Türkiye Jeoloji Bülteni

Abstract: The latest investigation on Kırka borate deposits reveals the existence of a new mineral; kernite(NaBB4O74H2O, which is a sodium-tetraborate ,and it is discovered for the first time in Turkey. After the geologicalposition of samples noted, they have been studied by microscope, chemical analysis, X-ray diffraction, differentialthermic analysis ,and infrared absorption analysis. Colorless, transparent but sometimes white needles / bunch of needles of kernite crystals were found in borax asellipsoidal form where the size, of ellipsoid is in the range of 40 to 60 cms. However, this is the only kernite ellipsoidfound in borax, it is believed that when the underground excavation advances new kernite ellipsoids may be found.Presence of kernite with borax in Kırka borate deposits reveals that the geological conditions differ locally duringthe crystallisation of borates ,and support the idea about the genesis proposed previously (Baysal, 1972 a; 1973 a). Inorder to precipitate kernite instead of borax / converting borax to kernite, it is not necessary to change the chemicalcomposition of the solution, but decrease the activity of water. Activity of water decreases when pressure / temperature / both increases. From this, two possibilities for the occurence of kernite can be suggested. First kernite mayform by dehydration of borax with subsequent local increase of pressure ,and temperature. But, due to structural differences between borax ,and kernite, ,and equilibrium conditions determined by Ataman ,and Baysal (1973) this possibilityless favorable from the second possibility which tiy* authors .believe. In accordance with this, kernite assumed to be formed in the cavities of borax by warmer solutions brought by tiny veinlets.

Abstract: Aktepe-Gökdere region consists of magmatic ,and sedimentary rocks ranging in age through Early Cretaceous to Tertiary. Emplacement of ultramafic magma took place during early stages of Upper Cretaceous in the region.It is thought that the magma was poured out in a wet, flyseh-like sedimentary matrix (Ağıltepe Unit) ,and mixedup with it, thus yielding a para-autochthonous melange structure. This structure became more chaotic during west to easttransportation due to tectonic forces of Alpine orogeny in which orogenic gravity ,and thrusting were also involved.Thrusting of ophiolitic melange over Paleocene ,and younger formations is obscured by tuffaceous cover of Miocene age ,and further tectonic movements.

Abstract: Rodingites observed in the serpentinites, at approximately 30 km east of Çelikhan, (Adıyaman - EasternTurkey) were formed by different degrees of transformation from basic segregations of gabbroic origin. Following thepetrochemical studies, it is concluded that the rodingitisation has «been developed by solutions created during the serpentinisation ,and which permit the metasomatism of calcium ,and other elements. A comparison between chemical analyses ofthe different parts of the rodingites studied ,and the ones of already known rodingites in Turkey, establishes that, duringrodingitisation, the quantities of CaO, Na2O, K2O, SiO2, A12O3 ,and MgO have more / less been modified.

Abstract: The effects in Sultan Mountains ,and their surrounding, of the Helvetian phase of the Alpine Orogeny werevery strong. Sultan ,and Emir Mountains uplifted as a block ,and Akşehir ,and Eber basins depressed as a graben due totectonic movements. Violent fluvial erosion began in Sultan Mountains ,and excessive sedimentation prevailed in the depressed areas. Akşehir, Eber ,and Karamuk basins were occupied ,by lakes since Miocene times. At the end of the UpperMiocene ,and in the Early Pliocene, violent tectonic movements became increasingly active. Finally the fault systems of Sul-tan Mountains were rejuvenated ,and new fault systems developed. Especially, a synthetic fault system formed as a parallel dip-slip normal fault system located along the north ,and north-east edges of Sultan Mountains. On the other hand,synthetic ,and antithetic fault system developed in depressed areas.There are two breaks in slope (threshold) on the stream profiles of Sultan Mountains. These breaks in slope havedirect relation to faults.Graaulometric ,and cumulative curves of Pliocene ,and Plioquaternary deposits to the north ,and north-east of Sultan Mountains, are logharltmic. These curves, too, indicate an accelerated process of sedimentation.

Abstract: The Bovinae fauna of the Middle Sinap consist of Palaeoreas forachyceras Ozansoy, Palaeoreas elegansOzansoy. Palaeoreas lindermayeri Gaudry is unknown in this locality. The representataive of the Bovinae of the MiddleSinap, Palaeoreas braelıyceras Ozansoy was found in the lower part of the Middle Sinap series, is older thanPalaeoreas elegans Ozansoy. There are many different points on the morphological, biometrical, the cross-section ofthe base, the tip of horn-cores of Palaeoreas braehyeeras Ozansoy, Palaeoreas elegans Ozansoy., In addtion, thereare also different turning form of the horn-cores of Palaeoreas brachyeeras Ozansoy, Palaeoreas elegans Ozansoy. Theconcavities of the inside - outside of the horn-cores of Palaeoreas bracnyeeras Ozansoy are deeper than Palaeoreaselegans Ozansoy. First studying about the biometrical, graphical on the materials of the species of Palaeoreas hadbeen made to me. Thus, it will be possible to find the evolutive forms of the species of Palaeoreas.

Abstract: La Presenle etude a pour but. de reflecter la petrographie des roch.es de la region de Cacas. I*`article base surcette etude comprend pltıtöt les roches m6tamorphiques et granites herpyniens situes au Nord du charriage frontal duMassif de Bitlis,.,Les leves de terrains et les recherches petrographiques detailles ont mis en evidence la presence du socle -ancien et desa couverture epim^tamorphiqiie parmis les roches m&tamorphiques du. massif de Bitlis.On, s*est persuadâ que part les formations du socle ancien proviendraient du, metamorphisme dans les conditions deTalmandin-arapfaibolite facias et. oelles de sa couverture meiamorphisees dans le plus, faible,. quartz-albite-muscovite-chlorite subfacies- du greensc-hist facies de type Barrow et d`autre parti* hiatus dans les parageneses :ne pouvant s`expliquer quepar un polymâtamorphisme^Be surcroît, des etudes peixochimique et geochronologique qui seront discutees ult.6rieurem.ent» out justîfîees les conclusions tirees uniquement des considerations patrographiques. 

Abstract: Antimony deposits, among many other sulphide deposits, generally occur as vein type ,and found in closevicinity of volcanic areas. However, it is usually the case that the vein type of mineralization is related to volcanism,strata-bound type of mineralizotion is also expected to be formed in the same area. Subsequent geological events may causemobilization of antimony in .both types ,and change the original setting of the mineralization.Petrofabric analysis of stibnite ores, fluid inclusion studies ,and radiometric age determinations at the MurchisonRange, (South Africa) antimony deposits, revealed that the mineralization is contempereneous with the sediments ,andvolcanics. On the other hand, petrochemical analysis of stibnite ores ,and country rock at Niğde, (Turkey), antimonydeposits, showed that the ore was mobilized from a strata-bound source. 

Abstract: ERTS-A. satellite imagery of.the Northern Kızılırmak basin, NE of Ankara, shows different, tectoniclimeation patterns for Kırşehir Massif in the SE» ,and the North Anatolian Fault Zone System, in the NW. The changeof pattern, seems to take place mainly across the Northern Kızılırmak basin (also known as the Çankırı basin), whichappears to be a gnaben, formed to compression. This may toe the location, of a closed trench, in which part of the Kırşehir Massif may have been dragged. Rocks of ophiolitic melange to the north of Yozgat seem to toe obducted southwardover the Kırşehir Massif. Clockwise hear movement, bad. probably started in the south affecting first the sedimentaryrocks covering the Massif. Later, the activity gradually shifted northwards to the present location of the North AnatolianFault Zone System. 

Abstract: Computer ,and finite-elements method have a very wide range of application in various fields of earth sciences. The results to be obtained from these applications may be of critical importance towards the advancement of ourknowledge of the physical constitution of the earth crust. The purpose of this paper is to introduce to earth scientists thefinite-elements method ,and its application techniques for the solution of various structural problems. In the example givenhere in, the distributions of gravitational ,and tectonic stress components in an elastically heterogeneous material under flatground are shown. From these distributions, the affects of the lithological heterogeneity to the deformation mode of themedium, the points of critical stress concentrations ,and the possible fracture surfaces with their locations ,and directionscould be determined. From the model studies, employing the finite elements method ,and from the computer data, providing that they are interpreted correctly, practical solutions for some structural geology problems could be obtained.

Abstract: La limite entre le Taurus occidental et la depression du Köprü Çay est tectonique, au moins dans la partie dedirection nord-sud, que nous nommerons l`accident de Kırkkavak. Cette limite correspond a un dâcrochement qui a fonctionnâ pendant le Miocene. Sur le trace de ce döcrochement se superpose une phase de compression posterieure au Miocene.La partie aü l`accident est decrochant s`observe entre Burmahan au Sud et le Deliömer Kayası au Nord. Des, Ğcailles tectoniques verticales sĞparent les marnes du Burdigalien â l`Ouest des shales triasiques â l`Est. La disposition des Ğcaillestectoniques suggere un decrochement de composante dextre. La partie chevauchante apparait au Nord du Dıeliömer Kayasıoû les calcaires mesozoiques du Taurus occidental viennent reposer sur le sommet de la serie miocene.

Abstract: As the copper ,and pyrite deposits of the Eastern Pontus ore province are known to be structurally controlled, structural characteristics of the sulphide veins ,and the Fe, Mn ,and Cd content ,and the distribution of theseelements in sphalerites of Southern Bulancak area (Giresun, Turkey) were investigated ,by means of detailed geologicalstudies ,and electron microskobe analysis.It is shown that lûKrieh sphalerites lie on a NW-SE trending zone while Fe, trending zone. These trends correlatewith two dominant fracture systems in the area. The low F,e-Content of the dark brown, black coloured sphaleritesshow no direct relationship between the colour ,and the iron content. 

Abstract: Epicontinental ,and partly basinal limestones of the Middle  Jurrasic-Lower Cretaceous together withpenecontemporaneous ophiolitic masses had been slumped down in to the sedimentary troughs ,and/ basins by thegravity slides in Upper Cretaceous time ,and, originated the limestone olistoliths which are preserved as multi-sized limestone mounds in the present ophiolitic complexes.The diagenetic ,and epigenetic changes in those limestones had followed by the dynamo-metamorphic activities wiclicaused generation of the martolized limestones ,and/ crush breccias. The prensence of the primary deposiitonal texturein the limestone olistoliths are concluded as clues of the modifying effects were superficial ,and limited.In the limestones of the study area (Rehafiye) which is one of those areas characteristics by ophiolitic olistoliths,following microfacies are discerned; a) Lime mud, b) Pelletoid lime mud, c) Mud supported (Lime wackestore), d) Grainsupported (Pack-grainstones) as "Sedimentary microfacies" ,and, e) Intermediate metamorphic (partly mar.blized limestones), f) Crystalline metamorphic (crush breccias) as "metamorphic microfacies".

Abstract: The stratigraphy of the Neogene basin between Çankırı ,and Kalecik has been studied by vertebrate fossils ,and pollen determinations.In the region studied Neogene is represented by the Middle Miocene ,and Pliocene series. The Middle Miocene seriesconsists of two fossiliferous parts. The lower part of this is characterized by Anchitherium aurelianense CUVIER, Micromeryx flourensianus LARTET, Ustriodon splendens MAYET ,and the upper part by Amphicyon major BLAINVILLE,Trilophodon angustidens CUVIER fossils. Trilopmo don pentelicus LARTET, Hipparion gracile KAUP, Gazella gaudryiSCHLOSSER, Paleoreas lindermayeri GAUDRY, Tragoceros amaltheus ROTH et WAGNER are collected from the LowerPliocene series. The Neogene lagoon is bordered by this studies. The correlation of the species found in Turkey with thoseof Asia and Europe shows that the similar species existed in these places.

Abstract: The structure ,and metamorphism of an area of 84 km.2 lying on the Taurus mountains of South-East Turkey was studied. The country around the city of Bitlis was mapped on 1/10 000 scale. The stratigraphical relations ofthe metamorphic rock units are quite obscure. Two major rock units mainly composed of unfossiliferous metamorphicrocks are distinguished on the basis of structural ,and petrographic evidences. Three deformation phases accompanied withprogressive ,and retrogressive metamorphism were distinguished.In the first phase, penetrative foliation which is subparallel to original bedding, has been produced. In the secondphase both bedding ,and foliation have been deformed by tight folding. Open folds ,and an incipient foliation have developed in the third phase. The rocks are metamorphosed to the biotite ,and garnet grade of the greenschist facies. The age ofthis metamorphism is still debatable. Intense thrusting of Alpine age ,and dynamic metamorphism in these thrust zonesare observed. Dating of the metamorphic events in the Bitlis massif are discussed in the light of data obtained from Bitlis ,and adjacent areas. 

Abstract: A linear correlation was found between Cd content ,and zinc wt % as a result of 77 ore specimen analyses for Harşit - Köprübaşı (Tinebolu) mine. Since the cadmium can be an economic by-product, its concentration canDe calculated (using the linear ,relation-ship) from the content of Zn present in the flotation stage.

Abstract: Study of the geomorphological features of an area in Northern Anatolia furnished some critical data tobetter understand Quaternary development of Northern Anatolia. Investigation of numerous river terraces leads to theconclusion that the area suffered severe epeirogenic movements during Quaternary. The presence of a heavily dissectedold peneplain has been proven. The presence of the valey slopes strongly convex upward ,and the summit plains also indicate the important role played by epeirogenic movements in Quaternary shaping of the area.Geomorphological map of the studied area was accomplished during the present study.

Abstract: Western half of the East Anatolian Fault Zone has been mapped for the first time. Its connection withthe Dead Sea Fault System has been confirmed. Types ,and senses of the movements along the East Anatolian Fault Zonesuggest northeasterly movement of the Arabian block rather than to the north.Some parts of the North Anatolian Fault Zone have been mapped. These maps show clearly the great earthquake danger presented by the North Anatolian Fault Zone.Southward tilting of the Menderes Massive has been documented. This tilting supports the view defending the activeuparching of the central part of the Menderes Massive.The presence of previously unknown active faults has been shown ,and the value of seismo-tectonic maps has oncemore pointed out in the light of these discoveries.