Türkiye Jeoloji Bülteni

Abstract: Thin bedded limestones covering large areas in the west of Darende and in the southwest of Gürün (westof Malatya) are found to be Lower Priabonian in age. A new species of foraminifera, Eoannularia conica n.sp. occurringin these limestones is described.

Abstract: The study aims to give a geological approach to the environmental problems of the Ortahisar town. Themajor problems encountered include the rockfalls from the castle, which symbdlizes the town ,and the possible failure ofthe roofs of the caves dwelled for accomodation purposes. The dominating- rock types of the area include the ash-flowtuffs ,and the pumice flows of Neogene age. The castle, which is made of the welded portions of ash-flow tuffs, had almostlost most of its strength due to excessive dwellings ,and now acts as a potential hazard for the buildings that surround it.For this reason, a fallout area is established around the castle ,and the levelling of this area is proposed. In order to avoidthe jump of the falling blocks, the fallout area must be covered with a blanket of pumice flows. The major causes of cavefailure include the seepage of rain water ,and the accumulation of small ponds on the floors of the caves, the runoff ,andthe surcharge load exerted by the newly built houses on topof the caves. It is thus necessary to drain the caves, to sealthe fractures to prevent seepage of rain water, to collect ,and canalize the runoff ,and to support the roofs of some caves.

Abstract: Systematic study and stratigraphic distribution of the species mentioned below of Alveolina, Nummulites,Ranikothalia and Assilina, collected from the south of Polatli (SW ANKARA), are given.Thanetian: A, (Glomalveolina) primaeva Reichel, A. .(Glomalveolina) pilula Hottinger, A- (Glomalveolina) telemetensisHottinger.Lower İlerdian: N. exilis Douville, A. cucumiformis Hottinger, A. ellipsoidalis Schwager.Middle ilerdian: A. blumenthali Sirel, A. pasticillata Schwager, A. avellana Hottinger, A. aragonensis Hottinger, A. moussoulensis Hottinger, A. minervensis Hottinger, A. ellipsoidalis Schwager, A. ankaraensis Sirel, A. laxa Hottinger, A.leupoldi Hottinger, A. aff. ciafaloi Checchia _ Rispoli, A. pisiformis Hottinger, A, corbarica Hottinger, A. subpyrenaicaLeymerie, A. ilerdensis Hottinger, A, varians Hottinger, N. atacicus Leymerie, R. couisensis (d’Archiac).Upper ilerdian: A, polathensis Sirel, A. sakaryaensis Sirel, A. decipiens d`Orbigny, A. rotundata Hottinger, N. murchisoni (Rütimeyer), R. nuttalli (Davies).Lower Cuisian: A. haymanaensis Sirel, A. oblonga d`Orbigny, N. planulatus (Lamarck), N. leupoldi Schaub, A. place.itula (Deshayes).Middle Cuisian - Upper Cuisian?: A. aff. lehneri Hottinger, A. aff. riitimeyeri Hottinger, A. aff. rugosa Hottinger, A. canavarii Checchia _ Rispoli, A. bayburtensis Sirel. 

Abstract: The rock units cropping out in the investigation area form two associations differing from each other bytheir stratigraphic and tectonic properties. The units are termed Ophiolitic melange and Other formations.The investigation area consist of a coloured melange including olisthostromes and blocks of various lithology andsize with an age between Middle Permian and Maastriehtian, Bloke and olisthostromes are emplaced in a matrix mostlycomposed of voleanies (diabase, spilite, dolerite, ignimbritic tuff, vitric tuff) and partly of sedimentary rocks(graywackes, clay, marl, radiolarite and pelagic limestones with aboundant Badiolaria). The minimum age of thismixture (coloured melange) is Maastriehtian and all of its members are of marine origin.The rock units forming the coloured meloured melange are covered by marine Miocene sediments. The Miocenesediments (polygenic conglomerates, sandstone, sand, silt, clay, marl, reef limostone, sandy limestone) showing laterallyand vertically gradation to each other and composing of different thicknesses and lithofacieses and also lacustrinePliocene limestones unconformably overlyines the Miocene sediments have been termed as Other formations. 

Abstract: Formations of Devonian, Middle Permian, Late Jurassic, Late Cretaceous, Lutetian and Miocene age Croppout in the investigation area. The Devonian consists of conglomerates, dolomitized limestones, quartzites and clayschist;The Middle Permian is composed of pisolitic-oolitic limestones; The Upper Jurassic formations consist of limestones anddolomitized limestones; The Upper Cretaceous is represented by pelagic limestones and serpentinites of melange character.The Lutetian transgressively covering the above mentioned formations is represented by a brecciated limestone outcrop.These rock units of an age between Devonion and Lutetian, and various lithology, constitute the Basement rock units inthis region.The Miocene sediments overlying the Basement rock unitsj as transgressive and grading in to each other vertically andlaterally are represented by polygenic conglomerates, sandstones, marls and reef limestones. Five planctonic foraminiferalblozones, which three of them of Burdiga`ian age, the others two of Helvetian to Tortonian (?) were defined in theseformations

Abstract: The Hırka diatomaceous earth deposit from Taşhan formation in the north of Kayseri (Central Anatolia)is Lower Pliocene age. Chemical analyses have been performed for quality tests and study of the origin. The results ofthe mathematical correlations show three element-assemblages in opal-, carbonate-, and detritic minerals (clay-minerals,plagioclases and others from volcanics) groups. Montmorillonite minerals are identified in diatomaceous earth layers.Based on paleogeography, distribution of the flora and clay minerals and on siliceous concretions, the origin of thedeposits is explained with silica - rich, postvolcanic springs and silicate alteration.

Abstract: Ergani (Maden) copper mineralization which takes place in "Ophiolitic Belt" of "Taurid Tectonic Unit" inSoutheastern Turkey, show some similarities to the Cyprus type of deposits assumed to be formed at sites of sea-floorspreading. The occurence of so many different ore minerals in Anayatak ore body and their puzzling relations to eachother, indicate that during and after mineralization equilibrium conditions changed continuously and the area was affected by drastic geological events. Interpretation of data reveals intensive marine volcanism and extensive tectonicdeformation have been taken place during and after mineralization. Such conditions, in the light of today`s tectonic understanding, may occur at sites of sea-floor spreading and deposits for med at such places may outcrop on the mainlanddue to later obduction. With the data at hand, it is assumed that Ergani copper mineralization is a Cyprus type deposit,formed at site of sea-floor spreading and pushed on the mainland by obduction. 

Abstract: Akseki Plain is a small intramontane basin located at the north of Alanya in the highest part of TaurusMountain Range. This plain is a polje as far as the geomorphological characteristics are concerned. Compared with itsnearest surroundings the geological structure of this polje shows close similarities to the intramontane plains whichare various in number and size at the central and the West Taurus. Almost half of the polje basin is surrounded byboth the karstic pure limestones of the mesozoic age and an old Paleo-Eocen flysh formation which doesn`t show anyevidence of karstification. The floor of the polje is covered by a thin alluvial soil. In a large pat of it the eroded headsof the beds of flysh marn and limestones are expodes; even in a small part, mostly in marginal areas, the formation ofkarstic island hills has been observed (hum). Although surface drainage is effective in a small part of this polje, thelarger pat is drained by ponors lying in the South and the West. In some areas where ponors are found surroundinglimestone mountains of polje are steeply sloping. In the same areas it is generally noticed that the chemical solutionhas continued progressively and still continues. As a result of this study it is found that there are many factors in theformation and the developement of Akseki Polje. Of which the most important one is the mechanical erosion and thecarrying capability of the rivers, yet the tectonic movements in part and the carstic solutions in some small areas aoreeffective. 

Abstract: In many aspects, the San Andreas and the North Anatolian fault zones show many similarities. Fromthe geological point of view, as the San Andreas Fault in California, the North Anatolian Fault Zone is one of the estknown structure of the world. They are similarly right-lateral, strike-slip faults, at the same time, are transforms.They are of Late Miocene - Pliocene in age (10-12 m.y.) and are about 1100 - 1600 km long. Their zonal widths (0.5 - 10km) are in the same order and magnitude. Although sense of their strike-slip movement is principally right - lateral,they have a lef t-lateral branch (The Bast Anatolian Fault of the North Anatolian Fault and the Garlock Fault of theSan Andreas Fault). However, they vary in the maximum amount of lateral displacement and show different topographic features. The maximum offset is nearly 300 km along the San Andreas Fault whereas it is approximately 85-90km along the North Anatolian Fault. As far as the physiographical characteristics are concerned, The North AnatolianFault Zone is more spectacular than San Andreas Fault. 

Abstract: Systematic description of the species of Nummulites have been studied in the marine Oligocène sediments of Kırklareliregion (North of Thrace), in the otherhand the stratigraphy of the region is given shortly.The rock units of Paleozoic and Paleogene ages crop out in the region. Paleozoic (Lower Paleozoic) sequence is composed of metamorphic rocks. The Paleozoic rocks are unconformably overlain by the sandy and algal limestones of theLutetian? age. Algal limestones contain genera of the Foraminifera such as Discocyclina sp., Rotalia sp., Priabonian sequence conformably overlies the algal limestones of Lutetian (?) age, it is composed of sandy limestones and it ischaracterized by the species of Foraminifera such as Nummulites fabianii (Prever), Chapmanina gassinensis (Silvestri), Fa.biania cassis (Oppenheim), Discocyclina sp., Asterocyclina sp. and Queraltina sp., Lower-Middle Oligocène sequence conformably overlies the sandy limestones of Priabonian age. It is composed of clayey limestone. Oligocène sequence containsabundant Nummulites species, such as Nummulites intermedius (d`Archiac), N. fichteli Michelotti, N. vascus Joly andLeymerie in large amount. 

Abstract: Deposits ranging from Upper Cretaceous (Maestrichtian) to Lower Tertiary in age crop out in Haymana - Polatlı region. At the base of these deposits there are Temirözü, Mollaresul, Dereköy Formations which are outof scope of present study. The formations, starting from Maestrichtian are as follows: Haymana Formation (Maestrichtian) is in flysch faeies, and 1850 m thick. Maestrichtian aged Beyobasi Formation is represented by coral sandstonesand conglomerates and 125 m thick. Çaldağ Formation (Montian) which is represented by algal limestones and 1187 mthick, crops out near Haymana. In the North, West and South of the region, this unit shows interfingering with redcolored Kartal Formation, and in the Southeast of the region wedges out to Yeşilyurt Formation which contains limestone .blocks. Thanetian aged Kirkkavak Formation is represented by algal limestone and black marls and 640 m thick.Ilgmlikdere Formation (Ilerdian) is in flysch facies and. 350 m thick. Eskipolatli Formation (lower parts Herdian, upperparts Cuisian) consists of marls with sandstone and limestone and limestone bands. Cuisian - Lutetian aged ÇayrazFormation consists of sandy limestones with abundan NummuUtes. This unit is equivalent to Beldede Formation (conglomerates, marls, limestones) in the North and West, and to Yamak Formation, which is in flysch facies, in the Southeast of the region. Neogene overlies all these formations unconformably. The thickness of the Upper Cretaceous -Lower Tertiary deposits is 5800 m in the region. Deposition was continious with the exception of the local unconformitybetween Çayraz and Eskipolatli Formations in the North of Haymana. Lateral and vertical facies changes are abundant. Interpretation of the facies studies shows that there existed a semicircle-shaped shelf near Haymana; Çaldağ andÇayraz Formations are deposited on this shelf. Behind the shelf partly continental units, Kartal, and Beldede, and infront of the shelf flysch units, Haymana, Yeşilyurt, and Yamak were deposited. Throughout Late Cretaceous - EarlyTertiary times, Haymana - Polatlı basin is believed to be joined with the Salt _ Lake basin toward the Southeast, andflysch deposits are accumulated in this part of the region. This shows that the North and West parts of the regionwere filled with sediments and were uplifted afterwards. 

Abstract: The analcime bearing pyroclastic rocks »situated at 45 km SW of Karaman (Konya) are interbedded within the rocks of Cretaceous age which have a thickness of approximately 600 m. These pyroelastites, formed by volcanicactivity, show a normal graded bedding. Their classification is based not on the size of the fragments, but the compositional properties of them.By XRF analysis, it has been found that these rocks contain Na2O in quantities higher than normal, and were probably rich in terms of volcanic glass. It is possible that this oxyde has entered in the composition of the pyroclastitesby chemical action of the sea water - probably metasomatic processes. In the first of two stages of transformations thattook place later, the analcime, which is the mos characteristic mineral of the pyroclastites, was most likely formed bydiagenesis of volcanic glass. Subsequently, a low grade metamorphism corresponding to the upper most part of zeolitefaeies occurred. In fact, the analcime is partially - totally transformed in a secondary albite in which relicts of theformer mineral can often be observed.