Türkiye Jeoloji Bülteni

Abstract: Gördes pegmatoids are the veins with the strikes of NE-SW and E-W, Eventhough their width is not more than 30m, their length can be several kilometers. They have very plane mineralogical composition. They contain Na-feldspar+Kfeldspar+quartz+muscovite+biotite+turmaline and garnet. E-W directional pegmatoid veins also additionally include the rarelyfound beryl. They are ordinary pegmatoids without zonetion. Pegmatoid veins with NE-SW and E-W direction present distinctions in terms of mineral and trace element contents, homogenization temperatures and salinity values of fluid inclusions ofquartz. K-feldspars of NE-SW directional pegmatoids contain higher amount of Ba, Sr respect to E-W directional pegmatoids,but lower degree of Rb/Sr rations. The both of vein groups had not very well defined fractional crystallization and NE-SW directional pegmatoid veins relatively formed earlier than the other. Albite-oligoclase composed plagioclases, and orthoclasemicrocline structured K-feldspar are dominant in the NE-SW directional pegmatoids and in the E-W directional pegmatoids respectively. K-feldspars of both pegmatoids veins are on the orthoclasemicrocline transformation boundary, and show as well asmonoclinic and hightriclinic symmetry. According to the equilibrium diagram of alkali feldspar, minimum formation temperature of K-feldspars are thought to be about 450-500°CIn quartz fluid inclusions of the NE-SW directional pegmatoids, 7-8%, 9-10 % salinity (Nacl) and 500-520°C formationtemperature, on the other hand in quartz fluid inclusions of the E-W directional pegmatoid veins 9-10%, 12-13% salinity and500-560°C formation temperature were obtained.The NE-SW directional pegmatoids can be exploited for muscovite, feldspars and to get beryl as by-product. It is mostlikely possible that these veins can contain 2053 tons of beryllium reserve.

Abstract: The Yalvaç-Yarıkkaya Neogene basin is located within the Isparta-angle which is known as common regionalstructure of Southwestern Anatolia. The pre-Neogene rock units around of the basin consist generally of meta-Sediments, carbonate rocks and ophiolite complex ranging in age from Ordovician to Cretaceous. The Neogene alluvial and lacustrine depositsoccurring in Yalvaç-Yarıkkaya basin are divided in ascending order; Bağkonak, Madenli, Yarıkkaya, Göksöğüt and Kırkbaş Formations. The total thickness of the Neogene sedimentary sequence of these basin is about 800 m.The Bağkonak Formation is composed of coarse-grained and poor-sorted conglomerates and mudstone intercalations, whichindicate an alluvial-fan origin. The maximum thickness of this unit is approximately 250 m. The Bağkonak Formation rests unconformably on the pre-Neogene basement rocks and letarally interfinger with Yarıkkaya Formation toward to the center partsof basin.The Madenli Formation consists of cross-bedded sandstones, channelfill conglomerates, and above in the section, mudstoneand non-economic lignite seams which are characterized the fluvial environment. The clastic sediments of the Madenli formationare transitional laterally and vertically with the underlying Yarıkkaya Formation toward to the northern part of basin. The Madenliformation have 250 m total thickness and rests unconformably on the ophiolitic basement rocks in the southern region of basin.The Yarıkkaya Formation comosed of an. alternation of calcerous shale, clayey, limestone, marly and mudstone, which areindicate the lacustrine environment. The total thickness of the unit is 200 m at the type locality, and grades laterally in Bağkonak and Madenli formations to the northern and southern margin parts of basin.The Göksöğüt Formation consists from bottom to top of coarse conglomerate and porous lacustrine limestone. These unitoverlies conformably on the Yarıkkaya Formation. The total thickness of the Göksöğüt Formation increases to the southernpart of basin and exceeds 150 m.The Kırkbaş formation consist mainly of reddish and poor-sorted conglomerate and mudstone intercalations which appear tobe alluvial-fan origin. These unit is wide-spread in the northern part of basin and overlies unconformably on the all old units.The Yalvaç-Yarıkkaya basin is limited by the normal faults and pre-Neogene hihg mountain belts, are resemble to a triangular shape close-basin. In the basin the lateral lithofacies changes of the sediments and geometric features and distribution of thedepositional environments, indicate the Yalvaç-Yarıkkaya Neogene basin have a typical inter-mountain basin character.

Abstract: The Palu Formation of Pliocene-Quaternary is found to the north of East Anatolian Fault Zone and Palu Anticline axis.Hacımekke and Avlağı villages in the north are surrounded by alluvial fan deposits and these deposits grade in thebraided river deposits to the south.Alluvial fan deposits consist of conglomerates and poorly sorted, pebbly sandstone with muddy matriks and show normal and reverse grading. Braided river deposits display two different depositional models. The Donjek type braided river deposists mainly consist of ibricated and organized conglomerates and through cross-bedded sandstones. These facies pass upwardsto te poorly sorted disorganized conglomearetes and sandstone layers of Scott type braided river deposits.Interrelations of the Donjek and Scott type facies show that tectonism was strong in the area during the PlioceneQuaternary period.

Abstract: The purpose of this study is to reveal the Neogenestratigraphy dependent upon foraminifer and ostracode fauna.In the region, 29 planktic foraminifer species were determined in the Lower-Middle Miocene and the following biozones wereestablished in the Burdigalian-Serravallian interval :Globorotalia mayeriOrbulina suturalisPraeorbulina glomerosa curvaGlobigerinoides trilobusHaving compared these zones with the previous results obtained in the region Mediterranean. New Zeland. Nord Karabian, Antalya-Korkuteli, Antalya-Mut-Adana Basins, Silifke Region and Tropical Zone, the similar results were seen. It wasindicated that the sea level change deeper to shallow from time to time in the Burdigalian-Serravalian by considering envirenmental characteristics of foraminifer and ostracode fauna.

Abstract: In the present investigation, The Upper Miocene biostratigraphy has been recognized in an area ofabout 100 sq. km. between Incipinan-Kurtkuyu west of Sinop Peninsula.The examination has been carried out at 106 samples, taken from four measured stratigraphic sections and twodrill-hole logs. In the Miocene sequence of the region with about 500 m of thickness representing, the marine and upward the continental transitional environments have been recognized five ostracode biozones.The choronostratigraphy of Neogene in the region using the stratigraphic distribution of characteristic ostracodesin the biozones of Turkey and other Tethys and Paratethys basins has been determined. Therefore the sequence at thebottom has been deposited during Meotian and the upper part of the sequence has been formed during Pontian. MarineMeotian deposits which has characteristic of the Tethys and Paratethys bioprovince has been determined and fresh waterPontian deposits which has characteristic of only Paratethys bioprovince has been established. 

Abstract: The Çaybağı formation (Upper Miocene-Pliocene?) which lies on E-W direction in the east of Elazığ, has beenfirstly recognized in this study. This formation mainly consist of conglomerate, sandstone, mudstone, coal interlayered claystone tuffite and limestone. It`s measuramble thickness is about 700 metres. To its sedimentary properties ten lithofacies havebeen recognized and grouped as lithofacies association. This lithofacies associations display of meandering river, braided riverand lake deposits.The braided river deposits consist of very coarse grained, poorly cemented,, trough cross-bedded sandstones whichbears red conglomerate lenses in some places. Meandering river deposits contain cannel fill, point bar and flood plain subassociations finning upward cycles. The lake deposits comprise marls with coal laminations and limestones including freshwater fossils (Unio indet). 

Abstract: The systematic investigasion of species of Cayeuxia, Lithocodium and Marinella of the Codiacea has beenconducted in the study area. Some of these fossils have been found in this area for the first time in Turkey. The similarities anddifferences between our result and those of earlier workers in stratigraphic disribution of algae have been put forth.