辽宁省地下水动态成因类型分析

根据辽宁省2006—2010年地下水水位实际监测数据,分析地下水水位动态变化规律、形成原因及发展趋势,再结合地下水动态变化的自然与人为影响控制因素,以及地下水的补给、径流、排泄条件等,将辽宁省地下水动态成因类型划分为:气候型、开采型、灌溉型、水文型和径流型,经过较为全面系统的统计分析计算,绘制出地下水动态变化历时曲线,对五种地下水动态成因类型分别予以较为详细的综合分析研究,总结出辽宁省地下水动态变化规律特征。     

Experimental and theoretical study of a cylindrical oscillating water column device with a quadratic power take-off model

The wave power extraction by a cylindrical oscillating water column (OWC) device with a quadratic power take-off (PTO) model was studied experimentally and theoretically. In the experiment, a scaled model OWC was tested in a wave flume, with an orifice being used to simulate a quadratic PTO mechanism. In the theoretical analysis, the quadratic PTO model was linearized based on Lorenz's principle of equivalent work, which allows us to perform a frequency domain analysis using an eigen-function matching method. The effects of higher harmonic components and the spatial non-uniformity of the surface velocity inside the chamber were discussed. A semi-analytical model was proposed to understand the viscous loss affecting the measured capture length. Our treatment of the quadratic PTO model was validated by comparing quasi-linear theoretical capture length and the laboratory measurement. Our results also showed that the effects of spatial non-uniformity and viscous loss could be noticeable for shorter waves.     

青岛冷水团的消亡机理研究

本文基于多年月平均水温资料,分析了青岛冷水团的长消过程,并利用气候态月平均大气数据和数值模拟结果,探讨了青岛冷水团的消亡机理。结果表明,青岛冷水团3月出现,4月成型,5月最盛,6月减弱,7月消失;南黄海6-7月间偏南风的增强和温跃层以下反气旋涡的减弱是青岛冷水团消亡的动力机制,而海面净热通量的下传和水平热量的输入则是青岛冷水团消亡的热力机制。     

中国城市流动人口户籍迁移意愿的空间格局及影响因素——基于2012年全国流动人口动态监测调查数据

基于2012年全国流动人口动态监测调查数据和相关统计年鉴数据,对中国地级以上城市流动人口的户籍迁移意愿、空间格局及影响因素进行了系统分析。研究发现,中国城市流动人口户籍迁移意愿的整体水平并不高;等级高、规模大的城市流动人口的户籍迁移意愿高,而等级低、规模小的城市流动人口的户籍迁移意愿低;沿海城市群流动人口的户籍迁移意愿高,其他城市流动人口的户籍迁移意愿低,但内陆部分省会城市和交通区位与资源禀赋较好的中小城市也已经形成了一批流动人口的户籍迁移意愿高值区。中国城市流动人口户籍迁移意愿的空间分布特征受到流入城市和流动人口自身双重力量的影响,流入城市因素的正向影响作用大于流动人口自身因素。其中,流入城市的社会、经济发展水平和流动人口在流入城市的社会融合程度是核心要素,对城市流动人口户籍迁移意愿的提升具有正向的促进作用,而流动人口过于集中在次级劳动力市场的就业特征和较高的家庭财富与收入对户籍迁移意愿的提升却具有显著的抑制作用。最后,提出了相关政策启示。     

沂蒙缺水山区地下水赋存规律及找水定井范例

沂蒙山区是山东省重点贫困缺水地区,缺水区域分布较广,区内地质条件复杂,找水难度极大。通过综合分析区内气象水文、岩性特征、地质构造及地形地貌等地质因素,初步查明了不同地段含水层的结构和富水性;并结合水文地质调查、物探、钻探等综合勘探方法和手段,实施了探采结合孔8口,成功率100%,满足了区内约3万余人的饮用及300余亩土地灌溉用水需求,取得了良好的经济和社会效益。为我国北方严重缺水山区找寻地下水起到了宝贵的指导和示范作用。     

Seismicity and fault aseismic deformation caused by fluid injection in decametric in-situ experiments

Seismicity induced by fluid perturbations became an important societal concern since felt earthquakes (M_w up to 6) occurred after anthropogenic activities. In order to mitigate the risks associated with undesired seismicity, as well as to be able to use the micro-seismicity as a probe for in-depth investigation of fluid-driven processes, it is of crucial importance to understand the links between seismicity, fluid pressure and flow. We have developed a series of in-situ, decameter-scale experiments of fault zone reactivation by controlled fluid injection, in order to improve the near-source geophysical and hydromechanical observations. The deployed geophysical monitoring close to the injection allows one to cover the full frequency range of the fault responses from the static deformation to the very high-frequency seismic emissions (up to 4 kHz). Here, we focus on the microseismicity (M_w ∼ –4 to –3) recorded during two fluid injection experiments in low-permeable shale and highly-fractured limestone formations. In both experiments, the spatio-temporal distribution of the seismic events, the energy balance, and the seismic velocity changes of the fractured medium show that most of the deformation does not actually emit seismic signals. The induced deformation is mainly aseismic. Based on these high-resolution multiparametric observations in the near-field, we therefore proposed a new model for injection-induced seismicity: the seismicity is not directly induced by the increasing fluid pressure, but it is rather triggered by the stress perturbations transferred from the aseismic motion caused by the injection.     

Hydrochemical characterization of groundwater in Balad district,Salah Al-Din Governorate,Iraq

The assessment of hydrochemical quality of groundwater is very important to explore its nature and usefulness. In this paper, groundwater quality evaluation is carried out in the Balad district, Salah Al-Din Governorate, Iraq. A total of 28 groundwater samples are collected from shallow tube wells and analyzed for various physicochemical parameters. Groundwater suitability for drinking is evaluated based on the World Health Organization (WHO) and Iraqi standards, and suitability of groundwater for irrigation is assessed based on various hydrochemical parameters. The results reveal that the dominant types of groundwater based on piper diagram are mixed CaMgCl and CaCl. Gibbs ratio indicates that the groundwater in the studied area is affected by the evaporation process. The cation-anion exchange reaction in the studied area demonstrates that 54% of the groundwater samples indicate a direct base (cation-anion) exchange reaction, while 46% of the groundwater samples indicating the chloro-alkaline disequilibrium. Furthermore, generally all of the groundwater samples are unsuitable for drinking and irrigation. Cluster analysis reveals two different groups of similarities between the groundwater samples, reflecting different pollution levels in the studied area.     

Contrasting water–rock interaction behaviors of antimony and arsenic in contaminated rivers around an antimony mine,Hunan Province,China

Although antimony (Sb) and arsenic (As) exhibit similar geochemical behavior and toxicity in the environment, growing evidence suggests that their water–rock interaction behavior in contaminated rivers is quite different. Twenty-nine river water samples were collected between September and November 2018 from contaminated rivers around an antimony mine in Hunan Province, China. The concentrations of As and Sb were inversely proportional to the water flow distance. The rates and magnitudes of Sb decrease were more prominent than those of As. Silicate mineral dissolution from rocks such as silicified limestone increased the As and Sb concentration of in-mine-district (IMD) water. Dissolution of carbonate minerals, ion exchange, and competitive adsorption were the major water–rock interactions, resulting in rapidly decreasing As and Sb concentration in IMD direct impacted water and IMD indirect impacted water. The behaviors of As and Sb during water–rock interaction were dissimilar for areas dominated by carbonate and silicate minerals.     

Composition and origin of the volatile components released from the Pesyanoe aubrite by stepwise crushing and heating

Aubrites are achondritic meteorites (enstatite pyroxenites) that were formed in highly reduced magmatic environments on a differentiated parent body sharing a common oxygen isotope reservoir with enstatite chondrites (EC), Earth and Moon, and could be considered as a geochemical model of the early proto-Earth. Some pyroxenes of the Pesyanoe aubrite have high abundance of gaseous inclusions, captured during the crystallization of the rocks. Investigation of the inclusions by IR spectroscopy reveals presence of OH⁻ groups and C–H bonds. The former are assigned to protonated point defects in enstatite lattice and the latter to compounds occupying void walls. Molecular water and CO₂ were not observed. Volatile components released from the samples of the Pesyanoe enstatite by stepwise crushing and heating are composed of CO₂, H₂O and a non-condensable phase. Hydrogen isotopic composition of volatiles extracted in form of molecular water in Px-separates varies in the range δD = −61 – −84‰ with mean value of δD = −73 ± 16‰ VSMOW and is within the ranges of ECs and Earth’s mantle. The total abundance of H₂ in the pyroxene of Pesyanoe were estimated as at least 0.047 ppm that is too low in comparison with that of enstatite chondrites (≥30 ppm H₂) and could indicate nearly complete degassing of the Pesyanoe primitive precursor material during the Pesyanoe parent body accretion or a mantle degassing in igneous differentiation process. In a last case a primitive precursor could have D/H ratio different from that of enstatite chondrites.     

On the origin of bleaching phenomena in red bed sediments of Triassic Buntsandstein deposits in Central Germany

The Lower Triassic Buntsandstein in Central Germany comprises one of the major clastic, lithified hydrocarbon reservoirs, it is a major groundwater aquifer and it is considered as a potential underground gas storage lithology. Thus, sandstones of the Buntsandstein from Thuringia and NE Hesse were used to analyse their geochemical composition combined with mineralogical data in order to investigate the origin of several bleaching phenomena in primary red beds, since these give a hint for mineral alteration, mineral formation and mineral reactivity in the course of fluid-rock-interactions. This is relevant for e.g. recent Carbon Capture and Storage (CCS) efforts. The origin of the observed bleaching phenomena is diverse and it is linked to certain stages of diagenesis and different episodes of fluid flow: (1) eodiagenetic bleaching coupled with palaeosoil formation and iron mobilisation, (2) mesodiagenetic bleaching as a result of hydrocarbon migration, (3) Tertiary bleaching due to CO₂ degassing from Miocene volcanism, (4) Tertiary telodiagenetic bleaching due to weathering under humid climate conditions, and (5) weathering processes related to recent telodiagenesis/pedogenesis. This study emphasizes the multiple nature of fluids, which can induce iron mobilisation and bleaching of red beds.