Croatia — a coastal and maritime country     

Nikola Stražičić 《GeoJournal》1996,38(4):445-453

Croatia, through its geographic position, is a Mediterranean/Adriatic and Central European/Danube state. As an Adriatic coastal state, it has a long maritime tradition, which is apparent in its well-developed shipping (2.4 million GT), the high-quality ship-building industry (among the top six in the world) and through its numerous sea ports, of which many were established in ancient times. The leading national port is Rijeka, which is at the same time an important transit port for Austria, Hungary, Slovakia and the Czech Republic.The exceptionally indented Croatian Adriatic coast with its attractive archipelagos and favorable climatic and oceanographic conditions in the coastal sea offers very advantageous conditions for comprehensive tourist utilization. This is particularly true of nautical tourism, which is complimented by a larger number of constructed and well-equipped yachting ports/marinas on the coast and islands.  相似文献   

Radon,Lung Cancer Risk and Environmental Geology in Gejiu Area     

卢伟  王任重等 《中国地球化学学报》1997,16(3):278-282

The incidence of lung cancer in the Gejiu area of Yunnan Province ranks the first in the world.The radon level(indoor,soil) was measured in the Gejiu area by the SSNTD method from 1990 to 1996,The result indicates an extensive high-level of indoor radon in that area though U and Th are lower in local limestones,The indoor radon level of houses located in the geologic fault zone is 6 times high that 2km far from the fault zone.The reason probably is that the radon level of soil in the fault is 6-8 times high that 1 km far from the faults.our data indicate that a lower range of radon levels,0-100Bq.m^-3,exists in healthy families.However,a higher radon level,over 800 Bq.m^-3,is often found corresponding to that of cancer patients‘ homes(the house-owners are suffering from either lung cancer or leukaemia or liver cancer),Obviously,an increase in lung cancer incidence follows an increase in indoor radon level,The risk of cancer induced by indoor radon is no longer an inference,but a fact.  相似文献   

The Carpatho-Balkanides and adjacent area: a sector of the Tethyan Eurasian metallogenic belt   总被引：3，自引：1，他引：3  

S. Janković 《Mineralium Deposita》1997,32(5):426-433

The Tethyan Eurasian metallogenic belt (TEMB) was formed during Mesozoic and post-Mesozoic times in the area of the former Tethyan ocean on the southern margin of Eurasia, with the Afro-Arabian and Indian plates to the south. It extends from western Mediterranean via the Alps and southeastern Europe through the Lesser Caucasus, the Hindu Kush, and the Tibet Plateau to Burma and SW Indonesia, linking with the West Pacific metallogenic belt. The Carpatho-Balkan region is one of the sectors of the TEMB, characterized by some specific features. The emplacement of ore deposits is related to a definite time interval, and to specific tectonic settings such as: 1. Late Permian-Triassic intracontinental rifting along the northern margin of Gondwanaland and/or fragments already separated. This setting involves volcanogenic and volcano-sedimentary deposits (iron, lead/zinc, manganese, antimony, mercury, barite), skarn deposits associated with volcano-plutonic complexes of bimodal magmatism, and low temperature carbonate-hosted lead/zinc deposits. 2. Jurassic intraoceanic rifting – ophiolite complexes: This setting hosts major magmatic (particularly podiform chrome deposits) and volcano-sedimentary deposits, mainly of the Cyprus type. 3. Subduction-related setting involves porphyry copper deposits, lesser skarn deposits (iron, locally Pb-Zn), massive sulphide Cu (e.g. Bor) accompanied locally by Pb-Zn of replacement type, epithermal gold deposits, associated with calc-alkaline igneous complexes of the Early Tertiary-Late Cretaceous, and the Neogene gold/silver and base metals deposits. 4. Post-collision continent-continent setting includes deposits of Pb-Zn, Sb, As, Au-Cu associated with volcano-plutonic complexes of calc-alkaline affinity. Several major Alpine metallogenic units are developed in the Carpatho-Balkanides and adjacent area, each characterized by specific development, mineral associations, and types of ore deposits. Received: 3 June 1996 / Accepted: 10 January 1997  相似文献   

Flexible spectral methods for the generation of random fields with power-law semivariograms     

Johannes Bruining  Diederik van Batenburg  Larry W. Lake  An Ping Yang 《Mathematical Geology》1997,29(6):823-848

Random field generators serve as a tool to model heterogeneous media for applications in hydrocarbon recovery and groundwater flow. Random fields with a power-law variogram structure, also termed fractional Brownian motion (fBm) fields, are of interest to study scale dependent heterogeneity effects on one-phase and two-phase flow. We show that such fields generated by the spectral method and the Inverse Fast Fourier Transform (IFFT) have an incorrect variogram structure and variance. To illustrate this we derive the prefactor of the fBm spectral density function, which is required to generate the fBm fields. We propose a new method to generate fBm fields that introduces weighting functions into the spectral method. It leads to a flexible and efficient algorithm. The flexibility permits an optimal choice of summation points (that is points in frequency space at which the weighting function is calculated) specific for the autocovariance structure of the field. As an illustration of the method, comparisons between estimated and expected statistics of fields with an exponential variogram and of fBm fields are presented. For power-law semivariograms, the proposed spectral method with a cylindrical distribution of the summation points gives optimal results.  相似文献   

Magnetostratigraphy and palaeoclimate of Red Clay sequences from Chinese Loess Plateau   总被引：5，自引：0，他引：5  

Donghuai Sun  Dongsheng Liu  Mingyang Chen  Zhisheng An  Shaw John 《中国科学D辑(英文版)》1997,40(4):337-343

Two Red Clay profiles near Xi’an and Xifeng were investigated in an attempt to determine magnetostratigraphic and palaeoclimatic records. The results show that aeolian dust accumulation and the related East Asia palaeomonsoon system had begun by 6.5 Ma, and it is deduced that the Tibetan Plateau had reached a significant elevation at that time. The late Tertiary palaeoclimatic history of the Red Clay as reflected by magnetic susceptibility is reconstructed during the period of 6.5–2.5 Ma. Stepwise increase in susceptibility of aeolian dust accumulation appears to have a close correlation to the uplift processes of the Tibetan Plateau. The remarkable increase of aeolian dust accumulation at 3.2 Ma appears to be due to the influence of global ice volume on the East Asia monsoon. Palaeomonsoon variation during the late Tertiary as recorded in the Red Clay sequences from the Chinese Loess Plateau can be regarded as the product of a number of interacting factors, such as uplift of the Tibetan Plateau, solar radiation, global ice volume, etc. Project supported by the National Natural Science Foundation of China and the Foundation of Xi’an Laboratory of Loess and Quaternary Geology, Chinese Academy of Sciences.  相似文献   

地电实验的电阻率变化形态特征     

陈峰  安金珍 《国际地震动态》2004,(Z1):94

在地震预报研究中,地电阻率变化形态被作为地震预报的一种前兆手段.迄今为止,国内外已经做了许多不同加载方式的室内和室外岩石或样品的电阻率变化实验,积累了相当丰富的承载岩石或样品的电阻率变化资料.本文介绍部分不相似的实验结果,以促使此项研究进一步深入发展.  相似文献   

冲绳海槽地区地壳结构与岩石层性质研究   总被引：9，自引：4，他引：9       下载免费PDF全文

郝天珧  刘建华  郭锋  黄忠贤  胥颐  戴明刚  李安春  付永涛 《地球物理学报》2004,47(3):462-468

用冲绳海槽地区地质、地球物理、地球化学数据与资料，对横跨大陆边缘—大洋板块的中国东部—冲绳海槽—琉球岛弧地区进行综合研究. 根据地震体波、面波成像结果，空间与布格重力异常及磁力异常的综合解释等结果，利用调和系数法对该研究区的地壳厚度进行了计算，并对地壳属性进行分析. 同时，选择中国东部东北地区的宽甸、华北地区的汉诺坝、华南的闵溪和台湾海峡的澎湖列岛与冲绳海槽和日本岛弧的新生代玄武岩开展元素—同位素对比研究. 结果认为冲绳海槽岩石层明显减薄，上地幔低速层已达到莫霍面，在地幔中已形成交代软流层. 元素—同位素研究表明：它不同于中国东部，与琉球岛弧地区的特点也不相同. 综合分析认为：冲绳海槽地壳属于过渡型地壳，与大洋地壳的许多特点颇为相似.  相似文献   

Research on Relationship Between Fluorine in Tap Water and That in Urine of Chinese Residents     

王滨滨  郑宝山  翟城  刘小静  安宁 《中国地球化学学报》2004,23(4):373-379

In this study, the relationship between fluorine in drinking water and that in urine of urban residents in China is assessed. Fluorine concentrations in tap water and those in urine show a good correlation with a linear regression coefficient of 0. 9798, indicating that the fluorine concentrations in big cities under investigation are extremely low, and the main source of fluorine is tap water. The weather effect on the intake amount of fluorine is also discussed. When air temperature is above 15℃, people would intake more fluorine through drinking water with the rise of air temperature. When temperature is below 15℃, no remarkable relationship is observed between air temperature and the intake amount of fluorine. This phenomenon indicates that the main source of fluorine in China is tap water instead of foodstuff.  相似文献   

The GIS and analysis of earthquake damage distribution of the 1303 Hongtong M=8 earthquake     

GAO  Meng-tan 《地震学报(英文版)》2004,17(4):398-404

The geography information system of the 1303 Hongton M=8 earthquake has been established. Using the spatial analysis function of GIS, the spatial distribution characteristics of damage and isoseismal of the earthquake are studies. By comparing with the standard earthquake intensity attenuation relationship, the abnormal damage distribution of the earthquake is found, so the relationship of the abnormal distribution with tectonics, site condition and basin are analyzed. In this paper, the influence on the ground motion generated by earthquake source and the underground structures near source also are studied. The influence on seismic zonation, anti-earthquake design, earthquake prediction and earthquake emergency responding produced by the abnormal density distribution are discussed. Foundation item: National important fundamental research “The Basic Research of Important Project in Damage Environment” and The important project “The Seismic Hazard Assessment Research and Anti-earthquake Structure Research” from China Earthquake Administration during the 10th Five-year Plan. Contribution No. 04FE1008, Institute of Geophysics, China Earthquake Administration.  相似文献   

Seismic studies of the Brasília fold belt at the western border of the São Francisco Craton, Central Brazil, using receiver function, surface-wave dispersion and teleseismic tomography     

Marcelo Assumpo  Meijian An  Marcelo Bianchi  George S.L. Frana  Marcelo Rocha  Jos Roberto Barbosa  Jesús Berrocal 《Tectonophysics》2004,388(1-4):173

The Tocantins Province in Central Brazil is composed of a series of SSW–NNE trending terranes of mainly Proterozoic ages, which stabilized in the Neoproterozoic in the final collision between the Amazon and São Francisco cratons. No previous information on crustal seismic properties was available for this region. Several broadband stations were used to study the regional patterns of crustal and upper mantle structure, extending the results of a recent E–W seismic refraction profile. Receiver functions and surface wave dispersion showed a thin crust (33–37 km) in the Neoproterozoic Magmatic Arc terrane. High average crustal Vp/Vs ratios (1.74–1.76) were consistently observed in this unit. The foreland domain of the Brasília foldbelt, on the other hand, is characterized by thicker crust (42–43 km). Low Vp/Vs ratios (1.70–1.72) were observed in the low-grade foreland fold and thrust zone of the Brasília belt adjacent to the São Francisco craton. Teleseismic P-wave tomography shows that the lithospheric upper mantle has lower velocities beneath the Magmatic Arc and Goiás Massif compared with the foreland zone of the belt and São Francisco craton. The variations in crustal thickness and upper mantle velocities observed with the broadband stations correlate well with the measurements along the seismic refraction profile. The integration of all seismic observations and gravity data indicates a strong lithospheric contrast between the Goiás Massif and the foreland domain of the Brasília belt, whereas little variation was found across the foldbelt/craton surface boundary. These results support the hypothesis that the Brasília foreland domain and the São Francisco craton were part of a larger São Francisco-Congo continental plate in the final collision with the Amazon plate.  相似文献