Hydrogen sulphide as a natural air contaminant in volcanic/geothermal areas: the case of Sousaki,Corinthia (Greece)

Volcanic and geothermal areas are one of the major natural sources of H₂S to the atmosphere. Its environmental impact is often the main cause of the opposition to the development of geothermal energy exploitation programs. In this paper, we analyze the air concentrations and dispersion pattern of naturally emitted H₂S at the geothermal area of Sousaki (Corinthia, Greece). Measurements, made with a network of passive samplers, evidence a rapid decrease of concentration values away from the emission points. The fact that the decrease is more pronounced in the summer with respect to the winter indicates that it is not only due to a dilution effect, but also to redox reactions favored by higher temperatures and intense sunlight typical of the summer period.     

宁洱火山区壳内岩浆囊现今温度:来自CO_2-CH_4碳同位素地质温度计的估计

温度是岩浆囊的重要物理参数,获取温度参数并监测其变化对更好地理解岩浆囊的物理化学性质和行为、评价火山的活动性和喷发危险性具有重要的理论和现实意义。火山岩浆-水热系统丰富的含碳气体,这些含碳气体间碳同位素温度计为我们解决休眠火山区地下岩浆囊的温度问题提供了可能。我们对宁洱火山区地表地热异常强度最高区的4个温泉点CO_2、CH_4碳同位素组成进行了2年的连续观测和2次平行观测,利用观测数据对CO_2、CH_4气体的岩浆来源进行了甄别,对CO_2-CH_4间碳同位素分馏是否发到平衡进行了判断,然后利用Horita CO_2-CH_4碳同位素平衡分馏方程计算了宁洱-通关火山区逸出气体的源区温度。结果表明:宁洱火山区4个样点中,1个样点的CO_2和CH_4均为非岩浆成因,其他3个样点的主要属于岩浆来源。剔除了非岩浆来源的数据后的δ-Δ图解法判断CO_2-CH_4间碳同位素分馏达到了平衡。3个样点的CO_2、CH_4碳气体源区温度分别为425~475℃、941~995℃和1179~1578℃。结合最上部地壳温度场结果,我们认为,宁洱火山区现今存在2个壳内岩浆房,分别位于宁洱火山以南和通关火山以北,宁洱岩浆房的温度为1179~1578℃,通关岩浆房的温度为941~995℃。2个岩浆房的现今温度已达到流纹岩浆(600~900℃)、安山岩(800~1100℃)和玄武岩浆(1000~1250℃)的形成温度。思普地震带空间上密集的6级地震丛集活动可以用宁洱岩浆房的高活动性来解释。δ-Δ图解法判断CO_2-CH_4间碳同位素分馏平衡准则应修正为:在保持两拟合直线的斜率符号相反的条件下,δ~(13)CCO_2-ΔCO_2-CH_4拟合直线和δ~(13)CCH_4-ΔCO_2-CH_4拟合直线应相交于δ轴附近截距差Δb≤0.16处。     

Reconstruction of deep fluid chemical constituents for estimation of geothermal reservoir temperature using chemical geothermometers

This paper elaborates the chemical constituent change principles of deep geothermal fluid during the process of upward movement. It summarizes research methods of hydrochemistry, isotope and numerical modelling technique for the physiochemical processes such as decreasing temperature, shallow groundwater infusion, and degassing. The multi-component chemical geothermometry methods including gas geochemical method are discussed. High-temperature geothermal fields in China are mostly located in the southwest with frequent new tectonic movements, especially in Tibet high-temperature geothermal areas. Therefore the paper also focuses the status of high-temperature geothermal fluid research. At last, it’s pointed out in the paper that in the future we can start from typical high-temperature geothermal zones and geothermal fields to explore optimization of the multi-component geothermometry method and use it in the reconstruction and analogue of the formation mechanism and internal relevancy of regional geothermal systems.     

基于全生命周期的褐煤制气与发电温室气体排放对比研究

我国褐煤资源较为丰富,主要分布于内蒙古东部、云南省和黑龙江省。褐煤主要的传统利用方式是直接燃烧发电,但其存在能效低、污染重等问题。除发电外,褐煤新型利用方式逐渐成熟,制取天然气以及提质后发电就是其中的代表。本文基于全生命周期评价法,计算了褐煤制取天然气与褐煤提质后发电在终端利用能效相同的情况下,产生1 GJ有效能量的温室气体排放量,分别为158.173/e kg/GJ、480.68/e kg/GJ(e为能源终端使用能效)。显然,从温室气体排放角度,褐煤制取天然气优于提质褐煤发电技术。     

A review of research on human activity induced climate change I. Greenhouse gases and aerosols

Extensive research on the sources and sinks of greenhouse gases, carbon cycle modeling, and the characterization of atmospheric aerosols has been carried out in China during the last 10 years or so. This paper presents the major achievements in the fields of emissions of greenhouse gases from agricultural lands,carbon cycle modeling, the characterization of Asian mineral dust, source identification of the precursors of the tropospheric ozone, and observations of the concentrations of atmospheric organic compounds.Special, more detailed information on the emissions of methane from rice fields and the physical and chemical characteristics of mineral aerosols are Dresented.     

温室气体与气候：过去变化对未来的启示

对20世纪气候变化原因存在的争议进行了综合分析,指出尽管气候变化的"温室气体理论"还存在许多来自冰芯和地质证据的冲击,然而大气温室气体含量增加对于气温的放大作用是肯定的。结合温室气体含量与气候变化这一论题,指出目前应重视的一些研究内容。同时简要分析了不同时间尺度气候变化的原因,认为太阳活动与地球气候系统之间关系研究将是一个活跃的领域。     

Difficulties with interpreting changes in groundwater gas content as earthquake precursors in Kamchatka, Russia

The Kamchatka peninsula, located in the far east of Russia, is a geologicallyactive margin where the Pacific plate subducts beneath the North Americanand Eurasia plates. This area is characterised by frequent and strong seismicactivity (with magnitudes of up to 8.6), with epicentres generallydistributed offshore along the eastern coast of the peninsula. Starting in1977, hydrogeochemical data have been collected with a mean samplingfrequency of three days in wells and springs located in the southern area ofthe Kamchatka peninsula. In order to reveal possible earthquake precursors,the groundwater gas content data collected in the last ten years at fivewells, were statistically analysed. Each signal exceeding a 3threshold was considered to be an irregularity and two different methodsof defining an anomaly were assumed. In the first, an anomaly was declaredwhen an irregularity occurred simultaneously on more than one gas contentat each well. In the second method, an anomaly was declared when anirregularity occurred simultaneously on a given type of gas at more thanone well. As a mechanism for associating an anomaly with an earthquake,the earthquakes that occurred with magnitudes greater than 6.5 and withina distance of 250 km from each well, were selected. Using this frameworkboth successes and failures were identified. It is shown that on the basis ofthis statistical analysis, there is a great probability that the successes revealedare not precursors but random coincidences.     

深源与浅源气体震前异常变化的差异性

本文根据１９９３年６月至１９９４年１月滇西及其邻近地区数次中强以上地震前ＣＯ２，Ｎ２，Ａｒ，Ｒｎ等气体组分释放动态的观测结果，研究了气体的物质迁移对其前兆异常变化的影响，发现深，浅源气体的震前趋势性异常释放和短临突跳异常的发生时间具有明显的有序性，基本模式是源自深部的气体组分的震前异常变化总是上先于浅源气体，这种现象在强震发生前更为明显。作者认为，导致深一浅源气体异常变化有序发生的原因与气体物质迁     

天然气水合物研究中的几个重要问题

综述了当前关于天然气水合物研究中的几个重要问题，提出了今后的主要研究方向，全球大约有10^19g碳以天然气水合物的形式储存在沉积物中，大约是其它所有化石燃料沉积物形式储存量的2倍多，因此，天然气水合物被认为是21世纪具有商业开发无景的潜在的战略资源，天然气水合物是一种亚稳态物质，极易受到温度和压力条件的影响，海底天然气水合物的分解将会影响沉积物的物理化学性质（如剪切强度和流变性等），地球物理性质（如地震波速和电导性），以及地球化学性质（如孔隙流体成分）的明显变化，导致诸如海底滑塌等地质灾害的发生，天然气水合物的分解会产生导致“温室效应”的甲烷气体，该气体进入大气圈中会引起全球气候和环境的变化。