Geological Bulletin of Turkey, established in 1947, is one of the oldest and best-known periodicals of this country. It is an open access journal and publishes original research papers after a peer-review procedure in Turkish or English.
Geological Bulletin of Turkey covers all aspects of the geosciences except for Engineering Geology.
Geological Bulletin of Turkey is indexed and abstracted in GeoRef, Geotitles, Geoscience Documentation, Bibliography of Economic Geology, Geology, Geo Archive, Geo Abstract, Mineralogical Abstract, ProQuest, GEOBASE, EBSCO, BIOSIS, ULAKBİM (TRDİZİN) and Thomson Reuters&Clavirate (ESCI) databases.
Geological Bulletin of Turkey is published three times a year (January, April and August). The articles submitted to the journal are evaluated by peer review.
Your new manuscript submission should be via DergiPark.
To download of all issues from Geology Bulletin of Turkey, published since 1947; https://tjb.jmo.org.tr
Contact to Editor in Chief: firstname.lastname@example.org
2023 OCAK Cilt 66 Sayı 1
View as PDF
Abstract: The Eşendere Group, identified in the Mordoğan sub-basin on the western edge of the Foça Depression, consists of the alluvial Saip, palustrine Boyabağ and lacustrine Çukurcak limestone formations. The Eşendere Group unconformably overlies the lacustrine deposits of the middle Miocene Hisarcık Formation. The Saip Formation consisting of alluvial fan deposits, reflects the beginning of late Miocene sedimentation. The Boyabağ Formation, which was described in this study for the first time, represents a palustrine mud flat succession and is located between the Saip Formation and the lacustrine Çukurcak Limestone. The Çukurcak Limestone is the last unit in the Eşendere Group. Hipparion aff. giganteum and Hippopotamodon major, that were found in the mudstone dominant succession of the Boyabağ Formation, are the first records from the MN10 biozone in the Western Aegean region. Based on these large mammal records, we assume that late Miocene sedimentation in the Foça Depression began ~10 million years ago.
View as PDF
Abstract: Inlice high sulphidation epithermal gold deposit is located in the Erenlerdağ-Alacadağ Volcanic Complex(EAVC), approximately 40 km southwest of Konya city centre. The volcanic and volcano-sedimentary rocks seen inthe study area are andesite, block and ash flow, basaltic andesite lava flow and andesite lava flow, from oldest to youngest. The youngest units unconformably covering the volcanic and volcano-sedimentary rocks are talus andalluvium. Four different alteration zones in the andesites moving from the centre of the alteration toward freshrock are i) silicified zones (consisting of vuggy-sugary and chalcedonic/opaline quartz veins), ii) advanced argillicalteration, iii) intermediate argillic and iv) propylitic alteration. In addition, a potassic alteration zone consisting of magnetite, quartz, biotite and anhydrite was identified in the deep part of the Merkez Zone. The mineralisationis commonly represented by pyrite, and to a lesser extent enargite, chalcopyrite, covellite, chalcocite, sphaleriteand marcasite. Petrographically, the fine-grained gold grains (between 2-6 µm) are only observed in areas where sulphide minerals are oxidised.The degree of geochemical variation in the alteration zones decreases from silicified zones to propylitic alteration,and this variation is largely consistent with the mineralogies observed in these zones. Moreover, enrichment in As,Sb, Bi, Ag and Au, and depletion in Zn and Ni are especially notable from fresh/least altered andesites towards advanced argillic alteration and silicified zones. In addition, studies showed that the high Pb value in chalcedonic/opaline textured quartz veins and low Rb/Sr value in advanced argillic alteration and silicified zones can be used asa geochemical guide, at least for the Inlice region.
View as PDF
Abstract: Spherulitic structures are classically defined as concentrically zoned crystal clusters that form in igneoussystems (especially in alkaline igneous rocks), and usually occur as different mineral layers ,or shells.The volcano-sedimentary series observed in the Kırka region, south of Eskişehir, within the Kırka-Afyon-IspartaVolcanic Province, Western Anatolia, consists predominantly of Lower Miocene volcanic ,and pyroclastic sequenceswith rhyodacitic-rhyolitic composition, lacustrine limestones, borate-bearing claystones, tuff, stromatoliticlimestones ,and rhyolites ,and basalts. The formation mechanisms of the spherulitic structures observed in themarginal zone of the sub-alkaline rhyolitic lava dome outcropping within the Neogene series west of İdrisyayla in Kırka (Eskişehir) region are described for the first time with this study. The rhyolites are grayish light brown in color,have hypocrystalline hyalopilitic-holohyaline texture ,and have spherical structures defined as spherulites. Theserocks have a completely flowing structure ,and are composed of volcanic glass containing rare euhedral plagioclase,sanidine ,and quartz microcrystals, the spherical structures observed on the surface of the rhyolites are up to 10-15cm in size. The spherulites, which are almost round in shape, appear as concentric rings within the lava flow bands.The flow band texture of the volcanic glass phase is continuous with the inner texture of the spherulitic structures.This study suggests that the spherulitic structures in the İdrisyayla (Kırka-Eskişehir) region formed by thedevitrification mechanism as a result of high temperature ,and rapid cooling. The petro-mineralogical features of thespherulitic rhyolites show that during the early magmatic stage, the oversaturated liquid crystallized in silica-richfluid phases with relatively different densities, ,and radial quartz-feldspar crystal growths from a center caused theformation of the spherulitic structure. It is also suggested that the lithophysae-like structures formed by the crystalgrowths representing the solid phase in axial cavities due to the local folding of flow bands ,and the later radialmineral growths representing the liquid phase also changed the laminated texture in the marginal phase of the rhyolite.
View as PDF
Abstract: The study area included low-grade metamorphic units representing the Karakaya Complex (LowerKarakaya-LKC) outcropping in the Armutlu-Ovacık zone in the Armutlu Peninsula. In this study, samples werecollected during field work in the Iznik and Yenişehir (Bursa) regions, and petrographic (optical microscope,SEM) and mineralogical (XRD) examinations were performed. Among the LKC units, the Iznik Metamorphics arerepresented by greenstone facies rocks (metasandstone, slate, schist, quartzite, metagabbro, metavolcanic, dolomiticmarble). Quartz, phyllosilicate (illite, chlorite, C-V, kaolinite, I-V, smectite, stilpnomelane, paragonite, antigorite),feldspar, calcite, pyroxene (augite), dolomite, amphibole (hornblende, tremolite/actinolite, anthophyllite) andopaque minerals (hematite and goethite) were identified in descending order of abundance among the LKC unit.The trioctahedral chlorites with chamosite composition had the IIb polytype, whereas the illites had 2M1 and2M+1M polytypes. The Kübler Index (KI; Δο2θ) values were in the range of 0.19-0.41 Δο2θ (mean: 0.25 Δο2θ), which indicates epi-metamorphic and very low metamorphic grade. The AI (Δο2θ) values were in the range of 0.26-0.32 Δο2θ (mean: 0.29 Δο2θ), which is compatible with the Kübler Index data from illites. Dioctahedral illites withphengite compositions had b0 values (Å) in the range of 8.952-9.030 Å (mean: 8.995 Å), and they were in the low- tomoderate-pressure facies sequence. Comparing the lithological, mineralogical and crystal chemistry parameterdata (crystallinity, polytype and b0) of the Iznik metamorphics representing LKC to those of equivalent units found incentral-northeastern Anatolia (Nilüfer Unit and Turhal Metamorphics), the unit showed diagenesis-metamorphismconditions with greenstone facies corresponding to the upper part of the Lower Karakaya (LKC-UP). Petrographicand mineralogical data (paragenesis, KI, AI, b0, index mineral associations) revealed that the Iznik Metamorphicswere affected by lower greenschist (high anchizone-epizone) metamorphism during the Permian-Early Cretaceousperiod.
View as PDF
Abstract: The Çal Canyon, one of the geological values of Denizli province, is located in the upper course of theBüyük Menderes River near the town of Çal. The oldest rock units around the canyon are schists and marbles ofthe Menderes Massif. The metamorphic units overlie the carbonate (limestone, dolomitic limestone) and ophioliticrocks of the Lycian nappes with a tectonic contact. These basement units were unconformably covered by the upperMiocene to Pliocene continental succession, which is composed of fluvial, lacustrine and alluvial deposits. The canyon, which is 65 km northeast of the provincial capital of Denizli, is 4 km away from the town of Çal.The depth of the canyon, which developed in the marble of the NE-SW trending Menderes Massif, is 60 meters. Thealtitudes of the entrance and exit points of the canyon are 760 m and 700 m, respectively; consequently, there is adifference of 60 m. The high slopes of the canyon are close to 90° at some points. The canyon, which started to format the end of the Pliocene, continued its development in the Quaternary. Its length is 3 km, in a N-S direction. Theridge where the canyon developed has a threshold between the Çivril-Baklan graben to the east and the Çal basin tothe west. The canyon also creates a hydraulic connection between these two depressions.On the cascading and irregular canyon floor, waterfalls a few meters high, along with potholes, have developed.In the study area, the canyon stands out as a geological value. However, apart from the canyon, there are alsohistorical and cultural values. To the south are the ruins of the ancient city of Lounda at the entrance of the canyon.On the other hand, there is the historical Hançalar Bridge and Kayı Bazaar to the north. As an intangible culturalvalue, a "sheep passing" festival is held in the waters of the Büyük Menderes River every year in the village ofAşağıseyit near Çal in the last week of August. The canyon area, which is easy to access and close to varioussettlements, is quite suitable for geotourism activities with its geological diversity and landscape features.The aim of this study was to investigate the geological-geomorphological features of the Çal Canyon and itssurroundings from a cultural-geological perspective as well as to reveal the extensive geotourism potential.
View as PDF
Abstract: In this study, the petrographical and geochemical signatures of the Kestanelik Granitoid outcropping nearthe Şahinli region (Lapseki, Çanakkale) on the Biga Peninsula and associations with Au-Ag mineralization weredetermined. The Late Ediacaran-Early Cambrian Çamlıca metamorphics form the basement of the study area withinthe Karabiga massif in the Sakarya Zone. These metamorphics were thrusted tectonically in the Upper CretaceousÇetmi mélange. The Çamlıca metamorphics are cut by the Eocene Kestanelik Granitoid, and the granodiorite isunconformably overlain by the Soğucak Formation composed of clastic sedimentary rocks. The Şahinli Formationcomprises andesite-basalt, fragmented pyroclastics, basalt dykes and lava flows, and mudstone. Quaternary alluviumunconformably covers all units in the area. The Kestanelik Granitoid is an intrusive mass in the form of a stock andcontains rocks with granite, quartz monzonite and quartz-rich granitoid composition. The main minerals in theserocks are quartz, K-feldspar, plagioclase, amphibole, hornblende and biotite, and there are secondary mineralssuch as sericite, illite, chlorite, smectite, kaolinite, dolomite, hematite, cristobalite and alunite. This granitoid hasundergone strong alteration and argillic, propylitic and silicification alteration are observed. The Kestanelik Granitoid generally has shoshonitic, calc-alkaline, subalkaline and metaluminous character,and was derived from an I-type magma. It has high silica content (64.9-75.49%), and major-trace element changesindicate that plagioclase and K-feldspar fractionation were effective in the development of the granitoid. In thegranitoid, LILE enrichment is quite high on the REE diagram normalized to the primary mantle. Normalized tochondrite, the granitoid is enriched in light REE and depleted in heavy REE, and also has a negative Eu anomaly(Eu/Eu*=0,87). The Kestanelik Granitoid comprises granites of synchronous age to the volcanic arc and collision,and has magmatic ,or crustal origin.
View as PDF
Abstract: Ecotourism is ecologically sustainable tourism, focusing on natural areas. Its aim is to fosterenvironmental and cultural understanding, appreciation and conservation. Geotourism isecotourism with an added geological theme.Geotourism has great potential as a new niche ecotourism product, but will require the samedisciplines that apply to other niche, "high value" tourism activities. Where ever tourismcontributes a direct environmental benefit to a visited location, its clients gain empathy for theholistic heritage of the area, and this reward creates enhanced customer loyalty to the operator.The Commonwealth Government`s 1994 National Ecotourism Strategy considered thatecotourists may include a mix of independent travelers, people who travel in organised groupsof a scientific, educational ,or recreational nature, and individuals ,or families who are interestedin an ecotourism experience as part of a varied holiday. Whilst based on limited sources, theStrategy then considered that the ecotourist appears to be well educated, professional/semiprofessional, 20-50 years of age, independent and individualistic, looking for alternatives to betraditional tourist destinations and experiences, and with significant spending power.Having regard to demographic and lifestyle considerations, it is hoped that geotourism, ifpositioned as a supplementary, knowledge-adding product within an attractive ecotourismexperience, will attract a different demographic i.e. affluent "over 45 y.o." customers. Thesemay come from amongst geoscience professionals from within these segmentations, as well astheir partners and friends, particularly through alumni and professional societies such as theGeological Society of Australia.Given the relatively small size of the Australian "geoscience interest" market, product contentpackaging will be critical. To address this issue, Leisure Solutions®and the School ofMarketing, Tourism & Leisure at Edith Cowan University are currently undertaking acooperative market research survey of members of the Geological Society of Australia.This paper addresses the rationale for and scope of this research work as well as reviews otheravailable research material which can assist marketers in understanding who are the people mostlikely to be interested in geotourism, as well as introducing some of the preliminary results fromthis study.