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东南大陆岩石圈板块地体构造 被引量:13
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作者 谢窦克 商玉强 《资源调查与环境》 1989年第4期1-12,共12页
东南大陆的地质构造模型,具有欧亚大陆边缘向洋增生的独特形式。除外来地体之外,或以扩张、地幔上涌,洋壳向大陆地壳转化,并不断向洋增生;或是大陆分裂,地幔柱——热点物质不断注入变薄和破裂了的地壳,形成区域性新的生长构造层,构造岩... 东南大陆的地质构造模型,具有欧亚大陆边缘向洋增生的独特形式。除外来地体之外,或以扩张、地幔上涌,洋壳向大陆地壳转化,并不断向洋增生;或是大陆分裂,地幔柱——热点物质不断注入变薄和破裂了的地壳,形成区域性新的生长构造层,构造岩浆地质体表现为有独特属性的“A型”花岗岩和流纹岩链。这些高DI值的富硅富碱富钠质岩石,出现在欧亚大陆边缘的重力梯度带上。裂解带的地壳结构模式是上地壳存在着重力不稳定的硅铝低速带;中地壳有洋——陆过渡型地壳的“类裂谷型”结构,P波速度为6.3~6.4km/s的中间壳层;在下地壳下部有速度为7.0~7.4km/s的壳——幔混合型高速层;随着“异常”的上地幔的形成,有大范围的热活动和壳——幔边界穹窿,穹窿的地盖比正常区为为薄。由于化学库和化学边界层的横向不连续,可划分出古老基底和后期地质发展史完全迥异的两个亚板块;和以壳层(或幔层)断裂为边界特点的八个地体;一个以分裂为主,并具热点径迹的最新生长构造层的扩张——裂解构造岩浆地体。 展开更多
关键词 扩张一裂解 生长地体 构造岩浆地体 洋壳大陆化 地壳结构
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The Actual Trends of Olive Growing in Albania
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作者 Dritan Topi Fadil Thomaj 《Journal of Environmental Science and Engineering(B)》 2012年第6期733-740,共8页
The olive tree (Olea Europaea) owns the status of national patrimony in Albania. In the past, olive plantations were dictated by Agricultural Policies, where olive trees were cultivated mainly in marginal lowland ar... The olive tree (Olea Europaea) owns the status of national patrimony in Albania. In the past, olive plantations were dictated by Agricultural Policies, where olive trees were cultivated mainly in marginal lowland areas and hills. The highest efficiency in olive production is reached mainly in the Southern and Central regions of the country. After 1990s, olive farming has been highly impacted due to shifts in the economic system. Its interest in the economical aspect is going to be very important in the near future. The government has developed a national scheme for the intensification of olive farming by increasing the planted area by 60,000 ha, or in total to 20 million olive trees. Our study presents an overall view of actual trends of olive farming, olive industry, subsequent environmental problems resulting from farming and olive mills by-products, and finally the role that the government has to play in that sector, 展开更多
关键词 Olea Europaea olive fanning rural economy developing countries environmental impact Albania.
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Influencing factors of gas content evaluation for shale gas:a case study of Lower Paleozoic Wuling fold belt in Upper Yangtze Basin
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作者 MIAO Qishi PAN Baozhi +1 位作者 ZHAI Ting YANG Mingyu 《Global Geology》 2014年第1期18-23,共6页
Factors of shale gas accumulation can be divided into the external and internal factors,according to accumulation mechanism and characteristics of shale gas. The internal factors mainly refer to parameters of organic ... Factors of shale gas accumulation can be divided into the external and internal factors,according to accumulation mechanism and characteristics of shale gas. The internal factors mainly refer to parameters of organic geochemistry,mineral components and physical parameters. Six factors were presented in this study,i. e.organic matter,maturity,quartz,carbonate,clay mineral and pore. The external factors mainly refer to geologic environment of shale gas reservoir,including four factors: temperature,pressure,depth and thickness.Based on the experiment results of 26 samples of drilling cores from Wuling fold belt in Lower Paleozoic Silurian of the Upper Yangtze Basin,combined with the integrated analysis of geology,logging and test,the correlation of the gas content of shale gas to the above-mentioned ten factors was concluded. Six important evaluation indicators were preliminarily established in the gas-bearing core area of marine shale in the Upper Yangtze Basin. 展开更多
关键词 shale gas gas content influencing factor marine shale Upper Yangtze Basin
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Fluid/melt in continental deep subduction zones: Compositions and related geochemical fractionations 被引量:11
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作者 XIAO YiLin SUN He +3 位作者 GU HaiOu HUANG Jian LI WangYe LIU Lei 《Science China Earth Sciences》 SCIE EI CAS CSCD 2015年第9期1457-1476,共20页
Plate subduction is the most magnificent process in the Earth. Subduction zones are important sites for proceeding matter- and energy- transports between the Earth's surface and the interior, continental crust gro... Plate subduction is the most magnificent process in the Earth. Subduction zones are important sites for proceeding matter- and energy- transports between the Earth's surface and the interior, continental crust growth, and crust-mantle interactions. Besides, a number of geological processes in subduction zones are closely related to human beings' daily life, such as volcanic eruptions and earthquakes, formation of mineral deposits. Subduction process thus has long been the centric topic of Earth sciences. The finding in 1980 s that continental crust could be subducted to mantle depths is a revolutionary progress in plate tectonic theory. Compared to oceanic crust, continental crust is colder, drier, lighter, and much more geochemically/isotopically heterogeneous. Hence, continental subduction process would affect the structure, compositions and evolutions of the overlying mantle wedge even more. During continental subduction and subsequent exhumation, fluids and melts can be generated in the(de)hydration process and partial melting process, respectively. These melts/fluids play important roles in crust-mantle interactions, elemental migrations, isotopic fractionations, and mantle metasomatism. By summarizing recent research works on subduction zones in this paper, we present a review on the types, physicochemical conditions and compositions of fluids/melts, as well as the migration behaviors of fluid-related characteristic elements(Nb-Ta-V) and the fractionation behaviors of non-traditional stable isotopes(Li-Mg) in subduction zones. The aim of this paper is to provide the readers an update comprehensive overview of the melt/fluid activities in subduction zones and of Li-Mg isotope systematics in subduction-related rocks and minerals. 展开更多
关键词 subduction process melt/fluid composition crust-mantle interaction elemental mobility isotopic fractionation
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