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1.
陈绍桔 《福建地质》2004,23(2):73-76
通过多年在山区寻找地下水的工作实践,介绍山区寻找地下水的工作经验和方法,并对三大主要影响因素进行初步分析,对今后找水,尤其是山区寻找地下水有一定借鉴意义。  相似文献   

2.
Microplastics (MPs) pollution has become a serious environmental issue of growing global concern due to the increasing plastic production and usage. Under climate warming, the cryosphere, defined as the part of Earth’s layer characterized by the low temperatures and the presence of frozen water, has been experiencing significant changes. The Arctic cryosphere (e.g., sea ice, snow cover, Greenland ice sheet, permafrost) can store and release pollutants into environments, making Arctic an important temporal sink and source of MPs. Here, we summarized the distributions of MPs in Arctic snow, sea ice, seawater, rivers, and sediments, to illustrate their potential sources, transport pathways, storage and release, and possible effects in this sentinel region. Items concentrations of MPs in snow and ice varied about 1–6 orders of magnitude in different regions, which were mostly attributed to the different sampling and measurement methods, and potential sources of MPs. MPs concentrations from Arctic seawater, river/lake water, and sediments also fluctuated largely, ranging from several items of per unit to >40,000 items m?3, 100 items m?3, and 10,000 items kg?1 dw, respectively. Arctic land snow cover can be a temporal storage of MPs, with MPs deposition flux of about (4.9–14.26) × 108 items km?2 yr?1. MPs transported by rivers to Arctic ocean was estimated to be approximately 8–48 ton/yr, with discharge flux of MPs at about (1.65–9.35) × 108 items/s. Average storage of MPs in sea ice was estimated to be about 6.1×1018 items, with annual release of about 5.1×1018 items. Atmospheric transport of MPs from long-distance terrestrial sources contributed significantly to MPs deposition in Arctic land snow cover, sea ice and oceanic surface waters. Arctic Great Rivers can flow MPs into the Arctic Ocean. Sea ice can temporally store, transport and then release MPs in the surrounded environment. Ocean currents from the Atlantic brought high concentrations of MPs into the Arctic. However, there existed large uncertainties of estimation on the storage and release of MPs in Arctic cryosphere owing to the hypothesis of average MPs concentrations. Meanwhile, representatives of MPs data across the large Arctic region should be mutually verified with in situ observations and modeling. Therefore, we suggested that systematic monitoring MPs in the Arctic cryosphere, potential threats on Arctic ecosystems, and the carbon cycle under increasing Arctic warming, are urgently needed to be studied in future.  相似文献   

3.
The occurrence of specific micropollutants (MPs), indicators of domestic and hospital wastewater, was investigated in a river connected to a karst spring based on two sampling campaigns under varying flow conditions. The MPs characterized by a high frequency of occurrence (acesulfame-K, ibuprofen, gemfibrozil, nonylphenol, and iohexol) were highly reflective of wastewater discharged in ephemeral streams and tributaries, as well as specific point sources such as farms and hospital effluents. A mixing model based on chloride mass fluxes allows the quantification of the percentage of untreated wastewater effluents in inflowing water from river tributaries, which varied between 0.7–99% and 5.0–10% in low flow and high flow, respectively. The frequency of occurrence of MPs is related to the volume of wastewater input, extent of river dilution, persistence of the MPs, and type of point source contamination on the river. Relationships were established between MPs such as ibuprofen and acesulfame-K (ACE-K), indicating their co-existence in highly consumed generic medicine and their suitability as wastewater co-tracers. Additionally, the number of consumers of gemfibrozil (GEM) and acesulfame-K were estimated based on mass loads in the river tributaries for management purposes. Groundwater contamination is mostly due to diffuse and point sources infiltration occurring on the spring catchment, including the sinking stream that could contribute up to 17% to the mass loads of some micropollutants (e.g., ACE-K and GEM) at the spring. Nevertheless, the increase of MPs use with growing urbanization is expected to have a much significant impact on the groundwater quality in the future.  相似文献   

4.
This paper describes the historical roots of an ongoing wildlife management dilemma involving decreasing opportunities for elk management via public hunting on private land in the context of an expanding elk presence on private land in southwest Montana. Our main focus is on the role of private ranchland in elk ecology, and the ability of land owners to set elk migration in new directions through cumulative decisions about hunting and tolerating elk. This takes elk management, traditionally the purview of the state, out of administrative control. We document connections between the region’s historical and emerging land tenure patterns, and analyze associated changes in hunter access. Elk numbers expanded rapidly in the Upper Yellowstone Valley at a moment of significant transition in ranchland tenure. New owners more interested in natural amenities than in livestock production encouraged the elk and discouraged hunting. This reinforced the spread of elk, and further weakened the ability of the state and other ranchers to manage elk (which interfere with livestock production in numerous ways). Though elk and cattle use the landscape in similar ways, elk became more effective agents of landscape change in a reflexive relationship with ideas of land that stress natural amenities over production.  相似文献   

5.
The micropiled raft (MPR) offers an efficient foundation system that combines the advantages of micropiles and piled rafts that can be used as primary foundation system or to enhance an existing raft foundation. In this paper, a calibrated and verified finite element model (FEM) with centrifuge tests was used to carry out a numerical investigation on the performance of MPR in sand. A total of 78 different cases were analyzed in this study to assess the behavior of MPR in sand taking into account a number of factors that may influence its behavior such as: the number of micropiles (MPs), the spacing to micropile diameter (S/Dmp), the raft thickness, type of loading and soil density. The outcomes of this investigation should help in understanding the effect of these factors on the MPR axial stiffness, including; differential settlement; load sharing between the MPs and the raft; and the raft bending moment. Moreover, the ability of the PDR method to evaluate the axial stiffness of a MPR for the preliminary design stage is examined. It was found that the MPR system has the ability to increase the tolerable bearing pressure by 190% compared to an isolated raft system. In addition, an adjustment factor (ωPR) for PDR method was introduced to account for the raft flexibility.  相似文献   

6.
This paper investigates the various ways in which migrants to the United Kingdom become illegally resident. Drawing on findings from a pilot study of undocumented migrants held in detention centres in the United Kingdom, it explores why respondents had chosen to come to the United Kingdom, how they came, and how they ended up residing illegally. In contrast to common assumptions about ‘illegal immigrants’, the present study reveals the diversity of paths into illegal residence, and stresses the importance of perceived safety, both from ‘persecution’ and more generalised violence, as well as the ease of finding work in a strong economy. The sample included both those who had knowingly come to the United Kingdom to live and work illegally, and those who had become illegal during their stay.  相似文献   

7.
美国地质灾害防治现状综述   总被引:1,自引:0,他引:1  
地质灾害的防治研究受到世界各国的广泛重视,本文从地灾防治基础理论、职能部门工作方式入手,对美国科研界的非饱和土理论最新研究进展、美国地质调查局(USGS)地质灾害防治中心的日常工作形式进行了较为全面的阐述。除此之外,还结合作者自身参与的滑坡灾害调研活动,对美国科研人员的野外基本工作方法、野外工作的最主要目的进行了描述。在此基础上,还对中美两国地灾防治现状进行了简要对比,本文所阐述的内容可为相关领域的研究人员提供一定的参考。  相似文献   

8.
闽东地区钼矿床控矿因素与成矿模式探讨   总被引:1,自引:0,他引:1  
雷广文 《福建地质》2010,29(3):194-200
通过对闽东地区地质背景、地球化学特征、主要钼矿床地质特征的阐述,重点剖析了钼矿床的控矿因素,探讨其成因,尝试性总结区内钼成矿模式,为今后在该地区寻找同类型的钼矿床提供找矿思路和借鉴。  相似文献   

9.
福建省物探找矿若干实例分析   总被引:1,自引:0,他引:1  
物探作为一种地质勘察技术方法在国民经济各个领域,得到广泛的应用,物探方法和其它地质学科一样都存在着不足为奇的解释多解性。通过对福建省金,多金属,煤等矿产的地球物理勘察实例分析。认为要取得物探找矿效果应注意以下几点;(1)分析矿产的地质规律和特点;(2)掌握矿体与围岩之间物性差异的特征,直接找矿与间接找矿并举;(3)选择适合的物探方法,发挥各种方法的长处,(4)建立和利用矿床的地质-地球物理模型。圈出矿床(体)赋存的部位。  相似文献   

10.
11.
甘肃北山地区钨矿特征及找矿远景   总被引:3,自引:0,他引:3       下载免费PDF全文
利用甘肃北山地区近几年地质大调查工作的成果,依据找矿信息及化探异常、重砂异常的分布范围,对该区划分为6个找钨矿远景区。各远景区存在着较大的钨资源潜力,具有良好的成矿条件和特定的成矿类型。以期为矿产勘查工作提供新的找矿思路和依据。  相似文献   

12.
福建省金矿控矿地质条件研究   总被引:2,自引:1,他引:2  
张克尧 《福建地质》2003,22(1):21-32
金矿系地质历史演化到一定阶段和特殊部位的产物,各类型金矿必然与特殊的地层、构造、岩浆岩在空间上形影相随,时间上相近,成因上密切相关。因此,系统地总结了地层、构造、侵入岩、火山岩等地质条件对金矿的控制特点,对福建省内在找金矿方面取得更大突破具有十分重要的意义。  相似文献   

13.
The global climate changings at the end of Pleistocene led to extinction of the typical representatives of Mammoth fauna–mammoth, woolly rhinoceros, wild horse, bison, muskox, cave lion, etc.–on the huge territories of Northern Eurasia. Undoubtedly the Mammoth fauna underwent pressure from the Upper Paleolithic Man, whose hunting activity also could play the role in decreasing the number of mammoths and other representatives of megafauna (large mammals). Archaeological data testify that the typical representatives of Mammoth fauna were the Man's hunting objects only till the end of the Pleistocene. Their bone remains are not usually found on the settlements of Mesolithic Man. Formerly it was supposed that the megafauna of ‘Mammoth complex’ was extinct by the beginning of Holocene. Nevertheless the latest data testify that the global extinction of the Mammoth fauna was sufficiently delayed in the north of Eastern Siberia. In the 1990s some radiocarbon data testified that the mammoths on the Wrangel Island existed for a long time during the Holocene from 8000 till 3700 y. BP. The present radiocarbon data show that wild horses inhabited the north of Eastern Siberia (the lower stream of the Enissey river, the Novosibirskie Islands, the East Siberian sea-shore) 3000–2000 y. BP. Musk-oxen lived on the Taimyr Peninsula and the Lena River delta about 3000 y. BP. Some bison remains from Eastern Siberia belong to the Holocene. The following circumstances could promote the process of preservation of the Mammoth fauna representatives. The cool and dry climate of this region promotes the maintenance of steppe associations – habitats of those mammals. The Late Paleolithic and Mesolithic settlements are not found in the Arctic zone of Eastern Siberia from the Taimyr Peninsula to a lower stream of the Yana River; they are very rare in the basins of the Indigirka and Kolyma Rivers. So, the small number of the Stone Age hunting tribes on the North of Eastern Siberia was another factor in the long-term preservation of some Mammoth fauna representatives.  相似文献   

14.
郴州芙蓉锡矿田成矿模式及资源总量预测   总被引:17,自引:0,他引:17  
本文简要地归纳了芙蓉矿田锡矿床类型,建立了锡矿成矿模式,并预测了锡资源总量。在垂深400m以内,预测有超大型锡矿床2处,大型锡矿床7处,中型锡矿床3处。  相似文献   

15.
The ongoing greenhouse gas buildup and increase in near-surface air temperatures may have an impact on severe weather events in the United States. Output from some numerical modeling simulations suggests that the atmosphere over mid-latitude land areas could become more unstable in the future thereby supporting an increase in convective activity. However, despite the numerical simulation results, empiricists have been unable generally to identify significant increases in overall severe storm activity as measured in the magnitude and/or frequency of thunderstorms, hail events, tornadoes, hurricanes, and winter storm activity across the United States. There is evidence that heavy precipitation events have increased during the period of historical records, but for many other severe weather categories, the trends have been downward over the past half century. Damage from severe weather has increased over this period, but this upward trend disappears when inflation, population growth, population redistribution, and wealth are taken into account.  相似文献   

16.
In evaluating international treaties, in particular, the United Nations Framework on Climate Change Convention, this paper shows that necessary preparations have not been made to protect the rights of individuals who are refugees or have been forced to migrate from their homeland. Immigrants are deprived of the most essential human rights, such as language, culture, and having a right to a healthy living environment. The current legal administration has not made the necessary contingencies for responding to the environmental consequences of immigration and is extremely inefficient in expanding this phenomenon. This paper seeks to address the question of to what extent existing forms of legal and operational protection can apply in climate change-related displacement in general and cross-border displacement in particular. In this work some strategies have been proposed for dealing with these existing gaps. It is expected that analyzing these gaps and determining the international community??s duties and commitments (governments and international organizations) can result in efficient management of this crisis and prevent the outbreak of chaos across the globe.  相似文献   

17.
总结了朝阳西北部金成矿区的区域磁场、重力场等地球物理场的特征及规律,指出了常规物探方法在该区的找金效果,预测了金成矿的远景区段。  相似文献   

18.
三明地区位于闽西北隆起带与闽西南坳陷带接合部,萤石矿资源丰富,其成矿受常口一瀚仙一余朋北东向断裂构造带控制。总结该断裂构造带地质条件.阐述已知萤石矿点基本特征及找矿标志,通过成矿预测,提出了清流余朋等五个成矿重点区.宜作为今后工作的重点。  相似文献   

19.
Global climate change at the end of Pleistocene led to extinction in the huge territories of Northern Eurasia of the typical representatives of the Mammoth fauna: mammoth, woolly rhinoceros, wild horse, bison, musk-ox, and cave lion. Undoubtedly the Mammoth fauna underwent pressure from Upper Paleolithic humans, whose hunting activity could also have played a role in decreasing the number of mammoths and other representatives of megafauna. Formerly it was supposed that the megafauna of the “Mammoth complex” had become extinct by the beginning of the Holocene. Nevertheless the latest data indicate that extinction of the Mammoth fauna was significantly delayed in the north of Eastern Siberia. In the 1990s some radiocarbon dates established that mammoths existed in the Holocene on Wrangel Island—from 7700 until 3700 yBP. Radiocarbon data show that wild horses inhabited the north of Eastern Siberia 4600–2000 yBP. Muskoxen lived here about 3000 yBP. Some bison remains from Eastern Siberia belong to the Holocene. The following circumstances could promote the survival of representatives of Mammoth fauna. Cool and dry climate in this region promotes the maintenance of steppe associations—the habitats of those mammals. Late Paleolithic and Mesolithic settlements are not found in the Arctic zone of Eastern Siberia from Taimyr Peninsula to the lower Yana River; they are very rare in basins of the Indigirka and Kolyma Rivers. The small number of Stone Age hunting tribes in the northern part of Eastern Siberia was probably another factor that contributed to the survival of some Mammoth fauna representatives.  相似文献   

20.
P. Dicken   《Geoforum》1980,11(4):289-313
The position of the United Kingdom as a host country for foreign direct investment in manufacturing is examined in the European context. Several trends are identified which suggest that the United Kingdom's relative position is changing. In particular, the balance of United States manufacturing investment has been shifting away from the United Kingdom and towards mainland Europe while the United Kingdom's membership of the EEC enables European countries to serve the United Kingdom market by exporting rather than by direct investment. As yet, the volume of Japanese investment in United Kingdom and European manufacturing is small. In the competition between nations for internationally mobile investment. Ireland has captured a good deal of new manufacturing investment, some of which may have been ‘diverted’ from the United Kingdom. The apparent decline in the attractiveness of the United Kingdom as a host country for foreign manufacturing investment could have serious consequences for employment in the peripheral regions of the United Kingdom particularly in the light of developments in the organization of multinational enterprise and the impending enlargement of the EEC.  相似文献   

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