Iodine concentrations of soils near Trabzon, Turkey: a region of endemic goiter     

E. ?ift?i  E. ?evketbeyo?lu  S. Tokel 《Environmental Geology》2007,53(2):457-465

Iodine contents of soils developed over the major rock formations of the northern zone of the Eastern Pontide Tectonic Belt (Northeastern Turkey) have been investigated with respect to soil-parent rock relationship, effect of topography, elevation, and climate to construe its effect on the health of the local population. Samples were collected from the A and B horizons of the soils developed over the major stratigraphic units constituting the eastern Pontides, including the Lower Basic Complex of Jurassic-Lower Cretaceous age, the Berdiga limestone (Jurassic-lower Cretaceous), the Dagbasi granitoid (Upper Cretaceous), volcano-sedimentary sequence of Upper Cretaceous age, ore-bearing and barren dacites of Upper Cretaceous age, and Neogene alkaline basalts. Chemical analyses of soil samples indicate significantly lower iodine abundances for all the soils studied (5–28 ppm) in comparison to the average abundance of iodine in analogous soils of other parts of the world (22–93 ppm). The concentration of iodine in soils developed over the same geologic formation decrease with increasing elevation. In certain cases, this decrease may reach up to 70%. Goiter is highly common throughout this region in Turkey. The results of this study suggest that the iodine deficiency of region’s soils may be a principal underlying cause for this area of Turkey being an endemic goiter region.  相似文献   

遥测地震台网记录限幅时速报震级的估算     

曹肃朝  高景春  刘继录  赵英萍 《山西地震》2001,(4):16-18,29

以遥测地震台网大量的观测资料为基础，拟合了限幅时间t的对数与近震震级ML的线性回归关系，结果显示二者有很好的相关性，相关系数为0．967，标准误差为0．2121。检验证实结果是可靠的。得出当台网记录限幅时，采用这种方法快速估算震级进行速报是可行的结论。  相似文献   

阿瓦提县地下水水化学特征及成因初探   总被引：5，自引：0，他引：5  

陈德斌  陈旭光  顾新鲁  黄新凤 《干旱区地理》2001,24(4):376-379

在大量的实测资料和参考资料的基础上，从第四纪地质演化史的角度，运用同位素方法理论，详细阐述了该地区地下水的水化学现状特征及在平面上和垂向上的变化规律，并对其水化学特征的形成机理进行了较为深入的分析、研究，得出了该地区地下水化学演化史，从而为当地的地下水资源开发提供了借鉴，并提出了水资源开发中注意的问题。  相似文献   

基于GIS的农用地质量综合评价方法研究--以无锡市马山区为例   总被引：14，自引：0，他引：14  

王铁成  周生路  王杰臣  彭补拙 《干旱区地理》2001,24(2):118-122

根据农用地质量综合评价因素所具有的空间特征和相关性，采用GIS技术和方法，对评价区农地的自然条件和社会环境信息以一定格式输入、存储、检索和操作，并根据GIS空间分析的类型和功能，结合模糊综合评判模型等数学方法，提出农用地质量综合评价系统的框架模型。并以无锡市马山区为例，开展了评价因子的量化、空间分析、等级划分、面积量算及评价图件输出等功能的试验，为进一步构建集成的土地评价信息系统原型奠定了基础。  相似文献   

Ophiolite emplacement by strike-slip tectonics between the Pontide Zone and the Sakarya Zone in northwestern Anatolia, Turkey     

Ali Elmas  Erdinç Yiğitbaş 《International Journal of Earth Sciences》2001,90(2):257-269

Northwestern Anatolia contains three main tectonic units: (a) the Pontide Zone in the north which consists mainly of the Gstanbul-Zonguldak Unit in the west and the BallLda<-Küre Unit in the east; (b) the Sakarya Zone (or Continent) in the south, which is juxtaposed against the Pontide Zone due to the closure of Paleo-Tethys prior to Late Jurassic time; and (c) the Armutlu-OvacLk Zone which appears to represent a tectonic mixture of both zones. These three major tectonic zones are presently bounded by the two branches of the North Anatolian Transform Fault. The two tectonic contacts follow older tectonic lineaments (the Western Pontide Fault) which formed during the development of the Armutlu-OvacLk Zone. Since the earliest Cretaceous, an overall extensional regime dominated the region. A transpressional tectonic regime of Coniacian/Santonian to Campanian age caused the welding of the Gstanbul-Zonguldak Unit to the Sakarya Zone by an oblique collision. In the Late Campanian, a transtensional tectonic regime developed, forming a new basin within the amalgamated tectonic mosaic. The different tectonic regimes in the region were caused by activity of the Western Pontide Fault. Most of the ophiolites within the Armutlu-OvacLk Zone belong to the Paleo-Tethyan and/or pre-Ordovician ophiolitic core of the Gstanbul-Zonguldak Unit. The Late Cretaceous ophiolites in the eastern parts of the Armutlu-OvacLk Zone were transported from Neo-Tethyan ophiolites farther east by left-lateral strike-slip faults along the Western Pontide Fault. There is insufficient evidence to indicate the presence of an ocean (Intra-Pontide Ocean) between the Gstanbul-Zonguldak Unit and the Sakarya Zone during Late Cretaceous time.  相似文献   

Potential use of fly ash and bentonite mixture as liner or cover at waste disposal areas   总被引：2，自引：0，他引：2  

Murat Mollamahmutoğlu  Yüksel Yilmaz 《Environmental Geology》2001,40(11-12):1316-1324

  相似文献   

中国西部汛期降水的时空演变分析     

朱姝  周亚军  蔡忠兰  卢俊山 《干旱气象》1996,(3)

用中国西部１０省区（１１０°Ｅ以西）１３０个站的月降水资料，分析夏半年４—１０月的月降水相对系数、月际和年际标准差变化特征。结果表明，各地区受不同降水体系影响，降水在时空上的差异很大。天山北部主要受西风带降水体系影响，月际降水差异不大；西北地区受西太平洋副热带高压雨带影响，降水具有西进北抬尔后东退南辙的特征；高原季风雨带对四川西部、云南和西藏有明显影响，雨季从东南向西北开始，而结束与此相反。月际和年际标准差表明，在以南疆盆地为主的东北—西南一带地区的标准差为高值区，而该地区以东和以北地区的标准差呈逐渐减小趋势  相似文献   

A finite element model for the diffusion—convection equation with applications to air pollution problems     

Erol Varoḡlu 《Advances in water resources》1982,5(1):35-41

A method of solution for the diffusion-convection equation in one spatial dimension has been developed previously. The generalization of this method into two-spatial dimensions will be presented. The method employs space-time volume elements with edges joining the nodes at subsequent time levels oriented along the characteristics of the associated pure convection problem. The accuracy and utility of the method are demonstrated by solving several examples and results are compared with the exact solutions.  相似文献   

Şarköy-Mürefte 1912 Earthquake's Tsunami, extension of the associated faulting in the Marmara Sea, Turkey     

Y. Altınok  B. Alpar  C. Yaltırak 《Journal of Seismology》2003,7(3):329-346

The historical tsunamis in the Marmara Seawere mainly caused by earthquakes andneeded to be documented. Following 1999Izmit earthquake occurred at the EasternMarmara region, a complete inventory ofactive faults in the Marmara Sea regionbecame much more stressed. To the west, thelatest event is 09.08.1912arköy-Mürefte Earthquake. Itoccurred on the active Ganos Fault zone andwas one of the largest earthquakes in theBalkans. The eastern termination of theassociated faulting is in the deep WestMarmara Trough, westernmost of thesuccessive basins forming the Marmara Sea.On the basis of recent multibeam bathymetryand seismic reflection data, estimatedtotal length of the surface rupture isabout 56 km. The historical data reviewedfrom library and archive documents,geological field surveys and offshoregeophysical investigations have shown thatthe 1912 earthquake produced a tsunami. Inaddition a seabed dislocation, the sourceof 1912 tsunami can also be assigned to thesediment slumps appearing in the form ofechelon landslide prisms along the southernslopes of the West Marmara Trough.  相似文献   

A comparative study of the design spectra defined by Eurocode 8, UBC, IBC and Turkish Earthquake Code on R/C sample buildings     

Adem Doğangün  Ramazan Livaoğlu 《Journal of Seismology》2006,10(3):335-351

Earthquake codes have been revised and updated depending on the improvements in the representation of ground motions, soils and structures. These revisions have been more frequently seen in recent years. One of the key changes in earthquake codes has been performed on the design spectra. In this paper, the design spectra recommended by Turkish Earthquake Code and three other well known codes (Uniform Building Code, Eurocode 8, and International Building Code) are considered for comparison. The main purpose of this study is to investigate the differences caused by the use of different codes in the dynamic analysis and seismic verification of given types of buildings located at code defined different sites. The differences in expressions and some important points for elastic and inelastic spectra defined by the codes are briefly illustrated in tables and figures. Periods, base shears, lateral displacements and interstory drifts for the analyzed buildings located at code defined ground type are comparatively presented.  相似文献