华北中元古代硫化物黑烟囟发现的初步报道   总被引：19，自引：1，他引：19  

李江海  冯军等 《岩石学报》2003,19(1):167-168

海底黑烟囟为当代海洋地质调查的重要发现，对于揭示地史时期块状硫化物的成矿过程中以及生命起源具有重要意义。本文初步报道在冀东中元古代块状硫化物矿床中首次发现保存完好的黑烟囟构造，它们保留了成矿流体运移的通道构造，围绕通道构造还显示良好的矿物分带现象。完全可以与现代海底黑烟囟对比，黑烟囟的发现证明了该区硫化物矿床的形成与海底喷流过程密切相关。  相似文献   

不同成矿阶段流体包裹体气相成分的四极质谱测定   总被引：14，自引：10，他引：14  

朱和平王莉娟  刘建明 《岩石学报》2003,19(2):314-318

四极质谱法测定的爆裂温度曲线，可区分出不同成矿阶段群体包裹体温度区间，并分别测定其气相组成。代表不同成矿阶段的包裹体气相组成有明显差异。本研究表明用四极质谱法测定同一样品中不同成矿阶段的包裹体气相组分是可行的，拓宽了成矿流体研究的思路，为研究多期次成矿流体的来源、演化和解译矿床成因提供了新的方法、手段。  相似文献   

惠家沟地区金矿化地质特征及其成因探讨   总被引：1，自引：0，他引：1  

董王仓 《陕西地质》1991,(2)

惠家沟金矿化区位于南秦岭印支冒地槽褶皱带东南端公馆—回龙汞锑矿带边缘。矿体呈层状,似层状赋存于中泥盆统杨岭沟组中上部碎屑岩—碳酸盐岩建造的浅变质细碎屑岩中。受层位、有利岩性和顺层韧～脆性剪切破裂带控制。矿化与硅化、黄铁矿化、毒砂化关系密切。金主要呈超显微自然金包含于毒砂黄铁矿中。矿化区中除 Au 外,尚伴有 As、Sb、Hg 等元素,并形成 Au—As—Sb—Hg 组合异常。成矿物质主要来源于容矿地层。成矿热液属大气降水与变顾热水的混合热液。成矿温度偏低、压力小。在矿化地质特征上,经初步研究认为类似卡林型金矿。由于该矿床多属地表工程控制,所获样品结果品位偏低,矿石中砷含量较高,且经初步选矿试验,金回收率较低,因此,矿石是否能被工业利用,尚待进一步研究探讨。  相似文献   

通渭—武都隐伏深大断裂构造的一些基本特征   总被引：1，自引：0，他引：1       下载免费PDF全文

段永民 《甘肃地质》2002,11(2):24-28,23

通渭—武都隐伏深大断裂为一近南北走向、隐伏的深部构造带 ,断面西倾 ,倾角约 6 0°～ 80° ,为高角度压性断裂。该断裂带发生于华力西期前 ,活跃于印支—燕山期 ,现仍处在活动期。断裂带两侧莫霍面深度、重磁场特征明显不同 ,带内岩浆活动强烈 ,是一重要的近南北向成矿带 ,也是一个现代活动带。  相似文献   

新疆准北地区铜矿床主要类型控矿条件及找矿前景分析   总被引：5，自引：0，他引：5  

王正云  唐红松 《矿产与地质》1997,11(5):319-324

准北地区铜矿床已发现有岩浆熔离铜镍硫化物型，海相火山岩型，隐爆角砾岩型和陆相火山岩型，那林卡拉－喀拉通克铜镍矿带受控于海沟岛弧盆地内基性岩带的控制，岩浆分异程度对铜矿形成具有明显的控制作用，海相火山岩铜矿受火山机构制约，常产出于海底火山喷发中心及附近洼地，将准北地区划分冲乎尔－麦兹铜多金属，阿舍勒铜锌，额尔齐斯铜（镍）金－萨吾尔－加波萨尔铜（钼）和谢米斯台－阿尔曼台－北塔山铜等五个具找矿前景的成矿  相似文献   

Biologischer Abbau von 2,4-Dinitrotoluol in einer kontinuierlich betriebenen Versuchsanlage und kinetische Untersuchungen     

L. Heinze  M. Brosius  U. Wiesmann 《洁净——土壤、空气、水》1995,23(6):254-263

Biological Degradation of 2,4-Dinitrotoluene in a Continuous Bioreactor and Kinetic Studies Experimental results on the aerobic biological degradation with complete mineralization of 2,4-dinitrotoluene (2,4-DNT) are presented. A culture of Pseudomonas sp. DNT from Spain and Nishino was used. The degradation was examined with batch cultures for the determination of kinetic and stoichiometric coefficients. Further experiments were carried out with a continuous culture in a fixed-bed reactor with recirculation in order to obtain high degradation rates. The reactor was packed with ceramic Raschig rings (55 mL) and had a liquid reaction volume of 160 mL. The minimal salt media from Spanggord et al. with and without (NH₄)₂S)₄ as nitrogen source was used as substrate. 2,4-DNT was the sole source of carbon and energy. From batch experiments a yield coefficient Y_B/S = (0.30 ± 0.05) g g^?1 was calculated from a mass balance of the elements. This result was confirmed by calculations using literature data. Fitting the experimental data to the Monod equation, μ_max = 0.1 h^?1 and K_S = 0.01…0.03 mmol L^?1 were obtained. It was demonstrated by batch experiments that 2,4-DNT is not only used as the source of carbon and energy but also as the nitrogen source. In the fixed-bed reactor, a degradation of 92…97% was reached with a maximal 2,4-DNT load of 95 mg L^?1 h^?1. The rate of continuous degradation could be described by a pseudo-first-order reaction (k = 9.73 h^?1). The complete mineralization of 2,4-DNT was verified by the measurement of DOC and the formed nitrite and nitrate. The formed nitrite was nitrified simultaneously. It was demonstrated by these experiments that large scale biological treatment of industrial effluent containing 2,4-DNT may be successful.  相似文献   

二密铜矿床成矿模式的研究     

冯守忠  姜建军 《矿产与地质》1993,7(5):324-328

二密中生代火山岩盆地矿产以铜为主,矿床主要产于盆地中石英闪长岩岩体东段,矿体分布在石英闪长岩内外接触带,均以脉状、细脉状、细脉浸染状、浸染状矿体为主,成群成带分布.从岩体和矿脉原生硫化物同位素测定.显示成矿热液与花岗斑岩、石英闪长岩是统一的硫源.其成矿与岩体侵入作用有关.在研究铜矿床地质特征的基础上,总结了二密铜矿床成矿模式.  相似文献   

中国铀矿地质工作的主要成就与展望   总被引：1，自引：0，他引：1  

刘兴忠 《铀矿地质》1989,(5)

本文系统总结了我国30多年来铀矿地质勘察和科研的主要成果,着重阐述我国铀矿地质的主要持点,铀矿床类型及地质矿化特征、产铀建造、铀矿分布规律,在此基础上提出今后找矿方向及依靠科技进步,培养人才等建议,促进铀矿地质工作的进一步发展,以适应发展核工业对铀资源的需要。  相似文献   

Effects of Pinus sylvestris var. mongolica afforestation on soil phosphorus status of the Keerqin Sandy Lands in China   总被引：2，自引：1，他引：2  

Q. Zhao  D.H. Zeng  D.K. Lee  X.Y. He  Z.P. Fan  Y.H. Jin 《Journal of Arid Environments》2007,69(4):569-582

Few studies have considered the effects of afforestation on soil phosphorus (P) status in semiarid regions such as the Keerqin Sandy Lands in China, though plantations have been widely established on P-deficient sandy soils to control wind-induced desertification. Phosphorus fractions and acid phosphomonoesterase (AP) activities were compared in the rhizosphere and bulk soils (0–5 and 5–20 cm) under Mongolian pine (Pinus sylvestris L. var. mongolica Litv.) plantations of different ages (15, 22, and 30 years old) and in bulk soils under grasslands to understand soil P behavior with Mongolian pine plantation development and to find out major factors controlling soil P cycling. Stand age and rhizosphere processes had similar effects on the soil P fractions. Labile inorganic P and phosphate absorbed on aluminum and iron oxides were not affected by stand age and rhizosphere processes. Rhizosphere effects of Mongolian pine accelerated the mineralization of organic P by increasing microbial and AP activities. Soil P properties in bulk and rhizosphere soils changed similarly with plantation development. In the first 15 years after afforestation, total organic P, calcium phosphate, labile organic P, microbial biomass P (MBP) concentrations, and AP activities were reduced sharply. About 73% of the reduction in total P came from mineralization of organic P and 24% came from solubilization of calcium phosphate. From 15 to 22 years onward, soil total organic P and calcium phosphate decreased gradually and labile organic P, MBP, and AP activities increased greatly, whereas total inorganic P remained constant. The results suggest that soil P pool was depleted with Mongolian pine plantation development, especially in the early stage. As the dominant form of soil P, organic P was the main source of available P and associated biological processes controlled soil P cycling under Mongolian pine plantations. To ensure sustainability of pine plantations, it is imperative that soil fertility is conserved by adding fertilizer, thinning, and protecting litterfall.  相似文献   

The role of discontinuous magma inputs in felsic magma and ore generation     

J.L. Vigneresse   《Ore Geology Reviews》2007,30(3-4):181-216

For a long time, granites have been considered as passive bodies ascending under intrinsic negative density and viscosity contrasts with their host rocks. Chemical variations within a granitic body resulted from in situ differentiation and crystal fractionation. Since the mid 1980s, this global view has been significantly modified by (i) shifting melting from water-saturated conditions to fluid-absent reactions, (ii) increasing the role played by the mantle during granite generation, (iii) reassessing the rheology of partially molten rocks, (iv) demonstrating stepwise segregation and ascent of magmas by analogue and numerical models, (v) combining structural, geophysical and geochemical studies to reveal the internal structures in granitic plutons. It results that a granitic body is built up by a discontinuous accumulation of successive magma intrusions. The discontinuous nature of magma emplacement has also significant consequences for its ability to generate ore. The processes that lead to ore deposits are examined, with a brief review of the magmatic and fluid phases that concentrate ore forming elements. Examples are taken from crustal-derived granites and porphyry-type deposits. Those are considered as the two end-members of magmatic and hydrothermal ore deposits. The source characteristics of the magma, the emplacement mechanisms and magma mixing processes are the frame that controls the potential to carry base metals with the magma. The distribution of elements is controlled by diffusion, partition between minerals and melt, solubility and redox conditions. Variations of those parameters are examined by considering their activation energy which controls the exponential dependence with temperature. A characteristic length depending on the activation energy, temperature variation and time is estimated for a characteristic time lag of 30 ka. The intrusion of a magma into a magma chamber of similar composition, hence temperature, has few effects on diffusion, partition coefficient and redox conditions, because of a too low temperature contrast. The intrusion of a mafic magma into a felsic one induces a variation of 300 °C in both magmas. The characteristic length of diffusion may vary by up to two orders of magnitude, whereas the variation of partition coefficients is only one order of magnitude. The redox conditions are about 2.5 log unit in the mafic magma, but they can vary by 7 log units in the felsic magma. Hence, a strong decrease in δD values is observed in porphyry-type deposits. The effect is a removal of the elements with higher activation energy (W, Sn, Zr) from the mafic to the felsic magma. Deformation during the late stages of emplacement also controls ore formation.  相似文献