锗、银、金大型超大型矿床的有机地球化学研究

锗、银、金大型超大型矿床的有机地球化学研究庄汉平（中国科学院地球化学研究所，贵阳５５０００２）关键词有机质—金属相互作用褐煤型超大型锗矿床黑色页岩型银钒矿床卡林型金矿床有机地球化学有机质—金属相互作用是有关超大型矿床基础理论研究的重要内容之一。在以往...     

龙海流会—漳浦将军澳断裂活动与地震

福建龙海流会 -漳浦将军澳断裂展布于九龙江口以南沿海 ,地质构造上属于长乐—诏安断裂带南段 ,是我国东南沿海晚第三纪玄武岩喷发的地区之一。本文分析了龙海流会 -漳浦将军澳断裂从晚第三纪 -第四纪晚更新世多次的玄武岩喷发及活动特征 ,探讨了活动断裂与地震的关系 ,分析了地质旅游综合开发的潜在优势。研究结果表明 :龙海流会 -漳浦将军澳断裂是晚第三纪 -第四纪晚更新世早期 (N2 -Q3)玄武岩循其多次喷发 ,晚更新世 (Q3)活动明显 ,属晚更新世活动断裂 ;该断裂附近今后仍有可能发生 5级左右地震 ,应加强地震监测 ;本区玄武岩火山口及名胜古迹旅游资源十分丰富 ,可努力使其成为今后发展的重要行业。     

花岗岩风化残积物粒度分维特征分析

对厦门某场地花岗岩风化残积物的粒度分布分析结果表明 :花岗岩风化残积物粒度分布具分形特征 ,风化程度越高 ,粒度分维越大 ;粒度分维反映颗粒粗细、颗粒级配 ,粒度分维可以作为划分风化带和评价力学性质、渗透性的一个指标。     

西藏斯弄多浅成低温热液型银铅锌矿床银的赋存状态研究

斯弄多银铅锌矿床是冈底斯成矿带林子宗群火山岩中发现的首例低硫化型浅成低温热液型中-大型多金属矿床。矿区矿物组合多样,矿石组构复杂,具有热液成矿作用的典型特征,成矿阶段可划分为(I)闪锌矿-黄铜矿-硫砷铜矿-黄铁矿-石英阶段、(Ⅱ)方铅矿-闪锌矿-银矿物阶段、(Ⅲ)黄铁矿-石英-方解石三个成矿阶段。通过野外调查、地质编录、显微观察和电子探针(EPMA)微区分析,本文对该矿床中银的赋存状态进行了详细的研究。结果表明,银主要以独立银矿物形式存在,方铅矿、闪锌矿、黄铁矿、黄铜矿等金属矿物中不可见银极少。银矿物种类主要为硫砷铜银矿、辉银矿、深红银矿、螺状硫银矿和自然银,呈裂隙银或粒间银形式赋存于矿区碧玉、铁锰碳酸盐和早期金属硫化物中,次以包裹银形式赋存于早期硫化物中。另,在硫砷铜矿中发育极少的类质同象不可见银。银矿化主要形成于成矿阶段Ⅱ,银主要以硫的络合物形式运移,随着成矿流体物理化学条件的变化而发生沉淀,形成银矿物。     

Initiation process of debris flows on different slopes due to surface flow and trigger-specific strategies for mitigating post-earthquake in old Beichuan County, China

The 12 May 2008 Wenchuan earthquake (Ms 8.0) in China, produced an estimated volume of 28 × 10⁸ m³ loosened material, which led to debris flows after the earthquake. Debris flows are the dominant mountain hazards, and serious threat to lives, properties, buildings, traffic, and post-earthquake reconstruction in the earthquake-hit areas. It is very important to understand the debris flow initiation processes and characteristics, for designing debris flow mitigation. The main objective of this article is to examine the different debris flow initiation processes in order to identify suitable mitigation strategies. Three types of debris flow initiation processes were identified (designated as Types A, B, and C) by field survey and experiments. In “A” type initiation, the debris flow forms as a result of dam failure in the process of rill erosion, slope failure, landslide dam, or dam failure. This type of debris flow occurs at the slope of 10 ± 2°, with a high bulk density, and several surges following dam failure. “B” type initiation is the result of a gradual increase in headward down cutting, bank and lateral erosion, and then large amount of loose material interfusion into water flow, which increases the bulk density, and forms the debris flow. This type of debris flow occurs mainly on slopes of 15 ± 3° without surges. “C” type debris flow results from slope failures by surface flow, infiltration, loose material crack, slope failure, and fluidization. This type of debris flow occurs mainly on slopes of 21 ± 4°, and has several surges of debris flow following slope failure, and a high bulk density. To minimize the hazards from debris flows in areas affected by the Wenchuan earthquake, the erosion control measures, such as the construction of grid dams, slope failure control measures, the construction of storage sediment dams, and the drainage measures, such as construction of drainage ditches are proposed. Based on our results, it is recommend that the control measures should be chosen based on the debris flow initiation type, which affects the peak discharge, bulk density and the discharge process. The mitigation strategies discussed in this paper are based on experimental simulations of the debris flows in the Weijia, Huashiban, and Xijia gullies of old Beichuan city. The results are useful for post-disaster reconstruction and recovery, as well as for preventing similar geohazards in the future.     

Determination of elemental affinities by density fractionation of bulk coal samples from the Chongqing coal district, Southwestern China

The occurrence and distribution of major and trace elements have been investigated in two coal-bearing units in the Chonqing mining district (South China): the Late Permian and Late Triassic coals.The Late Permian coals have higher S contents than the Late Triassic coals due to the fixation of pyrite in marine-influenced coal-forming environments. The occurrence of pyrite accounts for the association of a large number of elements (Fe, S, As, Cd, Co, Cu, Mn, Mo, Ni, Pb, Sb, Se, and Zn) with sulphides, as deduced from the analysis of the density fractions. The marine influence is probably also responsible for the organic association of B. The REEs, Zr, Nb, and Hf, are enriched by a factor of 2–3 with respect to the highest levels fixed for the usual worldwide concentration ranges in coal for these elements. The content of these elements in the Late Permian coal is higher by a factor of 5–10 with respect to the Late Triassic coal. Furthermore, other elements, such as Cu, P, Th, U, V, and Y, are relatively enriched with respect to the common range values, with maximum values higher than the usual range or close to the maximum levels in coal. The content of these elements in the Late Permian coal is higher than the Late Triassic coal. These geochemical enrichments are the consequence of the occurrence, in relatively high levels, of phosphate minerals, such as apatite, xenotime, and monazite, as deduced from the study of the density fractions obtained from the bulk coal.The Late Triassic coal has a low sulphur content with a major organic affinity. The trace element contents are low when compared with worldwide ranges for coal. In this coal, the trace element distribution is governed by clay minerals, carbonate minerals, and to a lesser extent, by organic matter and sulphide minerals.Major differences found between late Permian and Triassic coals are probably related to the source rocks, given that the main source rock of the late Permian epicontinental marine basin is the Emeishan basalt formation, characterised by a high phosphate content.     

虚拟化技术在公共服务平台中的应用

阐述了虚拟化技术及其优势,探讨在上海市公众网平台上建立公共虚拟机服务平台,并对上海市地理信息服务系统在公共虚拟服务平台上的应用进行实证分析,有助于为政府各部门提供更有效的基础地理信息服务。     

北冰洋中心区表层海水营养盐水平及浮游植物群落对快速融冰的响应

本文依托2010夏季中国第四次北极科学考察,通过对高纬度极地冰下水和冰芯的营养盐的连续观测及表层水颗粒物的藻类色素分析,获取了夏季快速融冰下冰水界面营养盐和光合色素的分布信息。结果表明调查期间表层水磷酸盐和硅酸盐相对于无机氮更丰富（依据Redfield比值）,表现为显著的氮限制。而冰芯无机氮浓度相对更高,融冰释放对水体无机氮有一定的补充。色素分析显示岩藻黄素（Fuco）和叶绿素a（Chl a）是水体颗粒物的主要光合色素。在8/15至8/18期间,叶绿素c（Chl c）、硅藻黄素（Diato）、硅甲藻黄素（Diadino）和岩藻黄素（Fuco）分别达到6,22,73和922μg/m3,体现了硅藻在群落中的优势地位。岩藻黄素（Fuco）的浓度在融冰快速期间有巨大的提升,主要来源于冰芯底部释放的衰老的冰生硅藻和浮游硅藻的生长。此外,青绿黄素（Prasino）和叶黄素（Lut）与岩藻黄素（Fuco）分布模式有明显的差异,暗示青绿藻和绿藻与硅藻对海冰融化的不同响应。     

东海盆地丽水凹陷CO2分布特征及成藏主控因素

基于丽水凹陷钻井和地震资料,综合天然气地球化学参数、基底断裂和岩浆底辟发育特征等,研究丽水凹陷CO₂的分布特征及其成藏主控因素.研究结果表明,丽水凹陷CO₂纵向上主要分布在灵峰组、明月峰组下段及元古界基底片麻岩中,不同层位CO₂的含量差别很大;平面上,温州13-1、丽水35-7和南平5-2 CO₂气藏均位于岩浆底辟体之上或者附近,同时周围亦发育断层,而丽水36-1高含CO₂气藏和LF-1井含CO₂气藏周围底辟不发育,均紧邻灵峰凸起西侧的控洼断裂.丽水凹陷幔源CO₂成藏主要受早中新世和晚中新世两期火山岩浆活动的影响,这两期火山活动将幔源CO₂带到地壳浅层,通过砂体侧向输导进入有利圈闭聚集成藏.      

Hydroelastic Investigation on A Pile Breakwater Integrated with A Flexible Tail for Long-Wave Attenuation

A novel concept of wave attenuator is proposed for the defense of long waves, through integrating a flexible tail to the lee-side surface of a pile breakwater. The flexible tail works as a floating blanket made up of hinged blocks, whose scale and stiffness can be easily adjusted. A two-phase-flow numerical model is established based on the open-source computational fluid dynamics (CFD) code OpenFOAM to investigate its wave attenuation performance. Incompressible Navier—Stokes equations are solved in the fluid domain, where an additional computational solid mechanics (CSM) solver is embedded to describe the elastic deformation of the floating tail. The coupling of fluid dynamics and structural mechanics is solved in a full manner to allow assess of wave variation along the deforming body. The accuracy of the numerical model is validated through comparison with experimental data. Effects of the flexible tail on performance of the pile breakwater are investigated systematically. Dynamic behaviours of the tail are examined, and characteristics of its natural frequency are identified. For safety reasons, the wave loads impacting on the main body of the pile breakwater and the stress distribution over the tail are specially examined. It is found that both the length and stiffness of the tail can affect the wave-attenuation performance of the breakwater. A proper choice of the length and stiffness of the tail can greatly improve the long-wave defending capability of the pile breakwater. The maximum stress over the flexible tail can be restrained through optimising the deformation and stiffness of the tail.