Türkiye Jeoloji Bülteni

Abstract: In Southwestern Turkey and adjacent areas, technical development is subdivided in three periods,namely Paleotectonic period, Transition period and Neotectonic period- The Transition period is characterized bya thick pile of molasse formations as in many parts of the Alpine orogenic belt. On the other hand, the Neotectonic period, which initiated locally at the end of Middle Oligocene time but regionally in Late Miocene to EarlyPliocene, is characterized by continental sedimentation, synsedimentary volcanism and the block-faulting developed under the control of tensional tectonic regime. The geologic events and the features representing the Neotectonic period in Southwestern Turkey and adjacent areas are a result of the tensional tectonic regime due to theAegean trench rather than the North Anatolian Fault- Because the region has been divided in many aseismicand seismic blocks bounded by the oblique type of normal faults.

Abstract: In this research, the odontology of Hipparion teeth of Eski Develiköy-Düzpınar biozone are investigated ,and stratigraphic results ,and environmental data are interpretated. As a result of this study, it has been confirmed that the Hipparion of Düzpınar kept their odontologic characters which appeared to resemble to those of the archaic North American Hipparion, For the age of biozone, the posibility of earliest Valesian is preferred.

Abstract: Results of the stratigraphic investigations on the magmatic and sedimentary rocks cropping out between Edremit and Korucu (Balıkesir) in Western Turkey have been presented and the origin of volcanic rocks o£the region have been discussed- The oldest volcanic sequence of the area is represented by the Bağburun formationwhich is probably of Paleocene-Eocene age. Magmatic activity continues with the Eybek and Kozak plutons whichare covered by the Hallaçlar volcanics of Upper Oligocene-Lower Miocene age and with the Dedetepe formation(Lower Miocene). This is in turn succeeded by the Ballıca formation (Middle Miocene), and Soma formation (MiddleMiocene-Lower Pliocene). The continental Neogene sequence ends with the Rahmanlar agglomerate of possible LowerPliocene age- From the point of view of regional geotectonic evolution and petrochemical properties, the Bağburunformation is derived from a subduction zone and may be assumed as an arc volcanism. The younger volcanicswhich are represented by the Hallaçlar and Dedetepe formations have been derived from the anatexis of thecontinental crust and they may be grouped as intracratonic volcanics. All these three volcanic phases show calc-alkaline characteristics.

Abstract: This work is carried on samples taken from wildcats drilled in Eastern Anatolia. The followinganalyses have been done on these samples : whole rock paragenesis, clay mineral paragenesis and its distribution,and calcite/dolomite ratio- From these results we tried to interpret the origin of petroleum.Illite is very rare or absent in all the investigated samples, so that we could not find the relationship between illite crystallinity index and burial diagenesis.The most abundant clay minerals are smectite, chlorite and kaolinites. The minor minerals are illite, disordered illite-smectite mixed layer clay minerals and corrensite.There are smectites in all the investigated samples of Pasinler-2 and 3 wildcat wells which are drilled in theErzurum-Pasinler basin. There results show that organic maturation is not reached in these levels.Similarly, there is smectite in all the investigated samples of Neftlik-1, 2, 3 and 4 wildcat wells which aredrilled in the Erzincan-Çayırh basin. These results also show that organic maturation is not reached in these levels.The clay mineralogical composition of samples of Tuzluca-1 wildcat well which is drilled in Kars-Tuzlucabasin shows that burial diagenesis is not completed in these levelsSamples taken from Hacilar-5, 6, and 7 wildcat wells which are drilled in the Malatya-Darende basin showthat there is a thrust fault in this area. This result is also confirmed by other geological investigations. There arepossible levels of reservoir rocks in all the investigated drillholes as indicated by calcite/dolomite ratios.

Abstract: The age-span of the genus Scandonea which was originally found in Italy by DE CASTRO in 1971as an individual of Miliolidae, is Turonian-Maastrlehtian. It is known,, from the publications and unpublished researches that various species of this genus are found in the Upper Cretaceous sediments exposed in various parts ofTaurids (Sultan dağları, Bey dağları, Geyik dağı, Korudağ) and in Western Anatolia {Bornova-îzmir).In Central Anatolia (Haymana-Ankara) however, the mentioned organism is found in various different stratigraphic levels of Paleocene aged Çaldağ Limestone- These specimens which are smaller and flattened comparedto the Upper Cretaceous forms, are found together with Laffitteina Mbensis MARIE, Miliolidae and Parachaetetesasvapatii PIA in. Montian and Lacazina sp,, Operculina sp.. Bolkarina aksarayi SİREL, Keramosphaera sp., Kathina•sp-, Planorbulfna cretae (MARSSON), Miliolidae and Parachaetetes asvapatii PIA in Thanetian.

Abstract: The rocks in the studied area consist of the metamorphic rocks of Menderes Massif and the Neogene aged sedimentary, volcano-sedimentary and volcanic rocks. The metamorphic rocks are unconformably overlain by the Neogene aged rocks. The rocks of Menderes Massif are represented by the following rocks : fine-grained sillimanite gneisses, the intercalated unit of the silDmanite-kyanite-staurolite-garnet schists, sillimanite-kyanite-staurolite-garnet schists and staurolite-garnet schists which contain muscovite-quartz schist interlayers, andthe marble with emery deposits. The pegmatoides investigated in the metamorphic rocks are classified in twogroups according to their mineral paragenessis as the kyanite-andalusite pegmatoids and the muscovite pegmatoids. Although the muscovite pegmatoids are observed in a wide-spread area, the kyanite-andalusite pegmatoids areonly found in the kyanite bearing schists. The kyanite crystals examined in the pegmatoids have been formed by aprocess of Al migration from the Al-rich country rocks during the metamorphism. The amount of kyanite in someof the kyanite bearing schists reaches economic concentrations. In the studied area, the metamorphie conditionsincreased from medium to high grade metamorphism.

Abstract: Samples of fluorite minerals collected from the northern part of Göktepe (Ermenek-Konya) Show Yvalues ranging from 2 to 23 ppm. It is suggested that the fluorite is derived from the formation waters and not ofmagmatic origin because of the very small and restricted range of Y values.

Abstract: The study area lies between Sarız-Şarkışla-Gemerek-Tomarza. Geyik Dağı Unit is situated in the southof the region and comprises a regular sequence ranging from Cambrian to Tertiary. This unit is relatively autochthonous with respect to allochthonous units.Allochthonous rock units of Paleozoic-Mesozoie age crop out towards north which preserve their primary properties,and are locally metamorphosed. These are: Kireçliyayla Nappe including Triassic-U- Cretaceous carbonates, Belören Nappe consisting of Triassic-Cretaceous rocks, Aygörmezdağ Nappe comprising a sequence from U. Devonian toU. Cretaceous, and Hmzırdağı Nappe consisting of metamorphosed Permian-L. Cretaeous rocks. The uppermostparts of some of these nappes are formed by the ophiolitic melange, and all the nappes are overlain by an ophiolitenappe. Emplacement age of the allochthonous units is Late MaestrichtianThe Tertiary formations unconformably overlying the allochthonous units crop out over extensive areas. ThePaleocene-Eocene formations to the nort of the region, which are olistostromal in character, indicate that thetectonic stability which prevailed after the emplacement of the allochthon was disrupted once again.

Abstract: Skarn rocks of the Akdağmadeni mining district are located on and around adamellite type graniticrock-regional metamorphic rocks contact. Skarn formations occur both within the granitic rock (endoskarns) and themetamorphic rocks (exoskarns).The character of the skarn alteration within the marginal zones of adamellite is closely related to the compositionsof the country rocks which are in contact with the adamellite. Endoskarns in contact with dolomitic marble have themineral assemblage of magnetite-pyroxene-phlogopite-and the usual silicates of adamellite. Alteration in the marginalzones of the magmatic rock, in contact with calcitic marble manifests itself as saussuritization, sericitization of feldspars and the presence of phlogopite.Exoskarns mainly developed within the carbonate rocks of the metamorphic rocks and show different features depending upon the composition of the parent rock. Field, petrographic, mineralogic and geochemical data indicate thatthe skarn alteration took place in different stages. In ca-.citic skarns four stages of alteration are identified; 1) M-ig*netit-garnet-pyroxene stage, 2) Epidote-amphibole stage, 3) Epidote-chlorite stage and 4) Kaolinite - muscovite-stageApparently conditions of these four stages overlapped, however mineral assemblages of each stage are still distinguishable and characteristic. It is understood from petrologic, geochemical and petrographic data that skarnizuigsolutions were iron-rich and gradually became aluminum rich and less hot in time and distance from contact. Activity of O2 was low and became lower probably due to temperature gradient. Activity of CO2 on the other hand wasmoderate and consequently neither wollastonite nor siderite and graphite formed. Mineral assemblages indicate thacthe formation temperatures for the alteration stages were; 600°C, 450-500°C, 400°C and 300°C respectively. The lowaO2 and moderate aCO2 despite such high temperatures and O2 and CO2 producing reactions, can only be exlained bythe escape of CO2 and O2 from the environment. Two step alterations occur in dolomitic marble which correspond tothe first three stages of the calcic skarns; 1) Spinel-forsterite-pyroxene-magnetite-phlogopite stage and 2) Serpentinealteration stage.

Abstract: In Southern Turkey, South-west of Antalya City, three of the measured sections (Teke Dağı, Saklıkentand Dömek Tepe) provide sufficient micropalaeontological base for future biostratigraphical studies. The Saklıkentsection comprises red or buff and grey biomicrite, both of which contain ammonites and conodonts. According tothe conodonts, it belongs to the Middle Triassie. The Dömek Tepe section consists of grey, mottled red biomicritewhich also contains conodonts. They indicate an Upper Triassie age. In the Teke Dağı, proposed as the type sectionof the Triassie rocks in Antalya, the succession is characterized by vermicular limestone and red calcarenite rich inmarine fauna (ammonites, conodonts, foraminifers... etc.) These Middle-Upper Triassie limestones are typical of Alpine-type Triassie and are thought to be pelagic sediments deposited on sea-mounts within ocean basins. In Antalyaseveral species of the Middle-Upper Triassie conodonts Crathognathodus, Cypridodella, DMymodella, Diplododella,Enantiognathus, Epigondolella, Glaiigonâolella, Meocavîtella, Neogondolella, Neohindeodella, Prioniodella, Prioniodiaaand Xaniognathus occur in this environment.