Free hydrogen-hydrocarbon gases from the Lovozero loparite deposit (Kola Peninsula,NW Russia)     

《Applied Geochemistry》2016

The Lovozero nepheline-syenite massif in the north-eastern Fennoscandian Shield, well-known to mineralogists and petrologists, is also interesting with its high contents of hydrogen-hydrocarbon gases in different forms of presence, which is untypical of magmatic rocks. The article systematizes and generalizes little known and unpublished data on the composition, location, character and scale (intensity) of the free gases (FG) emission within a major loparite deposit confined to the massif. СН₄ and Н₂ are dominant in the FG composition. The molecular weight distribution of hydrocarbon gas components corresponds to the classic Anderson–Schulz–Flory distribution with a steep gradient. Carbon and hydrogen of the gases are characterized by rather heavy isotope compositions, becoming lighter from the transition of methane to ethane. The FG volume has been estimated as 0.2–1.6 m³ of gas per 1 m³ of undisturbed rock. The gas recovery of walls in underground workings has been up to 0.2 ml/min/m² for СН₄ and 0.5 ml/min/m² for Н₂ in several years after their heading. The discharge of some shot holes that characterizes the gas emission intensity (1.8–2 m deep and 40 mm in diameter) is up to 300 ml/min, but its 1–2 orders lesser values dominate. The discharge time in some sections varies from several days to 20 years. The overpressure of gases towards the air mainly does not increase 100 hPa, sometimes reaching 120 kPa. It has been defined, that FG distribute irregularly (at the distance of centimeters to hundreds of meters) and their composition and particularly emission intensity perform different temporal fluctuations. The abiogenic origin of FG has been proposed, with FG appearing as a mixture of gases in various proportions: (a) gases remaining in microfissures at the massif's consolidation after the capture by fluid inclusions and those lost during degassing and (b) gases occurred in mechanic-chemical reactions, partial emission and concentration of occluded and diffusely scattered gases under the unstable stress-strain mode of the rock mass. Combustible and explosive hydrogen-hydrocarbon FG can accumulate in the air of underground workings and cause accidents, disrupting the workflow. The background for using characteristics of spatial-temporal variations of the FG emission as precursors of dangerous geodynamic phenomena has been indicated.  相似文献   

A comparative analysis of seismic response of shallow buried underground structure under incident P,SV and Rayleigh waves     

《地震研究进展（英文）》2022,2(4):100179

In this study, A time-domain seismic response analysis method and a calculation model of the underground structure that can realize the input of seismic P, SV and Rayleigh waves are established, based on the viscoelastic artificial boundary elements and the boundary substructure method for seismic wave input. After verifying the calculation accuracy, a comparative study on seismic response of a shallow-buried, double-deck, double-span subway station structure under incident P, SV and Rayleigh waves is conducted. The research results show that there are certain differences in the cross-sectional internal force distribution characteristics of underground structures under different types of seismic waves. The research results show that there are certain differences in the internal force distribution characteristics of underground structures under different types of seismic waves. At the bottom of the side wall, the top and bottom of the center pillar of the underground structure, the section bending moments of the underground structure under the incidences of SV wave and Rayleigh wave are relatively close, and are significantly larger than the calculation result under the incidence of P wave. At the center of the side wall and the top floor of the structure, the peak value of the cross-sectional internal force under the incident Rayleigh wave is larger than the calculation result under SV wave. In addition, the floor of the underground structure under Rayleigh waves vibrates in both the horizontal and vertical directions, and the magnification effect in the vertical direction is more significant. Considering that the current seismic research of underground structures mainly considers the effect of body waves such as the shear waves, sufficient attention should be paid to the incidence of Rayleigh waves in the future seismic design of shallow underground structures.  相似文献   

浅谈核废物地质处置     

楼凤升  徐增亮 《华东地质学院学报》1986,(1)

本文介绍美国、加拿大、西德等国的核废物地质处置状况。探讨核废物地质处置的意义、目的、任务、方法、技术和前景。提出在我国利用断裂构造频率法选择相对稳定地区的可能性。  相似文献   

A possible Caledonide arm through the Barents Sea imaged by OBS data     

Asbjrn Johan Breivik  Rolf Mjelde  Paul Grogan  Hideki Shimamura  Yoshio Murai  Yuichi Nishimura  Asako Kuwano 《Tectonophysics》2002,355(1-4)

The assembly of the crystalline basement of the western Barents Sea is related to the Caledonian orogeny during the Silurian. However, the development southeast of Svalbard is not well understood, as conventional seismic reflection data does not provide reliable mapping below the Permian sequence. A wide-angle seismic survey from 1998, conducted with ocean bottom seismometers in the northwestern Barents Sea, provides data that enables the identification and mapping of the depths to crystalline basement and Moho by ray tracing and inversion. The four profiles modeled show pre-Permian basins and highs with a configuration distinct from later Mesozoic structural elements. Several strong reflections from within the crystalline crust indicate an inhomogeneous basement terrain. Refractions from the top of the basement together with reflections from the Moho constrain the basement velocity to increase from 6.3 km s⁻¹ at the top to 6.6 km s⁻¹ at the base of the crust. On two profiles, the Moho deepens locally into root structures, which are associated with high top mantle velocities of 8.5 km s⁻¹. Combined P- and S-wave data indicate a mixed sand/clay/carbonate lithology for the sedimentary section, and a predominantly felsic to intermediate crystalline crust. In general, the top basement and Moho surfaces exhibit poor correlation with the observed gravity field, and the gravity models required high-density bodies in the basement and upper mantle to account for the positive gravity anomalies in the area. Comparisons with the Ural suture zone suggest that the Barents Sea data may be interpreted in terms of a proto-Caledonian subduction zone dipping to the southeast, with a crustal root representing remnant of the continental collision, and high mantle velocities and densities representing eclogitized oceanic crust. High-density bodies within the crystalline crust may be accreted island arc or oceanic terrain. The mapped trend of the suture resembles a previously published model of the Caledonian orogeny. This model postulates a separate branch extending into central parts of the Barents Sea coupled with the northerly trending Svalbard Caledonides, and a microcontinent consisting of Svalbard and northern parts of the Barents Sea independent of Laurentia and Baltica at the time. Later, compressional faulting within the suture zone apparently formed the Sentralbanken High.  相似文献   

大型开挖对环境的影响研究   总被引：4，自引：0，他引：4  

徐嘉谟 《地质灾害与环境保护》1997,8(1):35-49

岩土体开挖对环境的影响问题，实质上是开挖引起岩土体移动，变形，破坏和失稳的问题，主要从对环境影响的意义上，阐述了有代表性的两种大型开挖－露天开挖和地下开挖引起岩土体移动，变形和破坏后一些规律性问题，并从机理上对某些现象的规律性作了解释。  相似文献   

地下矿山工程围岩稳定性模糊动态聚类分区   总被引：10，自引：4，他引：10  

高谦  苏永华 《工程地质学报》1997,5(3):205-210

针对梅山铁矿二期工程开拓设计的需要, 本文介绍了梅山地下矿山工程围岩稳定性模糊动态聚类分区的研究方法及其部分结果。该研究首先涉及分区资料的获取, 整理与分析；其次是分区因素的选取与指标确定；最后是模糊动态聚类分析方法在工程围岩分区中的应用。  相似文献   

台湾南投7.6级地震地下流体远场异常及其前兆意义     

张仕印  李于民  陈学庭  杨刚宇 《地震研究》2001,24(3):208-212

深入分析了 1999年 9月 2 1日 0 1时 47分台湾南投 (2 3°42′N ,12 1°0 6′E) 7 6级地震时浙江省地下流体观测井出现的显著中、短期前兆异常。异常出现时间早 ,持续时间长 ,阶段性变化明显 ,特征明显 ,易于识别 ,与本区 (震中距≤ 40 0km)地震前兆异常有明显的区别 ,是具有预测意义的地震前兆异常。震中距约 70 0km左右 ,微动态异常基本没有显示 ,属场兆异常  相似文献   

气象文苑     

Zhang Bofu 《气象与环境科学》1997,(3)

气象文苑慈母情□任金良母亲已逾古稀。每当我看到她那张饱经风霜、沟壑纵横的脸，心里就格外难过。母亲辛劳一生，晚年还闲不住，不干活就浑身难受。７月２８日，母亲端一大盆水洗衣服，不小心脚下一滑，重重地摔了一跤。她是被人抬进屋的。她躺在床上，不能动弹。医生说...  相似文献   

同位素示踪方法测定柴达木盆地西台盐湖地下卤水参数研究     

孙亚联  马海洲  高东林  李继成  张明刚 《地下水》2007,29(5):16-18,28

为了测定柴达木盆地西台吉乃尔盐湖地下水流速、流向,从而来计算该区的渗透系数,正确确定其渗透系数,无论对科学研究还是对生产开采,均有着重要的理论和现实意义.介绍同位素示踪方法测定该区地下水卤水流速,流向实验原理及结果,并对实验数据进行分析整理.  相似文献   

单井同位素稀释技术测定西台吉乃尔盐湖水文地质参数   总被引：1，自引：0，他引：1       下载免费PDF全文

孙亚联  马海州  高东林  李继成  张西营  张明刚 《盐湖研究》2007,15(4):1-5

我国含水层的水文地质参数测定,主要依靠传统的抽水试验方法,然而此方法却需要花费大量的试验和钻井费用。同位素示踪方法比传统的抽水试验方法获得含水层参数的周期短、费用低,有效地提高了水文地质参数的测试精度、缩短了工期、节省了投资。为了测定柴达木盆地西台吉乃尔盐湖地下水流速、流向、渗透系数等水文地质参数,采用单井同位素稀释法测试水文地质参数,正确确定其水文地质参数,无论对科学研究还是对生产开采,均有着重要的理论和现实意义。  相似文献