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81.
初论地球自然灾害系统 总被引:4,自引:0,他引:4
在地核和太阳强大的热能驱动下,开放的地球系统固液气态物质发生不同尺度的循环运动。流体运动是地球物质运动的主导因子。地球不均匀热结构导致流体不均匀流动,涉及固流气耦合、天地耦合、地气耦合、洋陆耦合和盆山耦合,产生能量链、物质链、结构链、事件链、资源链、能源链、灾害链和环境链。地球内部热动力及其相关的重力、应力、引潮力联合作用于地球某个特殊部位,形成一系列具有成因联系、时空联系、前兆联系的自然灾害。通过灾害链的时空结构和有成因联系的前兆异常可以预测灾害,能够有效地防灾。地热异常区与灾害多发区吻合。在合适的构造部位系统开发地热和地气,能够有效地减灾和减排,并彻底改善能源结构,消除能源危机。 相似文献
82.
After the discovery of the Aguablanca ore deposit (the unique Ni–Cu mine operating in SW Europe), a number of mafic‐ultramafic intrusions bearing Ni–Cu magmatic sulfides have been found in the Ossa–Morena Zone of the Iberian Massif (SW Iberian Peninsula). The Tejadillas prospect is one of these intrusions, situated close to the border between the Ossa–Morena Zone and the South Portuguese Zone of the Iberian Massif. This prospect contains an average grade of 0.16 wt % Ni and 0.08 wt % Cu with peaks of 1.2 wt % Ni and 0.2 wt % Cu. It forms part of the Cortegana Igneous Complex, a group of small mafic‐ultramafic igneous bodies located 65 km west of the Aguablanca deposit. In spite of good initial results, exploration work has revealed that sulfide mineralization is much less abundant than in Aguablanca. A comparative study using whole‐rock geochemical data between Aguablanca and Tejadillas shows that the Tejadillas igneous rocks present a lower degree of crustal contamination than those of Aguablanca. The low crustal contamination of the Tejadillas magmas inhibited the assimilation of significant amounts of crustal sulfur to the silicate magmas, resulting in the sparse formation of sulfides. In addition, Tejadillas sulfides are strongly depleted in PGE, with total PGE contents ranging from 14 to 81 ppb, the sum of Pd and Pt, since Os, Ir, Ru and Rh are usually below or close to the detection limit (2 ppb). High Cu/Pd ratios (9700–146,000) and depleted mantle‐normalized PGE patterns suggest that the Tejadillas sulfides formed from PGE‐depleted silicate magmas. Modeling has led us to establish that these sulfides segregated under R‐factors between 1000 and 10,000 from a silicate melt that previously experienced 0.015% of sulfide extraction. All these results highlight the importance of contamination processes with S‐rich crustal rocks and multiple episodes of sulfide segregations in the genesis of high‐tenor Ni–Cu–PGE ore deposits in mafic‐ultramafic intrusions of the region. 相似文献
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85.
蒙亚啊铅锌矿床自发现至今尚未报道稀土元素地球化学的研究成果,本文通过ICP-MS方法测定了矿床金属硫化物和热液成因石英中稀土元素的组成。研究表明,磁黄铁矿、黄铜矿、闪锌矿和方铅矿中稀土元素总量有所差异,但总体均为右倾的轻稀土富集型配分模式;据Eu异常特征可将其分为3组,Eu异常的产生主要是成矿过程中物化条件的转变及方解石的大量结晶造成的。4件石英稀土元素总量亦有所差异,原因在于其结晶时间和结晶温度不同,其配分曲线亦为轻稀土富集的右倾型;不同阶段形成的石英各自具强烈的正铕或负铕异常,究其原因主要是由于后期大气降水的加入及方解石的形成引起的。 相似文献
86.
CHEN Zhong HUANG ChiYue WU BiHao ZHAO MeiXun & YAN Wen Key Laboratory of Marginal Sea Geology South China Sea Institute of Oceanology Chinese Academy of Sciences Guangzhou China 《中国科学:地球科学(英文版)》2010,(3)
Aluminum is an active amphoteric metal element, but native aluminum (Al°) can be formed and preserved in special condi- tions so that its occurrence has unique geological significance. In this paper, the coarse fractions ( 63 μm) of 269 samples of surface sediments and of 165 sediment samples in four cores from the South China Sea (SCS) were picked out and analyzed. Al° particles were found in only five surface samples and three samples in two sedimentary cores. The particles are grayish or silver white in color with a strongly metallic luster and high plasticity, and they occur as irregular plats, elongated shapes and spherules with botryoidal structures. The identified Al° particles belong to cubical system, Fm3m space group with a varying from 4.028×10?1 nm to 4.059×10?1 nm. Their chemical compositions consist mainly of Al (95.07%–99.84%) and minor amounts of Si, Fe, Ti, S, Zn, Mg, Ca and trace amounts of K, Na, Cu, Co, P and Mn. Our results show that the identified Al° is authigenic, formed in situ in the prospective areas of gas hydrates, and that it is an unreported type of Al° occurrence. A possi- ble mechanism of Al° formation is proposed: under the strongly reducing micro environments at cold seeps, dissolved Al3+ in sediments is reduced to its metallic state by the strongly reducing agent of H2 through microbial processes and enzyme action. As a result, the Al° particles from the prospective gas hydrate areas in the SCS are the special products, representing the first report on Al° from the sediments at cold seeps. The proposed mechanism provides a theoretical basis for further studies on the special biogeochemical processes at cold seeps. 相似文献
87.
88.
This study was performed to investigate the operating status, evaluate the problems, and discuss possible improvement methods
of passive treatment systems for acid mine drainage (AMD) in South Korea. Thirty-five passive treatment systems in 29 mines
have been constructed from 1996 to 2002 using successive alkalinity producing systems (SAPS) as the main treatment process.
We investigated 29 systems (two for metal mines), 19 of which revealed various problems. Overflows of drainage from SAPS,
wetland, or oxidation ponds were caused by the flow rate exceeding the capacities of the facilities or by the reduced permeability
of the organic substance layer. Leakages occurred at various parts of the systems. In some cases, clogged and broken pipes
at the mouths of the mine adits made the whole system unusable. Some systems showed very low efficiencies without apparent
leakage or overflow. Even though the systems showed fairly good efficiencies in metal removal ratios (mainly iron) and pH
control; sulfate removal rates were very poor except in three systems, which may indicate very poor sulfate reductions with
sulfate reducing bacteria (SRB) as a means. 相似文献
89.
对冲绳海槽Jade热液区块状硫化物中流体包裹体的氦、氖和氩同位素组成进行了测定,流体包裹体的3He/4He比值为(6.2~10.1)Ra,均值为7.8Ra,与大洋中脊玄武岩一致[3He/4He≈(6~11)Ra],20Ne/22Ne比值为10.7~11.3,明显高于大气值(9.8),而40Ar/36Ar比值的变化范围在287~334之间,接近大气值(295.5),这些结果表明,块状硫化物中热液流体捕获的稀有气体是地幔和海水源组分混合的产物,且流体包裹体中的氦主要来自地幔,氖和氩主要来自海水。 相似文献
90.
冷泉渗漏区海底微生物作用及生物标志化合物 总被引:8,自引:0,他引:8
在有冷泉活动和水合物产出的海底环境中,甲烷氧化古细菌和硫酸盐还原细菌十分发育,它们主导着海底天然气(主要是甲烷)的缺氧氧化作用,并在海底碳循环和生物种群繁衍中发挥着重要作用。海底天然气渗漏活动区的甲烷氧化古细菌使渗漏CH4缺氧氧化为HCO3-,硫酸盐还原细菌使SO42-转化为HS-,从而使细菌微生物获得生命所需的能量,生物种群得以发育和繁衍。甲烷氧化古细菌有ANME-1、ANME-2、ANME-3三个种群,形成相应的醚类异戊二烯类和类异戊二烯烃类生物标志物。硫酸盐还原细菌有Desulfosarcina和Desulfococcus两个主要的细菌群落,形成二烃基甘油二醚和脂肪酸生物标志化合物。这种天然气渗漏区内微生物活动产生的生物标志化合物都具有特别负的碳同位素组成,δ13C值为-41.1‰~-95.6‰,说明微生物群落在生命代谢过程中摄取了来自甲烷的碳,同时也反映了天然气渗漏系统缺氧带存在的古细菌和硫酸盐还原细菌活动。 相似文献