Türkiye Jeoloji Bülteni

Abstract: Variouspaleo-current ,and submarine mass- movement directions have been measured in the Lower Tertiarysediments of the region between Çankırı, Çorum ,and Yozgat, all situated to the east of Ankara. An attempt has beenmade to classify the:observed submarine mass-movements on the basis of their slide, flow / current origin. The author.believes that such an approach will. beı usefulin. the: interpretation ofthe sedimentation ,and tectonic activity during theformation of such mass-movements. Measured paleo-current directions have been used for the preliminary interpretationof the paleo-geography of this region.At this stage of the investigations, it appears that this region has basically a complex structural frame. The basement of Çankırı basin, situated in the northern part of this region, has been fractured by ENE - WSW oriented faultswhich were active during Lower Tertiary sedimentation. This basin was connected to neighbouring basins by narrowchannels, NNE - SSW oriented in the west ,and WNW - ESE oriented in the east. The basin as well as these channelshave been filled by various i submarine mass-movement. andpaleo-current material, formed during frequent tectonicactivities.

Abstract: The exposed core gneisses of the Menderes Massif had been sampled form three regions (form South toNorth, Çine ,and Ödemiş Massifs, Gördes Massif ,and Eğrigöz Massif). These samples had been investigated by the X-Ray,electronmicroprobe ,and microscopic methods .The cell parameters of K-feldspars ,and their bo, txm, tso, t2m values (thescattering1 probability of Al atoms in the four kinds of tetrahedrons) had been calculated from more than 50 samples bythe X-Ray Method. Chemical composition of K-fieldspars ,and their perthitic albite flakes ,and also coexistent plagioslaseswith K-feldspars had been determined by electronmicroprobe.From the point of structural view the calculated unit cell parameters, with small regional variations .display theK-feldspars to be in intermediate microcline state. Beside that, the K-feldsp,ars, derived as microcline f rom X-Ray filmsmust have been framed by very tiny triclinic domains .which could hardly be recognized by X-ray procedures. Also thetjO, tjin, tso ,and t2m values indicate that the studied crystalls are in intermediate microcline state.The An percent of coexistent plagioclases with K-feldspars shows a variation from 8 to 25. This variation is dueto Ca occurences of different values within the derived metamorphic rocks from sedimentary rocks. Over 17 >% Anvalues of plagioclase ,and observed poligonization texture of feldspar ,and quartz indicate that these rocks fiormed abovethe medium grade metamorphic phase (^,540°C).The results can be outlined under the scope of the petrogenetic evolution of Menderes Massif as follows: MonoclinicK-feldspar occurences in primary sedimentary units which had later .become Augen Gneisses of Menderes Massif, firsttransformed to triclinic forms by the rising temperature ,and then retransformed to monoclinic forms at the oligoclaseformation boundary (550°C).Occurence of sillimanite in the whole series from South to North indicates that the metamorphism reached to thebeginning temperatures of migmatization (680°C). But, triclinic metric, whick is a general retriclinization product inK-feldspar occurences in Augen Gneiss, conforms that the formation temperature is around 450° C. This evidence indicates that young alpidic phases made only retrograde metamorphic effects on Menderes Massif. The 66+4 milion yearsradiometric age of muscovites from Augen Gneisses near Çine shows an agreement with the age of the young alpidicphase. As a result, main metamorphic phases which caused to progressive metamorphism in Menderes Massif are olderthan that alpidic phase. 

Abstract: The mechanism of kink-bands, developed in experimentally ,and naturally deformed stibnite, could beexplained by studying them under the microscope ,and obtaining their X-ray pole figures. Naturally deformed stibniteis usually subjected annealing. Thus, twins, grains with low angle boundaries ,and elongated subgrains may be developed.When these features studied under microscope, some information is obtained about the deformation history of deformedstibnite.

Abstract: Primary ,and secondary dispersion patterns of Pb, Zn, Cu, Ag, ,and Hg in the wallrocks ot the Keban PbZn mine have been studied. It was found that the wallrock anomalies developed adjacent to the ore deposit are narrow.This was mainly due to the poor permeability of the wallrocks ,and also to the presence of chemically active limestoneat the footwall which was replaced by the ore. On the other hand, however, it was determined that the residual hydrothermal ore solutions carrying these elements have migrated upward from the deposit, following permeable channelsalong both the massive limestone ,and the sericite-schist contact ,and along the majör fractured zones in the vicinity ofthe deposit. The flow of these solutions have resulted in the formation of leakage anomalies at the surface 200 m abovethe ore deposit.It was concluded that the extencive leakage anomalies, which may be present in the surrounding area, can be utilised in searching similar blind ore deposits. In fact, strong primary ,and secondary Cu and Pb - Zn - Ag anomalies aredetected around Kebandere area at the North of the known deposit. II is strongly recommended that these leakageanomalies should be tested for the presence of a possible blind ore deposit.

Abstract: The lead-zinc occurrence in Ağızlar village of Gölköy township of Ordu province is a group of veins thatcut through altered biotite andesite. Five rock units whoseages ranging from Upper Cretaceous to Tertiary were differentiated by geologic investigation of the area. These are, from oldest to youngest, pyroxene andesite, biotite andesite,limestone, andesite, ,and basaltic dikes. Characteristic structural elements of the area are normal faults. Important oreminerals in the Ağızlar lead-zinc occurrence are sphalerite ,and galena; gangue minerals are quartz ,and pyrite. Accordingto their mineral content, two types of veins are distinguished in the area: pyrite veins ,and pyritic lead-zinc veins. Threepyrite veins ,and seven pyritic lead-zinc veins are found in the area. Wall rocks surrounding the veins were altered invarying intensity in zones as wide as 400 m. Alteration zones are sericitization as the veinward zone, argillization as theouter zone, ,and locally, propylitization as the outermost zone.

Abstract: Trend surface analysis of the chemical data on Mortaş bauxite deposit indicates existance of a commonNW-SE axis. AlpOg, iand TiO2 percentage decreases, P^Og and Na percentage increases towards this axis. SiO2 behavesdifferently and decreases radially away from the center of the deposit. Contour maps of the chemical data indicateexistence of a few circular anomalous areas. A12O3 and TiQ, percent decreases and Fe 200 increases towards such anomalous points.Origin of Mortaş bauxite deposit is controversial, magmatic as well as sedimentary origin has been postulated. Ourobservations suggest that Mortaş bauxites may have formed as a weathering product of limestones. The common NW-SEdirection may correspond to the long axis of ia karstic depression. Anomalous points may correspond to limestoneblocks included in bauxite within such depression. The negative correlation between Fe 20 o and Al,O3 as wel as TiO,, andthe independent behavior of SiO may be explained by secondary leaching.

Abstract: The descriptions of Involutina species are gdven and their stratigraphical levels are discussed. Involutingspecies is found in Turkey (Taurus) in various ages, places and association as follows.

a) Upper Ladinian: Involutina gaschei praegaschei Zaninetti with association of Involutina eomesozoica (Oberhauser), Involutina sinuosa pragsoides (Oberhauser), Endothyra sp., Trocholina sp..

b) Carnian: Involutina sinuosa pragsoides (Oberhauser), Involutina eomesozoica (Oberhauser), with associationojf Endothyra sp., Trocholina sp. and Endothyranella sp.

c) Nonian: All the Involutina species (present in our text) with association of Trocholina permodiscoides Oberhauser and Milioliporsb sp..

d) Rhetian: Norian association of Involutina and their associates are present with Triasina sp.. We thougt it asTriasina biozone.

e) Liassic: Apearence of piliate Involutina species. Involutina Hassica (Jones).

Abstract: The artesian aquifers show elastic response to alternate loading and unloading of short duration. Astudy has been carried out in order to investigate the effects of loading ofi long duration an<} continuous discharge fromthe aquifer on the elasticity of the aquifer. The artesian aquifer, underlain by Pineview reservoir, in the State of Utah(U.S.A.), has been selected for this purpose. In this study.the long term reservoir level measurements and the waterlevel measurements taken from the observation wells were compared and evaluated. As a conclusion, under the conditions of loading of long duration and continuous discharge, a slight reduction in the aquifer elasticity and thus a permanent deformation in the skeleton of the aquifer has been observed. This deformation causes a reduction in the yield ofthe aquifer. 

Abstract: Systematic descriptions of two newly discovered Pyrgula and Corymbina fossil species £ronı Afyon-Gürleydk area are given.Samples of Pyrgula species are collected from the Lower Pliocene and Corymbina species from overlying beds.Pyrgula species are different from the species collected from Paratethys and West Anatolian region (Denizli). Thereforetwo new species: Pyrgula hoyrani n.sp., Pyrgula costata n.sp. are proposed. All of the specimens of our Corymbina rhodensis Bukowski show slnistral features; a new sub-species, Corymbina rhodensis senestris n.ssp. is proposed. 

Abstract: Economically important borate deposits were formed as chemical precipitates in lacustrine environments.Factors controlling the formation of these deposits are mainly the composition, pH and the temperature of motherliquors.Experimental studies and field observations show that Turkish borate deposits can conveniently be divided in twogroups; a-those which have shown a complete sequence of precipitation in a Na;2O-CaO-B2O3-H.2O system (Kırkatype), and b-aJl other known deposits that do not contain Na borate.Deposits of group (a) were most likely formed from a solution having NaoO7CaO ratio close to unity and above,provided that the solution contains the necessary B concentration. The result of precipitation from such a solution would give a vertical sequence of Ca, Na-Ca and Na borate layers which indicates gradual increase in concentration within the lakesystem. The lateral variation in such a deposit is that Na-borates are dominant at the central and deepest parts of thedeposit. These Na-borate layers are progressively transformed in Na-Ca and Ca-borates towards the edge of thebasin.

Abstract: The area studied lies to the north of gulf of Antalya and to the SE of Lake Eğridir.The aim of the study is to find out the basic geological problems of the area lying between central and westernTaurus Mountains and the relation between middle and western Taurus Mountains.In the research area, the rocks are grouped as ` `Units" which are different from each other in stratigraphic andtectonic characters. These units are termed as Karacahisar unity, Oppiolitic Unity and Dulup Unity. All these units aretransgresively overlained by deposits of Miocene age.These units show similarites with the units found in the western Taurus Mountains by their tectonic and stratigraphic characters (Antalya nappes). They differ in tectonic style from central Taurus Mountains.

Abstract: This study concerns the recently discovered marine Oligocene series in Palu (NE of Elazığ) region emphasizing its stratigraphy and systematic study of its characteristic foraminifera.The rock units of Upper Cretaceous, Oligocene, Lower Miocene and Pliocene ages crop out in Palu ragion (NE of Elazığ). Upper Cretaceous sequence is composed of diorite, sedimentary rocks, spilite, serpentinite and albite - diabaseunits.The ophiolitic sequence is unconformably overlain by the Gevla Çayı Formation of Oligocene age. Gevla Çayı Formalion is composed of alternating conglomerate, sandstone, marl and Nummulitic limestone beds. This formation is unconformably ( ?) overlain by Okçular Formation of Lower Miocene age which is composed of algal and coral limestone.Systematic studies of Nummulites fichteli, Lepidocyclina (Eulepidina) dilatata Michelotti, Lepidocyclina (Eulepidina)favosa Cushman and Halkyardia maxima Cimerman, which are found in Gevla Çayı Formation, are given.

Abstract: Rock units of Upper Jurassic, Paleocene, Eocene and Neogene age crop out 10 km south of Polatlı. Limestones of Çaldağ Formation are definitely of Upper Jurassic age with Protopenoroplis striata Weynschek, LabyrintJiinasp. and Olypeina jurassica Favre. Kartal Formation ojf Lower Paleocene (Montian) age overlies uncomformably ÇaldağFormation, It is composed of conglomerate, lacustrine limestone, sandstone and lignite of laminations, which are deposited in delta enviroment. The marine limestone of the Upper part of Kartal Formation contains Rotalia trochidiformis Lamarck, Mississippina binkhorsti (Reuss) and Distichoplax biserialis (Dietrich). Kirkkavak Formation overlies uncomformably (?) the Kartal Formation. It is composed of sandstone, limestone and marls of Middle Paleocene (Thanetian) agewith Alveolina (G-lomalveolina) primaeva Reichel and Renz and Discocyclina sewnesv Douvilla at bottom. The upper partand the top of Kirkkavak Formation ise composed of sandy and clayey limestone, marls of Lower Ilerdian age with Nummulites solitarius de Lstf Harpe, N. eodlis Douville, Alveolia cucimijormis Hottinger and A. ellipsoidalis Schwager; MiddleIlerdian with RanikothaUa couisensis (d`Archiac) and Upper Ilerdian with Ranikothalia nuttalli (Davies) and the otherforaminifers. Eskipolatlı formation overlies uncomformably the Kirkkavak Formation and is composed of conglomerate,sandy and clayey limestone, sandstone and marls. The lowest levels o|f Eskipolatlı Formation is of Lower Cuisian age withNummulites planulatus (Lamarck) and Alveolina oblonga (d`Orbigny). The upper levels of this formation is of MiddleCuisian age with Alveolina canavarii Checchia ve Rispoli, A. lehn`eri Hottinger and the other foraminifers. Six new speciesof Alveolina are also established. 

Abstract: The description of Miscellariea meandrina (Carter) is given and its stratigraphical level is discussed. Miscellanea meandrina is found in Turkey in various ages, places and association as follows:1) In Lower Paleocene (Montian), associated with Orduina erki Sirel, Orduina erki conica Sirel, Laffitteina sp.,Karamosphaera sp. and Lockhartia? at Gölköy (SW Ordu).2) In Middle Paleocene (Thanetian), associated with Alveolina {Glomalveolina) primaeva Reiehal and Renz, Dictyoconus sp., Lituonella sp. and Lockhartia sp. around Van.3) In Paleocene (Thanetian), associated with Alveolina (Glomahfeolina) primaeva Reichel and Renz, Discocyc Unaseunesi Douville, Operculina sp., near Polatlı (SW Ankara).4) In Upper Paleocene (Ilerdian), associated with Sakesaria cotteri Davies and Ranikothalia sp., near Diyadin (SEAğrı). 

Abstract: The purposes of this work have been to obtain some general information on the actual mechanism of deformation and failure in both laboratory and `in-situ` shear test; and to shed light upon the development of progressive andretrogressive failure under varius test conditions.The study includes extensive laboratory testing and a theoretical approach to progressive deformation. In the latterapproach, a computer model of a shear block with certain discontinuities was developed. The method of calculation utilizes finite-element technique for the determination of the state of strain and stress in elastic and/or elastoplastic structures, for an assessment of the mechanical influence of a given discontinuity within the elastic structure, for a systematic evaluation of the effects of type of loading conditions on shear deformation and failure characteristics of the blockand to examine the actual mechanism of shear deformation and failure in a test block under direct shear loading. Thetheoretical program was accompanied by mechanisal laboratory tests designed to test the reliability and applicability ofconclusions suggested by the theoretical studies.It has been concluded that choice of boundarry conditions exerts an important control on failure mechanism. The tensile zones, which always develop within the test block, are of mechanical importance. Local failure which occurs in thesetensile zones, in the ‘separation’ mode, under certain boundary conditions, leads to progressive failure. Straight-linefailure envelopes can be interpreted as representation of a single (shear) failure mode. Parabolic failure envelopes aresuggestive of multiple modes of failure.‘In-situ’ shear tests on geological materials should be interpreted in more sophisticated terms; i. e., as a consequenceof variable combined stress state, involving inhomogeneous stress field; extensive stress reorientation, .and multiple crackpropagation.The theoretical approach to the mechanism of deformation and failure characteristics of `in-situ` shear tests, utilizingfinite-element method, appears to be a valid approach for prediction of certain experimental results.