Türkiye Jeoloji Bülteni

Abstract: Some new evidence about the metamorphic evolution of the Menderes Massif mostly obscured by the young events, has been recognized from both of the core and cover series. These can be given as i) Pan-African high-pressure and high-temperature metamorphisms under eciogite and granulite facies conditions in the core series and ii) Tertiary high-pressure/loo w temperature metamorphismunder epidote-blueschist/eclogite facies conditions in the cover series. The relics of granulite facies metamorphism which are mostlycharacterized by the orthopyroxene and pseudo-cordierite occur in most of the core units such as charnockite, orthopyroxene and/orpseudo-cordierite leptite-gneiss, orthopyrosene gneiss, metatonalite and metagabbro. The high-pressure relics in the Precambrian core series are defined by the eclogite occurrences which are related to the metagabbro stocks. These medium temperature eclogites under 650 °C and 13 kbar conditions which are made up of "omphacite (Jd20-25)+Garnet+Rutile±Kyanite" pass gradually to the garnet amphibolites resulted from the Barrowian-type overprint under upper amphibolite facies conditions. This multi stage sequence ofevents which follow a metamorphic path under eclogite, granulit and almandine-amphibolite facies conditions with migmatization and partial melting are regarded to be related to the Pan-African orogeneses similar to the Bitlis Massif. Tertiary HP/LT metamorphismunder epidote-blueschist/eclogite fades conditions which was mostly obliterated by the subsequently following Borrowian-type overprint are recognized in the Mesozoic cover units around Dilek peninsula, Selçuk and Gölmarmara, NW part of the Menderes Massif.The P-T estimations, less than 430 °C and minimum 10 kbar, and mineral assemblages mainly consisting of blue amphiboles and omphacite (jd37)+Garned, clearly reveal the subduction related character of this metamorphism. In the general evolution of the Neo-teth~yan-Vardar ocean, the Menderes Massif should have been buried dowh at about 35 km along a subduction zone during Tertiary (Eocene ?) time. Based on this new evidence about the two-fold Tertiary metamorphism, the Menderes Massif can be obviously correlated with the Cycladic Complex in terms of the metamorphic evolution and litostratigraphical rock succession.

Abstract: Lâdik-Sızma region is a currently inactive Hg province which, when in operation, met a third of all mercury production of Turkey. Stibnite is usually present in all the mercury occurrences of the region which are also locally accompanied by Cu and Pb-Zn enrichments. The mineralization is in the form of patches and veinlets and occurs along usually faulted and brecciated carbonaceousrock and phyllite contacts. The present work is based on a stream sediment sampling program in the vicinity of the Hg occurrencesand tries to evaluate Au, Ag and base metal potential in their peripheries. Gold concentrations are always below detection limit but,although erratic, Ag produced concentrations as high as 39 ppm. The distribution of high Ag concentrations points out three anomalous locations; two of these are likely to be resulted from known Hg occurrences whilst the third one, 2 km to the northwest of Sızma,is from an area of highly altered limestone but with no reported mineralization. To interpret the data a five factor model is used inthis study which produced reliable results. Factor 1 accounts for Cu enrichment and associated hydrothermal alteration, especiallyoxidation, characterized by high factor loadings for Cu and Fe (0.807 and 0.846 respectively). Factors 2 and 5 point out the lithological effects of phyllite, schist and metaporphyry, and carbonate rocks respectively. Factor 3 is the indication of Pb-Zn enrichments whilst factor 4 corresponds to Sb and As-enriched zones. The contour plots of factor scores for factors 1, 3 and 4 indicate thatfinding new Hg±Sb occurrences is unlikely and that the new projects should be concentrated on Pb-Zn and Cu prospection.

Abstract: Copper deposit of Maden has been operated since 2000 B.C. and the flotation waste water, slags, waste and metallic water aredirectly charged to Maden Çayı. Thus, plants along Maden Çayı accumulate very high levels of elements. Water, soil and plant samples (as leaves, stem and flower) were collected along Maden Çayı (before and after the discharge point) and at the unpolluted are(Malatya and Kralkızı Dam). Iron contents of samples were determined by flame atomic absorption spectrophotometer. Data for thestatistical significance of plant/soil relationship for iron are summarised. The Phragmites australis (cav) Trin. ex stuedel (r=0.8683)and Carex acuta L. (r=0.8945) species for Fe showed (in leaves) highly significant (P < 0.01) relationship. These plant species areapparently food indicators the these elements and could be successfully used for the further biogeochemical prospecting.

Abstract: Molluscan assemblages have been formed determining that the surface sediments of the Marmara Sea taken by grab method haddifferent fauna compositions showing different environmental features during Late Quaternary. According to this, the first assemblage represents Neoeuxinian (upper most Pleistocene) having a salinity of 2-8 %o on a gravel dominant base and it was formed mainlyby species such as Dreissena rostriformis distincta And., Lithoglyphus naticoides (C. Pfeif.), Hydrobia (Hydrobia) ventrosa (Mont.),Micromelania caspia lincta Mil.. During this period the sea level of the Marmara sea was at least 28 m. lower than that of today whichwas probably the sill depth where the Holocene transgression initiated. Later, the salinity of the environment increased a little due tothe Mediterranean transgression during Early Holocene and brackish water-marine environment conditions were formed (10 %o18%o salinity). The second molluscan assemblage which represents the above mentioned environment was formed mainly by eury haline marine species such as Rissoa (Rissoa) splendida (Eichw.), Parvicardium exiguum Gm., Cerastoderma (Cerastoderma) edule (L.).This period lasted shortly; Typical Mediterranean fauna comprising numerous species such as Jujubinus striatus (L.), Turritella (Turritella) tricarinata (Brocc.), Chrysallida (Parthenina) excavata (Phill.), Trunculariopsis truncula (L.) etc. became dominant due to theaccelerated transgression during Late Holocene, and consequently today`s conditions of the Sea of Marmara were formed. So thethird molluscan assemblage living in salinity varying from 18%o to 35%o was formed belonging to above mentioned period and wasdivided in  3 sub-groups according to lithology and depth.

Abstract: The purpose of this investigation is to introduce the ostracoda assemblages of the Kuzgun and Handere formation (Late MiocenePliocene) at the North of Yenice (Tarsus) within Adana Basin. An enviromental interpretation will be proposed with the use of these data. The Kuzgun formation observed broadly in the study area was placed with the units ofpebly sandstone, sandstone, siltstone andclay stone. The result of the paleontological study, 25 genera and 42 species of ostracoda were identified. The Kuzgun formation containing genera such as Aurila, Loxoconcha, Xestoleberis, Cytheridea, Cyamocytheridea, Cushmanidea, Carinocytherideis and Keijella showed that this fauna formation had deposited in the shallow marine environment. In the study area, the Handere formationwas represented by evaporitic units, conglomera, sandstone, stone, siltstone and claystone. No fauna which could give any information about age and environment could be found in the river deposits observed in the evaporitic units and the laterally of this in thefloor levels of the formation. These units were assumed to be paralic environmental product in the characteristic of transition-terrestrial. On the other hand, a Globoratalia suteare Catalono ve Sprovieri belonging to the planktic foraminifera was identified amongthe thin grained units located in the shore environment latarelly of the same units. After evaluation, it was understood that this fossiland the lithologic and the stratigraphic properties of the this units were Messinian old. Over this level, the units of conglomera, sandstone, siltstone and claystone of Handere formation-were presented. Sphaerodinellopsis seminulina (Schwager) ve S. dehiscens(Parker ve Jones) belonging to the planktic foraminifera determined among the thin grained units showed that the environment hadpassed to mar inal conditions at the Early Pliocene time.

Abstract: The changes of Orbitoides parameters, particularly internal ones, within time and place are controversial. This study examinesthe matter with Orbitoides examples from various localities of Turkey (Hekimhan, Darende-Malatya; Adıyaman; Pazarcık-KMaraş;Osmaneli-Bilecik). Biometrical analyses of more than 1250 specimens of the Orbitoides species particularly from the Early to Middle Maastrichtian of Turkey indicate that environmental factors affected the test shape, embryo size, the number of both auxiliary andperi-ebriyonic chamberlets. The effects of depth, substrate and changes related to time were discussed.

Abstract: The species of Donacosmilia corallina de Fromentel (hermatipic coral) have been defined as Upper Jurassic (Oxfordian-Kimmeridgian, Portlandian ? ) in age by most European research workers. The presence of this form has also been noted from the reefal limestones of Yukarıköy formation in the Araç-Daday (Kastamonu) region of Turkey. In this study systematic description of this formis presented and the associated reefal limestones are assigned to Upper Jurassic (Upper Oxfordian-Lower Kimmeridgian) in age.