Türkiye Jeoloji Bülteni

Abstract: Çökekyazı-Gökay area comprises the "lower unit" and the "upper unit" metamorphics of teh Bitlismassif. The lower unit metamorphics include various schists, gneisses and amphibolites as well as metaquartizites andmarbles, whilst the upper unit consists of micaschists, chloriteschists, metaquartzites, calcschists and marbles. Theupper unit rocks of the Upper Paleozoic possibly Permian age rest upon the older lower unit with an angular unconformity. These metamorphics, mapped on a 1/25.000 scaled map via fieldwork in different times, have been studied microscopically and geochemically. Thus, facies conditions affecting teh metamorphics in the district end mineral assemblages developed under these conditions have been determined and parent rocks elaborated. Studies have shown that mineralassemblages of both the amphibolite and greenschist facies co-exist in tha lower unit rocks. This situation probablyoriginates from the partial superimposition of the Post-Permian greenschist facies metamorphism onto the Pre-Permianamphibolite facies metamorphic activity. In the upper unit metamorphics, minerals of the greenschist facies are onlyseen and it is obvious that this was the Post-Permian metamorphism also affecting the lower unit rocks.Both fieldworkand data obtained throngh geochemical analyses have indicated that some gneisses and amphibolites in the region werethe derivatives of sedimentary, whilst the others were derived from igneous rocks. The various schists, metaquartzite andmarbles come from sedimentary origins.

Abstract: Küçük Menderes River Delta Complex, which developed in a large graben (Küçük Menderes Graben)through Pleistocene-Holocene time, consists of four, superimposed delta sequences (Dl=4) Each sequence was separatedby fine-grained, marine sediments and / or an erosion surface characterizing a sea transgression.The recent Küçük Menderes river delta (Dl) with a large subaerial plain, the youngest member of the complex, hasprograded since Late Holocene. Core and seismic data, collected from the gulf of Kuşadası, display that sea-level changes were typical during the Pleistocene and Holocene time, and shoreline prograded up to Recent shelf-break (-130 mwater depth) three times at least, after abrupt transgression periods. The last waste sea transgression was in Late Holocene and sea water advanced towards the east, up to 11 km.The delta complex was disturbed by many synsedimentary and post-sedimentary fractures, which are mostly downfaults. The active and relatively bigger ones are observed in the northern part of the gulf. Submarine sector, particularlyprodelta areas of the recent delta (Dl) has been growing towards the same direction, however the formers, apparently,D3and D4 sequences, developed mostly in southern side of the Kuşadası gulf occupying the Küçük Menderes graben. Thisrecognised relation presents that active graben tectonism importantly affected the deltaic deposition, in addition to global sea-level changes. 

Abstract: Kurşunlu (Ortakent-Koyulhisar-Sivas) Pb-Zn-Cu deposits are the typical examples of the vein styledeposits which are widely seen all over the sounthern and western parts of the Eastern Black Sea region in Turkey.Fluid inclusion studies were carried out on the primary and secondary types inclusions occured in the quartz and sphalarite crystals. These inclusions are very tiny, irregular shaped and two phases inclusions containing liquid and gas phases.Inclusions were divided in four different groups, according their tyapes and mineralagical relations, Their charecteristics are as follows: The first group; primary inclusions in quartz crystals, the second group; primary inclusions insphalarite crystals, the third group; secondary in elusions in the quartz craystals which in contact with the veinlets ofsulfide minerals and/or cut by these veinlets, and the last one; secondary in elusions in the quartz craystals which incontact with the hematite bearing veinlets and/or out by these veintels.First melting temperatures (TF Mp), last ice melting temperatures (TICE) and calculated salinity values in first, thirdand forth group inclusions are slightly different from them.

Abstract: Upper pPaleocene Güzeller formations is the oldest Tertiary unit which lies uncobformably on theauthochthonous and allochtonous units in the Bolkardağ region, south of Ereğli. Güzeller formation is conformablyoverlain by the Karaburun formation of Upper Paleocene-Middle Eocene age. The Paleogene rocks are overlain with anangular unconformity by te Neogene Kıraman formation and Karaisalı limestone. The youngest sediments in the regionare of Quarternary age.South of the studied area the Tertiary rocks are mainly marine sediments, they are bordered in the north by postMiocene aged terrigenous sediments.

Abstract: The basin extending from 18 km southwest of the Narman to 40 km northeast of Oltu is named asOltu-Narman Tertary Basin.The basement of the northeas section of this basin, was consructed by Permo-Carbmoniferous acidic agmatites andUpper Cretaceous volcano-sedimentary sexuences. In the basin, Eocene sedimentary rocks contain coarse-fine elastics atthe bottom and shallow marine sequence developed in volcano-sedimentary facies. They are overlain by Oligocene andOligo-Miocene continental sedimentary units whit angular unconformity. The whole sedimentary sequence infilled thisbasin, is covered unconformambly by post-Upper Miocene volcanics. 11 formations and 4 members are identified andinvestigated, in the lithofacial units outcroping in the stutied area.

Abstract: The rock units, in the study area are divided in two groups as autochthonous and allochthonousunits. The oldest rock of the autochthonous units is Erenler limestone of Cretaceous. This unit is overlain disconformably by Kızılkırma formation of Paleocene-Eocene, Yazır formation of Aquitanian covers Kızılkırma formation asdisconformably and its main lithology is reefal limestones. This formation is overlain by comformably by Ağlasun formation of Burdigalian. Ağlasun formation consists mainly of sandstone and shale.In the Middle Miocene, Akdağ limestone unit and ophiolitic melange are thrusted and overlies tectonically ontoAğlasun formation. This event is the most important tectonic feature in the region and this resulted of many folds andfaults.The basement rocks and the overthrust faults is overlain by Gönen conglomerate which is post orogenic and molasse type of Middle Upper Miocene.In the late Miocene-early Pliocene transition, the Gölcük volcanism activity starts in the region. Gölcük formationis formed result of this volcanic activity. The volcanic activity in the area, progressed, in two different stages. Result ofthe early volcanic stage, andesite lavas are spread of around the Gölcük area and result of the late volcanic stage, tuff andpyroclastic materials are spread of around the Gölcük area.The upper most unit is alluvium of Quaternary.

Abstract: Volcanic rocks cropping out around Sarıcakaya (Eskişehir) in Middle Western Anatolia have beenpetrochemically analaysed and they have been correlated with the similar volcanics surrounding the region. Their originhave also discussed. Eocen volcanic are of andesitic type. They consist of at least two volcanic phases and they showcalc-alkaline characteristic. In other words, Eosene is represented by andesites with calcalkaline affinities. Petrochemicalcharacteristics of the Sarıcakaya volcanics indicate that they have been derived from the continental crust.Conglomerate-sandstone-claystonc-marl sequence of Paleocene age is covered by andesitic lavas during Eocenevolcanism. 

Abstract: Volcano-sedimentary serie is situated in peripheral parts of ophiolites of the mirdita zone. It isnormally set above the Triassic- Jurassic carbonaceous basement and is tectonically covered by the ultrabasic massifsof the ophiolitic complex.