Türkiye Jeoloji Bülteni

Abstract: Crystalline basement in Gümüldür - Kesre region consists of the metamorphic rocks belonging Barrowian - type green - schist facies and subfacieses of quartz - albite - muscovite - chlorite and quartz - albite - epidote - biotite. These are Wide - spreaded in the form of garnet biotite schists, micaschists, chlorite schists and chloritoid phyllites. Two different foldings whose relative ages can not be clearly determined are found in the metamorphic rocks. All the minerals except for chlorites are pre - tectonic.Sediments in Triassic - Lias age are overthrusted on the crystalline basement. This type overthrusts are similarto the overthrusts in West Eagean (e.g. Karaburun Peninsula). Today this type of formations are seen klippe - likeforms. The age of overthrust is estimated as Late Eocene - Oligocene. Since there is no concrete data for the age ofPaleogene flysch, tfie position of this formation is open to discussion.Sedimentary rocks of Miocene age and the series overlained by these series are cut by the rh^olites of Plioceneage. Morphology of this region had his today`s shape most likely by the young tqctonism in Late Pliocene.

Abstract: In this article, metamorphic rocks of the Mid - Anatolian (Kırşehir) Massif are nkmed the KamanGroup, The Kaman Group is divided in three lithostratigraphical units, in an ascending order as follows: TheKalkanlıdağ Formation is characterized by a complex of gneisses, biotiteschists. pyroxeneschists, amphiboleschists,quartzites, quartzschists and jcalc - silicatic schists. The Tamadağ Formation is an intercalation of marbles, schistsand gneisses. The Bozçaldağ Formation is primarily composed of marbles, meta^chert - bearing marbles and metacherts.It is believed that the Kaman Group was originally made up of psammitic, orthoquartzitic, pelitic, semi - pelitierocks and sandy, marlly and chert-bearing carbonates. Inthe vicinity of Kaman, the mineral assemblages of therocks of different chemical composition indicate that the above - mentioned sedimentary sequence was regionallymetamorphosed under low pressure - high temperature conditions. It is also determined that the progressive metamorphism of the Kaman Group ranges from the high amphibolite to granuiite fades. Then, the rocks of this groupunderwent retrograde metamorphism ranging from low amphibolite to greenschist fades.

Abstract: Hoyran neritic carbonate platform which is a typical area for Taurus Carbonate Platform is initiatedto develop by the formation of an E - W trending gravity fault, which called Hoyran fault, at southern foot of Sultandağ during Lias. One of the characteristic sequences of Taurus Carbonate Platform which formed, in especially,during Mesozoic to Low Tertiary is exposed on the northern internal margin of İsparta Bend (Hoyran Basin). The sequence is composed of typical neritic carbonates deposited by a transgressing sea in overlap character from S W toward NE. Although the sequence, which is continuous from Upper Triassic to Upper Lutetian, is represented by onlylittoral to neritic carbonates up to Maastrichtian, pelagic facies also initiates to deposite locally between Maastrichtian and Upper Lutetian. Ultimately, deposition is ceased by the formation of a flysch facies.The platform, which was a stable, shallow-marine basin of deposition by Maastrichtian, is first initiated todestruct by vertical movements during Maastrichtian. Afterwards, the destruction is continued by predominantly tensional stress and intervening two compressional stress with short duration, up to the present day. Arızlı ophioliticmelange is emplaced on platform by the first compressive orogeny at the end of Upper Lutetian, and north and northern parts of platform start to uplift. The uplifting is continued during Lower to Middle Oligocene time, and sea goesbackwards south to southwestward (Regions of İsparta, Burdur and Denizli). The study area is complately emerged bythe second (compressional phase at the end of Middle Oligocene, and local thrusts are formed. Some phases of rifting,such as regional doming, faulting and volcanism are developed on the northern internal margin of İsparta Bendcontrolled by normal block - faulting from Middle Oligocene to the present day. The tectonic activity is also beingcontinued under the control of normal block - faulting in the present day.On the other hand, Taurus Mesozoic to Lower Tertiary Carbonate Platform is mostly different from Africa toArabic Platform, and it may be thought that Antalya Naps might have been emplaced from E to W.

Abstract: This paper has been prepared by the purpose of pointing out some of the structural clues supportingthat Early Kimmerian Orogeny, its presence in Seydişehir and Ermenek localities has been cited before by some other researchers, has also affected the Beyşehir locality.Rock stratigraphic units of the, Cambrian  age have been thrusted over the Middle Cambrian - Lower OrdovicianSeydişehir schists in Beyşehir area and after thrusting both Cambrian rocks and Seydişehir sahists iiave been overlain with the angular unconformity by Upper Lias - Lower Dogger carbonates.When these evidences are evaluated with other investigaters data, it can be suggested that the northern partof the Central Taurus Mountains was possibly subjected to Early Kimmerian orogenic events during Rhaetian.

Abstract: Upper Jurassic/Lower Cretaceous limestones in the Seben - Nallıhan - Atça region, form a continiouslithostratigraphic unit. Upper Jurassic pelagic and resedimented limestones have been deposited in the slope andbasin facies, showing flysch type sedimentation. Pelagic limestones contain Saccocoma, Gîobochaete and Calpionellafossils, which are the characteristic of the Jurassic of Mediterranean type. The Jurassic/Cretaceous boundary is defined by Calpionella biozones in the pelagic limestones, and with the index foraminifera (Protopeneroplis, ConicosprilUna, Labyrinthina, etc.) and Dasycladaeean algae îSalpmgoporella, Clypeina, Cylindroporella, Polygonella, etc.) inthe massive biocalcarenites along the Nallıhan-Atça line. The sequence begin with Lower Cretaceous in the Sebenregion. Limestones show completely different environmental properties and are represented by shelf carbonates bearing Orbitolina, Algae, and Rudist bivalves.

Abstract: The Neotectonic period in Eastern Turkey hasstarted a compressive regime in the Middle Miocene.This compressive regime has caused E - W thrusting which has dips to north and south, NE - SW striking left lateralfaults, NW - SE striking right lateral faults and N - S trending fractures and related volcanism.Eastern Turkey was almost a peneplain at the beginning of the Neotqctonic period. The structural developmentand volcanism in this period have changed the peneplain morphology. Geomorphologic development was in the formof ridges and basins which were formed from anticlines and synclines. Rivers flowing in N - S direction cut antecedentvalleys but rivers flowing in E - W directions formed meanders in coincidence with the morphology. This simplemorphological structure is controlled and complicated bythrusting, strike slip faulting, extension and volcanism. Asa result of these events ridges and narrow alongated basins lying roughly in the E - W direction were formed andthese basins gained low altitudes compared with the altitudes of the ridges. These basins are defined as inter - mourtain basins and a typical example for them is the Mus basin in Eastern Turkey. It is thought that the region has undergone crustal shortening and thickening and subsequent rising. This geologic and geomorphological developmentof Eastern Anatolia implies that the region is now at the stage of mountain building.

Abstract: Petrochemical features of the volcanics of the area between Tokat and Sivas are described. Volcanicswhich are found in the ophiolitic melange as being blocks have the characteristics of tholeitic rocks formed . atmid-ocean ridges. Upper Cretaceous (possibily Turonian) aged volcanics seem to be identical to those formed atsubdu;ction zones. They have the characteristics of calcal caline volcanics indicating the first phase and its continuation of island arc formation. Eocene  possibly younger volcanics indicate the last product of differentiation ofcalcalcaline rocks differentiation.

Abstract: Mineralogical studies on radioactive ore samples from the Kasar and Taşharman (Köprübaşı) uranium deposits, and Yeşilyurt (Alaşehir) uranium occurrence in Western Anatolia; Eskine and Asarcık uranium mineralizations in Şebinkarahisar district in the Eastern Black Sea Region, and Beylikahır (Sivrihisar) rare earth - thorium-fluorite deposit in Western Anatolia were carried out using microscopic, autoradiographic and X-ray powdercamera diffraction techniques.The Kasar and Taşharman deposits, and the Yeşilyurt occurrence are sandstone - type uranium mineralizations located in the Neogene f luviatite and lake sediments. Meta - autinite and meta - torbernite are the only uraniumminerals recognised in the ore samples from the Kasar deposit. These minerals occur as disseminations in thematrix, and as an envelope around the pebbles of the Neogene clastic series, and in places extend down in thefractures of the basement gneiss and schist. No uranium minerals were identified in a limited number of representative ore samples from Taşharman and Yeşilyurt mineralizations. Fine yellow coatings on some Taşharman conglomerate samples were found to be jarosite. Some indications of a radioactive disequilibrium in the Yeşilyurt uranium occurrence explains the scarcity of the uranium minerals.In the Çukurovası and Eskine mineralization in the Şebinkarahisar district meta - autinite, meta - torbernite andmeta - uranocircite II were identified. These minerals occurin a conglomerate - sandstone - siltstone unit of Eocene age,and in the fractures of a silicified andesite. Both of the uraniferous units overlie a granite, and are covered by thebasalt and andesite flows.Uraninite was observed in a highly radioactive, sulphide rich sample from the the Asarcık lead-zinc mine inthe Şebinkarahisar district.The Beylikahır rare earth - thorium - fluorite deposit is related to the alkaline magmatism of Tertiary age andoccur as veins and fissure zones located in tectonic breccia zones in the Paleozoic meta - sedimentary and volcaniccomplex. In addition to calcite, fluorite, barite, and bastnaesite as the rare earth - thorium mineral, psilomelane,limonite, dolomite, and in small quantities apatite and phlogopite were observed in the ore samples from this deposit.The bastnaesite from Beylikahır, which has been found to be more enriched in thorium than a normal bastnaesiteaccording to a previous study, deposited in the final stages of a multiphase mineralization process.

Abstract: The new genus Erkina is described with E. ankarensis n.gen.n.sp., as genotype, E. minuta n.sp. andE. n. sp., The structural features of Erkina and the associated fusulinids suggest that Erkina is the upper part of Middle Permian in age. 

Abstract: The specimen belonging to Anchitherium aurelianense Cuvier from the Çandır Formation is descrisbed and it is discussed that this form ranging stratigraphically form Early Mfcene to Early Upper Miocene Europelived in Çandır during the Astaracian (Late Middle Miocene) Stage.

Abstract: Detailed biostratigraphic zonation, based on foraminifers is established in the Lower CarboniferousNohutluk Tepe section in the Aladağlar region of the Eastern Taurids. For correlation purposes to be used in future studies, twelve biozones based on biostratigraphy have been differentiated. Reliable ages for the biozones are obtained using all the available palaeontological data (especially the brachiopods) from the section.The first two zones of the section (Archaesphaera minima and Endothyra inflata zones) are generally made upof microplanktons in this respect the Lower Carboniferous Nohutluk Tepe section is different from the other LowerCarboniferous sections in the Taurids.

Abstract: A lower jaw fragment belonging to Hemicyon sansaniensis from the Middle Miocene Anchitheriumfauna of İnönü 1 locality is described and compared with the other Hemicyon; species found in Europe. And it isdiscussed that İnönü 1 fauna can be a Lower Astaracian in age and placed in mammalian zone 6.

Abstract: Akkök (1981)`e göre, Alaşehir (Manisa) yöresi metamorfik kayaçları litolojik ve yapısal özelliklerine bağlı olaraküç grupta toplanmaktadır; gnays karmaşığı, şist karmaşığımermerler, Yazar, gnays karmaşığı içinde, porfiroblastikgnays, gözlü gnays, bantlı gnays gibi «dokusal özelliklere»dayalı bir ayrım biçimi Seçerken, şist karmaşığı içinde kuvarso - feldispatik gnays, granat-mikaşist, kuvarsit gibi «mineralojik bileşkne» bağlı bir tanımlamayla, yine şist karmaşığı içinde, gnays karmaşığının içinde ayırtlanandan başkaolduğunu öne sürdüğü ikinci bir gözlü gnays birimi tanımlayarak (şist karmaşığının içinde bile iki ayrı ölçüt kullanarak) bir ölçüde karmaşa oluşturmaktadır.Bilindiği gibi, kayaçların tanımlanmalarında çeşitli Ölçütler vardır (dokusal, yapısal, mineralojik, v.b.). Ancak, çalışma konusu olan kayaçların tanımlanmalarında - bir birimin farklı şekilde iki kez tanımlanmaması için-bir birlikolmalıdır. Bu çalışmada, şist karmaşığı içindeki birimler bileiki ayrı ölçütle değerlendirilmektedir.