Türkiye Jeoloji Bülteni

Abstract: The thick Miocene clastic sedimentary sequence (up to 1000 m), which overlies the Bey Dağları andSusuz Dağ carbonate massifs in SW Turkey is defined here in terms of modern stratigraphical usage.The succession which in some areas spans Lower Miocene (Burdigalian) to Upper Miocene (Tortonian) comprises dominantly terrigenous clastic sediments derived from two allochthonous ophiolites, the Antalya Complex inthe east and the Lycian Nappes in the west.Three formations and several members are recognised within the Karakuş Tepe Group, which encompassesthe entire succession.The Salir Formation records the tectonic emplacement of the Antalya Complex on the sedimentary basinfrom the east. Lower Miocene sedimentary sequences, deposited on a submarine fan, become more distal westwardsaway from the Antalya Complex. The sequence is terminated in the Middle Miocene by a thick conglomerate unit(Bağbeleni Member) deposited on an alluvial fan.The Kemer Formation records the emplacement of the Lycian Nappes from the northwest. Lower Miocenesediments pass from alluvial fans in proximal areas, close to the Lycian Nappes, to small submarine fans in distalareas.The Kasaba Formation, deposited on a terrigenous alluvial fan, marks the final stage of emplacement of theLycian Nappes and infilling of the sedimentary basin during the Upper Miocene.The sequence taken as a whole records the emplacement of two allochthonous ophiolites onto a subsidingcarbonate platform. Subsidence was followed by a regressive marine sequence which culminated in terrigenousalluvial deposits.

Abstract: At Köprübaşı most of the uranium deposits occurring in tabular lenses in conglomerates and sandstones of the Neogene alluvial fan are oxidized. These deposits can be divided in jarosite - vaylandite - rich andilmenite - magnetite - rich types both of which occur near exposures of metamorphic basement rocks. The unoxi-•dized uranium deposits are called as pyrite - siderite - rich type. Uranium is disseminated in the matrix of conglomerates and sandstones.Uranium contents found by laboratory gamma - ray spectrometric measurements are mostly much higherthan those found by fluorimetric analysis. Radiometric uranium contents (eU) in most deposits are 30 to 40 % greater than those of chemical uranium (U). Thorium contents found in the same deposits range between 40 to 340ppm.Therefore, ore grades in the deposits obtained by the gross gammabore hole techniques are, in fact, the total of radiometric uranium (eU) and thorium contents. Under the light of these data, the reserves of the uraniumdeposits in the Köprübaşı area must be reconsidered.

Abstract: The investigated area is located at the Elmadağ region (east of Ankara). The aim of this investigation is to establish the problematic age of the Elmadağ formation. This formation is composed offlysch - like sediments and limestone blocks of Carboniferous - Permian - Triassic age which were transportedby gravity - tectonics in the flysch - like sediments. Elmadağ formation shows a single - type flysch - like lithology (only clastic rocks), which, by means of sedimentologic features, can be subdivided in three members. Thesethree members are named from bottom to top as Arabıntaş member, Çakıllıdere member and Devecioğlu member,respectively. Elmadağ formation interfingers with Döşemedere formation which consists of basalt and spilitic basalt.The Irmak formation, an ophiolitic complex, overthrusts on the Elmadağ formation. According to our findings,the minimum age of the overthrusting of Irmak formation on the Elmadağ formation, can be given as UppermostCretaceous.The author, has identified the Werfenian - Hettangian age by the determination of biota and the microfaciesin the limestone pebbles of the fluxoturbiditic conglomerate bodies found within the Elmadağ formation. Accordingly, the age of Elmadağ formation should be Lower Jurassic (Lias) younger. 

Abstract: In the study area, galena - bearing barite occurrences in rocks of Permian age, are sedimentary inorigin. Despite the occurrences were affected by regional metamorphism, strongly repeated tectonic movements andkarstification, they show enough evidences of sedimentary structures. Barites are either stratiform or vein - like.Barite veins in sedimentary deposits are related to transport during karstification and the effect of diagenesis together with syntectonic movements. According to data obtained in this study, the ore deposits do not have any direct connection with magmatic activities.The origin of ore - forming metal ions can be explained by NaCl - rich formationwater in sediments or by direct selective precipitation rather than by an exhalative - sedimentary mode of formation. 

Abstract: Alkaline basaltic volcanism took place in three different phases during Quaternary in WesternAnatolia around Kula (Manisa). These volcanics were possibly derived from a hot spot over the mantle risingthrough a plume where graben type tectonics were active. «Base surge» bed forms have been observed around somemaar volcanoes of Kula. Base surge density flows produced by shallow, explosive steam eruptions are turbulent mixtures of steam and solid ejecta. Depositing currents originate within the craters and sweep outward at high velocities. Definition of «base surge» bed forms is given through brief descriptions of morphologic, geologic and petrologic features of Kula volcanics. 

Abstract: The teeth material of the Hipparions recovered from Gülpınar (Çanakkale) vertebrate fauna has beenstudied. The odontological and biometric specularities of the material indicate the presence of the species of Hipparion matthewi, Hipparion mediterraneum and Hipparion sp.. The relations between the odontological features andnutrition habitus suggest an intermediate environment between forest and steppe, or a savannah. A Turolian age issuggested on the basis of odontological evolution of Hipparions. 

Abstract: The mathematics governing most of the data processing operations on gravity and magnetic geophysical data is identical to that which describes the behaviour of electrical filter circuits. It is more convenientto sho™ physical values which varies with time or space, frequency or wavenumber domain to carry out operation: on them. Convolution operation is to obtain filtered output data from input data by folding backward and multiplication with filter operators. The filter operators for every kind of filters, analytical continuations and derivatives can be obtained after determining frequency responses from Fourier transforms. The important phenomenonfor all operations is to determine frequency responses in frequency or wave - number domain. The measured potential field includes effects from all bodies in the vicinity. The effects from different sources can be separated withdata analysis up to a point. Interpretation would be improved if they could be separated and examined one by one.The regional gravity and aeromagnetic (flight height is 700 metres) maps were analysed with the above mentioned techniques for the region between 32°-33° E and 39° - 40° 30` N coordinates around Ankara - Polatlı area.The main structural trends were found to be NE - SW. In the south of the region, the deeper structures were foundto be trending NW - SE. 

Abstract: The Campanian - Lower Maastrichtian Elazığ volcanic complex outcrops along the northern margin of the Bitlis suture in the Elazığ - Malatya region. A traverse from Sivrice to Elazığ reveals that it comprisesa large north dipping, internally imbricated thrust sheet composed of three units from base to top: 1. Gabbro, diabase, and basalt with siliceous intrusives metamorphosed to the lower greenschist facies, 2. Augite andesite volcanics and volcaniclastics with siliceous dikes metamorphosed to the prehnite - pumpellyite facies, 3. Unmetamorphosed andesite, hornblende andesite flows cut by mafic dikes, andesitic volcaniclastics, and pillow basalt cut bysiliceous dikes. The nature, distribution, and relative proportions of these lithologies suggest that the Elazığ volcanic complex represents a primitive ensimatic island arc.

Abstract: Erzin and Dörtyol plains are surrounded by Upper Cretaceous Ophiolite series in the east and Kuzgun formation of.Miocene age in the north. The latter consists of sandstones and conglomerates with occasional marlintercalations. The Pliocene conglomerates also containing thin layers and lenses of marl (Haydar formation) constitute the basement of the plains. In the north and northwest of Erzin plain widespread outcrops of Delihalil formation, represented by olivine basalts of Quaternary age, is observed. Caliche, alluvial cone deposits, coastal dunedeposits, and alluviums represent other Quaternary occurrences.Within the plains, which reveal typical features of a graben valley, the groundwater occurs under unconfinedaquifer conditions. The hydraulically connected Haydar and Delihalil formations constitute the major aquifer. Thehydraulic conductivities of Haydar and Delihalil formations range between 10-30 m/day and 50-150 m/`day, respectively. The latter supports numerous productive wells having specific yields of 10-100 lt/Sec./m.

Abstract: Öztürk ve Koçyiğit (19E2) de kanımızca bazı yanlış yorum Ye belirlemeler yapılmıştır. Söz konusu yayında yazarların birimlerin kökenleri, birbirleri ile ilişkileri konusunda ileri sürdükleri görüşler eldeki, verilerin yetersizliği nedeniyle halâ farklı yorum ve kabullere olanak tanımaktadır... Ancak birimlerin yaşları konusunda aşağıda belirtilendüzeltmelerin, yapılması ilerde yapılacak, çalışmaların doğru yönlenebilmesi bakımından gereklidir.