Bulletin of the Mineral Research and Exploration (BMRE)
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Early Miocene seed like plant remain fossils and facies associations from the Nallıhan district (NW Turkey)
No full textSeed like fossils recognized by their distinctive orbicular in shape are seen in the early Miocene of the Nallıhan area (NW Türkiye). We examined more than one hundred specimens and facies associations for interpreting of fossil morphology and its paleoenvironment. The fossils as dark crystallized dots on the bedding surface of clayey limestones are characterized by a thick edged lenticular shape with a smooth one side and concave another side with circular nucleus. Their internal structures have circular a few whorlings, too often radial calcitic lamellae on the upper side and a few circular coiling at the bottom side. SEM, EPMA and RAMAN data of soft nucleus, hard part, filling materials and surrounding sediments support its plant origin. The Paleogene aged Kızılbayır formation and early Miocene aged Karadoruk and Akpınar formations include the following facieses: non-channelized red sandstone and mudstone (F1), channelized “confined” reddish-beige pebbly sandstone and conglomerate (F2), medium to coarse siliciclastics (F3), mudstones interbedded with sandstones (F4), thin bedded clayey limestone bearing plant fossils (F5) medium to thick bedded limestone (F6) and rhythmic siliciclastics - clayey limestone including coal occurrences (F7). Abundant plant fossils indicate a planted shallow lake margin with low topography during the early Miocene. https://doi.org/10.19111/bulletinofmre.60969
Geochemical features and petrogenesis of Gökçeada volcanism, Çanakkale, NW Turkey
No full textGökçeada Island, which is situated west of Biga Peninsula, has widespread magmatism with variable ages. Lower-Middle Eocene Dağiçitepe volcanics are the oldest volcanic unit in the island and consist of lavas, tuff-tuffites. They are influenced by alteration and almost all minerals, except quartz, are transformed into other minerals. Lower Oligocene Gökçeada andesitic lava/ domes exhibiting hypocrystalline porphyric texture, are the products of NE-SW trending domes/ cryptodomes. The phenocrysts assemblages consist of plagioclase, hornblende, clinopyroxene ± biotite and quartz. Middle Miocene Eşelek volcanics, which occur as lavas and pyroclastic rocks, exhibit hypocrystalline porphyric and intersertal textures. They are composed of plagioclase, hornblende and clinopyroxene crystals. Rhyolitic Dağiçitepe volcanics and andesitic Gökçeada lava/domes have calc-alkaline, andesitic Eşelek volcanics have tholeiitic character. They have geochemical features similar to subduction-related magmas. Lower-Middle Eocene Dağiçitepe volcanics are the products of syn-collisional magmas that have undergone processes of crustal contamination due to thickened crust. Whereas, Lower Oligocene Gökçeada andesitic lava/domes are the products of post-collisional magmas and were derived from metasomatized lithospheric mantle. Middle Miocene Eşelek volcanics were also derived from lithospheric mantle but, the mantle source generating Eşelek volcanics were relatively depleted over time. Geochemical data demonstrate the decreasing role of subduction signature and crustal contamination during the genesis and evolution of Gökçeada volcanics from Lower-Middle Eocene to Middle Miocene.
https://doi.org/10.19111/bulletinofmre.54341
The electric power production targeted Unconventional Geothermal Systems (UGS), some conceptual designs and their thermodynamics classification
No full textThe geothermal energy is a renewable and relatively clean energy resource. The amount of geothermal energy stored just in the upper crust of the earth is large enough to meet the world’s energy needs for thousands of years. Unfortunately, only a small portion of this potential can be utilized today by the conventional methods. The rest corresponds to the hot, fluid-poor areas which cannot be utilized by the current technology. The first concrete steps towards the utilization of such high potential areas emerged in the late 1960s and early 1970s. These studies have gradually continued in the following years, and many new terms and conceptual designs have been proposed so far. Unfortunately, no comprehensive definition has been established on this subject yet. This may bring about some difficulties such as the failure to express the intended concept in the right manner, the inability to determine the legal boundaries for the regulations required by the countries to make use of these areas which pose high risks in the commercial point of view. In this paper, some of the major terms and conceptual designs used for the projects targeting the power generation from fluidpoor hot areas are discussed. Furthermore, all of these terms have been gathered under the title of “Unconventional Geothermal Systems-UGS” and these designs are classified according to the types of thermodynamic system for the first time in this study. In addition, some new suggestions that can be used to define the definitional boundaries of these terms are put forward. https://doi.org/10.19111/bulletinofmre.66070
Usability of PC-ash as lightweight aggregate in foam concrete
No full textFoam concretes can be produced with aggregate or without aggregate. In this study, the possibility of using PC ash as lightweight aggregate in the production of foam concrete was investigated. Waste- PC ash is emerging from the pulverized coal furnace about 10 tons/day in a textile factory located in the vicinity of Dinar (Afyonkarahisar). The chemical properties, particle size distribution and grain densities of PC-ash were determined. Foam concrete with a dry density of 450 kg/m3 at a cement dosage of 250 kg/m3 and w/c:0.65 was produced after the aggregate analysis. The PC-ash which is used in foam concrete mix is between 0 and 200 kg/m3. 100 mm cube and 300x300x50 mm prism samples were prepared with this foam concrete. The compressive strengths of the cube samples and the thermal conductivity coefficient of the prism samples were tested at the 28th day. The average compressive strength of foam concrete samples with a density of 452 kg/m3 was determined as 1.07 MPa and the thermal conductivity coefficient was determined as 0.097 W/mK. As a result, it has been determined that PC-ash as lightweight aggregate can be successfully used in production of precast element and light floor-screed.
https://doi.org/10.19111/bulletinofmre.54556
Neogene stratigraphy and regional correlation of the Çeşme Peninsula, Western Anatolia, Turkey
No full textThis study aims to investigate the stratigraphy and regional correlation of terrestrial Neogene sediments and volcanics in the Çeşme Peninsula. Neogene deposition is represented by two main sedimentary successions separated from each other by an angular unconformity. The lacustrine dominated Çeşme group characterized the Lower-Middle Miocene deposition is formed by Şifne, Ovacık and Çiftlik formations. The felsic pyroclastics (Alaçatı pyroclastics), which are the early products of the Armağandağı volcanism, laterally associated with the Çeşme group deposition, deposited on the Şifne formation and interrupted the lacustrine sedimentation. The lacustrine sedimentation continued uninterruptedly with Ovacık and Çiftlik formations after the deposition of pyroclastics, which terminated the sedimentation of the Şifne formation. The calc-alkaline Armağandağı volcanism is composed of felsic pyroclastics, andesitic volcaniclastics (Reisdere volcaniclastics) and lavas (Zeytineli lava) respectively from bottom to top. The Late Miocene-Early (?) Pliocene Kaştepe group, which covers all these units with angular unconformity, is represented by a succession, which grades from alluvial fan (Karagöz formation) up to lacustrine deposits (İnlice formation).
https://doi.org/10.19111/bulletinofmre.58165
Geochemical characteristics of the Eocene Karataş volcanics (Northeast Sivas, Turkey) in the İzmir-Ankara-Erzincan Suture Zone
No full textKarataş volcanics, is the product of Eocene volcanics crop out in the form of two belts along the northern and southern boundaries of the İzmir-Ankara-Erzincan Suture Zone. According to geochemical data, these volcanics have alkaline basic-intermediate character and consist of basaltic trachyandesite, trachyandesite and trachyte. This volcanic activity has been controlled by fractional crystallization and crustal contamination from basaltic trachyandesite to trachyte. Orientation of the samples towards amphibole area on the Rb/Sr - Ba/Rb ratio diagrams, dispersion of the Zr/Ba ratios (0.08 - 0.33) in the lithospheric mantle range, increase in the Ba/Rb ratio, decreases in the MgO, Ni and Cr contents point out that this volcanism originated from enriched lithospheric mantle rather than asthenospheric mantle. Geochemical data show that this enriched lithospheric mantle material is upper continental crustal material, main part of enrichment resulted by the subduction related fluids and also the contribution of the sedimentary materials. This situation may be explained that; the melts, derived from N-MORB or OIB bearing material ascended into the continental crust in a pre-collisional period and were reactivated by extensional tectonic and/or delamination processes during the post-collisional period, possibly caused the partial melting within the upper continental crust and produced the Karataş volcanics.
https://doi.org/10.19111/bulletinofmre.66971
Characteristic mollusc, larger foraminifera findings and environmental interpretations of the Middle Eocene Kocaçay formation deposits around Ayvalıca (Bayat, Çorum)
No full textAlthough the Çankırı-Çorum Basin was studied for various purposes such as geological, stratigraphical, tectonic, coal and oil exploration, studies on fossils are limited. Especially there have not been detailed studies on molluscs and larger foraminifera. The research area is located at the vicinity of Ayvalıca (north of Çankırı-Çorum basin). The Middle Eocene Kocaçay formation, which outcrops in the Çankırı-Çorum Basin, is widespread around Bayat Çorum in the north of the basin, Sulakyurt Kırıkkale in the west, Çiçekdağı Kırşehir in the south and Sungurlu Çorum in the middle of the basin. The formation is composed of conglomerate, carbonated sandstone, limestone and sandy marls and also includes rich larger foraminifera and molluscs. This study mainly focuses on taxonomy and environmental interpretations of Ostrea roncaensis (Partsch in coll. Bayan, 1870) de Gregorio, 1884, Velates perversus (Gmelin, 1791) species from Mollusca and Nummulites beaumonti d’Archiac and Haime, 1853, N. aturicus Joly and Leymerie,1848, N. perforatus (de Montfort, 1808) and Assilina exponens (Sowerby, 1840) species from larger Foraminifera. In addition, considering faunal features from bottom to top Ostrea roncaensis, Velates perversus, Nummulites aturicus and Assilina exponens Abundance Biozones were identified. The age range of the Kocaçay Formation is determined as Lutetian-Bartonian. Lithological and faunal contents indicate that sediments of the Kocaçay formation were deposited within lagoon to nummulitic sets in a shallow marine environment.
https://doi.org/10.19111/bulletinofmre.68546
Tectonic meaning of the deformation in shallow marine region between Gaziköy-Mürefte (Sea of Marmara) by using seismic reflection data, NW Anatolia
No full textWithin the scope of this paper, seismic reflection and bathymetry studies were carried out in the shallow marine area forming the westernmost part of the Tekirdağ Basin using the R/V Selen Research Vessel within the MTA Marine Research Department. In the study area, ~ 500 km length bathymetry data and ~191 km shallow seismic profiles ( 41 lines) were collected. By means of the data, tectonic structures and deformation textures of the North Anatolian Fault System (NAFS) in the marine area of Gaziköy were examined. As a result of the processing and interpretation of the seismic sections, compression structures occurring due to the SW rotation of the NAFS in the study area, the morphology of the Ganos depression that formed as a result of faulting and also three different stratigraphic units were distinguished. These units are separated from each other by distinct unconformity surfaces and each unit presents different deformation structures. One of the most significant results obtained from the seismic data is that the unconformity surface that separates the current sediments of the seafloor from the older units is represented by the overlapping structures indicate sea level changes. It has been assessed that this situation occurred as a result of the erosional process developed during sea level fall.
https://doi.org/10.19111/bulletinofmre.78447
2D inverse modeling of the gravity field due to a chromite deposit using the Marquardt’s algorithm and forced neural network
No full textIn this paper, two modeling method are employed. First, a method based on the Marquardt’s algorithm is presented to invert the gravity anomaly due to a finite vertical cylinder source. The inversion outputs are the depth to top and bottom, and radius parameters. Second, Forced Neural Networks (FNN) for interpreting the gravity field as try to fit the computed gravity in accordance with the estimated subsurface density distribution to the observed gravity. To evaluate the ability of the methods, those are employed for analyzing the gravity anomalies from assumed models with different initial parameters as the satisfactory results were achieved. We have also applied these approaches for inverse modeling the gravity anomaly due to a Chromite deposit mass, situated east of Sabzevar, Iran. The interpretation of the real gravity data using both methods yielded almost the same results.
https://doi.org/10.19111/bulletinofmre.58922
Morphological parameters causing landslides: A case study of elevation
No full textThe history of landslide susceptibility maps goes back about 50 years. Hazard and risk maps later followed these maps. Inventory maps provide the source of all these. There are different parameters selected specially for each field in the literature as well as parameters selected because they are easy to produce and obtain data. This study tried to research the effect of elevation on landslides by reviewing the literature in detail. The used class ranges and elevation values were reviewed and applied to map sections selected from Turkey. By analyzing the results, the goal was to determine at which elevation ranges landslides occurred. The study tried to investigate the effect of the parameter of elevation using data from the literature. It works to compare the elevation values for map sections selected to compare with the literature. The study comprises two stages. The first step tried to acquire statistical data by researching the data from the literature. The data were investigated in the second stage. For this purpose, close to 1.500 studies prepared between 1967 and 2019 were reviewed. According to the literature, the parameter of was used in analyses because it is easy to produce and is morphologically effective.
https://doi.org/10.19111/bulletinofmre.64975