The control of sea-level changes on sedimentation in the Mut Basin: Late Serravallian-Early Tortonian incised valley-fill

Yalvaç and Ilgın basins surrounding Sultandağları were opened due to the orogenic collapse in the early Miocene. The NW-SE trending Çakırçal and Akşehir fault zones, forming boundaries with these basins, caused both the opening of the basins and uplifting of Sultandağları. During the Miocene-Pliocene period, the alluvial fans fed from Sultandağları developed on the basin margins, while the lacustrine carbonate and clastic depositions formed in the basin’s interior. The alluvial fan deposits are laterally and vertically transitional with lacustrine sediments and alternate several times in the sequence. The alluvial fans, widespread in the region, consist of debris flow, hyperconsantrated stream flood, braided river and meandering river deposits. Fan deposits that pass from high-energy fluvial facies at the basin margin to the low-energy fluvial facies towards the basin interior have been interpreted as stream-dominated alluvial fan deposits. The age data obtained from the fan deposits of the Yalvaç and the Ilgın basins show that Sultandağları concurrently feeds the alluvial fans on both flanks. Alluvial fan deposition around Sultandağları formed under the control of tectonic and climatic processes. The tectonism led to the formation of basins and source areas. Simultaneously, the climate maintained the streams to be perennial by precipitation, thus proving a continuous sediment supply to the basins. Tectonism and climate-controlled base-level changes determined the quantity of sediments carried to the basin from the source area, causing regressive or transgressive developments.

Semi-enclosed Marmara Sea is a passage between the Aegean Sea (Northeastern Mediterranean Sea) and the Black Sea. The Marmara Sea is connected to the Black Sea and the Aegean Sea through the İstanbul Strait (Bosphorus) and Çanakkale Strait (Dardanelles), respectively. Despite the fact that the late Pleistocene-Holocene connections between the seas have been explored by many scientists, there are still uncertainties about the nature and timing of the connections. Within the scope of this study, a new approach has been displayed for post-glacial connections between the Black Sea, Marmara Sea, and the Aegean Sea. This study is based on 80 shallow seismic reflection lines, multibeam bathymetric data and 15 short gravity cores collected from the northeastern shelf of the Marmara Sea (between Silivri and Golden Horn). The sea bottom and sub-bottom morphology have a highly chaotic structure at the exit of the Büyükçekmece/Küçükçekmece lagoons and further east near the Marmara- İstanbul Strait junction. This chaotic bottom and sub-bottom surface morphologies are mainly controlled by the structure of the basin, current regime of the shelf, coastal drainage systems and by the sea/lake water level changes controlled by climate and the sill depths of the two straits, which in turn determined the water exchange between the seas. The sedimentological interpretation of the seismic reflection profiles and core sediments have allowed us to distinguish five stratigraphic units (S1-S5) and four sedimentary layers (A-D) over the acoustic basement. The lower stratigraphic unit and sedimentary layer are separated from the overlying acoustic basement by a chaotic to parallel and by a high amplitude seismic reflector. Seaward dipping units of the acoustic basement are inferred to be the seaward continuation of the Oligocene–Upper Miocene units widely exposed on land. The presence of three different marine terraces distinguished (T1-T3) along the northeastern shelf of the Marmara Sea have been associated with the six different curves of the post-glacial sea-level changes. From statistical point of view, the most significant terraces occur from -78 m to -80 m (T1), -58 m to -62 m (T2) and -28 m to -32 m at (T3). Considering the global sea level curves, these terraces can be dated 9.25, 12.25 and 13.75 Cal kyr BP, respectively. DOI: 10.19111/bulletinofmre.401208

This study consists of micro paleontological assessments of samples taken from drills carried out around Yedikule area for the micro zonation study made by the Istanbul Municipality in European side of Istanbul province. The investigation was performed on core samples in three drill wells excavated within Yedikule settlement area. Very well preserved ostracod fauna and micro mollusks at some levels were obtained from claystone, clayey limestone, limestone, fossilliferous sandstone, blackish-green and organic clays and marl layers. With these three drill core samples in which the microfauna occurs, the age of the succession was determined as Tertiary (Late Miocene-Early Oligocene) with microfauna.

As a result of complex studies - geological-structural, morphostructural analytical, mineralogical mapping of quartz formations, detailed geochemical work and analysis of geochemical fields – forecasting prospecting features of gold ore taxon’s: ore zone; ore field; deposit and ore body. They are characterized by groups of criteria: morphostructural, stratigraphic-lithological, structural-tectonic, magmatic, geophysical, metasomatic, mineralogical, geochemical factors and attributes, and a geological-genetic model of the gold-bearing ore-forming system in the collapse zone. Favorable geological and structural conditions for the localization of gold mineralization in the mountains of Karakchatau are associated with the areas of long-term tectonic-magmatic activation in metalliferous sediments of Є-О contrast lithological composition. The coincidence of manifestations of gold mineralization to the blocks formed by transverse faults at the sites where they intersected the Karakchatau crush zone was noted. To the channel-localizing parts inside are blocky and unextended interblock tectonic structures with positions in favorable “structural traps” in their azimuthal curvatures of executed productive types of hydrothermal, sulfidizing quartz. The results of mineralogical mapping of quartz formations along the Karakchatau crush zone (Western Uzbekistan) are considered. Five genetic types of quartz are distinguished. The most productive of them is hydrothermal quartz of types 3 and 4 associated with pyrite,arsenopyrite and gold, which forms vein fields in areas of kinks and expansion of the zone of crushing. Identification of any goods and services that can be used for commercial purposes, including in the geological structure, other regions of Western Uzbekistan. https://doi.org/10.19111/bulletinofmre.432046  

Each mineralization style is characterized by typical signature associations between elements due to elemental interactions, therefore the coherence and closure effects problem must be overcome in geochemical processing. The coherence indicates the ratios between two components (rows or columns) remains the same whether they are considered in a subcomposition or in the full composition. The log-ratio transformation (LRT) has recognized as a standard procedure to support subcompositional coherence. The log-transformed data is applicable for geochemical data to unveil such associations, prior to applying the multivariate analysis like correspondence analysis (CA) and principal component analysis (PCA). At the present study, subcompositional coherence is overcome by inverse iso-metric log-ratio transformation for geochemical compositional data at two polymetallic and porphyry deposits. Based on Ilr-transformed data, Ag, Au, As, Pb, Te, Mo and rather S, W, Cu are enriched as polymetallic elements at Glojeh, while Au-Cu-(Mo) compositions indicate a porphyry deposit occurred in Dalli deposit. The ability to handle zero values in the data matrix and determining an elemental eccentricity from the center of each axis based on Euclidean distances are the advantages of CA method, with compression to LRT. Whereas, loading factors which spread in every direction and providing subcompositional coherence are the competitive advantages of PCA based on LRT, for both case studies. Results with these techniques show significant ability to draw an inference in such geochemical data, and in improving the performance of multivariate techniques using LRT. https://doi.org/10.19111/bulletinofmre.456958  

This study was made for investigating the relationship between iodine and hydrocarbon accumulations and to determine iodine contents of formation waters in the Southeastern Anatolia basin oilfields where have been produced almost all of the Turkey oils (more than 95%). Formation water samples have taken from 234 production wells in 49 oilfields which have different geological structures where oil and gas production has performed by the Turkish Petroleum Company (TPAO). Also, the drilling mud samples from EBY-17 oilwell in Elbeyli (Adıyaman) field has collected, and their iodine analyses were carried out. Although the fields in the Southeastern Anatolia basin are old and some fields the secondary production methods are used, the high relationship between the oil and gas deposits and iodine were proved. As well as in other oil and gas fields in the world, not all reservoir waters in the Southeastern Anatolia basin are saline. However, all of them are rich in iodine. Therefore, the iodine-rich waters are a direct indicator for oil and gas producible reservoirs (containing mature hydrocarbon). Reservoir-targeted iodine geology and hydrogeology methods have simple sampling process, and laboratory analyses can result at a short time. The results are low cost, reliable and consistent. In the case when these data are utilized with other geological and geophysical methods, it is determined will be a practical and useful tool to reduce the hydrocarbon exploration risk to a minimum and to discover new deposits suitable for commercial production. https://doi.org/10.19111/bulletinofmre.501519