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安徽池州铜山铜矿深部找矿实践与启示 总被引:4,自引:0,他引:4
铜山铜矿资源储量日益枯竭。危机矿山接替资源勘查中,采用地质、物探综合手段圈定异常区,经深部钻探验证,取得突破。 相似文献
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对河南省栾川县大练沟泥石流治理的经验总结 总被引:1,自引:0,他引:1
随着国民经济迅速发展,对矿产资源的需求日益增多,20世纪七、八十年代的开采只追求产量和经济效益,而忽视了对环境的保护,开采的矿渣乱排乱放现象非常严重,严重破坏了环境,象这样的矿山在全国各地有很多,随着时间的发展,松散堆积的矿渣在洪水的作用下顺着沟道倾泻而下,形成泥石流,对下游的人民生命财产造成严重的破坏和威胁,矿山泥石流逐步发展,进入发展期和活跃期,必将造成更大的危害。因此对这样的泥石流沟进行研究和治理是很有必要的。在对河南省栾川县大练沟泥石流的治理过程中,得出以下几点体会,现总结归纳出来,希望对类似泥石流沟的治理提供借鉴。 相似文献
46.
Miwako Nakaseama Jun-Ichiro Ishibashi Keita Ogawa Hiroshi Hamasaki Keiko Fujino Toshiro Yamanaka 《Resource Geology》2008,58(3):289-300
The Wakamiko submarine crater is a small depression located in Kagoshima Bay, southwest Japan. Marine shallow‐water hydrothermal activity associated with fumarolic gas emissions at the crater sea floor (water depth 200 m) is considered to be related with magmatic activity of the Aira Caldera. During the NT05‐13 dive expedition conducted in August 2005 using remotely operated vehicle Hyper‐Dolphine (Japan Agency for Marine‐Earth Science and Technology), an active shimmering site was discovered (tentatively named the North site) at approximately 1 km from the previously known site (tentatively named the South site). Surface sediment (up to 30 cm) was cored from six localities including these active sites, and the alteration minerals and pore fluid chemistry were studied. The pore fluids of these sites showed a drastic change in chemical profile from that of seawater, even at 30 cm below the surface, which is attributed to mixing of the ascending hydrothermal component and seawater. The hydrothermal component of the North site is estimated to be derived from a hydrothermal aquifer at 230°C based on the hydrothermal end‐member composition. Occurrence of illite/smectite interstratified minerals in the North site sediment is attributed to in situ fluid–sediment interaction at a temperature around 150°C, which is in accordance with the pore fluid chemistry. In contrast, montmorillonite was identified as the dominant alteration mineral in the South site sediment. Together with the significant low potassium concentration of the hydrothermal end‐member, the abundant occurrence of low‐temperature alteration mineral suggests that the hydrothermal aquifer in the South site is not as high as 200°C. Moreover, the montmorillonite is likely to be unstable with the present pore fluid chemistry at the measured temperature (117°C). This disagreement implies unstable hydrothermal activity at the South site, in contrast to the equilibrium between the pore fluid and alteration minerals in the North site sediment. This difference may reflect the thermal and/or hydrological structure of the Wakamiko Crater hydrothermal system. 相似文献
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浅谈测井方法在工程勘察中的应用 总被引:1,自引:0,他引:1
地球物理测井应用于工程勘察中,能够较好地解决用钻探不易解决的问题,如有效判别薄夹层、寻找井旁隐伏断裂破碎带、判断孔内土层稳定性以及测定土层的速度等。其中自然伽马测井曲线在判定含砾粘土夹层及软弱薄粘土夹层等方面具有较高的准确性;声波、井径、自然γ、视电阻率等测井方法可有效查找井旁隐伏断裂破碎带,特别是声波测井曲线异常更为明显;另外跨孔实测剪切波速还可进行地基土加固效果检验。 相似文献
48.
H. Laubscher 《International Journal of Earth Sciences》1994,83(2):237-248
The deep seismic reflection traverses across the Central Alps (NFP 20, ECORS-CROP) contain a new set of data on the lower crust which has been interpreted in different ways. One currently fashionable model depicts the European lower crust (ELC) as gently dipping below the Adriatic crust. However, this model requires that an observed sharp termination of the ELC under the internal border of the External Massifs is due to the non-transmission of organized seismic energy through the complex upper crust. This explanation is questioned as other reflections in this and similarly complex areas are recorded, and as the same sharp termination of the ELC under the internal border of the External Massifs is observed on all seismic lines for a length of 300 km. A tectonic — metamorphic cause appears to more satisfactorily explain the obeservations, and therefore an alternative model combining surface and deep geophysical data is proposed. It consists of three mutually largely decoupled tectonic levels. (1) The shallow obducted part or lid, bounded at its base by the combined Late Miocene Jura and Lombardic basal thrusts. Estimates of shortening based on balanced sections are at least about 100 km. (2) The intermediate level between the brittle-ductile transition and the top of the subducted mantle. It contains a stack of lower crust imbrications (with a minor admixture of upper mantle) accommodated by (inducted into) the ductile middle crust. Estimates of shortening based on area balancing are again of the order of slightly more than 100 km. (3) The subducted upper mantle, for which there are no reflection data.In the Central Alps the Late Miocene phase was dextrally transpressive, producing flower structures at the shallow level (External Massifs); the stacks of lower crust imbrications at the intermediate level may be the equivalent of the External Massifs at that level. Inverted flower structures of the subducted mantle are possible, but no detailed data are available. 相似文献
49.
E. Ovando-Shelley 《Geotechnical and Geological Engineering》1995,13(1):1-16
Summary This paper presents results of static and cyclic direct shear tests performed on undisturbed and remoulded samples of Mexico City clays, including results of soil-on-interface tests. Experiments show that the static adhesion coefficient depends on the soils' liquidity index and that it diminishes due to the effect of repeated dynamic loads. Dynamic overstrength effects were not apparent, as has been observed when testing this clay in other apparatus. Interface strength in remoulded clays is initially less than half the strength of interfaces with undisturbed materials but it increases with time. At least in the materials tested in this research, it did not equal the strength of interfaces with undisturbed materials. Correction factors derived from experimental data can be used to modify the adhesion coefficient to account for dynamic and remoulding effects. 相似文献
50.
Partly laminated sediments were sampled from the brine-filled, anoxic Shaban Deep basin in the northern Red Sea. At about 4200 cal yr BP more than two millennia of anoxic sedimentation is replaced by a sub-oxic facies strongly suggesting the episodic absence of the brine. At the same time stable oxygen isotopes from surface dwelling foraminifera show a sharp increase (within less than 100 yr) pointing to a strong positive salinity anomaly at the sea surface. This major evaporation event significantly enhanced the renewal of deep water and the subsequent ventilation of the small Shaban Deep basin. The timing and strength of the reconstructed environmental changes around 4200 cal yr BP suggest that this event is the regional expression of a major drought event, which is widely observed in the neighboring regions, and which strongly affected Middle East agricultural civilizations. 相似文献