation is representedin Chios Island, Çeşme Peninsula and Foça Depression. Keramaria and Nenita units on Chios Island, the Çiftlik formation in Çeşme Peninsula, and Aliağa limestone in the Foça Depression can be correlated with the Hisarcık formation. Urla group deposits outcropping in the Urla basin and the Izmir Bay archipelago are the equivalent of the Hisarcık formation.

Abstract: This study aims to determine the provenance of grinding stone tools unearthed from the Neolithic phasesof Sumaki Höyük settlement using a portable Energy Dispersive X-ray Fluorescence Spectrometer (P-EDXRF) andX-ray Diffraction spectrometer (XRD). Sumaki Höyük is located in the Lower Garzan Basin of Batman province,Turkey. The settlement is dated to 9084±57 - 8123±50 cal BP. Grinding stone tools in this settlement are usually made of basalt. Albeit at low amounts, limestone was also used in the production of grinding stones. The Lower Garzan Basin, located to the east of Diyarbakır Basin, is surrounded by Mount Kıradağı to the west-southwest and Mount Raman to the south, the Garzan Anticlinal and Kentalan Anticlinal to the north-northeast. The basalt flow occurred in the Quaternary period. Samples collected from different parts of the Neolithic phase of Sumaki Höyük and the Kıradağı basalt flows were analysed using P-EDXRF to determine their chemical composition. The same samples were also analysed using XRD to determine their mineral composition. P-EDXRF and XRD analyses reveal that the samples from Sumaki Höyük and Kıradağı are in good accordance with each other. It is therefore understood that the basalt stone tools used in the settlement were taken from the Kıradağı basalts.

Abstract: Natural and geological heritage is an asset that adds value and identity to countries and is increasingly gaining attention for its preservation. Geological heritage represents the geological evolution of a region and the significant events that occurred during that evolution. Identifying and inventorying geological heritage based oncurrent scientific data falls within the responsibility of geologists, while registering and implementing conservation measures for these sites, as well as utilizing them for local development, rests with decision-makers.This study aims to introduce and identify the existing geological heritage in the districts of Konya province byutilizing the records of the Geological Heritage Conservation Association (JEMİRKO). The research is still in itsinitial stages and will be expanded over time. Investigations in Konya have revealed the presence of 61 geosites,many of which hold international significance. Additionally, there are 22 natural heritage sites and 9 registeredareas (national parks, nature parks), which offer a unique geotourism opportunity for the region.

Abstract: This study aims to reveal the relationship between the geological and geomorphological structure ofthe Adapazarı city center, which was largely destroyed by the earthquakes on 17 August 1999 (Mw: 7.4) and 12 November 1999 (Mw: 7.2), and the existing settlement areas and location selection of development areas. Adapazarıcity center, which is located on the Adapazarı Plain, has an alluvial soil structure carried by the Sakarya Riverand where the underground water level is quite high. Adapazarı was the most affected city by the 17 August and 12 November 1999 earthquakes, due to liquefaction. The Central Planning Region, which includes the entire Adapazarı city center, has been accepted as the study area within the scope of the Sakarya province 1/100,000 scale Land UsePlan for 2025, which was approved on 07.01.2010. The relationship between the geological-geomorphological structure of the study area and the city has been revealed by overlaying aerial photographs, satellite images, digital elevation models, and digital data obtained by using Geographical Information Systems (GIS). The objective of thestudy is to investigate the effect of the geological and geomorphological structure on the urban pattern after the  1999 earthquakes. The geological and geomorphological factors affecting the urban development were weightedby the Analytical Hierarchy Process (AHP) method and their relationship with the changing urban pattern was discussed. After obtaining the synthesis map by overlapping the thematic maps, it was found that the constructionson unsuitable land (65% of the study area) continued after the 1999 earthquakes. The newly developed areas locatedin the northmost part of the existing city center are suitable for settlement in terms of geology and geomorphological criteria.