滇西北衙斑岩型金多金属矿床成矿流体特征及其演化

北衙超大型金多金属矿床位于扬子陆块西缘与三江特提斯造山带的结合部位。本文通过对北衙矿区内的斑岩体石英斑晶、斑岩型矿化、矽卡岩矿化中的矽卡岩及外围似层状热液型铅锌银矿化的岩(矿)石中发育的流体包裹体进行了系统研究,发现北衙矿区内主要发育CO2、富CO2、含CO2、含子矿物三相、富气相水溶液及气液两相水溶液包裹体六类流体包裹体;与斑岩型矿化有关的成矿流体为中-高温Na Cl-H2O-CO2体系热液,矽卡岩矿化相关成矿流体为一种高温的Na Cl-H2O及Na Cl-H2O-CO2体系热液,而外围似层状铅锌银矿化相关的成矿流体则为中温的Na Cl-H2O-CO2体系热液。对比分析表明,矽卡岩矿化中的矽卡岩矿物(以绿帘石类矿物为主)形成较早,其中发育富气相的流体包裹体,可以推断岩浆侵位后先分异出富水蒸气的流体,此后CO2才从成矿流体中大量分异。斑岩型矿化及外围地层中似层状铅锌银矿化脉体中发育的流体包裹体与斑岩体石英斑晶内发育的流体包裹体组合类型基本一致,表明成矿流体主要来自斑岩体结晶分异出的岩浆热液。流体包裹体研究表明,北衙金多金属矿区内的矽卡岩型(金铜铁)、斑岩型(铜金钼)及外围碳酸盐岩等地层中的似层状热液型(铅锌银)矿床系列为与富碱斑岩体侵位活动有关的,由岩浆分异热液并逐渐演化形成的斑岩型金-铁铜-铅锌(银)多金属成矿系统。     

川西坳陷什邡地区蓬莱镇组天然气藏特征及成藏过程分析

川西坳陷什邡地区蓬莱镇组气藏属于浅层常规—致密砂岩次生气藏,其形成机制不同于下伏须家河组储层的致密砂岩气。研究区内主要发育岩性圈闭,天然气来自于下伏须家河组煤系烃源岩及部分受到调整和改造的须家河组原生气藏,经长距离运移后在蓬莱镇组圈闭中聚集成藏。气层集中在蓬莱镇组中上部,天然气干燥系数大,以煤型气为主。流体包裹体分析表明,研究区内蓬莱镇组共经历3期热流体活动,前两期分别为液态烃充注及气液混合烃充注,但并未形成规模油藏;第3期为大规模天然气充注,对应成藏时间为晚白垩世晚期至古近纪早期(78~34Ma)。在此基础上,结合地质构造演化、烃源岩生排烃期、储层致密化窗口及生储盖组合特征,确定了蓬莱镇组天然气藏的形成过程及成藏特征:蓬莱镇组下部储层在晚白垩世中期达到致密化,已不利于天然气聚集成藏;喜山运动时期,下伏须家河组气藏受到调整和改造,早期发育的深大断裂得以扩展,大量深部气源沿断层向上运移至蓬莱镇组中上部,形成了浅层次生气藏。     

风化煤及提腐植酸后残渣热解行为与动力学分析

应用热重-质谱(TG-MS)联用技术对风化煤(WC)及其腐植酸提取后残渣(WCR)的热解行为进行了研究,分析了非烃类(H2、H2O、CO和CO2)、低碳烃类(CH4、C3H6和C3H7)和芳烃类(C6H6)的实验结果,并利用Coast-Redfern积分法对其热解和烃类生成动力学进行了探讨,获得了热解过程和烃类生成动力学参数。结果表明:热解过程中风化煤的质量损失率(38.9%)略大于其腐植酸提取后残渣(36.6%);除CO和CO2外,残渣中非烃类、低碳烃类和芳烃类产物的逸出量都稍微或显著多于风化煤中各类组分的逸出量。用Coast-Redfern积分法求得的动力学参数很好地解释了这一结果。     

A Preliminary Review of Metallogenic Regularity of Silver Deposits in China

China has widely distributed silver deposits,and is rich in silver resources.Although silver deposits are mainly associated with Pb-Zn deposits,a number of independent silver deposits have also been discovered in recent years.Silver deposits include different types,such as submarine volcanism and continental volcanism related type,intrusion related type,and sedimentary related type.This study summarized the metallogenic regularity of China’s silver deposits systematically based mainly on the data from 490 silver deposits.It is shown that submarine volcanic sedimentary type,continental volcanic or sub-volcanic type,skarn type,hydrothermal type(including vein type and stratabound type),sedimentary metamorphic type,sedimentary type and regolith type should be regarded as the most important prediction types of silver deposit.A total of 32 silver mineralization belts and 111 silver concentration areas have been delineated.The map of "Spatial distribution of silver mineralization belts in China" and other series of maps finished in this study may provide a theoretical basis for the evaluation and prognosis of silver resources potential in China.     

Using of Key Stratum Theory to Study the Structural Development of Roof Aquifer

<正>During the underground mining of coal resources,overlying rocks on the roof of excavated tunnels will be destroyed due to ground pressure,and as a result,part of them will break and fall into the tunnels.How to determine the distribution of fractured areas and fissures presents a major problem for preserving the overlying aquifer.In most cases,the distribution of fissures induced     

Critical Controlling Factors of Shale Gas Enrichment and Accumulation, and Remaining Uncertainties

<正>Shale gas exploration have yielded remarkable achievements recently in China,and four national demonstration areas for shale gas exploration and production have been established respectively as FulingJiaoshiba,Changning-Weiyuan,Zhaotong and Yanchang.During recent few years,nearly 400 wells have been drilled including 143 exploratory wells(vertical wells)and     

The Formation and Evolution Mechanism of Tight Oil and Gas in Lacustrine Carbonate Rocks in the Bohai Bay Basin

<正>Tight oil,a kind of unconventional oil accumulation that accumulates in source rocks in a free or adsorbed status in low or ultra-low porous sandstones or carbonates rocks which are interbedded with or adjacent to source rocks.Generally,the oil has not experienced a large-scale,long-distance migration(Zhang Jinchuan,et al.,2012;Jia     

Zircon U-Pb Geochronology and Geochemical Characteristics of the Volcanic Host Rocks from the Tongyu VHMS Copper Deposit in the Western North Qinling Orogen and Their Geological Significance

Precise in situ zircon U-Pb dating and Lu–Hf isotopic measurement using an LA-ICP-MS system, whole-rock major and trace element geochemistry and Sr–Nd isotope geochemistry were conducted on the volcanic host rocks of the Tongyu copper deposit on the basis of further understanding of its geological characteristics. Three zircon samples from the volcanic host rocks yielded 206Pb/238 U weighted average ages ranging from 436±4 Ma to 440±5 Ma, which are statistically indistinguishable and coeval with the ca. 440 Ma northward subduction event of the Paleo-Qinling oceanic slab. The volcanic host rocks were products of magmatic differentiation that evolved from basalt to andesite to dacite to rhyolite, forming an integrated tholeiitic island arc volcanic rock suite. The primitive mantle-normalized trace element patterns for most samples show characteristics of island arc volcanic rocks, such as relative enrichment of LILE(e.g. Th, U, Pb and La) and depletion of HFSE(e.g. Nb, Ta, Ti, Zr and Hf). Discrimination diagrams of Ta/Yb vs Th/Yb, Ta vs Th, Yb vs Th/Ta, Ta/Hf vs Th/Hf, Hf/3 vs Th vs Nb/16, La vs La/Nb and Nb vs Nb/Th all suggest that both the volcanic host rocks from the Tongyu copper deposit and the volcanic rocks from the regional Xieyuguan Group were formed in an island arc environment related to subduction of an oceanic slab. Values of ISr(0.703457 to 0.708218) and εNd(t)(-2 to 5.8) indicate that the source materials of volcanic rocks from the Tongyu copper deposit and the Xieyuguan Group originated from the metasomatised mantle wedge with possible crustal material assimilation. Most of the volcanic rock samples show good agreement with the values of typical island arc volcanic rocks in the ISr-εNd(t) diagram. The involvement of crustal-derived material in the magma of the volcanic rocks from the Tongyu copper deposit was also reflected in the zircon εHf(t) values, which range from-3.08 to 10.7, and the existence of inherited ancient xenocrystic zircon cores(2616±39 Ma and 1297±22 Ma). The mineralization of the Tongyu copper deposit shows syn-volcanic characteristics such as layered orebodies interbedded with the volcanic rock strata, thus, the zircon U-Pb age of the volcanic host rocks can approximately represent the mineralization age of the Tongyu copper deposit. Both the Meigou pluton and the volcanic host rocks were formed during the ca. 440 Ma northward subduction of the Paleo-Qinling Ocean when high oxygen fugacity aqueous hydrothermal fluid released by dehydration of the slab and the overlying sediments fluxed into the mantle wedge, triggered partial melting of the mantle wedge, and activated and extracted Cu and other ore-forming elements. The magma and ore-bearing fluid upwelled and erupted, and consequently formed the island arc volcanic rock suite and the Tongyu VHMS-type copper deposit.     

地下水砷污染研究进展

砷是一种毒性很强的致癌物质,地下水的砷污染严重破坏生态环境,危害人类健康,已成为近年来国内外学者研究的热点问题。本文针对地下水的砷污染问题进行综述,介绍了地下水砷污染研究现状,并简单介绍了地下水中砷的来源。另外,还针对地下水中砷的存在形态及其影响因素等方面作了详细介绍,对砷污染的预防控制和修复治理起到指导作用。     

遥感技术在江西永丰县地质灾害调查中的应用

本文论述了遥感技术在江西永丰县1∶50000地质灾害调查中的应用,表明地质灾害遥感调查应用的效果。文中简述了遥感解译的工作方法,通过MAPGIS平台进行图像处理,建立了滑坡、崩塌、泥石流、地面塌陷等地质灾害的解译标志。在Google earth高清影像覆盖区,可对小型地质灾害进行精确的解译;通过相关的图像处理技术,对断裂构造,岩溶盆地也可进行相关解译;最后提出了地面野外调查的相关建议。实践证明,遥感解译可对地质灾害地面调查起互补验证作用。