Türkiye Jeoloji Bülteni

Abstract: The Kızılcaören district is situated about 150 km. west of capital Ankara, is an unique LREE andthorium deposit of Turkey. The deposit is located on the eastern margin of the Karakaya formation between the Pontidebelt in the north and the Anatolide-Tauride platform in the south.The basement consists of serpentinites in late Paleozoic to early Triassic age, overlain by highly deformed andlocally variable anchimetamorphic sediments which are related to Triassic. Dominant Ethologies of Triassic formationinclude phyllite, sandstone, shale, slate and mudstones. This formation also contains limestone olistolithes of Permianage, diabasic dykes and lava flows with pillows. Standstone and massive fossiliferous limestone of Jurassic age overliethe Triassic formation. Late Oligocene intrusive activities produce carbonatites. Early Miocene extrusive activitiesproduce trachytic pyroclastic pyroclastics, trachytes and phonolites. Two different phase of carbonatite have been distinguished. The oldest ones occur as dykes up to 1.5 m. in widthand cut through the Triassic host rocks and ophiolities. Younger generation of carbonatites occur in the form of dykesranging in size 1-10 cm. and cut through the breccia pipes and veins.The deposit consists of bastnaesite-fluorite-barite mineralizations in economic grade. The mineralization ismainly hosted by anchimetamorphic sediments and rarely trachytic tuffs and breccia pipes. There are five breccia pipes inthe area which are formed by magmatic process. The mineralization consists of the infilling of radial circular and funnelshaped fractures and breccia pipes.Fracturing, brecciation and mineralization are associated with the late Oligocene carbonatite intrusions.Prebreccia mineralization is dominated by fluorite and barite. Post-breccia mineralization is dominated by REEmineral phases. Thorbastnaesite is the most abundant and widespread mineral phase.Minör phases are fluocerite andbrockite. Fluid inclusion studies suggest that early stage of prebreccia mineralization was between 550-300° and latestage 300-190 C°. The early stage of postbreccia mineralization was between 300-500 C°, whereas the final stage wasbelow 250 C°.The bastnaesite-fluorite-barite deposit of Kızılcaören is formed by the upwelling of the high temperaturecarbonatitic magmatic fluids (carbo-thermal fluids) guided by circular, radial and funnel shaped fractures, at lateOligocene-early Miocene time.

Abstract: The purpose of Ms study is to reveal `the statigraphy of the Tertiary sequence together with ostracodsand foraminifera» cropped out aroend tlıe Darende (Malatya). 20 genera and 28 species of ostracods were described fromthe sedimentary sequence in the Darende region. These benthonic and planktooic foraminifers, which compared with theother studies publicated in Turkey and Europe dealing with this subject» were found that they corresponded to Lutetian.Also ostracods and foraminifers indicated that Tertiary sequence was deposited under the conditions of shallow and dephtmarine environment

Abstract: A subalkaline volcanism of Upper Cretaceous age is extensively dominated in the eastern Pontides. However, the volcanism is changed to an alkaline and shoshonitic character at its terminal stages.

Abstract: In this study; some new observations are discussed on Cideina soezerii (Sirel) identified in the UpperMaastrichtian outcrops around the Niksar, Reşadiye, Koyulhisar, Elazığ and Malatya areas in Turkey. The tests surfacesof this foraminifer are ornamented by honeycomb shaped hexagonal hols, but notwith net like figures. This teststructure, trochospiral coiling and ombilical fillings suggest that this genus be identified in the Rotaliidae family, butnot in the Lepidorbitoididae family as assumed by Sirel (1991). Lectotype and paratypes are shown on plates.

Abstract: The area is Located at the northeastren section of the Eastern Taurus Mountains which is a part of theAnatolide-Toride platform. The Akdere basin presented in this paper is a typical example of a foreland-intermontanebasin. In general, foreland basins, resulting from the downward warping of the crust overlain by huge allochthonousunits (nappes) are of compressional in origin.The Akdere basin is surrounded by allochthonous units at its northern and southern margins. Thus, it differs fromthe similar compressional basins.Major unit exposed in the Akdere basin is the Middle Jurassic-Tertiary Geyikdağı rock assemblage. It consists offour lithostraüğraphic units, namely the Yüceyurt, Yanıktepe, Akdere and Demiroluk formations, The Yüceyurt formation (Middle Jurassic-Cenomanian) consists of platform facies such as dolomite, dolomitic limestone, foraminifer-algaepellet-intraclast-bearing mudstone and wackestones, The Yanıktepe formation is composed of rudist boundstonepackstone facies (Santonian-Campanian). The Akdere formation (Campanian-Paleocene-Lower Eocene) is composed ofsemi-pelagic facies, some carbonate fan deposit such as microbreccias turbidite of pelagic nature, pebble-bearing mudstones, calcarenite and channel cast conglomerate/breccia are also observed. The Demiroluk formation of Middle Eocene(Lutetian) age is composed of polygenic conglomerate/breccia, pebble bearing sandstones and marls. Facies changes inthe platform carbonates were resulted from lilting. In the same way, the fan deposits in the basin were accumulated under the control of a synsedimentary fault.The Akdere basin was formed an four stages. These are Middle Jurassic-Cenomanian stable platform stage, Turonian - Late Santonian flexural uplift and erosion, Late Santonian-Paleocene dismemberment of platform and formation ofa foreland-intermontane basin, and finally, Early Eocene deepening of the Akdere basin. 

Abstract: In the Şarkikaraağaç-Çarıksaraylar region, there have been found to be geological units of ages varyingfrom Paleozoic to Senozoic. Paleocoic aged the Sultandede formation at the basement is divided in  two membersnamed on the the Subaşı and Kocakızıl limestone members and is overlain with in angular unconformitiy by Mesozoicaged the Hacıalabaz formation. In the region, the age of the lateritized dolerites extending several kilometers in NW-SEdirection is thought to be Pre-Jurassic, and above all these units, Quaternary aged alluvium can be seen.Two kinds of barite mineralizations are observed in the north of the Çanksaraylar. One of these barite depositionis sülfide-bearing barite deposits. Seconds one is eluvial barite depositions developed from the first barite depositionwith external effects.The Çanksaraylar lead-bearing barite mineralization, is found within the metasediments, calcschists of theSultandede formation and the dolomites and limestones of the Subaşı member of the same formation, and in theboundaries of these lithologies as vein, lens and stratiform. The mineralizations deposited with various thickness (10-70cm) extend in NW-SE direction and dips towards SW and NE.During the ore deposition the occurrences of silicification, sideritization, ankeritization, dolomitization in thewall rocks of the lead-bearing barite deposits is a charecteristic feature associated with the mineralizations.Barite, galena, sphalerite, chalcopyrite, pyrite, tetrahedrite minerals are found as primary minerals in theparagenesis of the ore mineralizations. However, calcite, dolomite, siderite, ankerite and quartz are gangue minerals inthe deposits. In addition to these chalcocite-covellite, neodigenite, cerussite-anglesite, limonite, malachite and azuriteminerals are also found as secondary minerals occurred by the result of oxidation of sulfide-bearing minerals.The type of deposition, paragenesis, texture and alteration of the Çanksaraylar lead-bearing barite ores indicatedthat they are the hydrotermally deposited ores. However, second type barite deposition in the area is eluvial baritedeposits occurred from the first type barite deposition by the effect of external conditions.

Abstract: In this study, the geological and geotechnical properties of the rock units along the derivation tunnelalignment were evaluated before construction of the Güledar dam. The main two formations crop out on the tunnelalignment and its vicinity. Güledar formation in Triassic aged consist of volcanic and metamorphic rocks with thePermian-Carboniferous limestone blocks. Sirkeli Formation which overlay Güledar Formation unconformably, consistof weakly consolidated and unconsolidated conglomerate, sandstone and siltstone with clay interclations. Q andGeomechanical RMR rock classifications were made by using the geotechnical parameters evaluated from the rock unitsof the tunnel aligment. The different support categories have been proposed for the rock units of the derivation tunnel ofthe Güledar dam.

Abstract: In the south of Yıldızeli region mainly metamorphic and igneous rock of Akdağ massif and its cover rocks of Tertiary age are exposed.The varieties in metamorphic rocks reveal the existence of heterogenous metamorphism processes. This metamorphic suite has been intruded by some plutonic rocks in Pre-Eocene time. The regional metamorphism which isreached to a medium pressure/high temperature level, and the contact metamorphism caused by intrusion have beencompleted by the end of Late Cretaceous.The Akdağ metamorphic series are transgressively coverd by the units of Lutetian age in the south of Yıldızeli. Lutetian is unconformably overlain by the fluvial and limnic lithologies of Late Miocene time. As for the Pliocene rockunits which are exposed in throughout Kızılırmak valley at the south, are mainly represented by fluvial sediments andcover the older series unconformably. The Akdağ metamorphic rocks form a horst structure in the south of Yıldızeli and show normal faulted contacst to Lutetian and the younger units. The compressive deformational period had develeoped as a skin tectonics in the region after Lutetian time.

Abstract: The purpose of this study is to investigate the environmental features and stratigraphy, with ostracodefauna, of Tertiary sequence Karsantı Region (NNE Adana)In this study, 31 Ostracode genus, 5 subgenus and 31 species have been «identified from the Oligocene-Mddle Miocene age of detritic units cropped out the region. Neomonoceratina helvetica-Aurila soummamensis Zone,Gökçen (1984) has been defined from the Burdigalian-Lower Langhian by using of these species. This zone has been correlated within the previously-studied Tethys-Paratethys regions and with contemperary sequences deposited in Turkey.According to the ostracode fauna, various deposition environments that Early Oligocene is shallow marine, LateOligocene is continental/transition and Burdigalian-Early Langhian has shallow marine features are indicated fromOligocene to Early Langhian in the study area.

Abstract: Alkaline basaltic rocks of Quaternary age are dominant in the vicinity of Kula town in the Manisaprovince in Western Anatolia (Turkey). Tliese volcanics are represented by three distinct stages of volcanic activity. Thefirst stage forms I, I m. y. old flood basalts. The last stage occured about 20.000 years ago and are of cinder and spattercones, "aa" type lava flows, tuffs and tephras. "Base Surge" type bed forms have been observed around some maarvolcanoes of second stage and pirimitive human footprints are observed in third stage tuffs. Kula alkali volcanics arelocated within the Western Turkey Graben System which was formed as a result of the Aegean extensional tectonicregime. Abundant mantle xenoliths were brought up by the eruptions of the second and third volcanic activity periods.These xenoliths consist of olivine + kaersutite + apatite + cpx ± phlogopite ± sphene indicating modal metasomatismof the Subcontinental lithosphere. Strontium isotopic ranges for Kula basalts are 87 Sr/86 Sr= 0,7020 - 0,7035.According to petrochemical investigations there is no chemical difference between the lavas of all three stages and all thelavas are more alkaline. They derived from an alkali olivine basaltic magma and have a mantle origin. The lavas arepartly sodic and partly polassic. Their potassium content increase from first to third stage. The younger lavas are morepotassic then the old ones. Noble gas and helium isotopic composition in gas samples from the Kula volcanic provincewere measured and nearly mantle-derived helium was found in all the samples. The highest 3He/4He ratio was3,92x10*6. Volatile gasss including helium released from mantle or diapiric magma interact chemically with marinecarbonate in the crust and evolved carbon dioxide and radiogenic helium dilute the original magmatic gas. Therefore, it ispossible that Kula volcanism will be re-active and new alkali basaltic lavas will be formed in the future.

Abstract: The purpose of this research is the investigation of the paleontology and stratigraphy of studied area,located to the south of Hekimhan (Malatya, 1/25 000, feste).The oldest unit in this area is Ophiolites which is emplaced pre-Upper Cretaceous. Campanian-Maestrichtianaged flysch sediments overlies this Ophiolite unconformably. Yığma member, locating at the bottom of the Hekimhanformation codnsisting of conglomerate, sandstone, claystone and mudstone in 110 m. thickness. This unit overlivedconformably by sediments called as Çöreklik member in flysch facies. Reefal limestones area named as Kuşkayamember in 28 m. are located at the top this cequence.After investigation several samples taken from four stratigraphic sections which are measured from the flyschsediments, planktonic foraminifer zones have been classified as follows; Globotruncanita elevata (Campanian).Globotruncana area (Lower Mazstxichtian) and Rosita contusa (Middle Maestrichtian).

Abstract: This study investigates three-dimensional geometry of en echelon folds. To elicit the geometry,twenty-four fold azimuths were examined on twelve separate anticlines in the Los Angeles and Ventura areas. Field datashow that hinge azimuths of en echelon folds deviate to new orientation and acquire smaller angles to the sheardirection. The change in orientation of the fold azimuths is interpreted as the consequence of difference in duration ofdeformation and physical parameters between the levels studied.

Abstract: The oldest unit exposed in the study area is the Gürgendağ Yayla formation of Liass-Dogger agecomprising of weatheret purble colored basalt, andesite and their pyroclastics. This formation is conformably overlainby pyroclastics. This formation is conformably overlain by massive and thick-bedded limestones of the Berdigaformation of Upper Jurassic-lower Cretaceous. The Berdiga formation is inturn unconformably overlain by the Düzköyformation of Campanian-Maastrichtian age wich consist of andesite, basalt and dacite lava and their pyroclastics. Thisformation grades upward in to white colored limestone and marl intercalations of the Tonya formation ofMaastrichtian-Danian age. The Foldere formation of Lutetian age consisting of andesite, basalt lava and pyroclasticswith sedimentary intercalations rests disconformably on the Tonya formation. All these units are disconformablyoverlain by the Karadağ formation of Mio-Pliocene age comprising olivine-augite basalt and its pyroclastics. 

Abstract: Metamorphic basement complex are unconformably overlain by the Triassic Dışkaya (Karakaya) formation which is intruded by the Paleocene Çataldağ granidiorite unit. Lower Miocene andesite-aglomera and tuff unitrest top of all these older unit with unconformity, Midle-Upper Miocene sediments overly all the older units, and contents in ascending order, basement conglomarate, lower limestone, sandy claystone and upper limestone units. According to the petrographic studies, metamorphic basement complex are composed of amphibolite and quartz -muscovite schist, whereas Dışkaya formation are composed of neomorphic limestone blocks, shale and lithareniüc sandstones, Sandstones taken from basement conglomerate unit show feldspatic litharenite composition.Boratiferous gypsum beds varying 10 to 15 metre in thichnesses, occur within the sandy claystone unit. Nodularpandermite and howlite minerals are present within these gypsum horizons. Chemical analysis shows that pandermiteand howlite minerals have 46.49% and 40.69% B2O3 mean values respectively, It is estimated that the reserve of theSultançayır borate deposit is approximately 1 million metric tons. Howewer, a great amount of this reserve was minedout by the French and English companies during the period between the years of 1865 and 1955. In addition, probabledistribution of gypsum beds are determined and 300 million ton geologic reserv arc calculated. These gypsum beds have34% SO3 mean value and the properties of gypsum beds are suitable for the cement industry.