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开展煤矿区构造环境类型划分是提高采煤沉陷预计精度的有效途径。将影响采煤沉陷地质因素总结为构造介质、构造界面、构造形态和构造应力4个因素,在此基础上探讨了煤矿区构造环境的内涵,确定了煤矿区构造环境类型分类的指标。认为煤矿区构造环境突出采煤沉陷灾害发生的地质构造背景是地质环境的重要组成部分,更多地反映着地球的内动力地质作用。按照构造介质的不同,把煤矿区构造环境划分为浅埋介质型和深埋介质型;按照构造界面的不同,将其分为连续型、似连续型和不连续型;按照构造形态的不同,将其划分为近水平型、倾斜型和褶皱型;按照煤矿区构造应力的性质,把煤矿区构造环境划分为自重应力型、挤压构造型和拉张构造型。以铜川矿区为例,对煤矿区构造环境类型做了划分,铜川矿区以A型构造环境为主。 相似文献
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多层介质含水系统中石油类污染预测评价:以大庆市纳污湖泡区为例 总被引:4,自引:0,他引:4
本文选取大庆贴不贴泡区的多层介质含水系统为研究对象,在分析水文地质条件和研究各层介质渗透规律的基础上,运用地质统计学方法和数值模拟技术建立起此类含水系统中石油类污染运移数值模拟模型,应用所建模型对地下水污染趋势进行了预测,并提出了污染控制措施。 相似文献
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多环芳烃(polycyclic aromatic hydrocarbons,PAHs)是一种难降解、毒性强的致癌性污染物,其广泛分布于各环境介质中,陆地环境中90%的PAHs累积在土壤中。随着资源的开发,由油品泄漏、垃圾渗滤、污水排放等行为造成的多年冻土区PAHs土壤污染问题日益突显,并且在气候变化背景下,多年冻土中的PAHs具有重新释放而造成二次污染的风险,多年冻土区土壤多环芳烃污染分布特征和迁移规律研究对评估多年冻土区生态环境风险,防治土壤持久性有机物污染,保障广大多年冻土居民生命健康安全具有重要意义。通过回顾目前国内外多年冻土区土壤中PAHs污染的相关研究,分析发现多年冻土区未受污染的土壤中PAHs的污染水平远低于中低纬度人口密集区域,可代表地球土壤中PAHs的背景值;高纬度或高海拔的地理位置以及严寒的气候使得冻土区土壤中PAHs一个普遍且最重要的来源是大气远距离传输;活动层的冻融作用主要通过改变土壤理化性质和控制水分运移方向影响PAHs在多年冻土区土壤中的垂向分布特征,多年冻土的低渗透性具有阻碍PAHs垂向迁移的作用。综合分析已有研究成果,表明目前冻土区土壤PAHs污染研究还是大量集中于表层土壤中的污染分布调查和来源解析,而关于PAHs在活动层和多年冻土层中的垂向迁移研究还仅限于对其在土壤剖面中分布状况的解释性分析,冻融作用对PAHs在土壤中的迁移、转化和归宿的影响机制还不清楚。未来多年冻土区土壤中PAHs的研究将集中于迁移转化机理与污染治理技术两方面,针对PAHs在多年冻土区土壤中迁移行为的模拟模型亟待研究开发,以实现PAHs污染储量和迁移通量的定量预测;此外,多年冻土区土壤污染问题的深入研究还需要紧密联系多圈层、多界面、多介质、多要素以及多目标污染物而开展。 相似文献
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《矿物岩石地球化学通报》2016,(6)
为了探讨地气成矿元素分布特征及微量元素、稀土元素示踪方法在地气物质来源研究中的应用效果,本文对黄土覆盖区蛟龙掌矿区不同介质的成矿元素、微量元素和稀土元素分布特征进行了研究。结果表明,矿体上方地气异常元素与矿石富集元素一致;背景区地气样品微量元素和稀土元素分布特征明显不同于异常区和其他固体介质,可能受到多种因素(地质体、分析环境和空白)的影响。异常区地气样品微量元素分布特征与矿石相似,受到了矿体的影响;异常区地气样品个别稀土元素分布与固体介质差异很大,可能与分析精度不够和捕集效率太低有关,只要不断改进稀土元素分析方法和捕集效率,稀土元素示踪方法可提供地气物质来源信息。 相似文献
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文章选取山西大同矿区和长治矿区,从煤矸石堆放区土壤污染及开采沉陷区土壤养分变化两方面进行了煤矿区土壤环境质量评价,认为煤矸石中污染土壤的主要污染因子有SO42-、Cu、Zn等,其中SO42-污染范围较大,Cu、Zn受环境背景条件影响较大,其它污染因子如NO3-、As、Pb、Cd等均对土壤有不同程度的污染。而开采沉陷对沉陷区土壤中的P、K、N和有机质等养分含量有一定的影响,但影响程度不是很明显。 相似文献
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轻非水相液体(light non-aqueous phase liquid,LNPAL)在地下介质中的运移分布与残余捕获受多种因素影响和控制。LNAPL污染场地概念模型中一般视LNAPL从地表泄漏后穿过包气带至潜水面。然而地下介质的非均质性与包气带含水量的空间变异分布可形成复杂的LNAPL污染源区结构,LNAPL可能无法到达潜水面,而在毛细水带蓄积。文章基于数值模型综合分析了LNAPL泄漏量、介质非均质性与含水量空间变异分布、潜水面周期性变化等多种因素对LNAPL污染源区结构的影响。研究表明:(1)当泄漏量较大时,LNAPL可运移至潜水面;(2)当泄漏量较小时,对于上粗下细的层状非均质条件,LNAPL可能在毛细水带边缘发生蓄积,无法到达潜水面;(3)包气带中黏土透镜体并非都是LNAPL运移的阻碍,LNAPL可以穿透低含水量的黏土透镜体,只有高含水量的黏土透镜体才对LNAPL的入渗有阻碍作用;(4)潜水面周期性变化将导致污染范围扩大。 相似文献
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兰坪中新生代盆地沉积岩源区构造背景和物源属性研究--砂岩地球化学证据 总被引:14,自引:3,他引:14
沉积盆地中砂岩的地球化学成分主要受物源区控制。因此,通过分析砂岩的化学成分可以揭示盆地沉积岩的源区构造背景和物源属性。对兰坪盆地中新生界砂岩的常量成分、稀土和微量元素进行的分析,揭示盆地沉积岩的源区构造背景属被动大陆边缘和大陆岛弧,结合岩相古地理资料认为在中生代以前,盆地东侧可能主要处于被动大陆边缘环境。而西侧则可能以大陆岛弧环境为主,这与区域地质资料相吻合。沉积物源岩的原始物质应来自上地壳,以长英质岩石为主,并有少量安山质岩石和古老沉积物的混入,故兰坪中新生代盆地属典型的大陆型盆地。从而为正确认识古特提斯洋的演化和盆山转换过程提供了强有力的地球化学证据。 相似文献
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以世界被动大陆边缘含油气盆地构造演化、油气田资料为基础,采用地质综合分析方法,探讨了不同类型被动大陆边缘盆地在不同构造演化阶段深水区烃源岩的形成条件:开阔海型被动大陆边缘盆地群裂谷阶段发育大型局限湖盆,区域分布的厚层湖相富生油黑色泥页岩为主力烃源岩;边缘海型被动大陆边缘盆地群裂谷阶段发育受河流—波浪控制的大型三角洲,海陆过渡相富生气炭质泥页岩和煤系为主力烃源岩;被动大陆边缘阶段盆地群发生持续性海侵,在高水位体系域缺氧环境下的富有机质海相泥页岩为盆地重要的烃源岩。 相似文献
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《地学前缘(英文版)》2016,(5)
The late Paleozoic evolution of the Wulijishanhen(WSH)-Shangdan(SD) area near to the Chaganchulu Ophiolite belt is reinterpreted. Analysis of the upper Carboniferous to lower Permian sedimentary sequence, biological associations, detrital materials, sandstone geochemistry and volcanic rocks indicates that the SD area was an epicontinental sea and rift during the late Paleozoic rather than a large-scale ocean undergoing spreading and closure. This study reveals that the actual evolution of the study area is from the late Carboniferous to the early Permian. The fusulinids Triticites sp. and Pseudoschwagerina sp.in the limestones demonstrate that the Amushan Formation develops during the late Carboniferous to the early Permian. The limestones at the base of the SD section indicate that it is a stable carbonate platform environment, the volcanic rocks in the middle of the sequence support a rift tectonic background, and the overlying conglomerates and sandstones are characteristic of an epicontinental sea or marine molasse setting. The rift volcanism made the differences in the fossil content of the SD and WSH sections and led to two sections expose different levels within the Amushan Formation and different process of tectonic evolution. Moreover, the geochemical characteristics and detrital materials of the sandstones show that the provenance and formation of the sandstones were related to the setting of active continental margin. The quartz-feldspar-lithic fragments distribution diagram indicates that the material source for the sandstones was a recycled orogenic belt. Thus, the source area of the sandstones may have been an active continental margin before the late Carboniferouseearly Permian. The characteristics of the regional tectonic evolution of the area indicate that the region may form a small part of the Gobie Tianshan rift of southern Mongolia. 相似文献
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The geochemical composition of the terrestrial surface (without soils) and comparison with the upper continental crust 总被引:1,自引:0,他引:1
Jens Hartmann Hans H. Dürr Nils Moosdorf Michel Meybeck Stephan Kempe 《International Journal of Earth Sciences》2012,101(1):365-376
The terrestrial surface, the “skin of the earth”, is an important interface for global (geochemical) material fluxes between
major reservoirs of the Earth system: continental and oceanic crust, ocean and atmosphere. Because of a lack in knowledge
of the geochemical composition of the terrestrial surface, it is not well understood how the geochemical evolution of the
Earth’s crust is impacted by its properties. Therefore, here a first estimate of the geochemical composition of the terrestrial
surface is provided, which can be used for further analysis. The geochemical average compositions of distinct lithological
classes are calculated based on a literature review and applied to a global lithological map. Comparison with the bulk composition
of the upper continental crust shows that the geochemical composition of the terrestrial surface (below the soil horizons)
is significantly different from the assumed average of the upper continental crust. Specifically, the elements Ca, S, C, Cl
and Mg are enriched at the terrestrial surface, while Na is depleted (and probably K). Analysis of these results provide further
evidence that chemical weathering, chemical alteration of minerals in marine settings, biogeochemical processes (e.g. sulphate
reduction in sediments and biomineralization) and evaporite deposition are important for the geochemical composition of the
terrestrial surface on geological time scales. The movement of significant amounts of carbonate to the terrestrial surface
is identified as the major process for observed Ca-differences. Because abrupt and significant changes of the carbonate abundance
on the terrestrial surface are likely influencing CO2-consumption rates by chemical weathering on geological time scales and thus the carbon cycle, refined, spatially resolved
analysis is suggested. This should include the recognition of the geochemical composition of the shelf areas, now being below
sea level. 相似文献
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The distribution of As in a variety of sample materials was studied at different scales, from continental to local, combining published data sets with the aim of delineating the impact and relative importance of geogenic vs. anthropogenic As sources. Geochemical mapping of As with a variety of sample materials demonstrates that variation is high at all scales (local to continental) – from sample densities of 400 sites per km2 to 1 site per 5000 km2. Different processes govern the As distribution at different scales. A high sample density is needed to reliably detect mineralisation or contamination in soil samples. In both cases the impact on the much larger geochemical background variation is limited to a local scale. Distribution patterns in geochemical maps on the sub-continental to continental scale are dominated by natural variation. Given that the geochemical background is characterised by a high variation at all scales, it appears impossible to establish a reliable single value for “good soil quality” or a “natural background concentration” for As for any sizeable area, e.g., for Europe. For such a differentiation, geochemical maps at a variety of scales are needed. 相似文献
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《Applied Geochemistry》2001,16(11-12):1323-1331
This paper reports the first results of a low-density geochemical survey covering the whole continental area of Portugal, taking both topsoils and active stream sediments as the sampling media. The data were obtained in a consistent way from 653 sites at a sampling density of 1 site/135 km2. The samples were analysed for 31 elements by ICP-AES and after quality control the following 19 were selected: Al, As, Ba, Ca, Co, Cr, Cu, Fe, K, La, Mg, Mn, Ni, P, Pb, Sr, Th, V and Zn. The baseline levels for these elements are presented. The first geochemical maps of Portugal were prepared and the geochemical patterns are generally well correlated to geological factors sometimes combined with anthropogenic influences. Some general trends can be observed between geochemical patterns and soils distribution. 相似文献
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Permian deep‐water mudstones in the Tanqua Basin, South Africa, have been studied using geochemical and spectral gamma ray techniques. The mudstones occur as thick sequences between sand‐rich submarine fans, but also occur as thinner mud‐rich units within each fan. The interfan mudstones are interpreted to have accumulated during transgression and the consequent period of relatively high sea‐level, while the submarine fans and their intrafan mudstones were deposited during regression and relatively low sea‐level. Geochemical analyses revealed systematic differences between interfan and intrafan mudstones because the two types of mudstones have slightly different source lithologies. Differences between the two types of mudstone suggest that changes in relative sea‐level played a role in controlling exposure of sediment source areas. There are geochemical signals that display systematic stratigraphic trends within both interfan and intrafan mudstones. These are best explained by gradual denudation, exposure and weathering of different lithologies within a single sediment source area. Both interfan and intrafan mudstones have uniform geochemical signals along the flow direction except for the relative amount of uranium. It is most likely that the basinward increase in uranium in the mudstones is the result of reduced clastic dilution of uranium‐bearing pelagic fallout. 相似文献
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通过对中国东部陆上及海域大量地质地球化学资料的分析,重点对CO2成因及运聚成藏规律与主控因素进行了深入地探讨,并在此基础上对有利CO2分布区进行了初步预测。研究表明,中国东部陆上诸断陷盆地与东南沿海海域的东海盆地及南海北部大陆架琼东南盆地和珠江口盆地CO2气藏及高含CO2油气藏中,CO2均属典型的火山幔源型成因,其运聚富集主要受控于幔源型火山活动与沟通深部气源的基底深大断裂的导气配置作用,CO2气源主要来自地壳深部幔源火山活动伴生的大量CO2;南海北部大陆架西区莺歌海盆地CO2气藏及含CO2油气藏中的CO2,属于壳源型及壳幔混合型成因,主要受控于泥底辟热流体晚期分层分块多期的局部上侵活动与沉积巨厚海相含钙砂泥岩的物理化学作用,其运聚分布具多期和分层分区的特点。因此,根据不同成因类型CO2运聚成藏规律,可以追踪气源,分析和预测天然气尤其是CO2的运聚分布,评价其资源潜力,为天然气勘探部署及决策提供依据,降低勘探风险。 相似文献