Characteristics of Pegmatite-Related Fluids and Significance to Ore-Forming Processes in the Zhaxikang Pb-Zn-Sb Polymetallic Deposit,Tibet,China

The Zhaxikang Pb-Zn-Sb polymetallic deposit is one of the most important deposits in the newly recognized southern Tibet antimony-gold metallogenic belt.Compared to the porphyry deposits in the Gangdese belt,much less researches have addressed these deposits,and the genesis of the Zhaxikang deposit is still controversial.Based on field investigation,petrographic,microthermometric,Laser Raman Microprobe（LRM） and SEM/EDS analyses of fluid,melt-fluid,melt and solid inclusions in quartz and beryl from pegmatite,this paper documents the characteristics and the evolution of primary magmatic fluid which was genetically related to greisenization,pegmatitization,and silification in the area.The results show that the primary magmatic fluids were derived from unmixing between melt and fluid and underwent a phase separation process soon after the exsolution.The primary magmatic fluids are of low salinity,high temperature,and can be approximated by the H_2O-NaCl-CO_2 system.The presence of Mn-Fe carbonate in melt-fluid inclusions and a Zn-bearing mineral（gahnite） trapped in beryl and in inclusions from pegmatite indicates high Mn,Fe,and Zn concentrations in the parent magma and magmatic fluids,and implies a genetic link between pegmatite and Pb-Zn-Sb mineralization.High B and F concentrations in the parent magma largely lower the solidus of the magma and lead to late fluid exsolution,thus the primary magmatic fluids related to pegmatite have much lower temperature than those in most porphyry systems.Boiling of the primary magmatic fluids leads to high-salinity and high-temperature fluids which have high capacity to transport Pb,Zn and Sb.The decrease in temperature and mixing with fluids from other sources may have caused the precipitation of Pb-Zn-Sn（Au） minerals in the distal fault systems surrounding the causative intrusion.

Fluid Evolution and Ore-forming Processes of the Jiama Cu Deposit, Tibet： Evidence from Fluid Inclusions

The Jiama deposit is a large copper deposit in Tibet. Mineralization occurs in three different host rocks： skarn, hornfels and porphyry. A detailed fluid inclusion study was conducted for veins in the different host rocks to investigate the relationship between fluid evolution and ore-forming processes. Based on examination of cores from 36 drill holes, three types of veins （A, B and D） were identified in the porphyries, four types （I, II, III and IV） in the skarn, and three （a, b and c） in the hornfels. The crosscutting relationships of the veins and that of the host rocks suggest two hydrothermal stages, one early and one late stage. Fluid inclusions indicate that the Jiama hydrothermal fluid system underwent at least two episodes of fluid boiling. The first boiling event occurred during the early hydrothermal stage, as recorded by fluid inclusions hosted in type A veins in the porphyries, type a veins in the hornfels, and wollastonite in the skarns. This fluid boiling event was associated with relatively weak mineralization. The second boiling event occurred in the late hydrothermal stage, as determined from fluid inclusions hosted in type B and D veins in the porphyries, type I to IV veins in the skarns, and type b and c veins in the hornfels. This late boiling event, together with mixing with meteoric water, was responsible for more than 90% of the metal accumulation in the deposit. The first boiling only occurred in the central part of the deposit and the second boiling event took place across an entire interlayered structural zone between hornfels and marble. A spatial zoning of ore-elements is evident, and appears to be related to different migration pathways and precipitation temperatures of Cu, Mo, Pb, Zn, Au and Ag.

Dynamics of Ore-Forming Processesof the Stratabound Skarn Copper Depositsof Tongling, Anhui Province

The skarn and ore bodies of the stratabound skarn copper deposits of Tongling, Anhui Province, are both controlled by definite stratigraphic horizons, and they are concordant with the strata. They occur as layers and layer-like bodies in permeable carbonate rocks of the Middle-Upper Carboniferous Huanglong and Chuanshan Formations which are underlain by impermeable shale or siliceous rocks of the Upper Devonian Wutong Formation. The authors study the dynamics of ore-forming processes of the ore deposits with the dynamic model of coupled transport and reaction, and the following results are obtained: The salinity gradient and flow rate of the ore-forming fluids can both promote the mixing and reaction of juvenile water and formation water, and the permeable strata are favourable sites for the intense transport-reaction of mixing and the formation of deposits. (2) As isothermal transport-reaction took place along the bedding of strata, the moving transport-reaction front formed at the contact between the ore-forming fluids and the rocks advanced slowly along the permeable strata, and then stratiform skarn and ore bodies concordant with the strata were formed. (3) The gradient transport-reaction taking place across the isotherms in the cross-bedding direction caused the mineralogical composition to alter gradually from magnesian skarn to sulphide ore bodies.

Machine learning-based method to adjust electron anomalous conductivity profile to experimentally measured operating parameters of Hall thruster

The problem of determining the electron anomalous conductivity profile in a Hall thruster,when its operating parameters are known from the experiment,is considered.To solve the problem,we propose varying the parametrically set anomalous conductivity profile until the calculated operating parameters match the experimentally measured ones in the best way.The axial 1D3V hybrid model was used to calculate the operating parameters with parametrically set conductivity.Variation of the conductivity profile was performed using Bayesian optimization with a Gaussian process(machine learning method),which can resolve all local minima,even for noisy functions.The calculated solution corresponding to the measured operating parameters of a Hall thruster in the best way proved to be unique for the studied operating modes of KM-88.The local plasma parameters were calculated and compared to the measured ones for four different operating modes.The results show the qualitative agreement.An agreement between calculated and measured local parameters can be improved with a more accurate model of plasma-wall interaction.

智能电网用电异常诊断和调控策略

为了针对智能电网不同异常用电的原因制定分类调整方法,提出了基于二次根式函数电价调整和计算定界的策略,该策略基于自动过程控制和模糊综合评价进行监控、诊断及分类调整。首先,通过指数加权移动平均值作为自动过程控制的控制变量并确定上下界来监控用电量,建立监控模型;其次,用模糊综合评价法诊断异常用电原因;最后,根据不同原因制定分类调整策略,建立电价需求响应调整模型。算例仿真结果表明,提出的基于二次根式函数电价调整策略在调整频次、残差标准误差、全社会福利和电力公司利润等方面均优于线性函数调整。应用模糊综合评价方法能有效分析异常用电原因,制定分类调整策略能消除异常并获得平稳波动用电量。

基于SOM的长江流域持续性强降水过程典型环流的客观分型

利用1961—2021年逐日降水格点化观测资料和ERA5再分析资料,基于无监督深度学习的自组织特征映射神经网络(SOM)方法,将与中国长江流域夏季持续性强降水过程对应的大尺度环流客观划分成4种典型环流型(P1—P4)。各环流型呈现出的关键环流系统配置影响异常雨带的形成及落区。P1和P3中、高纬度分别为典型的单阻型和双阻型环流形势,且西太平洋副热带高压(简称副高)显著偏强并向西延伸。P2和P4表现出较为明显的低压异常,P2中的巴尔喀什湖到贝加尔湖以西为宽广低槽,贝加尔湖以东为脊区,形成入梅期间的稳定环流形势,长江流域受到低值系统的控制,副高位置靠南。P4在巴尔喀什湖以西和以东分别表现出位势高度异常偏低和偏高,长江流域表现为气旋性环流异常,同时副高位置偏北。P1、P2有来自高纬度冷空气的影响,P3和P4的冷空气较弱。以副高北跳为主要特征的东亚夏季风向北推进与4种环流型的出现以及相应的雨带位置有紧密联系,P1、P2主要对应6月至7月上旬持续性强降水,P3、P4则主要对应7月上旬至8月持续性强降水,导致P1和P2降水异常中心位于长江中下游的江南地区,P3和P4的降水异常中心分别位于长江流域和长江以北地区。P1、P3的水汽输送相比另外两类明显偏强,造成的降水强度也更强。此外,对典型环流型的稳定性分析表明,长江流域持续性强降水过程与上述4种典型环流型的稳定维持密不可分。持续性强降水过程中93.2%的环流表现出持续性的特征,P1和P2、P3和P4持续天数分别主要集中在5和3 d。从长期趋势来看,P1和P3环流型出现频次增多,P2和P4趋于减少。这意味着从有利环流的角度来说,持续性强降水倾向于在长江以南和长江中下游地区发生。

2021年秋季中国气候异常特征及主要气象灾害

利用1961—2021年中国区域2400余站地面气象常规观测资料,根据2019年中国气象局发布的《区域性重要过程监测和评价业务规定》,对2021年秋季中国气候基本概况及主要气象灾害进行全面分析。结果表明:(1)2021年秋季,中国气候状况总体偏差,平均气温较常年同期偏高,平均降水量较常年同期偏多;由于台风登陆个数偏少,且强降水以及冷空气过程影响区域叠加累积效应显著,导致北方部分省份雨、雪和冰冻灾害影响明显高于南方。(2)2021年秋季,我国气象灾害形势复杂严峻,极端天气气候复合事件多发,以暴雨洪涝、高温干旱、低温冰冻雨雪灾害为主,灾害极端性和区域性特征显著。区域暴雨过程较常年同期偏多4.2次,北方多地发生罕见秋汛,山西、陕西等地洪涝灾害较重;阶段性区域高温天气多发,区域高温过程较常年同期偏多2.4次,导致江南、华南高温干旱复合发展;寒潮过程较常年同期偏多1.2次,过程影响区域叠加累积效应显著,东北三省和内蒙古部分地区雪情较重。

新疆2018年冬季雨雪风沙强降尘事件

2018年11月30—12月3日中国西北新疆地区发生了罕见的冬季雨雪风沙强降尘天气事件,基于气象观测记录、环境监测和大气降尘连续观测数据,分析研究了此次异常天气过程的大气污染物的时空变化特点及其环境影响。结果显示:该天气过程造成新疆90%以上的绿洲城市遭受大气颗粒物污染,污染组分主要以粗颗粒污染物为主,环境PM_(10)(空气动力学直径≤10μm的颗粒物)最大浓度高达4745μg·m^(-3);大风天气与PM_(10)浓度以及空气质量指数(Air Quality Index,AQI)高度正相关;首府乌鲁木齐市大气颗粒物总沉降量约90×10^(4)~152×10^(4)t,大气降尘强度均值为85 g·m^(-2),超过城市年均值的60%。此次冬季异常雨雪风沙天气过程导致环境空气重污染和高降尘量,风蚀沙尘颗粒物在大气环流场急流作用下传输到绿洲区域,对城市大气环境质量的恶化影响显著,塔克拉玛干沙漠是造成此次西北新疆地区大范围强降尘事件的主要源地。

The solubility of a metallic mineral with other coexisting minerals and the ore-forming processes of metallic sulfides

Most metallic minerals in ore deposits are sulfides. When a sulfide mineral coexists with rock-forming minerals, its solubility is distinctly different from itself alone. The change in dissolution character of a mineral with coexisting rock-forming minerals leads to particular geochemical be-havior. The concept of solubility of a metallic mineral with coexisting rock-forming minerals and its theory and model of calculation are put forward. Taking Tianmashan Cu-Au ore deposit of sulfide minerals in Tongling district as an example, solubilities of some metallic minerals with other coex-isting minerals, such as pyrite or chalcopyrite with quartz (representing sandstone) or calcite (rep-resenting limestone), are calculated. The results show the mechanism of ore-forming processes. As the ore-forming fluid flows through sandstone, it dissolves pyrite in the sandstone at first, then transports the iron and sulfur to the interface between sandstone and limestone and eventually precipitates them on the interface.

分数阶扩散系统子区域能控性研究的现状与发展

近年来,随着分数阶微积分理论研究的不断深入,分数阶扩散系统因更有效描述自然界和工程中的反常扩散现象而引起了学者们的广泛关注,并取得了较为丰硕的研究成果.然而,据作者所知,目前鲜有文献总结分数阶扩散系统子区域能控性研究的相关内容.因此,本文首先详细综述分数阶扩散系统能控性、子区域能控性的研究进展,并予以分析;然后给出仍需解决的问题和可能的研究机遇.

Evidence from pseudomorphous β-quartz phenocryst for decompression of rock-forming and ore-forming processes in Shapinggou porphyry Mo deposit

The Shapinggou porphyry molybdenum(Mo) deposit, located in Jinzhai County, Anhui Province, China, is the largest in the Qinling-Dabie Mo Metallogenic Belt. The intrusive rocks in the Shapinggou Mo ore district formed in the Yanshanian can be divided into two stages based on zircon U-Pb dating and geochemical features. This study focuses on the late stage intrusions(quartz syenite and granite porphyry), which are closely genetically related to molybdenum mineralization. Petrographic observations identified two quartz polymorphs in the quartz syenite and granite porphyry, which were derived from the same magmatic sources and similar evolutionary processes. The quartzes were identified as a xenomorphic β-quartz within quartz syenite, while the quartz phenocrysts within the granite porphyry were pseudomorphous b-quartz, characterized by a hexagonal bipyramid crystallography. The pseudomorphous b-quartz phenocrysts within the granite porphyry were altered from b-quartz through phase transformation. These crystals retained b-quartz pseudomorph. Combined with titanium-inzircon thermometry, quartz phase diagrams, and granitic Q-Ab-Or-H_2O phase diagrams, it is suggested that the quartz syenite and granite porphyry were formed under similar magmatic origins, including similar depths and magmatic crystallization temperatures. However, the β-quartz within quartz syenite indicated that the crystallization pressure was greater than 0.7 GPa, while the original b-quartz within the granite porphyry was formed under pressures between 0.4 and 0.7 GPa. The groundmass of the granite porphyry which formed after the phenocryst indicated a crystallizing pressure below 0.05 GPa. This indicates that the granite porphyry was formed under repetitive and rapid decompression. The decompression was significant as it caused the exsolution of the ore-forming fluids, and boiling and material precipitation during the magmatic-fluid process. The volumetric difference during the phase transformation from b-quartz to β-quartz caused extensive fracturing on the granite porphyry body and the wall rocks. As the main ore-transmitting and ore-depositing structures, these fractures benefit the hydrothermal alteration and stockwork-disseminated mineralization of the porphyry deposit. It is considered that the pseudomorphous β-quartz phenocrysts of the porphyritic body are metallogenic indicators within the porphyry deposits. The pseudomorphous β-quartzes therefore provide evidence for the formation of the porphyry deposit within a decompression tectonic setting.

Numerical Study for the Role Playing of Atmospheric Dynamic Processes Caused by Seasonal and Non-seasonal Forcings in Formation of the Short-Term Anomalous Climate Change

In this paper, it has been pointed out that anomalous climate change can be found, which is similar to that caused by anomalous external forcing, in the 25-year simulations from the model without non-seasonal external forcings. It shows that the short-term anomalous climate change can be formed by dynamic processes in the atmosphere caused by seasonal and non-seasonal external forcings.In this research, two numerical experiments with different initial states and different time sub-series of the natural climate change have been done using the IAP atmospheric general circulation model with same sea surface temperature anomalies in the tropical Pacific. The results reveal that anomalous climate phenomena in the atmosphere can arise as a result of interaction between the inherent internal dynamic process (caused by seasonal external forcings) in the long-range climate natural change process of the atmosphere and the dynamic process caused by non-seasonal external forcings (external dynamic process); in the northern winter, features of anomalous climate change appearing in the model atmosphere bear a strong resemblance to the behavior resulting from the external dynamic process caused by non-seasonal external forcings while in the southern summer, it resembles the behavior resulting from the internal dynamic process caused by seasonal external forcings.

多测井曲线的综合处理合成

测井曲线是地质分层的基础,但在利用单一测井曲线解决复杂地质问题时也存在多解性和局限性。为克服多解性,人们采用多种测井曲线进行地质分层,提高了分层的精度。本文在此基础上提出把多条曲线分别赋予不同的加权因子,然后进行归一化处理,形成一条标准综合参数测井曲线。此综合参数曲线突出了所选的多条测井曲线的公共信息,减少或削弱了单一测井曲线中的偶然误差,提高了综合后测井资料的可信度。该方法可应用于地质分层、岩性分析、含油气预测等诸多领域。应用时要注意,并非所选择的测井曲线种类越多越好。

事件地质激发成矿作用异常与超巨量金属工业堆积

本文提出成矿学中的事件地质,系指在成矿历史演化进程中发生的地质事件激发正常成矿作用异常形成超巨量金属工业堆积和特大型矿床。重点探讨跨区域壳幔结构不连续性、幔根构造的形成和构造圈热侵蚀事件与成矿,并列举美国西部有色金属成矿区和中国南岭钨锡多金属矿集区与幔根构造有关地质事件形成超大型矿床的实例。

海南数字地脉动参数处理系统

该文编制了一个基于服务器数据库的地脉动参数自动处理系统,它利用FTP协议每天自动从测震台网中心的服务器中获取地脉动波形,自动计算各个地脉动参数,并自动把参数添加到地脉动参数数据库中。同时编制地脉动参数查询与图形显示系统,用户可使用IE浏览器查看地脉动参数和绘制变化图形。初步研究认为,在海南及邻区显著地震前和地震活动活跃时地脉动参数有一定的异常变化。

“0801南方雪灾”与同期蒙古高压中期活动的关系

用1951—2008年58 a 1月10日—2月2日1 000 hPa高度场逐日NCEP/NCAR再分析格点资料,求得逐日蒙古高压的强度P和中心位置λc、c指数,用其对"0801南方雪灾"期间蒙古高压的中期演变过程进行统计分析。结果表明,2008年1月10日—2月2日蒙古高压强度P和中心所在纬度φc出现了连续4次振荡,它们与我国南方降温、降水振荡过程准同步。由P、(λc,c)给出的综合动态图上蒙古高压4次活动过程也很明显地与降温、降水中期过程一一对应。分析表明2008年1月10日—2月2日蒙古高压的这一中期演变特征,是1951年以来仅有的一次。因此,可以认为,在充沛水汽供应条件下蒙古高压强而连续的爆发是导致"0801南方雪灾"产生的直接环流成因。

基于分层抽样算法的异常攻击流量检测

在高速互联网应用中,海量数据无法逐包检测分析,异常攻击流量也不易被识别。为解决该问题,利用泊松帕累托突发过程的经典流量模型对网络流量自相似特性进行分析,将网络流量分为长流与短流,并根据数据流到达时间的抽样比增量进行分层抽样,由此实现异常攻击流量的检测。在基于数据报文级检测的snort异常入侵检测系统上对该方法进行仿真实验,结果证明其能有效缩小异常攻击数据范围,快速准度地检测出攻击。

中文网络聊天语言的奇异性与动态性研究

随着互联网走入社会生活,网络聊天逐渐成为一种新的沟通渠道,网络聊天语言便应运而生。这类语言的日益丰富,给语言信息处理带来了新的挑战。研究发现,困难主要来自网络聊天语言的奇异性和动态性。本文借助真实网络聊天语言文本,对网络聊天语言的奇异性和动态性进行详细分析和归纳,并设计了面向解决奇异性和动态性问题的网络聊天语言文本识别与转换方法。我们先以网络聊天语言语料库为基础建立网络聊天语言模型和语言转换模型,通过信源?信道模型实现网络聊天语言向标准语言的转换。但该方法过于依赖网络聊天语言语料库,虽然能较好解决奇异性问题,但不能处理动态性问题。因此,我们进而以标准汉语语料库为基础建立文字语音映射模型,对信源?信道模型进行改进,最终有效解决了网络聊天语言的动态性问题。

特大型矿床与异常成矿作用

特大型矿床具有成矿偏在性并受控于异常成矿构造聚敛场。它们是常规成矿作用 (过程 )中发生“引潮共振”而爆发的异常成矿作用的产物 ,具有与中小型及大型矿床显著不同的成矿机制。异常成矿作用的发生与一定地质历史时期出现的全球性重大异常地质事件有关 ,如太古宙氧大气变态(过氧事件 )、元古宙还原大气变态 (缺氧事件 )和显生宙构造圈热侵蚀 (大规模构造岩浆事件 ) ,其结果导致在短时限内发生成矿物质的超巨量工业堆积。研究和探索异常成矿作用的“基因”

中国大陆边缘构造属性与超巨量金属工业堆积

研究了大陆边缘的形成与演化,以中国大陆已存在的3条陆壳对接消减带为界,划分了5个大陆边缘构造带、13个次一级的边缘构造区及其内部的58个时空配置结构,并据区内现有金属矿产地计算了其发现几率。依据大陆边缘的形成、演化及其动力学特征,将中国大陆边缘划分为离散型、汇聚型、对接碰撞型和转换型4类,并总结了其成矿专属。大陆边缘虽然有利成矿,但是超巨量金属工业堆积应取决于其成矿有利因素是否达到最佳耦合。提出了最佳耦合应是异常地质事件激发正常成矿作用发生“引潮共振”①的结果。