Türkiye Jeoloji Bülteni

Abstract: This study is aimed to establish the depositional model and fades properties of Upper Cretaceous Carbonate apron sediments in the Akdere Basin, at Eastern Taurus (Gürün - SW Sivas). In the area, 2 - 7 m thick and km`s in length; resedimented calciclastic deposits and not including channel systems which are parellel to the basin slope - platform margin are present in tlie Akdere Basinslope developed as a result which as a result of partly collapsed and subsidence of carbonate platform during the Late Cretaceous.These deposits are an example of carbonate apron model which is an alternative to the submarine fan models of the siliciclastic deposits. These mainly consist of materials derived from platform margin rudistic reef buildups. The thin bedded - laminated limestone and marl is observed in the area of platform margin, whereas, in the basin slope thick conglomerate I breccia levels and intercalatedcalcarenites are encountered within basin, clayey limestone and marl dominated lithologic assemblage transitional with basin - slope units are present. The one or more of these rock units make upper slope, apron and basin fades assemblages. Syndeposition altectonism, low stand and highstand in sea level changes effectively controlled the deposition. Due to continued faulting of platform margin and basin slope and increased slope amount, the materials derived from platform margin rudistic buildups resedimented inthe basin slope, in the form of calciclastic sequences. Although these type of sediments sliould form the submarine fan, due to highslope amount, they are deposited as subslope areas. These sediment fills are inter fingering with basinal, basin slope, sedimentarydeposits and comprise the pelagic mudstone - wackestone, conglomerate I breccia, bio - lithoclastic packstone - grainstone fadesand mudstone fades of an carbonate apron fill models. 

Abstract: Pseudedomia hekimhanensis, a new species of Pseudedomia Henson 1948 from t ite Late Campanian of Hekimhan, NW Malatya,Turkey, is described. It differs from the other Pseudedomia species by its test size, chamber and chamberlet arrangments.

Abstract: The metamorphic rocks exposing in the Yıldızeli region (west of Sivas) to the east of Kırşehir block (Central Anatolian massif orKırşehir massif comprising metamorphic and associated magmatic rocks) are named as Yıldızeli metasedimentary group. It is divided, based on the rock types, in four units as, from bottom to top, the Aşılık metamorphics comprising pelitle gneiss and migmaiites, the Fındıcak metamorphics including the pelitic schist and gneiss, and calcsilicates, the Pelitlikaya quartzite consisting ofquartzite and quartzitic schists, and the Kadıköy metacarbonate.The microscopic study of Fındıcak metamorphite, yields sillimanite + kyanite + muscovite + ortoclase + quartz; sillimanite +muscovite + biotite + ortoclase; quartz + plagioclase, diopside + hornblend + plagioclase + quartz; hornblende + plagioclase +quartz and diopside + hornblend + quartz + plagioclase + scapoUte + calcite paragenesis. In addition to these paragenesis, post -tectonic epidote overgrowth in the hornblende - gneisses, replacement of diopside by tremolite in the diopsite - hornblende gneisses,transforation of calcsilicatic gneiss in talc - tremolite schist, and mica overgrowths on feldspars in the mica gneiss are also common and characteristic features of Fındıcak metamorphics were also determined.The hornblende - plagioclase, garnet - muscovite - biotite - plagioclase - kyanite, garnet - muscovite - biotite - plagioclase andmuscovite - biotite - chlorite geobarometries show that the first metamorphism occured under high pressure conditions. Followingthe high pressure metamorphism, the temperature increased, resulting in the transformation of kyanite in fibrolitic sillimanite. During the uplifting, a retrograde greenschist fades cataclastic metamorphism overprinted on the earlier fabrics due to decompressional regime. The last metamorphic event occured during Santonian - Maestrihtian time (K - Ar ages of muscovite and biotite, are71.8 ±23 Ma-77.7±1.8 and 68.1 ±1.8 Ma -723 ±2.1 Ma, respectively). 

Abstract: The stratigraphy in the investigated area shows different properties in the northern and the southern parts of Kermelik village.Malak formation of Lutetian age, which is represented by terrestial and marine fades, overlies unconformably the basement, Akdağmetamorphics and Kuştepe gabbro, Silahtar meta granite and Atderesifoid syenite intruded in them. This formation is overlain byKaracaören formation which is represented by limnic and fluvial fades of Late Miocene - Early Pliocene age with angular unconformity. Subaerial basaltic lava flows which outcrop around Amar at village accompanies to this sedimentation. This succession endswith terrestrial elastics belonging to Sızır formation of Early Pliocene - Quaternary age.The oldest rock unit in the southeast of Kermelik village is Tuzla formation of Late Cretaceous - Early Paleocene age which isrepresented by low grade metamorphosed pelagic limestone and volcanics. This unit overthrusts to Cevizcik formation of Oligoceneage which is represented by terrestrial elastics and gypsum.The metamorphic basement and its Tertiary cover have different structural features with respect to each other in t lie area. Thestructural elements of Tertiary units in the area are thrust faults, strike - slip faults and axial plane folds which were created under acompressional regime inNeotectonic period. After that, several normal faults developed during the releasing period of the region.

Abstract: Laffitteina (Marie, 1946) species are characteristic foraminifer as of Maastrichtian - Middle Paleocene units in Turkey. Laffitteina aff. marsicana Farinacci and Laffitteina marsicana Farinacci from upper part of Early Maastrichtian; up to Middle part of Late Maastrihtian Laffitteina oeztuerki İnan from middle part of Late Maastrichtian; Laffitteina boluensis Dizer from middle of Late Maastrihtian to end Danian; Laffitteina erki (Sirel) from middle part of Early Donion to middle part of Early Thanetian; Laffitteina cfmonodi Marie from middle part of Early Danian to end of Late Danian and Laffitteina bibensis Marie from Early Maastrichtian lastto end of Early Thanetian show stratigraphical distribution in Turkey. Laffitteina species are very important for transition of Cretaceous I Tertiary particulary in Eastern Pontids. Laffitteina`s are observed only in Maastrichtian levels in İlgaz and Beydağları (WAntalya) regions. On the other had (W Pont ids, Anatolids, Bolkardağ and Adıyaman regions), Laffitteina outcrops of Turkey are Paleocene in age.

Abstract: The Nevşehir - Acıgöl maar is one of the eruption centers of Quaternary volcanism in central Anatolia. The Maar - lake fill contains clastic, chemical and organic deposits, including high - calorific peats formed in late Holocene. The main (host) sediments ofthe infill are tuffaceous sandy mudstones. The other accesory fades, controlled mainly by climate, are peats and plant - bearingmudstones, brecciated mudstones, limestones and also travertines originated by thermal waters at the top of the succession. According to the C.I4 dating of the peats, they formed ca. 2000 yrs BP; their calorific values are 2300 to 3165 kCallkg. These values arevery high, considering the yoimgness of the peats. It is thought tliat the lake was primarily dependent on climate; and deposition wasfurtlier controlled by the hydroihermal system. The associated heat flow played an important role in sedimentation by creating amicro - climatic niche, where late - Quaternary (cold regional climate) vegetation could flourish and form substantial peat deposits.The heat flow through the groudwater and clastic sediments was crucial to the high maturation of the peat deposits.

Abstract: This study aims to investigate the interaction between Lake Girdev and ground water in the allochthonous limestones which cropout in the area between Lake Girdev and Kazanpınarı spring. In particular, the flow direction and velocity of ground water, its relationship with Lake Girdev and the effect of lithological and structural features on the ground water circulation were analyzed.The apparent ground water flow velocity was found to he 31 m h-1 using the fluorescein tracer. The ground water flows in ENEdirection. Tritium and Oxygen -18 isotope data suggest that the water of Lake Girdev and ground water are likely to be of the sameage and the water sinking in Lake Girdev recharges the aquifer without any change in its composition. The rainfall belt in the Elmalı Polje falls on a zone between the Eastern Mediterranean and Central Anatolia regions. It is interpreted that the allochthonuos limestone aquifer has been developed as a result of the jointed, faulted and thrusted nature of limestones.

Abstract: Koçpınar springs emerge on strike - slip Hasandağı Fault Set (HFS) along Tuzgölü Fault Zone (TFZ) which extends in northwest - southeast direction. The exposed rocks, most of which are volcanic, exhibit different hydrogeologic properties in the studyarea. As meteoric waters rise to the surface ion concentration occurs through water - gas - rock interaction. Marbles of Paleozoicage form the aquifer of the springs. The CO2 gas content of the springwaters is high enough to produce dry ice (solidified carbon dioxide). The CO2 gas is also responsible for the calcite dissolution in the marbles forming carbonic acid through reactions with water. On the basis of ion concentrations, two hydrochemical fades have been identified as Ca - Mg - HCO3 andNa - HCO3 springwaters meet the drinking water standards. Three protection zones are suggested against the external effects in the spring area.

Abstract: The Gediz, Büyük Menderes and Küçük Menderes grabens have been formed in relation to detachment faulting. The Gediz graben, which is active at the present time, is a WNW - ESE trending half graben. The youngest graben fill is the sediment of the Salihli- Alaşehir plain. The initation of the Gediz graben has started with the activity of the Karadut fault which is the youngest detachment fault of the region. The low - angle detachment fault of the Karadut which cut the Early Miocene granodiorite has produced acataklastic - mylonitic zone of a regional extent. The shear sense indicators along this zone were the product of the same kinematicactivity and the tectonic transport has occurred along top to the north - northest direction.The footwall section of the Karadut fault consists of schists and marbles of the Menderes Massif In thefootwall section granodiorite stocks have been emp laceddue to the activity of the fault. The hanging - wall section consists of rocks of the Menderes Massifand a Neogene sedimentary succession. Along the surface of the Karadut fault, erosion of the Neogene rocks has exposed in someplaces the hanging - wall slivers, which are gneisses and schists of the Menderes massifIn the Itanging - wall of the Karadut fault, detrilal sedimentary succesions of graben -fill were deposited and they were controlled both by blocks of the initial fault system and also by the new high - angle syntetic faults. The region is still active presently as theoccurrences of earthquakes along of the graben indicate.

Abstract: The stratigraphic and paleogeographic properties of the Pirnos block which forms the southern part of Anamas - Akseki autochthonous (Central Taurus) is investigated. Pirnos block were represented by, fi`om bottom to top, Upper Anisian - Upper Nor ionsandstone and shale (Kasımlar fm.); Rhaetian dolomite (Menteşe dolomite) and limestone with Megalodon (Leylek limestone); Upper Rhaetian - Lower Liassic sandstone, conglomerate and mudstone (Üzümdere fm.); Middle - Upper Liassic limestone with Paleodasycladus (Alıçbeleni fm.) and dolomite (Hendos dolomite); Dogger - Malm oolitic limestone (Çamkuşağı fin); Malm calciturbidite(Karlığın fin.); Berriasian cherty limestone (Susuzkır fm.); Campanian - Maastrichtian calciturbidite and cherty limestone (Dumanlıfm.); and finally Danian olistostrome (Çamlıdere olistoslrome).Pirnos block was affected by a regression at the Upper Rhaetian, a transgression at the Lower Liassic, a regression at the beginning of Lower Dogger and to be followed by a transgression immediately. Block area which was subjected to uplift mg affected by arepeated transgresion at the begining of Campanian period and was finally covered by Antalya nappes tectonically at the end of Danian. At the and of Eocene, it was affected by compression.The repeated transgressive - regressive cycles clearly indicate that the southern edge of the Anamas - Akseki autochthonous wasnot tectonically stable during Mesozoic period.Lithological properties of Pirnos block show that southern part of the block was characterized by relatively deeper water environment in comparison with northern part during the Dogger - Malm period and during the Campanian - Maastrichtian. It is thought that this deeper part of the Anamas - Akseki autochthonous might have formed the northern edge of the Antalya basin (Pamphylien Basin).

Abstract: During this study, fosil assemblages like Meandrospira cf. dinarica Kochansky - Devide and Pantic, Glomospirella sp., Planiinvoluta sp., Turriglomina sp., Aulotortus sp., Spirorbis phlyctaena Bronnimann - Zaninetti, Duostominidae, Hydrozoa, Halobiasp.,Daonella sp. indicating Anisien - Ladinien; Valvulina sp., Trocholina sp., Textularia sp., Pseudocyclammina sp., Ophthalmidiidae,Protopeneroplis striata Weynschenk, Conicocurnubia sp., Salpingoporella sellii (Crescent), Labyrinthina mirabilis Weynschenk, Valvulina gr. lugeoni Septfontaine, Kurnubia cf. palastiniensis Henson indicating Upper Dogger - Malm; Globotruncana sp., Globotruncaniidae molds indicating Upper Cretaceous and Stafellidea, Hemigordiopsidae, Mizzia sp. indicating Upper Permian were determined from the samples collected in Deresinek formation of Middle Carboniferous - Upper Permian age which is situated at thenorth of Sultandağlan.Based on the determined fossils, lithological features and structural setting, two tectonic slices with different stratigraphy wereidentified within the Deresinek formation. Of these, the lower one comprises of Middle Triassic - Cretaseous rocks and is tectonically overlain by the another one, comprising rocks of Upper Permian.In this study, the lower slice and its upper level of Upper Cretaceous age were named as Deresinek and Eber der e formations,respectively. In the upper slice, a formation of Upper Permian age, Kocatepe, was differentiated.

Abstract: Permo - Triassic Keban Metamorphites outcrop at the North of Elazığ. The plutonics of Yüksekova Complex intruded in to the metamorphites during Late Cretaceous and caused formations of skarn zones and related Fe-Ti mineralizations along the contacts. Endoskarn formations exhibite various mineral assemblages; pyroxene (ferrosalite - hedenbergite) - garnet, pyroxene (fassaite)- skapolite and epidote - garnet. Mineral assemblages of exoskarn formations are garnet (andradite), skapolite, pyroxene, epidote, sphene and magnetite.The mineralizations occur along the metamorphites - plutonics contact, in the pockets and fractures extending towards marble.The thickness of the mineralized bodies can reach up to 1 -15 m. The ore minerals are; magnetite, hematite, ilmenite, specular ite,limonite, geothite, pyrite, pyrrhotite, chalcopyrite, covellite - chalcocite, geikilite and pyrophanite.

Abstract: The Bozdağlar massif, (NW of Konya), tectonostratigraphically consists of from bottom to top, autochthonous U. Permian - Cretaceous Gökçeyurt group, Mesozoic Çayırbağı ophiolite, and Silurian - Mesozoic allochthonous Ladik metamorphites. U. Miocene -Quaternary rocks consititute neo - autochthonous cover. Both the autochthonous and allochthonous metamorphites, indicates at least three phases of deformation. The first phase produced recumbent folds under high Pi low T metamorphic conditions. The second and the third phases represent post - metamorphic episodes and developed Type 3 ve Type 1 refolded folds. The massif gained its polyphase deformational history and imbricated structures during the Late Cretaceous and following times respectively. The post - orogenic movements during M. - L. Miocene formedlacustrine basins due to block faultings accompanied with volcanism. At E. Pliocene time, rocks of the massif thrusted over the coverunits and finally gravity faultings occurred. All of these movements caused uplift that ranges from 600 to 850 m in the region.

Abstract: The ancient city of Hierapolis is situated on the Pamukkale fault which bounds the northern margin of the Gediz graben in its south - eastern end. Hierapolis was damaged by many earthquakes in historical times but the most damaging one was in 60 AD. One of the main objective in this study is, detailed investigation of surface ruptures that damage Roman and Byzantine buildings within the ancient city of Hierapolis. Surface ruptures within and near Hierapolis can be traced along about 1250 m. Surface ruptures vary in length from 10 cm to tens of metres and they vary in width from vefew millimetres to about 1 m. There are also normal and lateral displacements along them. As a result of detailed investigation, it is concluded that these surface ruptures at Hierapolis formed during an earthquake with magnitude 6.0ruptures formed during one of 1354,1702 (1703) or 1717 earthquakes. The other main objective in this study is, as this paper points out, to indicate that ancient sites which are located on active faults provide useful information for earthquake frequency, earthquake magnitude, amount of displacement during earthquake and earthquake risk in that region.

Abstract: The main purpose of this study is to determine the comparative geochemical features of the Upper Miocene and Pliocene volcanics outcropping in the southern part of the Yamadağı Region located between Sivas and Malatya, and Pliocene volcanics are transitional - calcalkaline, and transitonal - alkaline in characters, respectively. The determinations based on the trace element data also indicate that Upper Miocene and Pliocene volcanics are transitional and alkaline characters, respectively.Large ion lithophile element (LIL) and high field strength (HFS) element enrichments imply that the volcanics were generatedfrom the enriched mantle source or they may have undergone the crustal contamination. K/Rb - Rb and Y - Rb variation diagramsmay indicate the crustal assimilation - fractional crystallization processes in the Upper Miocene volcanics, and the fractionalcrystallization process in the Pliocene volcanics.When the major and trace element characteristics are considered together with the post - collisional tectonic evolution of theEastern Anatolia; Upper Miocene volcanics have been generated by the crustal contamination of melt derived from mantle by thethickened crust, and Pliocene volcanis reveal little or no crustal contamination.

Abstract: In this study, the occurrence of Sirelina orduensis Meriç and înan (1996) in Upper Maastrichtian levels in the different outcropsof Ilgaz (Çankırı) region was discovered. Sirelina orduensis was described first time by Meriç and İnan (1996) in Gölköy formation(Ordu).Sirelina orduensis Meriç and İnan different from other foraminifera by their microgranular test structure, different coil according their development stages and lateral orbitoidal chambers.This species was discovered abundantly in Upper Maastrichtian aged sandy limestone levels of Ödemiş formation (Pehlivan etal, 1987) crop out at Ilgaz (Çankırı) region which was represented by sandstone, sandy limestone, limestone and claystone.

Abstract: Harşit - Köprübaşı (Tirebolu) volcanic associated ore deposit which situated in the Pontid belt, is a pollymetallic massive sulphide deposition hawing its own characteristics.By the geochemical method regional backgraund, treshold and anomaly values ofCu, In, Pb elements were determined and relation between the existing anomalies and known ore lenses are examined.The resulted moddeling can be used as target definition for the similar but unexplored Pontid type deposits.

Abstract: The basement in the study area is represented by the Palaeozoic Akdağ metamorphics. These metamorphics are unconformably overlain by basal red conglomerates of the Tlianetian - Lutetian Belkaya formation. This formation consists of red sandstone, marl, Nummulitic limestone, limestone - marl alternation and pebbly sandstone. OUgocene Cevizcik formation which is composed of continental grey - yellow marl and gypsium lenses rests unconformably on the Belkaya formation. The alternation of Upper Miocene -Pliocene conglomerates and sandstones of the İncesu formation overlies the older units with an angular unconformity. All units cropout in the region are covered by the Plio - Quaternary Sekikaşı basalts.The fossil assemblage of the Belkaya formation suggests that the age of oldest unconformable rocks above the Akdağ metamorphics is Late Paleocene, not Lutetian as previously believed.It has been observed that strike - slip faults in this part of the Kırşehir massive are generally right lateral and deform the UpperMiocene - Pliocene rock units. In addition, thrust faults develop within the Thanetian - Lutetian Belkaya formation itself and alongits boundary with the Upper Miocene - Pliocene deposits. General trend of these thrust faults suggest a transport direction from northeast to southwest.