Türkiye Jeoloji Bülteni

Abstract: The Upper Eocene Kösedağ pinion, outcropping in the eastern pat of the CE Anatolian alkaline province, intrudes in thetrachybasalts and basalt ic-trachyandcsites of the M.Eocene volcano-sedimentary unity and is unconformably overlain by the LowerMiocene (Aquitanian) lagoonal limestones. The main structural elements are composed of oblique and normal faults with NE-SW direction and some joint systems developed in the pluton. Kösedağ pinton represents an isotropic joint system character, however, some joints with the directions ofEWl 40S and N65EI perpendicular are seen to be dominant. The eastern part of Kösedağ pluton canbe mapped as two mapahle fades such as medium to coarse, and fine-grained fades. The medium to coarse grained fades, constituting the main body, consists mainly of quartz-syenite, syenite and rarely of monzonilic rocks. The fine-grained rocks which are seenas small intrusions within the main body arc syenitic in composition. The major mafic constituents of the syenitic and monzoniticrocks of the eastern part of Kösedağ pluton consist ofamphibole (hornblende,kaersutite), clinopyroxene (augite and scarcely aegirine-augite) and biotite minerals. These rocks show cafemic (CAFEM), metaluminous (Na+K< Al), and silica saturated alkaline(ALKS) character. The RI-R2 parameters indicate a "late orogenic" setting, and also some trace element data such as Y-SiO2, NbSiO2, Rb-SiO2, Nb-Y and Nh+Y-Rb diagrams represent a WPG origin for the Kösedağ pluton. These features are thought to be sourced in a post-coUisional (POST-COLG) environment. This is also supported by some trace element diagrams. On the basis of all tliese data and regional geological setting, the Kösedağ pluton can be considered to be derived from a magma which was generatedfrom the upper mantle by the tensional regime in the passive margine towards the final stages of the crustal thickening just after the collision related to the northward subduct ion of the northern branch of the Neo-Tethys. On the other hand, such a magma source is thought to have been contaminated by some crustal material.

Abstract: Batı Kef chromium deposit is located just over the tectonite harzburgite, lower member of t lie Guleman ophiolite assemblageand the base of cumulate d unites. Considering its dimensions, it is among the major chromium deposit of Türkiye.The tectonites having porphiroclastic texture and forming thefootwall of the deposit are represented by harzburgites and occasionally by dunitesy while the cumulates having adcumulate texture and forming the hanging wall, gang and partings in the orebody are represented by dunites, harzburgites and Iherzolites.The general strike and dip of the deposit is N59E/54SE. The outcrop occurs between 1448-1580 m levels and can be followed1000 m along the direction. At the south-west end it thins out by primary contact and in the north-east it is terminated by great Keffault. The thickness varies cosiderably reaching a maximum of 52 m. The drill holes indicate thai the deposit extends to 1153 m level. The orebody is occasionally divided in two branches. The upper branche is poor in chromium and probably formed at a laterstage.The ore shows a disseminated texture. The relative quantitative variations of the olivine and chromite results in layering parallelto the general setting of the deposit. At the bottom of the orebody, some massive layers up to 1 m thick can be seen.The deposit is divided in  two major tectonic slices by an important reverse oblique sinistral slip fault (KOT Fault) having a general setting ofN55El76NW. Several minor reverse faults with general strike of NW-SE and dip to NE, and some normal faults having no apparent systems result in smaller tectonic slices within the orebody. Based on the surface and drift geology and drill hole data and using cross-sections method, the Batı Kef chromium deposit proven resenes are calculated as 7.6 million tons with an average grade of 30,06% Cr2O3.

Abstract: In the Beypazarı, region, metamorphic rocks of the Middle Sakarya massif are intruded by a low temparatured and shallowemplaced batholite. Composition of the batholite body shows variation from granite to diorite,but the granitic rock are predominantoverall in the region. The batholitic body, generally named as the Beypazarı granite, outcrops at the south of the Kirmir stream, isprobably connected to those granites occuring around Sivrihisar; although it is unconformably overlain by Paleocene, Eocene andMiocene rock units from place to place. The homogeneous batholite has a small varience within its body and shows a sharp instrusive contacts with the surrounding metamorphic rocks, consisting of phyllite,schist and marble. Hornfelses, which range between 3 to10 m in thickness, are present along the contact zones from place to place. The batholite has xenoliths taken from wall rocks alongthe marginal parts during its emplacement. Siliceous iron formations are observed in some places wherever the batholite cuts theiron-rich met amorphics.Joint systems and fractures were formed penecontemporaneously paralel to tlie cooling of the magmatic body during the graniteemplacement. Aplite and pegmatoid dykes which vary 10cm to 6m in thickness and 10m to 350m in length, trending NE-SW and NW-SE are formed along the fracture at the later phase. Granite and granodiorite componets of the batholitic body have xenoliths *••of monzodiorite and diorite, which were formed in an earlier phase according to magmatic differantiation.Granites consist principally of quartz plagioclase, orthoclase and minor amphibole, biotit, chlorite; zircon, sphene, apatite andopaque mirerals. Felsic minerals decrease whereas mafic minerals increase towards the diotiritic parts of the body and pyroxenemineral are also observed. Plagioclase and orthoclase show sericization, wfiereas biotite show chloritization. Predominantly holocrystalHne, hypidiomorphic and less commony, myrmekitic and allotrimorphic textures are present in the granits.AFM and (NaO+K20) /SiO2 diagrams show calk-alkalen character of these rocks. Alteration and metasomatism have modifiedRb/Sr, K/Rb, and K/Na rations. The initial 87Sr/ * Sr rations, ranging between 0.706 and 0.707 indicate that the Beypazarı graniteswere formed by anatexis of older continental cruts, and are shallowly intruded to the region probably during the Upper Cretaceoustime.

Abstract: The Gürleyikdere formation consists mainly of limestones of algal biomicritey algal biosparite, bryozoans biosparite, biomicriteand boundstone character. Micritic matrix and spar it ic cement are dominant from place to place. Abundant benthic-planctonic foraminifer a, algae, bryozoa, nannoplancton, coral and brachiopoda fossils occasionally reflect shallow marine (litoral) and reefal conditions. Gürleyikdere formation Itad been deposited on the wave base and it has a reefal character according to its several properties.Three different fades zones have been determined in four different standard microfacies, characterizing deep shelf margin, platformmargin, shelf lagoon, reefal and reef front environments. Deeper locations of the deposilional area were situated in the E and S E part of the area at the Paleocene-Eocene period, while locally stable and deeper regions were determined at the W and SW part of the investigation area.

Abstract: The Munzur mountains, which reflect typically the geological peculiarities of the Taurides, are situated at the north-eastern endof this unit. In this study the subsequent formations have been distinguished from bottom to top: Munzur limestone (Liassic-EarlyCretaceous), Uluyamaç ophiolithe (Jurassic-Cretaceous), Eric melange (Late Campanian-Early Cretaceous), Yakuplu plutone (Paleocene), Haslar andesite (Pat eocene), Dedek formation (Eocene), Kemah formation (Miocene).The uppermost levels of the Munzur limestone, deposited on an isolated carbonate platform, include biomicrits with Globotruncana. These biomicrits were formed as a conscnquence of the breaking and sudden collopse of the platform. The Uluyamaç ophiolithe that does not manifest a uniform sequence in the area, consists ofophiolithic rocks with a nontabular appearance. The Eric melange is made up of a chaotic mixture of rock blocks of different ages and fades in a pelagic matrix. Both of these lit hostr at graphicunits are in tectonic contact with each other and with the Munzur limestone. Both the I-type Yakuplu plutone, formed as a consenquence of partial melting of the subducting oceanic crust and of the mantel material, and Haslar andesite, crosscut all the rocks already present. The Dedek and Kemah formations unconformably overlay the other units.

Abstract: The study area is located on t fie NE Zone of the Pontid Tectonic Unit. The basalts outcropping in the study area are observed intwo different levels as Liassic, and Upper Cretaceous age-levels. Tliere are distinct dissimalarities between them with regard to their petrographic and alteration character. The basalts of Upper Cretaceous age are c ale-alkali and the Liassic ones are tlioleiitic in composition.

Abstract: This study describes the fades and environmental aspects of the Güvenç formation (Burdigalian-Serravalian) of the TertiaryAdana Basin. For this purpose. Karaisalı-Güvenç-Kuzgun and Çukurköy stratigraphic sections are measured, and geometry, sedimentary structures with paleocurrent patterns and micropaleontological (bentonic, planktonic foraminifera and nannoplankton) deter mi nat ions!countings are evaluated.The Güvenç formation comences with talus deposits and fore-reef shales on the trangressive cycle deposits of the Adana Basinof the Karaisalı formation and grades up in the  basinal shales. In accordance with the general shallowing of the basin, these basinalshales are overlain by the shallow marine and terrestrial Kuzgun formation (regressive cycle) at the upper parts of the succestion.The unit shows relativly deep marine conditions with decreasing amount of the sandy layers and benthonic foraminifera, andincreasing amount of the planktonic foraminifera and Discoaster type of nannofassiU from bottom to the middle part of the succession. Dominant pyrilization between 562-2000 meters of the succession indicates aneorobic environmental conditions for this interval. On the other hand, increasing amount of detrial material, benthonic foraminifera and Braarudosphaera discula, Braarudosphaera bigelowi type nannoffossils also display that relatively shallow marine conditions for the uppermost parts of the succession.

Abstract: This study comprises the properties of Samandağ Formation (Piacenzian) exposed in a wide area between Antakya and Saman­ dağ (Halay), based on its molluscan faunal content. In thisframe 46 genus and 57 species have been determined in the samples, col­ lected fromfive measured stratigraphic sections. It has been revealed that the age of the formation is Piacenzian (Upper Pliocene)according to the faunal associations wich includes marineforms in the lower, and fluvialforms İn the upper levels ofthe successi­ on. This stand points to a change İn the environmental conditionsfrom normal marine to oligohaline, and faunal properties alsosuggest that the subtropical climatic conditions predominated in the region during the Piacenzian time.

The classification of organic fades is made with respect to t lie chemical properties of kerogene, maseral types, and microscopic analyses. Seven types of organic fades are defined considering the composition, formation and diagenetic condition of organic matter.The formation with the characteristics of the source rock in tlie study area are Akgöl, Çağlayan and Görsökü formations. As aresult of a series of analyses , it was found that: Akgöl formation can only produce natural gas and has organic fades of C, CD andgas and has organic fades of BC, C, CD and D; and Gürsökü formation can CD and D.D; Çağlayan formation can produce oil and natural gaproduce low amount of gas and has organic fades of CD and D.

Abstract: The rock units in the study area have been divided mainly in  two groups as autochthonous and allochthonous. The Cretaceouscarbonate rock sequence is the oldest autochthonous rock unit in this region. The carbonate sequence consists of two units. Theseare in ascending order from bottom to top; (I) Söbüdağ formation (Cenomanian-Turonian), and (2) Senirce formation (Middle Maastrichlian). All Cretaceous rock units are overlain unconformably by Tertiary detritic sediments. The Tertiary sedimentary sequence has been divided in two units. These are from bottom to top; (I) The Kizilkirma formation is Upper Paleocene-Lower Eocene inage and (2) The Kayıköy formation is Middle Eocene in age. The Gölcük volcanism was active in the region during the Late Miocene to Early Pliocene period. The Gölcük formation is originated from the Gölcük volcanic materials. The Quaternary alluvium andalluvial-fan deposits are the youngest units for the study area. The Gökçebağ ophiolithic melange and Akdağ limestone units (Jurassic Cretaceous) are the allochthonous rocks in this region. Tliese allochthonous rocks were primarily emplaced in the region duringLate Cretaceous to Early Paleocene period. In the study area, the common tectonic structures such as reverse, overt hrust faultsand fold axis are extending along the NW-SE direction. On the other hand, the dominant normal faults and fracture systems aretrending along the NE-SW direction. It is possible that all these structural features in this region resulted under the NE-SW compressional forces, and NW-SE tensional forces.

Abstract: This study investigates the stratigraphy of the Hekimhan-Hasançelebi region situated on the eastern Tauride system, the evolution of the basin named as Hekimhan basin and the position of this with respect to the regional geology. The Hocalıkova ophiolite which was emplaced approximetly from north to south in the Late Campanian consitutes the basement of the region. Hekimhan basin was opened after the emplacement of the ophiolite. The Karadere formation, that is composed ofelastics was deposited in fluvio-deltaic, delta and shallow marine environments in the Late Campanian-Early Maastrichtian unconformably overlies the ophiolite. The Upper Campanian-Upper Maastrichtian aged Hekimhan formation that composed of mostlyelastics was deposited by tectonically controlled trangresion. Hasançelebi volcanites of alkaline character are intertongued with themiddle and upper parts of Hekimhan formation indicating a contemporary occur ence. The alkaline Yüceşafak syenitoid cuts the volcanites by causing contact metamorphism and metasomatism. The above mentioned magmatism indicates the progressive thinningand enlargement of the basin. The Hüyük limestone deposited in two different environments as inner shelf at the north and middleshelf at the south, reflects the deepening and maturation of the basin towards the south. At the northern parts Zorbehan dolomite was formed in the logoonal conditions under the influence of the volcanism and tectonism that gained activation intermittendly. Thebasin reached its maximum depth and width in the Late Maastrichtian. The economic iron ore deposits were formed in that period.The Tertiary and Cretaceous units are conformable in Hekimhan region whereas they are uncorformable in Hasançelebi region. According to the stratigraphy explained above, the crust thickness was increased by the emplacement of the ophiolite. Therefore the region was tr(informed in positive area by an uplift, and an ensialUc back-arc basin was opened at the north of the Yüksekova Baskil arc under the control of ienskmal forces in the Late Campanian. The basin became mature at the Late Maastrichtian and closed at the end of the Middle Eocene.

Abstract: In the present paper the Bi, La, Ce, Th and U minor elements of Ergani-Maden copper ore deposit, are studied and their relations to Cu and to each other are investigated. The results show that the studied elements are not enriched in ore deposit and have notany significant geochemical relationship to Cu and to each other.