Sulfur-isotope distribution and contamination related to the Balya Pb–Zn Mine in Turkey     

Murat Budakoglu  Lisa M. Pratt 《Environmental Geology》2005,47(6):773-781

Sulfur-isotope (³⁴S) values and weight (%) of acid-volatile sulfur (AVS), chrome-reducible sulfide (CRS), elemental sulfur (ES), and acid-soluble sulfates were determined in Balya Mine ore rock, mine wastes, and Kocacay River and Lake Manyas sediments. Estimation of isotopic fractionation (³⁴S) between product sulfate and initial CRS (pyrite) was used to evaluate the progress of sulfide oxidation in the mine-waste area. Water- and acid-soluble sulfate produced from different mine-waste samples, such as metallurgical waste (MW) and waste rock (WR), in laboratory experiments also shows distinct ³⁴S values and allows identification of the acid-mine-drainage sources in the mine-waste area. Average ³⁴S_SO4values are –1.43 for MW (n=4) and +2.06 for WR (n=8). Short (24 hr) and long (60 days) term leach experiments were considered using alternating wet/dry conditions to simulate sulfate-production capacity and metal-discharge characteristics for MW and WR piles. Release of heavy metals follows the order of Pb²⁺ >Mn²⁺ >Zn²⁺ >Cu²⁺ for these pile samples. Values of ³⁴S_SO4 for river water that was collected after 3–4 h of heavy rainfall are close to values of ³⁴S_SO4 for water-soluble sulfates from mine-waste piles used in laboratory leach experiments.This revised version was published in February 2005 with corrections to the placement of the figures.  相似文献   

A Coupled Calibration and Modelling Approach to the Understanding of Dry-Land Lake Oxygen Isotope Records     

Matthew D.?JonesEmail author  Melanie J.?Leng  C. Neil?Roberts  Murat?Türke?  Rana?Moyeed 《Journal of Paleolimnology》2005,34(3):391-411

Comparisons between climate proxies and instrumental records through the last two centuries are often used to understand better the controls on palaeoarchives and to find relationships that can be used to quantify changes in pre-instrumental climate. Here we compare an 80-year-long annually resolved oxygen isotope record from Nar Gölü, Turkey, a varved lake sequence, with instrumental records of temperature, precipitation, wind speed, relative humidity and calculated values of evaporation, all of which are known to be possible controls on lake oxygen isotope systems. Significant relationships are found between the isotope record and summer temperatures and evaporation suggesting these are dominant controls on the isotope hydrology of this non-outlet lake. Modelling the stable isotope hydrology of the lake system allows these relationships to be tested independently. We show that the isotope record follows the same trends in the temperature and evaporation records but that, even when combined, these two climatic factors cannot fully explain the magnitude of change observed in the isotope record. The models show the lake system is much less sensitive to changes in evaporation and temperature than the climate calibration suggests. Additional factors, including changes in the amount of precipitation, are required to amplify the isotope change. It is concluded that proxy-climate calibrations may incorrectly estimate the amplitude of past changes in individual climate parameters, unless validated independently.  相似文献   

Relation between electrical resistivity and earthquake generation in the crust of West Anatolia, Turkey   总被引：1，自引：0，他引：1  

Aysan Gürer  Murat Bayrak   《Tectonophysics》2007,445(1-2):49

In this paper, we present a relation between the earthquake occurrence and electric resistivity structures in the crust, in West Anatolia and the Thrace region of Turkey. The relationship between magnetotelluric georesistivity models and crustal earthquakes in West Anatolia, during a period from 1900 to 2000, is investigated. It is found that most of the large crustal earthquakes occurred in and around the areas of the highest electrical resistivity in the upper crust, although rare small magnitude earthquakes are observed in some parts of the conductive lower crust in West Anatolian extensional terrain. The high-resistivity zones may represent rocks that are probably mechanically strong enough to permit sufficient stress to accumulate for earthquakes to occur in western Anatolia and the Thrace region. However, some recent studies state that the generation of a large earthquake is not only a pure mechanical process, but is closely related to fluid existence. We also reviewed recent world-wide researches including results from the Anatolian data for the first time and discussed all general findings in combination. Our findings show that the boundary between the resistive upper crust and the conductive lower crust correlates well with the cutout depth of the seismicity in West Anatolia and Thrace. This boundary is also attributed to the fluid bearing brittle–ductile transition zone in world literature. Fluid migration from the conductive lower crust to the resistive upper crust may contribute the seismicity in resistive zones. Alternatively, the upper–lower crust boundary may act as a stress concentrator and fluids may help to release strain energy in brittle parts of lower crust, by small magnitude earthquakes, whereas they may help in focusing strain in mechanically strong and electrically resistive zones for large earthquakes to occur.  相似文献   

Failures of structures during the January 24, 2020, Sivrice (Elazığ) Earthquake in Turkey     

Bayrak  Osman Fatih  Bikçe  Murat  Erdem  Muhammet Musab 《Natural Hazards》2021,108(2):1943-1969

Natural Hazards - On January 24, 2020, a severe earthquake of magnitude Mw 6.8 hit the Sivrice district of Elaz?? province at 20:55 (17:55 GMT) local time. This earthquake caused...  相似文献   

Experimental and numerical analyses of circular footing on geogrid-reinforced granular fill underlain by soft clay     

Ahmet Demir  Abdulazim Yildiz  Mustafa Laman  Murat Ornek 《Acta Geotechnica》2014,9(4):711-723

Experimental and numerical investigations into the bearing capacity of circular footing on geogrid-reinforced compacted granular fill layer overlying on natural clay deposit have been conducted in this study. A total of 8 field tests were carried out using circular model rigid footing with a diameter of 0.30 m. 3D numerical analyses were performed to simulate soil behavior using finite element program Plaxis 3D Foundation. The results from the FE analysis are in very good agreement with the experimental observations. It is shown that the degree of improvement depends on thickness of granular fill layer and properties and configuration of geogrid layers. Parameters of the experimental and numerical analyses include depth of first reinforcement, vertical spacing of reinforcement layers. The results indicate that the use of geogrid-reinforced granular fill layers over natural clay soils has considerable effects on the bearing capacity and significantly reduces the lateral displacement and vertical displacement of the footing.  相似文献