Deglacial meltwater drainage and glaciodynamics: inferences from Laurentide eskers, Canada

This paper evaluates current knowledge of Laurentide eskers in Canada in the light of developments in glacier hydrology and glacial sedimentology. Questions regarding the morpho-sedimentary relations of eskers, the synchroneity and operation of R-channel systems, the role of supraglacial meltwater input and proglacial water bodies, the controls on esker pattern, and the glaciodynamic condition of the ice sheet at the time of esker formation are discussed. A morphologic classification of eskers is proposed. Five types of eskers are identified and investigated. Type I eskers likely formed in extensive, synchronous, dendritic R-channel networks under regionally stagnant ice that terminated in standing water. Type II eskers likely formed in short, subaqueously terminating R-channels or reentrants close to an ice front or grounding line that may have actively retreated during esker sedimentation. Type III eskers plausibly formed in short R-channels that drained either to interior lakes in, or tunnel channels under, regionally stagnant ice. Type IV eskers may have formed as time-transgressive segments in short, subaerially terminating R-channels (or reentrants) that developed close to the ice margin as the ice front underwent stagnation-zone retreat or downwasted and backwasted regionally (stagnant ice); however, formation in synchronous R-channels cannot be discounted on the basis of reported observations. Type V eskers may have formed in H-channels that terminated subaerially. The spatial distribution of these esker types is discussed. The factors that determined Laurentide R-channel pattern and operation were likely a complex combination of (i) supraglacial meltwater discharge, (ii) the number and location of sink holes, (iii) the ice surface slope, thickness and velocity, and (iv) the permeability, topography and rigidity of the bed. These factors cause and respond to changes in ice dynamics and thermal regime over the glacial cycle.     

珠江流域经济带源头山区生态环境与经济协调发展

珠江流域经济带是我国南方地区唯一一条正在隆起的东西向经济长带，其源头山区是我国三大流域经济带中唯一能达到的源头，也是唯一适合发展的源头。本文从保护珠江源山区生态环境的角度出发，通过实地详尽调查，系统分析了源头山区生态环境与经济协调发展优势与机遇，把珠江源头山区总体定位为珠江流域经济带新的经济增长点，云南省优质资源产业化基地，云南省重要的能源生产基地和烤烟生产基地，滇东地区最重要的交通枢纽和最具吸引力的生态旅游休闲胜地之一，突出发挥珠江流域经济带东西部工业合作发展示范基地的功能、绿色农业产业化示范生产加工基地的功能、珠江源生态旅游休闲胜地功能、交通枢纽服务功能和国家可持续发展示范的综合示范功能。提示了农业富区－推进高效生态农业产业化、工业强区－加速实现城乡生态工业化、旅游活区－大力发展生态旅游业和生态保区－建设国家级生态自然保护区的基本发展思路。     

我国煤矿井下复杂地质条件下钻探技术与装备进展

针对钻机在复杂施工环境下所面临的劳动强度大以及安全风险高等问题,采用电子电路技术、测量传感技术、远程控制技术、视频监测技术以及大数据技术,研制出一套适用于煤矿自动化钻机的远程监控系统。该系统以ZDY4500LFK型煤矿用钻机为主体,实现了视距内控制、井下集控以及地面远程监控3种控制模式,并构建了云端自动化钻机管控平台。具体而言,视距内监控模式通过遥控器、控制器及配套传感器,实现了对井下视觉范围内钻机的精确操作;井下集控模式则集成了集控舱、隔爆兼本安型计算机、本安显示器、隔爆兼本安型交换机、本安摄像头以及本安操控箱等设备,实现了对井下危险钻场的钻机远距离安全监控;地面监控模式则通过地面操控台、地面服务器、显示器、交换机以及AI智能分析盒子等设备,为自动化钻机的地面远程监控提供了有力支持。此外,云端自动化钻机管控平台则主要用于自动化钻机群运行状态和施工状态的数据统计与分析。研制的远程控制系统应用于ZDY4500LFK、ZDY6500LDK型钻机,并实现了视距内遥控、井下集控以及地面远距离控制等多种控制方式的稳定运行。现场试验和测试研究结果表明：(1)钻机视距内遥控系统遥控器按键丰富、控制器具有CAN、RS485等丰富的接口,手机升级便捷方便,可广泛应用于钻机电控化升级和改造。(2)远程集中控制系统可以实现10 km距离的远程控制,控制响应时间小于200 ms。视频、参数采集数据响应及时无卡滞,可以满足井下钻机远程监控的需求。(3)地面远程监控系统可以实现地面钻机远程监控并具有AI识别功能,可实现人员闯入预警和停机功能。(4)自动化钻机管控平台经过功能、压力、并行、访问测试,功能正常,响应及时,系统无崩溃,可用于自动化钻机数据和工况的统计分析。该控制系统的应用在保证钻孔施工安全的同时也为煤矿钻机实现少人化、智能化、信息化提供了借鉴。

     

郑州市矿井水资源利用模式研究

为了进一步促进矿井水的开发利用,提高矿井水利用率,以郑州市为例,通过问卷调查、现场调研、专家座谈等方法调查研究了郑州市矿井水的分布及利用总体情况,从区域、矿区、矿井涌水量及利用量、用水特点等角度总结分析了郑州市矿井水开发利用的矿区高效自用、作为城市集中供水水源以及与工业用水大户连供3种模式,并结合实际提出了相关的对策和建议。     

Arsenic — a Review. Part I: Occurrence,Toxicity, Speciation,Mobility

In natural waters arsenic concentrations up to a few milligrams per litre were measured. The natural content of arsenic found in soils varies between 0.01 mg/kg and a few hundred milligrams per kilogram. Anthropogenic sources of arsenic in the environment are the smelting of ores, the burning of coal, and the use of arsenic compounds in many products and production processes in the past. A lot of arsenic compounds are toxic and cause acute and chronic poisoning. In aqueous environment the inorganic arsenic species arsenite (As(III)) and arsenate (As(V)) are the most abundant species. The mobility of these species is influenced by the pH value, the redox potential, and the presence of adsorbents such as oxides and hydroxides of Fe(III), Al(III), Mn(III/IV), humic substances, and clay minerals.     

Seasonal mixing from intermittent flow drives concentration-discharge behaviour in a stream affected by coal mine drainage

Abandoned mining operations continue to severely degrade many ecosystems worldwide by releasing acidic water and/or heavy metals into surface and groundwater. Contaminant concentrations in affected streams vary with discharge in patterns that reflect both geochemical reactions and variable mixing of contaminated and non-contaminated waters. However, controls on concentration-discharge (C-Q) patterns remain unclear, particularly for constituents that experience changing solubility across redox and pH gradients. Understanding the C-Q behaviour of contaminants aids in predicting both downstream transport and effects on aquatic life under variable flow. Here, we examined the C-Q behaviours of non-reactive (Na, K, Ca, Mg, Cl⁻) and reactive (Fe, Mn, Al, H⁺, SO₄²⁻) solutes in a stream contaminated with acid mine drainage in northeastern Ohio, USA. Concentration-discharge patterns at the watershed outlet primarily reflected mixing of contaminated baseflow with intermittent inputs of high pH water draining from a passive limestone treatment system into the stream. The treatment system acted as an ephemeral tributary that mitigated contamination in the stream by diluting solutes, raising pH, and driving metal precipitation, but only when flow was present during wet seasons. Consequently, AMD-derived reactive solutes (H⁺, Fe, Mn, Al) decreased with increasing stream discharge while relatively conservative solutes (e.g., Ca, Mg, K, Na) decreased only slightly or were chemostatic. This study highlights both the unique C-Q patterns of reactive solutes when compared to those of non-reactive solutes and the potential for intermittent streams to control C-Q behaviour in headwater catchments.     

Ocean Rise Instability in Coastal Clay Slopes and Possible Countermeasures: A Centrifuge Modeling Study

Increase in saturation in natural clayey slopes along coastal zones as a result of tsunamis or storm surges may cause flow slides or failures. One of the common treatments is to increase the overall stability by soil replacement and/or re-compaction, which is often difficult to implement, expensive, and, most importantly, damages the natural vegetation. In this paper, remedial effectiveness of a relatively economical and environmentally friendly method involving insertion of geotextile strips with drainage capability into natural clayey slopes is evaluated through a series of centrifuge tests. The test results demonstrate the effectiveness of the employed technique to increase the stability of slopes and their drainage capability as well as to reduce the deformations under surcharge loadings.     

Application of several potential field separation methods of gravity data in Vientiane of Laos area

Gravity data observed in geophysical surveys are the sum of potential field produced by all underground inhomogeneous geological sources with different scales, different patterns and different depths.The aim of gravity exploration is mainly to extract the meaningful local anomaly from the regional gravity anomaly which is helpful to detect the deep structure and delineate the favorable area for mineral prospecting.In this paper, several anomaly separation methods are theoretically discussed, including trend analysis method, finite element method, interpolating cut method and analytic continuation method.And, these methods are applied to achieve the delineation of potash-mine deposit in Vientiane.Through experiments, analysis and comparison, the separating result of upward continuation is shown to be satisfactory, for that can separate the ore body anomaly from the background field more effectively.Further, with the combination of the geological information and gravity anomaly, it infers four rich potash zones in the study area of Vientiane which is significant for future geological work.     

冀中平原历史地貌研究与白洋淀成因的探讨

使用1926年出版的顺直地形图做历史地貌研究,发现冀中平原、白洋淀流域存在大量的特殊地貌单元"碟形洼地"。研究这些特殊洼地的个体形态、群体分布规律,特别是使用数字高程模型(DEM)分析这些洼地,发现"碟形洼地"可能是分布在第四纪松散沉积物上撞击坑的遗迹。初步推测这种地貌可能是全新世中期以后不久一次规模巨大的陨石雨撞击的结果,白洋淀更可能是一些较大的撞击坑在地表流水的侵蚀、后经人工改造逐步形成的。陨石雨的撞击导致了重大的史前环境灾害,这可能涉及到全新世中-后期自然环境的变化等一系列重大科学问题。     

胶东大尹格庄-曹家洼金矿床三维空间特征及矿化富集规律新认识

基于291个钻孔资料建立了大尹格庄-曹家洼金矿床三维地质模型,剖析了金矿床的三维空间特征,指出了深部找矿方向。矿床主要由4个规模较大的矿体组成,矿体赋存于招平断裂下盘,主要分布在0~-1740 m标高之间。赋矿的招平断裂表面起伏变化明显,表现出浅部倾角较陡,向深部逐渐变缓的特征。招平断裂及金矿体受后期断裂切割。将被切割的矿体复原后进行三维可视化分析表明,主矿体厚度三维分布不均匀,呈厚、薄相间分布;主矿体品位分布较均匀,厚度较大区域品位也较高,二者相关系数为0.352;厚度×品位三维分布显示了明显的NEE向侧伏特征,侧伏向75°。矿床有4个矿化富集段,其空间位置与断裂倾角沿倾向呈现的三段陡-缓转折和相对缓倾角位置吻合,构成阶梯成矿特征。这说明,断裂倾角变化对金的沉淀富集有明显的控制作用,今后找矿中应重视对断裂倾角变化的研究和探测。分析认为,①-1与Ⅰ-2号矿体之间、Ⅰ-2号矿体北侧、沿②-69矿体75°方向延深位置均具有较好的找矿前景。研究成果为该矿床的深入研究和进一步深部找矿提供了重要的依据。