A preliminary study on the spatial distribution characteristics and causes of strontium-rich mineral water in the Dushan complex

The mountain rocks in the Dushan Complex are Sr-rich granite with a much higher Sr level than those in other crustal lithospheres in eastern China. That presents a high potential for developing Sr-rich mineral water. In this study, 6 groups of rock samples, together with 30 groups of water samples, were collected. Combining with the existing data, the Sr contents in three different types of underground water were obtained, which are the Quaternary pore water, the meshed bedrock fissure water in weathered zones and the tectonic bedrock fissure water. On the basis of preliminary understanding for the distribution characteristics of Sr-rich mineral water in the Dushan Mountain region, the causes for the Sr-rich mineral water were investigated. Our results showed that the Sr content of the rocks in the studied area ranges from 988 to 1 950 μg/g. In the horizontal direction, those in both the pore water and the meshed bedrock fissure water in weathered zones show high values in the west but low ones in the east, and high ones in the south but low ones in the north. Furthermore, both types of water meet the standard for Sr-rich mineral water in the western areas. In the vertical direction, the Sr content shows the lowest value in pore water(the average value is 0.707 mg/L), middle value in the meshed bedrock fissure water in weathered zones(the average value is 1.415 mg/L) and the highest value in the tectonic bedrock fissure water(the average value is 8.331 mg/L). It was thought that the widely-developed Sr-rich granite in this region provides physical sources for the formation of Sr-rich mineral water. The continuous dissolution of Sr during underground water runoff is the internal mechanism. In addition, the hydraulic interrelations may exist between the three vertical aquifers, leading a continuous accumulation of the Sr level during infiltration.     

Synthesis and characterisation of a multifunctional oil-based drilling fluid additive

An oil-based drilling fluid additive H-DEA (or humic acid-cocamide diethanolamine) was synthesised using humic acid and cocamide diethanolamine as raw materials. The rheological behaviors of H-DEA showed that the synthesised product has the good properties in both decreasing the filtrate loss and improving rheology property of oil-based drilling fluids compared with other commercially available additives. Under the optimal additive amount of 3%, both API filtrate loss and yield point changed remarkably from 5.40 to 0.41 mL and 9.0 to 25.6 Pa, respectively. Furthermore, differential scanning calorimetry (DSC) showed that H-DEA has good thermal stability in a wide temperature range up to 170 °C. Infrared spectroscopy (IR) and rheological analysis revealed that the possible mechanism of the multifunctional effects may be attributed to the existing of high density of strong polar groups, hydrogen bonds, electrostatic forces, and intermolecular association on H-DEA molecular structure. The results of the study showed that the synthesised H-DEA can be potentially used as a multifunctional oil-based drilling fluid additive in oil-drilling excavation.     

A GIS-based method of risk assessment on no. 11 coal-floor water inrush from Ordovician limestone in Hancheng mining area,China

The no. 11 coal seam in the deep area of Hancheng mining area is mining in recent years, which is threatened by the water inrush from the Ordovician limestone aquifer. Coal-floor water inrush is governed by the water abundance of coal-floor aquifer, the water-resisting performance of coal-floor aquitard, and the pathway connecting the water source and the working face. To make an accuracy risk assessment of water inrush from the no. 11 coal seam floor, a GIS-based vulnerability index method (VIM) is adopted for its superior comprehensive consideration of more controlling factors, powerful spatial analysis, and intuitively display functions. This study firstly established an index system including the water pressure of the coal-floor aquifer, the unit water inflow, the thickness, the core recovery percentage, the thickness ratio of brittle rocks to ductile rocks, the thickness of effective aquitard, and the accumulated length of faults and folds, of which the former six indexes governed the water abundance of the coal-floor aquifer which was combined with the last two factors to determine the risk of coal-floor water inrush. Secondly, the thematic map of each controlling factor is established by GIS using the geological prospecting data, and the weight of each factor is determined by the analytic hierarchy process (AHP) after consulting the expert review panel. At last, a vulnerability index is obtained and used to assess the risk of coal-floor water inrush of the no. 11 coal seam. The risk of water inrush of the no. 11 coal seam of the study area was ranked to three zones: the southeastern shallow area in red color is the dangerous zone, the wide northwestern area in green color is the safe zone, and the transition area in yellow color is the moderate-risk zone. Compared with the actual water-inrush incidents, the risk assessment result was verified to achieve an accuracy of 82.35%, which is proved to be a dependable reference for the prevention and controlling of coal-floor water inrush of the no. 11 coal seam in Hancheng mining area.     

渝东北城口地区Y1井页岩有机地球化学特征及勘探前景

基于钻井资料,以总有机碳(TOC)、干酪根显微组分、等效镜质体反射率(Ro)及碳同位素等测试数据系统分析了渝东北城口地区Y1井五峰组—龙马溪组页岩的有机地球化学特征,利用页岩流体包裹体的显微特征、均一温度及激光拉曼数据深入分析了Y1井页岩气成藏特征。结果表明:Y1井上奥陶统五峰组—下志留统龙马溪组炭质页岩发育,TOC含量2%的富含有机质页岩厚度达83 m,干酪根类型以Ⅰ型干酪根为主,处于湿气生烃阶段。页岩裂缝脉体中大量烃包裹体和富含甲烷气体的含烃盐水包裹体证实城口地区五峰组—龙马溪组页岩发生了充足页岩气供给,具有高均一温度、高盐度的伴生盐水包裹体表明城口地区页岩气成藏时期的保存条件良好。这些Y1井页岩有机地球化学特征研究成果揭示了城口地区下古生界具备良好的页岩气勘探前景。     

北淮阳东段卢镇关群和佛子岭群地层含矿性地球化学评价

卢镇关群和佛子岭群广泛分布于北淮阳成矿带内,但是对其含矿性研究一直较为薄弱。文章通过对卢镇关群和佛子岭群成矿元素的地球化学特征研究,评价地层含矿性。成矿元素富集系数(K)分析表明卢镇关群和佛子岭群各组中Mo元素均富集,W、Pb、Ag、Cu元素也存在不同程度的富集,存在潜在成矿可能;成矿元素后期叠加强度(D)分析表明本区的Mo、Ag、Cu等元素存在不同程度的后期叠加作用;成矿元素变异系数(CV)分析表明本区成矿元素具有一定的成矿潜力。对卢镇关群和佛子岭群成矿能力评序得出最优势矿种为Mo元素,并且卢镇关群和佛子岭群是北淮阳钼矿的理想矿源层,为区内钼矿提供了成矿物质。成矿元素与主微量元素的相关性分析表明Cu、W、Ag、Pb、Zn等元素受碎屑岩特征和氧化还原环境控制。     

Interpersonal communication sources and natural hazard risk perception: a case study of a rural Chinese village

This exploratory study contributes to our knowledge about the relationships between interpersonal communication sources and risk perception regarding natural hazards. Survey data (N?=?186) from a small village in northwest China was used, and the correlations between eight types of interpersonal communication sources related to disaster risk reduction and the perceived severity and perceived likelihood of occurrence of eight types of natural hazards were explored. Past studies have suggested that interpersonal communication sources are more likely to influence individuals in their perceived severity of natural hazards than in their perceived likelihood of occurrence. The results of this study moderately corroborate this finding. The results indicated that different sources have different relationships to risk perception, as positive correlations were found between obtaining information via certain trained science professionals (science teachers, emergency responders, scientific experts) and certain natural hazard risk perceptions, while negative relationships were found between obtaining information via certain personal contacts (other villagers and relatives and friends) and certain natural hazard risk perceptions. However, the strength of these relationships was weak (??0.197?≥?r?≤? 0.245). Age showed statically significant correlations with the perceived severity of most of the natural hazards. Studies with more representative samples and controls for theoretical factors are needed to better understand how interpersonal communication sources affect individuals' natural hazard risk perceptions.     

综合物探方法在广西妙皇隐伏多金属矿勘查中的应用

妙皇多金属矿区位于来宾凹陷东缘与大瑶山隆起西侧交接部位,广西大瑶山及其西侧铅锌成矿带中部成矿条件优越,历年来开展过多种研究和找矿方法,但找矿效果不佳。通过研究妙皇铜铅锌银矿区的地质条件和成矿背景,运用综合物探方法,对区内部分地质问题及矿产特征进行了推断和预测。2012年,依据地质物探综合成果布置了ZK22701号验证孔,取得了突破性的进展。同时,依据物探成果推测了矿区成矿机理和成矿模式,在找矿方向和找矿潜力方面进行了分析探讨,对中深部找矿具有很好的指导意义。     

香溪河流域岩溶洞穴发育与分布特征

结合1∶5万水文地质调查,对香溪河岩溶流域溶洞特征进行了探究,统计其溶洞的规模、形态、发育地层、发育方向及分布高程,结果表明:该区洞穴规模中等,受岩性的控制,溶洞的发育表现出对碳酸盐岩岩组类型的选择性,其中寒武-奥陶系地层溶洞发育程度最高;溶洞的发育方向多为北北东和北北西向,与区域构造线一致,同时受本区构造运动间歇性抬升的影响,溶洞集中发育于4个高程区;从溶洞发育的构造部位来看,溶洞主要分布在宽缓向斜的东南翼及向斜核部,平面分布表现出分带性;该区溶洞多发育至早期就停止进一步发育,其规模、类型、分布特征等与鄂西南地区溶洞均存在差异。      

Spatiotemporal change patterns of urban lakes in China’s major cities between 1990 and 2015

China has experienced unprecedented urbanization in the past decades, resulting in dramatic changes in the physical, limnological, and hydrological characteristics of lakes in urban landscapes. However, the spatiotemporal dynamics in distribution and abundance of urban lakes in China remain poorly understood. Here, we characterized the spatiotemporal change patterns of urban lakes in China’s major cities between 1990 and 2015 using remote-sensing data and landscape metrics. The results showed that the urban lake landscape patterns have experienced drastic changes over the past 25 years. The total surface area of the urban lakes has decreased by 17,620.02?ha, a decrease of 24.22%, with a significant increase in the landscape fragmentation and a reduction in shape complexity. We defined three lake-shrinkage types and found that vanishment was the most common lake-shrinkage pattern, followed by edge-shrinkage and tunneling in terms of lake area. Moreover, we also found that urban sprawl was the dominant driver of the lake shrinkage, accounting for 67.89% of the total area loss, and the transition from lakes to cropland was also an important factor (19.86%). This study has potential for providing critical baseline information for government decision-making in lake resources management and urban landscape design.     

地理国情普查成果在土地资源监测中的应用初探

以江西省某县地理国情普查数据为基础,研究其与土地变更调查数据的相似性与差异性,结合土地资源监测的热点,初步探究地理国情普查成果在土地资源监测中应用,为地理国情普查成果应用提供思路与方向。