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71.
J. Plomerova L. Vecsey V. Babuska M. Granet U. Achauer 《Studia Geophysica et Geodaetica》2005,49(4):541-560
We present results of an array study of seismic anisotropy beneath the Bohemian Massif (BM) showing distinct lateral and directional
variations of the fast shear-wave polarization and split-delay time consistent with variations in the P-residual spheres,
in which directional means of relative residuals are subtracted. Our analysis of the S- and P-wave anisotropy suggests that
the mantle lithosphere of the BM consists of at least three large domains with different orientation of the large-scale fabric
separated by sutures cutting most likely the whole lithosphere. Boundaries of the units are characterised by a null or small
shear-wave splitting, as well as by smaller values in the P-residual spheres. We present self-consistent 3D anisotropic models
of the lithosphere domains of the BM resulting from joint inversion of anisotropic parameters searching for a 3D orientation
of mantle fabric. While in the Saxothuringian and Sudetes parts of the BM the (a, c) foliations dip prevailingly to the N-NW,
they dip to the S and SW in the southern and eastern parts of the Moldanubian. 相似文献
72.
M. U. Shirazi M. Y. Ashraf M. A. Khan M. H. Naqvi 《International Journal of Environmental Science and Technology》2005,2(3):233-236
Water culture experiments were conducted to study the response of ten wheat genotypes to external K application (10 mmol KCI dm?3) at seedling stage under saline condition (0 and 100 mmol NaCl dm?3). The data showed that there was an increase in the shoot and root length with the application of external K. The increase was more pronounced under control than under saline conditions. The better performing genotypes under two treatments were Bhitai, NIAB-41, NIAB-I076 and Khirman. The enhanced growth of these genotypes under saline condition might be due to the quick response to external K application, resulting in high K/Na ratio. The results indicated that the genotypes, which have the ability of enhanced K/Na discrimination, might perform better under saline conditions when sufficient potassium is applied in the rooting medium. 相似文献
73.
Late Paleozoic Fluid Systems and Their Ore-forming Effects in the Yuebei Basin, Northern Guangdong, China 总被引:1,自引:0,他引:1
DENG Jun YANG Liqiang SUN Zhongshi WANG Jianping WANG Qingfei CHENG Xueming ZHOU Yinghua State Key Laboratory of Geological Processes Mineral Resources China University of Geosciences Beijing Key Laboratory of Lithosphere Tectonics Lithoprobing Technology of the Ministry of Education China University of Geosciences Beijing School of Earth Sciences Jilin University Chuangchun Jilin 《《地质学报》英文版》2005,79(5):673-687
Based on detailed and systematic researches of the geology of ore deposits, fluid inclusions and isotope geochemistry etc., and regarding the Late Paleozoic fluid system of the Yuebei Basin as an integrated object in this paper, we have revealed the temporo-spatial evolution law of the basin's fluid system and discussed its ore-forming effects by simulating and analyzing the distribution of ore-forming elements, the fluid thermodynamics and dynamics of evolution processes of this basin. The results show that Late Paleozoic ore-forming fluid systems of the Yuebei Basin include four basic types as follows. (1) The sea floor volcanic-exhalation system developed during the rapid basin slip-extension stage in the Mid-Late Devonian, which affected the Dabaoshan region. It thus formed the Dabaoshan-type Cu-Pb-Zn-Fe sea floor volcanic-exhalation sedimentary deposits. (2) The compaction fluid system developed during the stable spreading and thermal subsidence-compression stage of the basin in the Mid-Late Devonian. The range of its effects extended all over the whole basin. It resulted in filling-metasomatic deposits, such as the Hongyan-type pyrite deposits and pyrite sheet within the Fankou-type Cu-Pb-Zn-S deposits. (3) The hot water circulation system of sea floor developed during the stage of basin uplifting and micro-aulacogen from the late Late Carboniferous to Middle Carboniferous. The range of its effects covered the Fankou region. It thus formed MVT deposits, such as the main orebody of the Fankou-type Pb-Zn-S deposits. (4) The gravity fluid system developed during the stage of fold uplifting and the basin closed from Middle Triassic to Jurassic, forming groundwater hydrothermal deposits, e.g. the veinlet Pb-Zn-calcite orebodies of the Fankou-type Pb-Zn- S deposits. Migration and concentration of the ore-forming fluids were constrained by the state of temporo-spatial distribution of its fluid potential. Growth faults not only converged the fluids and drove them to move upwards, but also the fluids often crossed the faults to the edges of the basin at the bottom of these faults and the lithologic interfaces, and even migrated to the basin's edges from top to bottom along the faults, which may be one of the basic reasons for the stratabound deposits to cluster mainly along the contemporaneous faults on the inner border of the basin. The superposed mineralization resulting from the multi-stage activity of contemporaneous faults and ore-forming fluid systems in the basin may be one of the key factors for forming superlarge ore deposits. 相似文献
74.
75.
Tectonic Evolution of the Himalayan Collision Belt 总被引:5,自引:0,他引:5
Cui Junwen Institute of Geology Chinese Academy of Geological Sciences Beijing 《《地质学报》英文版》1997,71(2):133-143
This paper discusses the tectonic divisions of the Himalayan collision belt anddeals with the tectonic evolution of the collision belt in the context of crustal accretion in thefront of the collision belt, deep diapirism and thermal-uplift extension and deep material flow-ing of the lithosphere-backflowing. Finally it proposes a model of the tectonic evolution-progressive intracontinental deformation model-of the Himalayan belt. 相似文献
76.
沉积岩中蒙脱石-伊利石混层矿物的SEM/EDAX分析 总被引:1,自引:1,他引:1
本文利用扫描电子显微镜与X射线能量色散分析联合法,对沉积岩中蒙脱石-伊利石混层矿物进行系统微区成分分析,求出混合层中伊利石的百分含量。 相似文献
77.
High quality marine source rock (HQMSR) is the key prerequisite for medium to large hydrocarbon accumulations. However, the forming mechanism remains unclear. On the basis of the in-vestigation for the geodynamic setting of the Middle-Upper Yangtze during the Early Cambrian in dif-ferent spatial scales and the analysis of trace elements, the main controlling factors of the development of high quality marine source rock are discussed, with specific consideration of the burial rate of the organic matter. The ... 相似文献
78.
近10余年来,特别是2000年召开第三届地层会议后,中国年代地层研究得到很快发展。首先,在全国地层委员会主持下,经各断代工作组专家们的共同努力,编制完成了《中国区域年代地层(地质年代)表》,系统建立了从震旦系至第四系中共102个阶(其中包括52个陆相地层区的阶)和新建3个系级单位。从2001年开始,在中国地质调查局的大力支持下,由全国地层委员会主持,组织全国知名地质科研院所、高校和部分地质调查院的专家,围绕中国区域年代地层表,开展了系统的建阶研究。5年来,共涉及45个阶,9个界线层型和2个新建系及2个统级单位的研究,取得重要进展。先后已有4个全球界线层型(GSSPs)被国际地质科学联合会批准建立在中国,还有3~4个全球界线层型正待国际地质学科学联合会批准建立在中国,另有3~4个界线层型剖面有望争取成为全球的界线层型。其他研究所涉及到的阶、系、统等单位,也有明显进展,成熟度明显提高,为《中国区域年代地层(地质年代)表》的广泛应用奠定了重要基础。 相似文献
79.
藏北祖尔肯乌拉山地区新生代高钾钙碱岩系火山岩同位素地球化学研究 总被引:3,自引:1,他引:3
通过对藏北祖尔肯乌拉山地区新生代高钾钙碱岩系火山岩Sr,Nd,Pb同位素成分的系统测试分析表明,火山岩具有相对高的^87Sr/^86Sr和低的^143Nd/^144Nd值及高的Pb同位素组成特点,且Sr,Nd,Pb同位素比值变化范围很窄,反映了其具有同源岩浆的特点,并且经历了类似的地球化学动力学过程。Sr,Nd,Pb同位素组成及相关图解判别表明,藏北祖尔肯乌拉山地区新生代高钾钙碱岩系火山岩来源于被大洋沉积物和地壳物质所混合的不均一富集地幔源区,显示源区具有壳幔混源性质,与EMⅡ型富集地幔源特征一致。 相似文献
80.