Türkiye Jeoloji Bülteni

Abstract: The soulheastren part of Turkey is easily correlated with the Zagros and shows form South to North: the ArabianPlatform, the ophiolitic and radiolaritic nappes emplaced during the Meastrichtian, the Bitlis-Pütürge metamorphic belt emplacedduring the Mio-Pliocene. Correlatione are given in terms of structural units and paleogeographic zones.North oî the Bitlis-Pütürge massives appears the typical Tauric organisatino, 1. e. an east-west belt of limestone outcropsextending from the Aegean Sea to the Munzur dağ, the Taurus Calcareous Axis, surrounded by radiolaritic series, ophiolites andmetamorphic massives. A stratigraphic and structural analysis shows that these limestone outcrops are tectonec windows beloningto the Arabian platform and covered by radiolaritic, aphiolitic and metamorphic nappes.Consequently a paleogeographic recontruction is given for the mesozoic times in wich the Apullian, Ionian and Gavore zones inGreece, the Taurus limestone Axis and the Arabian platform all belong to the same arabo-african platform over wich te formations coming from the Tethys will be overthrusted from North to South in three mainsstages: meastrichtian, eo-oligosene andmio-pliocene.

Abstract: Tpo types of lead-zinc deposits were studied in western Anatolia. Tha first is the strata-bound type deposits (IzmirBay mdir-Sariyurt) and the second is the hydrothermal-contact metasomatic type deposits that are related to the granitoid intrusions in the Biga Peninsula.All the deposits studied occur in similar metamorphic schists, except for the Yenice-Arapuç an hydro thermal-matasonaticdeposit that is found in sandstones and the Balya deposit that is in dacites at the contact with limestones.Galena and sphalerite are the main ore minerals in both types of the lead-zinc deposits. Chalcopyrite, pyrite, pyrrhotite,hematite, magnetite, ilmenite and rutile may also be present in minor quantities. In addition, minor- trace quantities of tetrahedrite-tennantite, antimonite, arsenopyrite, bournonite, boulangerite, jamesonite, heyrovskyite, bismuthinite, native bismuth,orpiment and realgar were found in the Balya deposit; and jamesonite, mareasite and arsenopyrite in the Torbalı-Taşkesik deposit.The geological and mineralogical studies suggest that the hydro termal-contact metasomatic lead-zinc deposits of the BigaPaninsula were formed as a result of the remobilization of the strata-bound type deposits by the granitoid intrusions in this region.In conclusion, the lead-zinc deposits of the Biga Peninsula can be attributed to the polygene tic class of ore deposits.

Abtract: The Oligocene-aged sediments of the investigated areas were deposited in fluvial and deltaic environments. This canbe stated on the basis of the lithofacies, sedimentary structures, fossil content and geometry of the sedimentary bodies involved;also on their relation in vertical sequences and comparison with the studies made in modern environments.Furthermore in the fluvial environments we distinguished both braided and meandering channel deposits and flood-plaindeposits.In the deltaic deposits we have seen deltasand interdeltaic sediments such as lagoon.Lignites are found in the Keşan-area in the marshes of deltaic plains and lagoons. In Marmara Ereğlisi they are enconunteredin the flood-plains meandering rivers.

Abstract: To the south of Bornova, on the bases of stratigraphic and depositional characteristics, three different flysch units arerecognized. These are, in ascending order, (1) the Arapdere litharenite-shale unit, which is Late Cretaceus in age and underlies theKurudağ limestone unit, (2) the Izmirlik shale-litharenite unit which is Late Cretaceus and early Paleocene in age and overlies theKurudağ limestone unit, (3) Beşiktaş litharenite-shale unit which is middle Paleocene in age and rests unconformably on the olderunits.Paleocurrent data from the Paleocene and Cretaceus flysch units, indicate that the main current directions were from south.Vertically drapped N-S trending older faults, are cut by E-W trending younger faults. The study area is divided in a mozaicblock pattern by two main fault systems. The folds have NNE trending axes. The overturned folds to the south recognized bydepositional features are trending in ENE-WSW direction. 

Abstract: In Attepe, the ore is found within the Cambrien Limestones. Structural control has played an important role in theemplacement of the ore body. The ore has replaced the limestone in a faulted syncline.Primary ore mineral is siderite with lesser amount of hematite. Siderite has almost totaly altered to geothite and limonite,except in few places. Due to this alteration, grade of the ore has increased and impurities have been washed out.The ore minerals, transported in hydrothermal fluids, replaced the limestone. Locally the ore minerals filled the fault zones.The source of the ore bearing fluids is thought to be a deep seated intrusion, which is expressed as a domal structure on the surface.The ore bearing fluids reached the surface by NNE-SSW trending faults.During the exploration activities, 4900 m diamond drill holes have been made, and reserves are estimated as 34 million tonsof iron with a grade 58.44 % Fe, 2.94 % SiO2 and 0.55 % Al2O3.

Abstract: The formations of Campanian-Lutetian age are exposed in the region of Haymana, SW of Ankara. These formationsof about 5000 m thickness are represented lithologically by conglomerates, sandstones, shales, marls and a veriety of limestones.The formations named by Yüksel (1970) as Haymana, Kavak, Çaldağ, Kadıköy, Gedik, Karahoca and Çayraz were sampled, and107 Nannoplankton species have been distinguished in the samples collected. By means of these Nannoplankton forms that thefollowing biozones have been defined in the area studied: Tetralithus gothicus, Tetralithus trifidus, Arkhangelskiella cymbiformis,Lithraphidites quadratus, Cruciplaculithus tenuis, Chiasmolithus danicus, Ellipsolithus macellus, Fasciculithus tympaniformis,Heliolithus kleinpelli, Discoaster gemmeus, Discoaster multiradiatus, Marthasterites contortus, Discoaster binodosus, Marthasteritestribrachiatus, Discoaster lodoensis, Discoaster sublodoensis. These zones of the research area were correlated with the other regions,and their compatiblity with the planktonic Foraminifera zones described there were proved. Moreover, an environmental interpretation based on the Nannoplankton species is also provided here. 

Abstract: Strata of various facies of Middle Jurassic-Pliocene age invertal outcrop in the area between Ünye-Ordu-Koyulhisar-Reşadiye. Of these rocks, limestone of Middle-Upper Jurassic-Lower Cretaceous age forms the basement. Tuffite, andesiteflows, agglomerate, limestone and sandstone alternation of Cenomanian-Campanian age covers the limestone with an angularunconformity. That unit is cut by dacite and syenites especially at Gölköy and Ulubey areas. Tuffite-argillaceous limestone alternation at the north, sand, and argillaceous limestone alternation at the south overlie the previous unit. These two sequences ofMaastrichtian age are thought to have a lateral interfingering below the younger units. Paleocene aged tuffite, agglomerate andlimestone with coal seams, argillaceous limestone and sandstone alternation is deposited as a continuation of the units of Maastrichtian age. Limestone and at some places basalt cover these units with an angular unconformity. Then agglomerate and andesiteflows and sandstone with agglomerate beds are deposited. These units are of Eocene age. Various basaltic formations are developedduring Miocene-Pliocene period. These are followed by young alluvium and landslides. 

Abstract: Lower Carboniferous sequence of Nohutluk Tepe in the Aladağ region of Taurus Mountains consists of "deep-water" (basinal-lower slope) facies in the lower parts and "shallow-water" (shelf edge) facies in the upper parts.Basinal-lowerslope facies is generally represented by silicified limestones. These rocks have turbiditic origin. They showlamination and fine grading; they contain radiolaria and other planktonic fossils with transported echinoderm fragments. Associatedrocks are shale, radiolaria bearing lime mudstones, limestone with volcanic grains and altered tuffs.Shelf-edge facies is represented by skeletal and oolitic limestones. There are quartzite and quartz sandstone interbeds withlimestones. Previous studies in the Taurus Mountains have indicated the presence of Lower Canboniferous sequence of shallow waterfacies in a near shore environment. It is the first time that this study distinguished the presence of deep-water facies in the LowerCarboniferous sequence of Nohutluk Tepe in the Aladağ region.

Abstract: The aim of this study is to introduce the Upper Trassic sequence around Dol Village (Palu-Elazığ).in the studied area the magmatic rocks which are composed of metabasalt and metadiabase are in primary relation and alsocontemporaneous with the Norian sedimentary sequence. This sedimentary sequence is represented by crystalline limestone,marble, silicified shale, radiolarite, radiolarian chert, sericite-chlorite schist, glaucophane schist, metaquartzite and metatuff.In the crystalline limestone which is interfingering with metabasalt, Megalodont fragments have been found.By this study the presence of Upper Triassic aged volcanic material bearing sedimentary sequence in Bitlis metamorphites hasbeen proved for the first time by all its evidences. It is known that the splitting of the Arabian and Anatolian continents andforming of an ocean have started in Upper Triassic. At the beginning of rifting a deep trough has formed on the continental crustby block faulting. The Norian aged sequence around Dol Village has been deported in this trough. 

Abstract: In this paper, some data related to the regional metamorphism, obtained during a study on mineralization around a graniteintrusion in the east of Akdağ madeni (Yozgat Î35-c2 sheets), are presented.The study area has a southwest plunging anticlinal structure with a granite intrusion in the center. Indications of contact metamorphism in the rock groups, namely calcsilicatic gneiss, marble, quartzite/quartzschist, gneiss and amphibolite around the graniteintrusion, are clearly seen. Calcite+diopside+scapolite+plagioclase+sphene paragenesis in the calcsilicatic gneisses, and sillimanite+orthoclase paragenesis in the gneisses are observed. Reddish-brown pleochroism color in biotites of the gneisses, and brownishgreen pleochroism color in hornblendes of the amphibolites were determined. All the mineral groups which exist in the abovementioned rocks indicate a high degree of regional metamorphism in the area.On the basis of the petrological data obtained in this study, it is not possible, as it was done by some previous investigtors, todivide the regional metamorphic rocks as upper and lower series and to map them as such. It is not also possible to state thatinitially a high degree of metamorphism, has been effective in the area.In the study area, a carbonaceous series with about 1500 m thickness wnich includes some pelitic layers, had been subjected to anintermediate pressure/high temperature metamorphism, as it is in the vicinity of Kırşehir. It was not possible to differentiate anymetamorphic zoning in the study area; and it is accepted that all the rocks in the area belong to a single metamorphic zone.