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地震前兆含义,科学问题与研究途径的研讨 总被引：5，自引：2，他引：3
地震前兆的研究已经取得了很大的进展,地震前兆的复杂性引起了广泛的关注,对地震预报、有关科学问题和探索途径的研究现状及其前景有各种评价。文章认为由于一些科学问题没有解决,尽管对中缅边境１９９５年７月连７．３级地震作出了成功预报,经验性预报有一定的局限性,文中讨论了广义地震前兆和狭义地震前兆,广义地震前兆包含二类前兆：场兆和源兆;而狭义前兆仅指后者。大陆震例前兆的系统研究证实了广义地震前兆的存在,然而 相似文献
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Molar‐Tooth Structure from the Mesoproterozoic Wumishan Formation in Lingyuan,Yanshan Region,North China,and Geological Implications 总被引：1，自引：0，他引：1
KUANG Hongwei LIU Yongqing PENG Nan LUO Shunshe LI Jiahu CEN Chao CHEN Mingpei 《《地质学报》英文版》2012,86(1):85-95
Although its origin has not yet reached a consensus so far, MTS (Molar-Tooth Structure) has been documented for more than 100 years. Current study reports a discovery of MTS from the Mesoproterozoic Wumishan Formation, Lingyuan, Yanshan Region, North China, and the features and geological implications of MTS are further discussed. Here, straitigraphic horizons of MTS’s occurrences show that it was mainly located within the top part of the Wumishan Formation, i.e., limestone unit. Four kinds of morphology of MTS, i.e., fine fusiform, debris, ribbon, ptigmatic and nodular (irregular), were recognized and thought to be highly related to the sedimentary environments and facies. Geochemistry of MTS including oxides, trace elements and C, O and Sr isotopes indicates that the horizons of MTS-bearing is of higher Sr/Ba and Ca/Mg ratios, lower positive δ13C and highly negative δ18O values than the adjacent stratigraphic levels of rare MTS. Lithology, morphology and geochemistry of MTS in the Wumishan Formation suggest that MTS occurs mainly in shallow subtidal near the storm wave base, which is typically characterized by warm temperature, oversaturated calcium carbonate seawater and high organic productivity. Furthermore, occasional enrichment of algae bacteria here is more favorable for the calcification of calcium oozes and catalytic for MTS. C isotope composition of the Wumishan Formation and MTS of this study is well correlated with that of the Mesoproterozoic Belt Supergroup, North America and Riphean, Siberia, suggesting that MTS acts as a sedimentary record responding to global changes and is a perfect indicator in Precambrian stratigraphic correlation worldwide. 相似文献
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Gavin Musgrovl 《中国地理科学(英文版)》1994,(3)
金玉献ＣＨＩＮＡ＇ＳＲＡＤＩＣＡＬＢＩＲＴＨＣＯＮＴＲＯＬＰＯＬＩＣＹＡＮＤＩＭＰＬＩＣＡＴＩＯＮＳＦＯＲＩＮＤＩＡ￥ＧａｖｉｎＭｕｓｇｒｏｖｌ（ＴｒｉｎｉｔｙａｎｄＡｌｌＳｏｉｎｔｓＣｏｌｌｅｇｅ，ＡＣｏｌｌｅｇｅｏｆＬｅｅｄｓＵｎｉｖｅｒｓｉｔｙ... 相似文献
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《Norsk geografisk tidsskrift. Norwegian journal of geography》2012,66(1):17-25
The fish-processing industry, one of the most important industries of coastal Norway, consists of approximately 500 firms employing 12,500 people. This article draws attention to the regional specialisation of the Norwegian fish-processing industry. Changes in the level of activity and in profitability at the regional level can to a large extent be linked to characteristics of the regional production system in different areas. In order to develop a more profitable and market-oriented industry, we argue for a regionalised policy approach that encourages the establishment of inter-firm relations and collective learning processes at the level of the regional production milieux. A regionalisation of the national policy would be the most sustainable way of stimulating more efficient longterm business strategies in this industry. 相似文献
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TEM observation of geogas-carried particles from the Changkeng concealed gold deposit,Guangdong Province,South China 总被引：2，自引：0，他引：2
Geogas prospecting is a relatively new technique in exploration for deep-seated and concealed mineral deposits. Now, the technique is to reveal the presence of concealed ore bodies by analyzing the element concentrations of substances that are transported by geogas from concealed ore bodies to the Earth's surface. However, the element concentrations provide us with limited information about the concealed ore bodies. In our work, to investigate the category, size, shape, chemical component of geogas particles, copper grids for transmission electron microscopy measurement were directly used to capture the geogas-carried solid particles in Quaternary sediments overlying the Changkeng concealed gold deposit, Guangdong Province, South China. In the samples, we found Au, PbSO4, WO3, Fe2O3, SiO2, TiO2, and Al2O3 particles, etc. using a transmission electron microscopy. Of which, gold particles, and Hg-, Zn-, Pb-, W-bearing particles may originate from concealed ore bodies and can provide more direct information than those provided by element concentrations. 相似文献
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China has been firmly carried out her birth control policy for over 2 decades, and this has been very srccessful in practice.
India is the second populous country in the world. Although overpopulation problem was identified in the 1950s, and birth
control policy was implemented since then, the situation has not yet been improved. The aim of this paper is to make comparisons
between these two countries, in terms of social and cultural background, geographical distribution of population, national
minority structure, in order to reveal the reasons behind the China’s success, and implications for India. 相似文献
7.
腾冲地块江东花岗岩体分布于芒市江东镇—项丘一带,主要由黑云母二长花岗岩组成。该花岗岩锆石LA-ICP-MS U-Pb定年结果表明,锆石U-Pb年龄加权平均值为58.29±0.44 Ma,表明该花岗岩体的形成时代属于古新世。岩石地球化学研究表明,该花岗岩具有中等SiO2(68.66%~73.50%),高碱(K2O+Na2O=6.87%~9.04%),高钾(K2O/Na2O=1.87~2.20),铝饱和指数(A/CNK)为0.97~1.36的特征。岩石属钾玄岩—高钾钙碱性系列,为过铝质S型花岗岩。稀土元素总量(ΣREE)为158.85×10-6~304.26×10-6,稀土元素配分曲线呈右倾型,具有弱到中等程度的负铕异常。根据岩石地球化学特征判别,该花岗岩的源岩可能是富含粘土的变质杂砂岩,在构造体制由挤压向拉张转变的后碰撞环境下部分熔融形成的。江东古新世后碰撞环境黑云母二长花岗岩的形成,预示着印度板块与冈底斯-波密-腾冲板块的主体碰撞在60Ma之前(即古新世初期之前)已经发生。冈底斯-滕冲构造带古新世构造岩浆造山事件与新特提斯洋的闭合及印度板块与冈底斯-滕冲板块间的俯冲、碰撞造山作用密切相关。 相似文献
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