Türkiye Jeoloji Bülteni

Abstract: The gneiss complex which consists of augen, granitic and banded gneisses and migmatites, occurs atthe lowest level of the metamorphic sequence in the menderes Massif. This unit is conforambly overlain by the metavolcanics (leptites) and these metavoleanics are covered by a schist series with an apparently conformable contact*The schist series mainly consist of kyanite-staurolite-garaet schist at the lower levels and garnet-mica schist at thei. upper levels. The schist series conformably overlain by the platformtype marbles-with emery lenses. Paleocene aged redcoloured, thinbanded marbles occur at the uppermost level of the metamorphic sequence in the Menderes Massif, Theposimetamorphic granodioritic and gabbroic plutons are the other units of the rock succession of the Massif,It is possible to observe all the succession of the metamorphic zones from the low-grade to high-grade mefamorpÄcconditions in the Menderes Massif. The presence of the widely-developed migmatites in same places and the variation ofthe metamorphic conditions from the diaspore/corundum isograd to sillimanite-orthoclase assemblage at the lowest level| of the sequence indicate that in the course of the metamoiphism, the temperature and pressure conditions have prevailedbetween 420-650°C and 5-6,5 Kb. respectively.The age of the gneisses was determined to be about 500 Ma using Rb/Sr radiometric technique. This evidence suggests that the first metamoiphism of Menderes Massif occured between Cambrian/Ordovician and the metagranodioriteswhich are assumed to be product of the first metamoiphism, were dated about 480 Ma, The metavolcanics (leptites)which are regarded to be surface*equivalents of the metagranodiorites, show a great similarity with the Pan-African arcivolcanics in terms of age, chemical composition and geological setting. The same aged*inigmatitic rocks (462 ± 48Ma) are also observed at the Cyclade Islands which are regarded to be Western extention of the Menderes Massif* According to these evidences, it may be suggested that, at least, these major units of the Menderes Massif are the parts of theEburaean Craton situated at the present position of the NE Africa,The sequence of the Massif continued until Paleocene, was subjected to the "Main-Metamorphism11 which has giventhe present position of the Menderes Massif related to ttie thrusting of the Lycian nappe comlex between Paleocene-LateEocene time. This metamorphism which was taken place under the medium Pressure/high temperature contions, givenrice the formation of the Borrowian-Type mineral assemblages.

Abstract: Rize-Fmdıklı-Çamlıhemşin area of, Eastern Black Sea region aie geologically studied. Petrographicaiand geochemical characteristics of the formations, tectonic environments and origin of the magmatic rocks are discussed.Within the study area Hemşindere foımation of Upper Cretaceous age, which formes the basement, comprise basic andacid volcanics like basalt, basaltic andésite, dacite, rfayodacite and rhyolite and rarely some andesitic intermediate volcanies, Volcanic members of Melyat formation of Eocene age are basaltic and generally subalkaline (calcalkaline + tholeiitic) in compostions. Infusions of the basic and acidic plutonic rocks (Upper Cretaceous-Paleocene), varies from gabbroto granite, cut the volcanics of Hemşindere formation. As a result of petrochemical studies, these plutonic rocks aremainly composed of gabbro, quartz diorite, tonalite, granodiorite and adameiiite. According to classification of Debonand Le Fort, plutonic rocks are calcalkaline having kafemic association properties. Within the study area magmaticrocks represent the characteristics of island arc magpiatism formed on subduction zone. Also distrubition and the originof the magmatic rocks around Eastern Pontids are discussed.

Abstract: Erencik formation, outcropped in the southeastern Niksar (Tokat) and the surrounding area, is the typitcal formation which is representing the continuity on the Cretaceous/Tertiary boundary. This formation is characterizedby the yellowish gray, thin to medium dedded limestones and clayey limestones containing three microfacies from bottom to the top: Biosparite with intraclast, biosparite with Miliolidae, micrite with fossils. At the bottom of Erencikformation, there are the beds containing Maastrichtian benthic forams (Assemblage I) and followred by the benthic foraminifers of Danian as Laffitteiiia bibensis Marie, Laffitteina aff. bibensis Marie, Idalina aft sinjaricaGrimsdale, Scandonea aff. samnitica De Castro, Rotalia cf. perovalii Terquem, Kathina cf. delseota Smout,Anomalina sp„ Eponides sp., Planorbulina sp, (Assemblage II), The systematic characters some of the foraminifers are also given and the formation is thought to be the deposited in a fore reefal to lagunar environment.

Abstract: In this paper, the important geochemical features of the auriferous quartz veins and sulphide lodes aswe as surronding alteration zones and the host rock were investigated in detail.Work to date has shown that the surrounding alteration zones of the veins and the host rocks were affected by hydrothermal fluids in various degrees but in decreasing values towards to the host rocks.The alteration zones were found to be enriched gold and silver, whereas the host rocks, diabase dikes and gabbroswere found to be affected by hydrothermal flued but free of gold and silver at all, IAnother results of this study is that to show the geohemical differences between trace and rare earth elements (REE)contents of the auriferous quartz veins and sulphide lodes.It is found that the auriferous sulphide lodes contain Sc, Co, Rh, Cd, In, Sn, Sb, I, Cs, Ba, Hf, Ta, W, Ir, Pt, La,Ce, Pr, Tb, Ifo, Yb, Lu and In various grades, beside common elements with auriferous veins, whereas the auriferousveins contain some Ba, Rb, Y, Zr, Nb, Cd, Tm, Po, Eu, Ru, Sr, Th, Pa, Re and Fr, which are never met in thesulphide lodes.Furthermore, 38 elements were detected in various combination in gold particles, which are mainly found in quartz,arsenopyrîtê, chalcqpyrite, sphalerite şnd pyrite as native or disseminated grain.According to the stated differences, besides the geological and mineralogical differences, it is surely believed that thesources of the auriferous quartz veins and the sulphide lodes should have been different.

Abstract: The Laleköy Formation of the Mesozoic carbonate sequence of the Karaburun Peninsula is characterizedby red pelagic limestones. The formation contains a Late Anisian conodont fauna including Chirodella dinodoldes,Crathognathodus kochi, Diplododella (riassica, Enantiognathus zîeglerl, Gladigondolella tethy*dis, Hibbardella magnidentata^ Neogondolella constricta, R cf, bîfurcata, N. cf. cornuta, Neohindodella triassica, and Prioniodina (Flabellignathus) spp.

Abstract: Planktonic foraminifera İn the Lower-Middle Miocene turbiditic Cingöz Formation cropping outaround the Karaisalı-Çatalan-Eğner region have been recognized and determined for the first time in this study, Planktonic foraminifera occur in sequence identified as submarine fan deposits and some preliminary observations on the evolution of these submarine fans are also given. Fourteen planktonic foraminifera species have been identified and assignedto three biozones in this succession. The Lower Miocene is represented by Praeorbulina glomerosa curva Zone,while the Middle Miocene is marked by the Orbulina suturalis and Globorotalia mayeri Zones. This planctonie foraminifera biozones have been correlated with previous studies carried out in Turkey and some other regions of theworld. The Lower Miocene ostracods have also been defined in a few samples taken from the lower part of the CingözFonnation, which has a transitional contact with the shallow marine Kaplankaya Formation.

Abstract: The studied area is located between Çiniyeri and Küre of Menderes Massif at the East of Tire (Izmir), Inthe region metamoiphic units belong to Menderes Massif which have been locally intercepted by numerous quartz veinsare arranged in an ascending order as augen gneiss, kyanite-garnet schists, garnet-mica schists and marbles, THe pétrographie and chemical studies show that kyanite-garnet schists and quartz veins are important source rocks for rutile deposits in detritical sediments. Rutiles in high grade metamorphic rocks have metamorphic origin rather than detriücal andfonns as a function of oxygen pressure and chemical composition of rock.Garnets and rutiles seem to from an important plrt of heavy mineral concentrations. Rutile in the sediments of theinvestigated area is generally most abundant in the -0.149+0.077 mm fraction with an average 1,33 percent, The totalproven reserves for all grain size fractions are detemiined to be 2 million metric tons. The detailed grain size analysisr applied to the fluvial originated sediments indicate that the material used should be considered as coarse sand size.

Abstract: The Cretaeeous-Tertiary boundary is gradually transitional in the carbonate rocks of Tecef Formation.This transition has no fossil and it can be distinguished by lithologie, minéralogie and geohemical data. Typical fossilsrepresenting the Uppermost Maastrichtian and Danian have been seen in the lower and upper parts of K-T transtition,The carbonate mineral of Upper Maastrictian formed of limestone is calcite, and the main minerals of its clay fractionare illite and chlorite. Dolomite appears in both K, T and Danian-Montian-Thanetian transitions. Smectite and 14S-14Cin the Paleocene are the dominant clay minerals. The mean amounts of Mg, Fe, Cr, Ni and Zn in the carbonate mineralsrelating to Paleocene increase, when compared with those of Upper Cretaceous, In addition, it has been detected that Fe,Cr, Co and Zn contents of non-carbonate residual fraction are more abundant in the Paleocene.

Abstract: Lithological units outcroping in the investigation area, formed in various environments which are developed through the time invertal from Permo-Carboniferous to recent. Acidic magmatites of Permo-Carboniferous ageform basement of the area of investigation. Shallow marine Liassic-Lower Malm sequence with volcano-sedimentarycharacter overlies this basement by angular unconformity. This unit is overlain conformably by Upper Jurassic-LowerCretaceous limestones» The Hotnvian-Campanian flysck formed by rapid deepening of the environment during middleLower Cretaceous, conformably deposited on the Upper Jurassic-Lower Cretaceous carbonates. Upper Campanien andLower Maastrihtien are represented by volcanics and pelagic carbonates respectively.Thus, uninterrupted marine sedimentation starting at Liassic continued till end of Upper Cretaceous. Eocene sequencehas shallow marine elastics at the base, but terminates by volcano-sedimentary units. Oligocène is represented by terrestrial elastics and basic volcanics. These units are overlain unconformably by Plio-Quaternary volcanics widespread inthe region. 

Abstract: The tithonic faciès of pelagic limestones which are Upper Jurassic-Lower Cretaceous in age located inthe studied area are rich in Caipionellids, The stratigraphie columnar section are measured to study biostratigraphy ofCalpionellids and to define the boundary of Jurassic-Cretaceous, The thickness of this unit is about 500 m. According tothe sedimentologic and pétrographie studies of thin section of collected samples of this limestones are micrite. Accor«ding to the result of paléontologie and biostratigraphic studies, this unite contents 4 Calpionellid biozones such as:Crassicollaria intermedia Zone (at the bottom of upper Tithonian), Calpionella alpına Zone (at the top ofUpper Tithonian), Calpionella elliptica Zone (Lower Berriasian) and Calpionellopsis simplexCalpionellopsis oblanga Zone (Upper Berriasian), On the other hand, the age of this unit is determined as Tithonian-Hautrivian (?) and a new species of Calpionellid (Crassicollaria remanei n, sp.) is found. These biozones arecompared with the biozones which are previosly described. This tithonic facies limestones are also compared with theother similar facies located in the Pontid zone, The boundary of Jurassic - Cretaceus is determined 185th meter of stratigraphie section that Calpionella elliptica Cadisch is appeared.

Abstract: Stream sediment geochemical prospection results for Cu find Zn in an area of 60 square kilometers within the Çangal metaophiolite, promising for copper and zinc mineralization were comparatively examined,The widespread rock unit found in investigated area are metalavas and metapelites that have similar frequency distributions for concantrations of copper and zinc. In order to separate these elements in the two lithologies, the linear discriminant analysis with its basic principles and test statistics was applied to the present data. It was detenmined that thistechnique is harmonious with geological observations particularly indicating the primary element in investigated areaand defining the relationships between the variables.