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LAI Shaocong QIN Jiangfeng LI Yongfeng LIU Xin 《中国地球化学学报》2007,26(3):305-311
Neogene volcanic rocks in the Belog Co area, Qiangtang, northern Tibet, are represented by a typical intermediate-basic and intermediate alkaline rock association, with latite-trachyte as the main rock type. The results of chemical analysis are: SiO2=52%–62%, Al2O3>15%, Na2O/K2O>1 and MgO<3.30%. In addition, the volcanic rocks are LREE-enriched with LREE/HREE=10–13, (La/Yb)N=15–19, and show a weak negative Eu anomaly with δEu=0.71–0.89. The close relationship between Mg# and SiO2 and the co-variation of the magmatophile elements and ultra-magmatophile elements such as La/Sm-La and Cr-Tb indicate that this association of volcanic rocks is the product of comagmatic fractional crystallization. The rock association type and lower Sm/Yb values (Sm/Yb=3.23–3.97) imply that this association of volcanic rocks should have originated from partial melting of spinel lherzolite in the lithospheric mantle. On the other hand, the weak negative Eu anomaly and relative depletion in Nb, Ta and Ti reflect the features of terrigenous magma. So the Neogene Belog Co alkaline volcanic rocks should be the result of partial melting of the special crust-mantle transition zone on the Qinghai-Tibet Plateau. 相似文献
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根据福建省县(市)地质灾害调查与区划已入库的资料,通过对地质灾害类型与植被类型关系的统计分析和局部林地的植被雨水截留率和土体径流路径的研究,表明了植被对于水文效应和土体性质的改良作用,从而揭示了植被对于防治地质灾害作用机理,同时指出植被对阻止各类地质灾害的发生还有许多积极作用及局限性,植被作用于滑坡的各种参数并不是一成不变的,需要根据当地树种、土壤、气候等综合因素判定。 相似文献
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Time is a crucial factor for many remote sensing applications such as emergency response. The traditional approach requires users to spend a lot of time downloading, processing, and viewing satellite images with specialized software. Realizing interactive real‐time processing and visualization of satellite images online is our focus. This article presents an On‐Demand computing schema for remote sensing images. A processing chain model is proposed for satellite images on a private cloud computing platform designed for the China Centre for Resources Satellite Data and Application (CCRSDA). The architecture, processing flow, optimization method, fault tolerance, and user interface are described in detail. To test the efficiency and scalability of the platform, 11 processing chains were created and three load balance experiments were executed. The results from these experiments show the validity of the proposed methods and architecture. 相似文献
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本文首先推导出单位失变率的矢量表示式.然后将该式应用于惯性系运动学问题,以球坐标系为例导出了曲线坐标系中速度、加速度的分量表示式,导出了自然轴系中切向加速度和法向加速度的表示式.最后将该式应用于非惯性系运动学问题,在导出绝对变本与相对变率关系的基础上,进而得出绝对运动与相对运动的关系.显示出此种方法在研究运动学问题时的优越性. 相似文献
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MA Changqian SHE Zhenbing XU Pin & WANG Lingyan State Key Laboratory of Geological Processes Mineral Resources and Faculty of Earth Sciences China University of Geosciences Wuhan China 《中国科学D辑(英文版)》2005,48(8):1134-1145
The Dabieshan Orogenic belt is well known for the exhumation of early Mesozoic ultrahigh-pressure (UHP) metamorphic rocks and Jurassic–Cretaceous emplacement of voluminous granitoids. However, the tectonic evolution in the orogen during the Paleozoic, especially its magmatic response to tectonism has not received much attention. As indicated by published data, the Dabieshan orogenic belt contains different records of Paleozoic magmatic-tectonic association in different tectonic units. Occ… 相似文献
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A possible role of solar radiation and ocean in the mid-Holocene East Asian monsoon climate 总被引:8,自引:5,他引:3
An atmospheric general circulation model (AGCM) and an oceanic general circulation model (OGCM) are asynchronously coupled to simulate the climate of the mid-Holocene period. The role of the solar radiation and ocean in the mid-Holocene East Asian monsoon climate is analyzed and some mechanisms are revealed. At the forcing of changed solar radiation induced by the changed orbital parameters and the changed SST simulated by the OGCM, compared with when there is orbital forcing alone, there is more precipitation and the monsoon is stronger in the summer of East Asia, and the winter temperature increases over China. These agree better with the reconstructed data. It is revealed that the change of solar radiation can displace northward the ITCZ and the East Asia subtropical jet, which bring more precipitation over the south of Tibet and North and Northeast China. By analyzing the summer meridional latent heat transport, it is found that the influence of solar radiation change is mainly to increase the convergence of atmosphere toward the land, and the influence of SST change is mainly to transport more moisture to the sea surface atmosphere. Their synergistic effect on East Asian precipitation is much stronger than the sum of their respective effects. 相似文献