Yazar "Aydemir, Attila" seçeneğine göre listele

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    Crustal Structure of Turkey from Aeromagnetic, Gravity and Deep Seismic Reflection Data
    (Springer, 2012) Ates, Abdullah; Bilim, Funda; Buyuksarac, Aydin; Aydemir, Attila; Bektas, Ozcan; Aslan, Yasemin
    In this paper, aeromagnetic and gravity anomalies obtained from the General Directorate of Mineral Research and Exploration were subjected to upward continuation to 3 km from the ground surface to suppress shallow effects and to expose only regional, deep sources. Then, a reduction to pole (RTP) map of aeromagnetic anomalies was produced from the 3 km upward continued data. A sinuous boundary to the south of Turkey is observed in the RTP map that may indicate the suture zone between the Anatolides and African/Arabian Plates in the closure time of the Tethys Ocean. The sinuous boundary can be correlated with the recent palaeo-tectonic maps. The southern part of the sinuous boundary is quite different and less magnetic in comparison with the northern block. In addition, maxspots maps of the aeromagnetic and gravity anomalies were produced to find out and enhance the boundaries of tectonic units. Crustal thickness, recently calculated and mapped for the western Turkey, is also extended to the whole of Turkey, and the crustal thicknesses are correlated with the previous seismological findings and deep seismic sections. The average crustal thickness calculations using the gravity data are about 28 km along the coastal regions and increase up to 42 km through the Iranian border in the east of Turkey. Density and susceptibility values used as parameters for construction of two-dimensional (2D) gravity and magnetic models were compiled in a table from different localities of Turkey. 2D models indicate that all of the anomalous masses are located in the upper crust, and this could be well correlated with the earthquakes which occurred at shallow depths.
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    Evaluation of Gravity and Aeromagnetic Anomalies for the Deep Structure and Possibility of Hydrocarbon Potential of the Region Surrounding Lake Van, Eastern Anatolia, Turkey
    (Springer, 2014) Aydemir, Attila; Ates, Abdullah; Bilim, Funda; Buyuksarac, Aydin; Bektas, Ozcan
    The North Anatolian Fault (NAF) is not observed on the surface beyond 40 km southeast of Karliova town toward the western shoreline of Lake Van. Various amplitudes of gravity and aeromagnetic anomalies are observed around the lake and surrounding region. In the gravity anomaly map, contour intensity is observed from the north of Mus city center toward Lake Van. There is a possibility that the NAF extends from here to the lake. Because there is no gravity data within the lake, the extension of the NAF is unknown and uncertain in the lake and to the east. Meanwhile, it is observed from the aeromagnetic anomalies that there are several positive and negative amplitude anomalies aligned around a slightly curved line in the east-west direction. The same curvature becomes much clearer in the analytic signal transformation map. The volcanic mountains of Nemrut and Suphan, and magnetic anomalies to the east of the Lake Van are all lined up and extended with this slightly curved line, provoking thoughts that a fault zone that was not previously mapped may exist. The epicenter of the major earthquake event that occurred on October 23, 2011 is located on this fault zone. The fault plane solution of this earthquake indicates a thrust fault in the east-west direction, consistent with the results of this study. Volcanic mountains in this zone are accepted as still being active because of gas seepages from their calderas, and magnetic anomalies are caused by buried causative bodies, probably magmatic intrusions. Because of its magmatic nature, this zone could be a good prospect for geothermal energy exploration. In this study, the basement of the Van Basin was also modelled three-dimensionally (3D) in order to investigate its hydrocarbon potential, because the first oil production in Anatolia was recorded around the Kurzot village in this basin. According to the 3D modelling results, the basin is composed of three different depressions aligned in the N-S direction and many prospective structures were observed between and around these depressions where the depocenter depths may reach down to 10 km.
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    Geophysical investigation and hydrocarbon potential of Cankiri-Corum Basin, Turkey
    (Elsevier Science Bv, 2013) Aslan, Yasemin; Buyuksarac, Aydin; Erik, Nazan Yalcin; Aydemir, Attila; Ates, Abdullah
    The Cankiri-Corum Basin is one of the larger, onshore sedimentary basins in central Turkey. In this paper, the integration of geophysical data and geological findings in the Cankiri-Corum Basin was performed and they both present a complex basin structure. In the frame of geophysical study, two-dimensional (20) models were constructed using gravity and magnetic anomalies. Seismic sections were interpreted and correlated with the 2D models using the borehole data as control. Basement depth, basin geometry and sources for magnetic anomalies along the 20 model profiles were determined in integration of seismic, gravity, aeromagnetic and borehole data. Seismic section CC-L-1 is correlated with the Topuzsaray-1 well. Tuffs and volcanic units penetrated in this well might be correlated across a reverse fault close to the borehole. Seismic sections, CC-L-2 and CC-L-3, are consistent with the gravity models at the deeper parts of the sections. On the other hand, there are inconsistencies in the shallow sections with the gravity models due to unexpected velocity variations in both the horizontal and vertical directions. The average depth of basement was found to be about 5 km by means of gravity modelling, which was correlated with the seismic sections. Magnetic anomalies are represented by intense values in the NW portion of the study area, but they indicate very low intensities in the middle of the map. A reverse magnetised body to the north of the study area was modelled in 2D along a profile and it was interpreted that this body might be an ophiolitic remnant. Polarities of many anomalies to the south and northeast of the region indicate remanent magnetisation. Alignment of the polarities extends in the northwest direction, indicating that the region rotated in the anticlockwise direction. Because there is around a 5 km sedimentary basin fill in the study area, it may exhibit hydrocarbon potential and the Yesilcat oil seep evidences this potential. Surface samples were collected to examine source rock potential and to correlate with the Yesilcat seep by analysing the organic geochemical properties. In this study, 72 samples were collected from different formations and it was found that the Yoncali Formation displays better source rock potential than the other formations studied. (C) 2013 Elsevier B.V. All rights reserved.
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    Indoor and outdoor Radon concentration measurements in Sivas, Turkey, in comparison with geological setting
    (Elsevier Sci Ltd, 2010) Mihci, Metin; Buyuksarac, Aydin; Aydemir, Attila; Celebi, Nilgun
    Indoor and soil gas Radon (Rn-222) concentration measurements were accomplished in two stages in Sivas, a central eastern city in Turkey. In the first stage, CR-39 passive nuclear track detectors supplied by the Turkish Atomic Energy Authority (TAEA) were placed in the selected houses throughout Sivas centrum in two seasons; summer and winter. Before the setup of detectors, a detailed questionnaire form was distributed to the inhabitants of selected houses to investigate construction parameters and properties of the houses, and living conditions of inhabitants. Detectors were collected back two months later and analysed at TAEA laboratories to obtain indoor Rn-222 gas concentration values. In the second stage, soil gas Rn-222 measurements were performed using an alphameter near the selected houses for the indoor measurements. Although Rn-222 concentrations in Sivas were quite low in relation with the allowable limits, they are higher than the average of Turkey. Indoor and soil gas Rn-222 concentration distribution maps were prepared seperately and these maps were applied onto the surface geological map. In this way, both surveys were correlated with the each other and they were interpreted in comparison with the answers of questionnaire and the geological setting of the Sivas centrum and the vicinity. (C) 2010 Elsevier Ltd. All rights reserved.