内蒙古撰山子金矿床地质、地球化学特征及成因研究

撰山子金矿床产出在赤峰-朝阳矿集区北段,是赤峰地区唯一位于兴蒙造山带内的金矿床,构造-岩浆控矿作用明显。金矿化主要受断裂控制,呈脉状、细脉状产出,矿化至少经历了三个阶段:黄铁矿-石英阶段、石英-硫化物阶段和石英-碳酸盐阶段。本次主要开展对撰山子矿区的矿(岩)石硫同位、铅同位素和氢氧同位素研究,讨论撰山子金矿床的基本特征及成因机制。研究结果表明:撰山子成矿流体主要以岩浆水和大气降水的混合水为特征,矿石中的硫和铅主要源于岩浆,部分继承了围岩的特征。需要指出的是,矿石铅同位素和撰山子岩体铅同位素组成具有良好的相似性,指示其具有同源性的成因联系。因此,撰山子金矿床可能为深部大规模富金的烧锅营子岩浆侵入活动的晚期隆起(撰山子岩体)的产物,可能为一个典型的与侵入岩有关的金矿床,而非造山型金矿。     

Heavy metals in sediments as evidence for recent pollution and quasi-estuarine processes: an example from Lake Druzno,Poland

This article presents the results of a geochemical investigation of sediments from Lake Druzno (northern Poland), a reservoir fed by freshwater from the catchment, with periodic input of brackish water from Vistula Lagoon. This study analyzed the spatial variation in heavy metal content in surface sediments as well as the temporal changes in metal content in two sediment cores dated using the ²¹⁰Pb method. In the surface sediments, the highest metal concentrations were recorded in the northern part of the lake, with lower concentrations in the central and southern parts. Absolute values of metal concentrations in the cores were low, but normalization with respect to Al showed an increase during the second half of the 20th century. Mean enrichment factors (EF) in sediments from the second half of the 20th century ranged from insignificant (1–1.2) for Fe to (1.55–3.3) for Cu, Cd, Pb and Zn. The sediments deposited before 1950 had lower EF values (>1.5) and had low variability. Results from both the surface sediments and the cores indicate that the main source of lake pollution is brackish water intrusion from the Vistula Lagoon via the contaminated River Elbląg.     

内蒙古夏尔楚鲁金矿床辉钼矿铼-锇同位素年龄及成矿事件

本文为查明内蒙古四子王旗夏尔楚鲁金矿床的形成时间,对金矿体中发育辉钼矿的5件辉钼矿样品进行了铼-锇同位素分析,所获同位素等时线年龄为263.8±4.4Ma,其MSWD值为1.3.即矿体的形成时间为早二叠世,属海西期构造—岩浆作用及相关流体活动的产物.辉钼矿样品中的铼含量较低,为1.153×10-6～2.740× 10-6,平均为1.622×10-6,这说明成矿过程可能与地壳重熔的S型花岗岩岩浆活动或地壳流体有关.鉴于辉钼矿呈浸染状和团块状分布于黑云母花岗岩中,并且与石英和钾长石呈共生结构关系,可以推测夏尔楚鲁金矿床和黑云母花岗岩的形成时间均为早二叠世,属海西期构造—岩浆活动的产物.     

The characteristics of the Mocoa compound disaster event,Colombia

A rainfall-induced compound disaster happened in Mocoa in the pre-dawn hours of 1 April 2017. More than 300 people were killed, and a large number of houses and roads were destroyed in the worst catastrophe in the history of Mocoa. To investigate this disaster, a detailed interpretation was carried out using high-resolution images. Analysis of disaster characteristics based on satellite image revealed that the disaster could be identified as a consequence of compound mountain hazards including landslides, debris flows, and mountain torrents. The mountain hazards converged in the mountain watershed, which amplified the disaster’s effects. Analysis considers that this disaster is the result of heavy rainfalls. Moreover, in-depth interpretation of rainfall data and satellite images spanning over 16 years reveals that the previous El Niño event (2014–2016) also played an important role, which caused reduced rainfall and vegetation coverage. The long period of drought brought by El Niño affected the growth of vegetation and reduced the ability of vegetation to cope with heavy rainfalls. The results reveal that both antecedent rainfalls and climate impact need to be taken into consideration for mountain hazard analysis.     

Effects of particle size of mono-disperse granular flows impacting a rigid barrier

Understanding the interaction between complex geophysical flows and barriers remains a critical challenge for protecting infrastructure in mountainous regions. The scientific challenge lies in understanding how grain stresses in complex geophysical flows become manifested in the dynamic response of a rigid barrier. A series of physical flume tests were conducted to investigate the influence of varying the particle diameter of mono-dispersed flows on the impact kinematics of a model rigid barrier. Particle sizes of 3, 10, 23 and 38 mm were investigated. Physical tests results were then used to calibrate a discrete element model for carrying out numerical back-analyses. Results reveal that aside from considering bulk characteristics of the flow, such as the average velocity and bulk density, the impact load strongly depends on the particle size. The particle size influences the degree of grain inertial stresses which become manifested as sharp impulses in the dynamic response of a rigid barrier. Impact models that only consider a single impulse using the equation of elastic collision warrant caution as a cluster of coarse grains induce numerous impulses that can exceed current design recommendations by several orders of magnitude. Although these impulses are transient, they may induce local strucutral damage. Furthermore, the equation of elastic collision should be adopted when the normalized particle size with the flow depth, δ/h, is larger than 0.9 for Froude numbers less than 3.5.     

Macrocrystal Garnet and Its Inclusions in Kimberlite Pipes from the Mengyin Area, Shandong Province, China

Abstract: Based on previous studies of kimberlite xenoliths and diamond inclusions in this region, macrocrystal garnet was analyzed with the electric microprobe technique (EPMA). The garnet is collected from the Shengli No.1 kimberlite pipe in the Mengyin area of Shandong Province, China. The results indicate that the garnet contains two kinds of multiphase inclusions: one is K-, B-, and Cl-bearing oxygen-free phase, K- and Cl-bearing oxygen-free phase, and volatile-bearing garnet inclusions (in1 and in3); and the other is chlorite, phlogopite, apatite and calcite (in2). It is suggested that the formation of garnet and its inclusions is associated with strongly reduced mantle fluid. Such a fluid was transformed from ultra-deep high-reduction oxygen-free fluid into low-reduction alkaline fluid, and finally into oxidized fluid with low oxygen fugacity. This result confirms that the Mengyin area underwent metamorphism of slightly active deep fluid, and provides evidence for searching diamond by means of indicative minerals.     

Numerical simulation of carbon dioxide migration in a sandstone aquifer considering the fluid–solid coupling

Very limited investigations have been done on the numerical simulation of carbon dioxide (CO₂) migration in sandstone aquifers taking consideration of the interactions between fluid flow and rock stress. Based on the poroelasticity theory and multiphase flow theory, this study establishes a mathematical model to describe CO₂ migration, coupling the flow and stress fields. Both finite difference method (FDM) and finite element method (FEM) were used to discretize the mathematical model and generate a numerical model. A case study was carried out using the numerical model on the Jiangling sandstone aquifer in the Jianghan basin, China. The rock mechanics parameters of reservoir and overlying strata of Jiangling depression were obtained by triaxial tests. A two-dimensional model was then built to simulate carbon dioxide migration in the sandstone aquifer. The numerical simulation analyzes the carbon dioxide migration distribution rule with and without considering capillary pressure. Time-dependent migration of CO₂ in the sandstone aquifer was analyzed, and the result from the coupled model was compared with that from a traditional non-coupled model. The calculation result indicates a good consistency between the coupled model and the non-coupled model. At the injection point, the CO₂ saturation given by the coupled model is 15.39 % higher than that given by the non-coupled model; while the pore pressure given by the coupled model is 4.8 % lower than that given by the non-coupled model. Therefore, it is necessary to consider the coupling of flow and stress fields while simulating CO₂ migration for CO₂ disposal in sandstone aquifers. The result from the coupled model was also sensitized to several parameters including reservoir permeability, porosity, and CO₂ injection rate. Sensitivity analyses show that CO₂ saturation is increased non-linearly with CO₂ injection rate and decreased non-linearly with reservoir porosity. Pore pressure is decreased non-linearly with reservoir porosity and permeability, and increased non-linearly with CO₂ injection rate. When the capillary pressure was considered, the computed gas saturation of carbon dioxide was increased by 10.75 % and the pore pressure was reduced by 0.615 %.     

西沙大气二氧化碳浓度变化特征研究

CO2是引起全球气候变暖的最重要温室气体。大气中过量CO2被海水吸收后将改变海水中碳酸盐体系的组成,造成海水酸化,危害海洋生态环境。本文采用局部近似回归法对2013年12月—2014年11月期间西沙海洋大气CO2浓度连续监测数据进行筛分,得到西沙大气CO2区域本底浓度。结果表明,西沙大气CO2区域浓度具有明显的日变化和季节变化特征。4个季节西沙大气CO2区域本底浓度日变化均表现为白天低、夜晚高,最高值405.39×10-6(体积比),最低值399.12×10-6(体积比)。西沙大气CO2区域本底浓度季节变化特征表现为春季和冬季高,夏季和秋季低。CO2月平均浓度最高值出现在2013年12月,为406.22×10-6(体积比),最低值出现在2014年9月,为398.68×10-6(体积比)。西沙大气CO2区域本底浓度日变化主要受本区域日照和温度控制。季节变化主要控制因素是南海季风和大气环流,南海尤其是北部海域初级生产力变化和海洋对大气CO2的源/汇调节作用。     

深海法视域下的深海资源调查装备发展研究

辽阔的海洋是人类资源的宝库,尤其是海洋深处蕴含极为丰富的矿产和生物资源。随着人类对资源的需求与日俱增以及陆地资源的开采耗竭,深海海底这一特殊区域无疑具有十分重大的战略意义。为有效保护和利用深海海底资源,2016年我国颁布实施《中华人民共和国深海海底区域资源勘探开发法》,这是我国积极践行担保国义务的重要举措,为深海资源的合理调查开发提供法律基础。文章分析深海资源调查的必要性和我国深海资源调查的主要成果,梳理《中华人民共和国深海海底区域资源勘探开发法》等一系列涉及深海资源调查的法律规范,重点分析我国深海资源调查装备的发展,并对深海资源调查装备促进深海资源可持续利用进行展望。     

不同湿地植物对污水中氦磷去除的贡献

选择5种湿地植物(芦苇、东方香蒲、菖蒲、茭白、鸢尾)和1种喜湿灌木(蒿柳),研究重度富营养化水体中植物的生长特性和氮磷去除效果.研究发现,所选用的6种植物在实验池中均生长良好.稳定生长105d以后,各种植物的总生物量在424-1772g/m2之间,除了香蒲的地上地下生物量比(A/U)达到3.23外.其它的比值在0.63-1.49之间.6种植物地上部N和P浓度分别在13.12-28.83mg/g及1.55-3.77mg/g之间,地下部N和P浓度在7.76-15.60mg/g及1.70-2.71mg/s之间,大部分植物地上部N和P的浓度大于地下部.6种植物平均氮、磷积累量分别为20.60g/m2和3.08g/m2,其中地上部平均氮、磷积累量分别占66.60%和58.22%.不同植物筛选池对不同污染物的净化效果有差异,鸢尾池对TN的净化效果最好,芦苇池对TP的净化效果最好.植物的氮、磷积累量与浓度及生物量之间均存在显著相关.