Türkiye Jeoloji Bülteni

Abstract: In this study, Ostracoda fauna of three deepest drilling samples (Çanankkale Formation), which have been derivedrom line drills, certified foot place of Çanakkale Bridge in Kilitbahir region has been determined. in these circum--tances, 111 samples from claystone, sandstone and marl sediments have been paleontologically evaluated.As result of systematic investigations and determinations, 27 taxa belonging to 8 families, 10 genera have been`etermined. Two species are described new as Cyprideis dardanellesensis n. sp., Heterocypris kilitbahirensis n. sp.and`e others 25 species have been known. These determined ostracoda assemblages clear/y indicate the middle-late Panonian ages. This age determination have been correlated and supported by using the other fossil group (spor-polens,astropods and chara). Ostrocoda fauna obtained in this study clearly reveals the transitional (shallow marine, lagoon, fresh water) environment. Due to dominance of ostracoda species and lithological properties of studied samples, it can be concludedthat mainly brackish (lagoonal) occasionally fresh water and saline water (sea) affects were prevailed in the environment. In the chronostratigraphic nomenclature, stage names have been chosen from Paratethyan ones, as most ofostracoda species belongs to Paratethys bioprovince. 

Abstract: Organisms as carbonate producers in modern and ancient mavine environments were investigated in our countryrecentyears in detail because of preserving biochemical history on their shells. in this study, the relations amongfossil species, environmental conditions and modem geological anomalies were scarched throughly by dceermintng paieontologic, mineralogical and geochemical features of some modern foraminiferal shells. Foraminiferal tests collectedfrom two submarine sediment samples in İskenderun Bay were studied by whole-rock (XRD and AAS) and microprobemethods, and in this way elements being the cause of colorful on the shells were semi-quantitatively / quantitativelyneasured. ıı genus and 17 species of modern foraminifers were observed in these samples. Green, black, pınk, grayand yellow coloredparts are observed in the encountered foraminiferal species. Foraminiferal shells of Sample No. 36nainfy contain aragonite and Mg-calcite, less anhydrite, dolomite and quartz. Foraminiferal shells of Sample No. 125ire made up of abundantly calcite, Mg-calcite, aragonite and rarely dolomite, auartz and siderite. The richnesses inZu, Zn and Pb were determined although element concentrations of foraminifer shells show a variation in wide range.`t is explained that an abnormal contamination within the shells are caused by enrichments in the sea water ofionsransported with hot waters comingfrom active faults. Moreover, it should be expected that these elements are secondırily got rich during metabolism by livings. Mg/Ca ratios ofshells vary between 11.63 and 219.23. A temperature of11-51 "C arefound by setting up a relationship between Mg/Ca ratio of calcites in benthic foraminifers and sea-floorvater temperature. The anomaly in the sea-floor water temperature and richness in the concentrations ofsome elenents can indicate hydrothermal springs related to present fracture lines.

Abstract: The purpose of this study is to evaluate the flood potential, which can be considered as one of the mostimportant natural hazards, in Northwest Black Sea region. For this purpose, the parameters can be usedfor evaluating the flooding phenomena are taken in account with the aid of Geographical InformationSystem (GIS). Precipitation climatology, Digital Elevation Model (DEM), land-use and drainage networkcharacteristics are considered as input parameters. Potential flood areas are determined for a period of50 years. Northwest part of the study area is found as relatively susceptible to flooding according to theanalyses perfored.

Abstract: Menderes massif is commonly affected by extensional regime and a good example of forming a metamorphiccore complex. Simav detachment fault in the northern part of Menderes massif separated footwall and hanging wallrocks, which is thefeature of lithologic, metamorphism and deformation mismatch between them. The footwall consistsof medium-high grade metamorphites, pegmatoids andgranitoids. Schist-marble unit and ophiolitic melange comprisethe hanging wall. Neogene and Quaternary sedimentary and volcanic rocks lie both ımconformably and İn fault contact above the footwall and hanging wall rocks.Simav shear zone, characterized by deformed rocks below the Simav detachment fault, has two deformationalevents; these are ductile (mylonitic) and brütle (cataclastic) deformations. Ductile deformation event is the formation ofvariably developed mylonites in the footwall The degrees of mylonite development vary from protomylonite toblastomylonite. The majority of deformed rocks in the shear zone have mylonitic foliations and lineations. Myloniticfoliation is parallel and/or sub-parallel to the earlier foliation of metamorphic rocks. Mylonitic foliation is definedby preferred grain-shape orientation of biotite, muscovite and auartz ribbons. Lineation, other important element, isdefined by stretched auartz, and preferred orientations of feldspars, kyanite, hornblende and mica grains. The common kinematic indicators found in the zone is asymmetric porphyroclasts, mica fish, S-C and S-C fabric, recrystallizedoblique foliation, displacement grains and `V`-pull-apart fabrics. These asymmetric structures indicate a top-to-theN-NE shear sense. Recrystallization, neo-mineralization and other deformational features of grains in the shear zonesuggest medium-high-grade greenschist - amphibolite facies metamorphism conditions. Resent 40Ar39Ar isotopic dating implies that minimum age of shear zone is Oligocene - Early Miocene.Progressive stage of extension regime in the region constitutes brittle deformation that involves the development ofthe cataclastic zone below the Simav detachment fault and high-angle normal faults in later stage. Cataclastic zone,describing an area here affected by brütle deformation in the detachment fault of footwall, include breccia/cataclasitethat is product of mylonitic rocks of a variably fracturing, fragmentation, crushing, and alteration product. Exhumation of the northern part of Menderes massif was controlled by Simav shear zone. Structural, micro-tectonic featuresand izotopic data indicate that Simav shear zone is resultedfrom asymmetric exhumation of Menderes massif.