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591.
以鸡冠咀铜金矿床深部及其外围找矿预测为目标,在深入认识鸡冠咀铜金矿床地质特征的基础上,对研究区重力、磁测、电法测量资料进行精细反演,研究含矿地质体与物探异常的对应关系,获取矿区深部和外围物探异常信息。证实研究区岩矿石物性差异明显、与矿有关的地质体与重磁异常具有良好的吻合性,证实研究区内断裂接触带、大理岩俘虏体、隐伏岩体表现出重磁同高、重磁异常梯度带等特征,是寻找深部盲矿体的有利部位。总结了5种地球物理找矿标志,构建了“一个主要目标,两种分析,三种方法,五个找矿标志”的矽卡岩型铜金矿床的地球物理找矿模式,对鸡冠咀矿区深部及外围进行靶区优选,指导鄂东南矿集区矿产勘查工作,具有良好的示范作用。 相似文献
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Sylvain Nguyen † Reda Baina Mathias Alerini ‡ Gilles Lambaré Vincent Devaux Mark Noble 《Geophysical Prospecting》2008,56(5):613-625
Depth velocity model building remains a difficult step within the seismic depth imaging sequence. Stereotomography provides an efficient solution to this problem but was limited until now to a picking of seismic data in the prestack time un-migrated domain. We propose here a method for stereotomographic data picking in the depth migrated domain. Picking in the depth migrated domain exhibits the advantage of a better signal-to-noise ratio and of a more regular distribution of picked events in the model, leading to a better constrained tomographic inverse problem. Moreover, any improvement on the velocity model will improve the migrated results, again leading to improved picking. Our strategy for obtaining a stereotomographic dataset from a prestack depth migration is based on migration of attributes (and not on a kinematic demigration approach!). For any locally coherent event in the migrated image, migration of attributes allows one to compute ray parameter attributes corresponding to the specular reflection angle and dip. For application to stereotomography, the necessary attributes are the source/receiver locations, the traveltime and the data slopes. For the data slope, when the migration velocity model is erroneous, some additional corrections have to be applied to the result of migration of the attributes. Applying these corrections, our picking method is theoretically valid whatever the quality of the migration velocity model. We first present the theoretical aspects of the method and then validate it on 2D synthetic and real seismic reflection data sets. 相似文献
594.
Sb, As, Cu, and Zn toxicity and contamination have become a growing concern in recent years. Phytoremediation, a plant based and cost effective technology, may be an effective approach in the cleanup of water contaminated by these metals. In this study, the aquatic macrophyte Eleocharis acicularis was used in laboratory and field experiments to assess its capability to accumulate Sb, As, Cu, and Zn, and thereby investigate its potential application in phytoremediation. The results showed that E. acicularis adapted well to water contaminated by these metals. The removal rates of Sb, As, Cu, and Zn in the laboratory experiment were 3.04, 2.75, 0.417, and 1.49 μg/L/day, respectively. The highest concentrations of these metals accumulated in E. acicularis after 10 days of the laboratory experiment were 6.29, 6.44, 20.5, and 73.5 mg/kg dry weight, respectively. Only 8% of As, 12% of Sb, 87% of Cu and 93% of Zn removed from the water were used by E. acicularis. The highest concentrations of Sb, As, Cu, and Zn accumulated in E. acicularis after 10 wk of the field experiment were 76.0, 22.4, 33.9, and 266 mg/kg dry weight, respectively. The results indicate that E. acicularis has the ability to accumulate Sb, As, Cu, and Zn from contaminated water. 相似文献
595.
苏州城市游憩场点系统空间结构分形 总被引:7,自引:2,他引:5
城市游憩场点系统是和谐城市规划建设的核心对象,也是一种结构复杂的自然-人文复合系统.本文选取随机聚集维数、空间关联维数、网格维数三项指标.以苏州市区为例,对新时期我国城市游憩场点系统的空间结构分形及优化进行了系统论证与解析.研究发现:①城市游憩场点系统的空间结构是具有分形特性的;②各分维指标能够准确地刻画城市游憩场点系统的空间结构及其分异,也为环城游憩带理论及城乡二元游憩结构分异现象等提供了分形解释依据;③苏州游憩场点系统的空间结构呈现出一种核心松散-外围紧致、白组织能力离心化现象比较严重的结构递变趋势,这种结构模式与游憩需求的空间分布结构基本吻合,它准确反映了成熟型游憩场点系统的空间发展态势,也说明加强对游憩场点系统的自组织能力的引导和提升,是和谐城市规划建设中的一项不可或缺的重要工作;④与以往研究结论相对比,发现游憩场点系统与旅游景区(点)系统在空间结构上存在合理的分形差异. 相似文献
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598.
Strategies for High Precision Processing of GPS Measurements with Application to the Amery Ice Shelf,East Antarctica 总被引:3,自引:0,他引:3
A number of statistic Global Positioning System (GPS) measurement campaigns have been made on a floating Antarctic ice shelf,
the Amery Ice Shelf, as part of ongoing glaciological studies designed to investigate the ice shelf dynamics, grounding zone
definition, and ice shelf strain. Such studies ar fundamental to improving out knowledge of the Antarctic ice-sheet mass balance
and dynamical models of ice sheet/ocean interaction. This article describes two techniques used to process the statistic GPS
data. One approach uses a segmented version of the classical static methodology, and the other approach adopts a new sequential
processing technique. Both approaches yield similar results for the station coordinates and demonstrate the potential of GPS
for extracting the tidal signal on the ice shelves and giving information on the dynamical motion of the ice sheet. To verify
our results for the vertical component, we compare the ice shelf GPS tidal signal with a tidal model derived from tide gauge
measurements at nearby Beaver Lake. Comparison of the GPS results with the tide model give good agreement in amplitude at
the few cm level (GPS results always larger) but clearly shows evidence of phase propagation of the ocean tidal wave under
the ice shelf. Improving the resolution of the tides over the ice shelves will be of tremendous benefit for future satellite
missions, such as Ice, Cloud and Land Elevation Satellite (ICESAT), and the integrated use of GPS and satellite data will
be fundamental for any on-going Antarctic ice sheet mass balance studies. ? 2000 John Wiley & Sons, Inc. 相似文献
599.
A cross-system analysis of sedimentary organic carbon in the mangrove ecosystems of Xuan Thuy National Park, Vietnam 总被引:1,自引:0,他引:1
Nguyen Tai Tue Nguyen Thi NgocTran Dang Quy Hideki HamaokaMai Trong Nhuan Koji Omori 《Journal of Sea Research》2012,67(1):69-76
A cross-system analysis of bulk sediment composition, total organic carbon (TOC), atomic C/N ratio, and carbon isotope composition (δ13C) in 82 surface sediment samples from natural and planted mangrove forests, bank and bottom of tidal creeks, tidal flat, and the subtidal habitat was conducted to examine the roles of mangroves in sedimentation and organic carbon (OC) accumulation processes, and to characterize sources of sedimentary OC of the mangrove ecosystem of Xuan Thuy National Park, Vietnam. Sediment grain sizes varied widely from 5.4 to 170.2 μm (mean 71.5 μm), with the fine sediment grain size fraction (< 63 μm) ranging from 11 to 99.3% (mean 72.5%). Bulk sediment composition suggested that mangroves play an important role in trapping fine sediments from river outflows and tidal water by the mechanisms of tidal current attenuation by vegetation and the ability of fine roots to bind sediments. The TOC content ranged from 0.08 to 2.18% (mean 0.78%), and was higher within mangrove forests compared to those of banks and bottoms of tidal creeks, tidal flat, and subtidal sediments. The sedimentary δ13C ranged from − 27.7 to − 20.4‰ (mean − 24.1‰), and mirrored the trend observed in TOC variation. The TOC and δ13C relationship showed that the factors of microbial remineralization and OC sources controlled the TOC pool of mangrove sediments. The comparison of δ13C and C/N ratio of sedimentary OC with those of mangrove and marine phytoplankton sources indicated that the sedimentary OC within mangrove forests and the subtidal habitat was mainly composed of mangrove and marine phytoplankton sources, respectively. The application of a simple mixing model showed that the mangrove contribution to sedimentary OC decreased as follows: natural mangrove forest > planted mangrove forest > tidal flat > creek bank > creek bottom > subtidal habitat. 相似文献
600.
This study evaluates the performance of two low cost and high performance adsorption materials, i.e., activated carbon produced from two natural waste products: Bamboo and coconut shell, in the removal of three pesticides from drinking water sources. Due to the fact that bamboo and coconut shell are abundant and inexpensive materials in many parts of the world, they respond to the “low‐cost” aspect. The adsorption capacities of two local adsorbents have been compared with commercial activated carbon to explore their potential to respond to the “high quality” aspect. Two pesticides were selected, namely dieldrin and chlorpyrifos, because they are commonly used in agriculture activities, and may remain in high concentrations in surface water used as drinking water sources. The results indicate that the adsorption of pesticides on activated carbons is influenced by physico‐chemical properties of the activated carbon and the pesticides such as the presence of an aromatic ring, and their molar mass. The activated carbon produced from bamboo can be employed as low‐cost and high performance adsorbent, alternative to commercial activated carbon for the removal of pesticides during drinking water production. The performance of activated carbon from bamboo was better due to its relatively large macroporosity and planar surface. The effect of adsorbent and pesticide characteristics on the performance was derived from batch experiments in which the adsorption behavior was studied on the basis of Freundlich isotherms. 相似文献