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1.
《水经注》中有关北京地理的科学思想 总被引：1，自引：0，他引：1
《水经注》是我国古代著名的地理学著作之一,作者郦道元是北魏时期范阳(涿州—北京)人,因此书中对北京附近的水系和地理情况进行了描述。书中称拒马河为巨马水、大石河为圣水、永定河为漯水、清水河为清夷水、温榆河为湿馀水、潮白河为鲍邱水、泃河为泃水,称永定河出山段为清泉河、流经北京城内的什刹海和中南海为高粱河。对家乡附近的地理进行了描述,称房山为大房岭、石景山为梁山,记录了昌平县、密云戍、平谷县等行政区域,记录了羊头埠(羊头岗)、马兰(马栏)、芹城(秦城)、独乐水(独乐河)、良乡、居庸关、盘山等地名。记录了中国最早的首都——涿鹿,记录了中国现代首都蓟城(北京)内曾有蓟丘,说明永定河沟通了古今首都。记录了北京最早的水利工程戾陵堰和车箱渠。 相似文献
2.
激光剥蚀-电感耦合等离子体质谱准确测定锆石中钛的含量 总被引：2，自引：2，他引：0
外标物质及内标元素的选择是激光剥蚀-电感耦合等离子体质谱(LA-ICP-MS)准确测定元素含量的关键因素之一。文章选用玻璃标准参考物质NIST 610、GSE-1G、BHVO-2G、BCR-2G、ATHO-G、KL2-G和T1-G作为外标,Si或Zr作为内标,对锆石M257中的Ti进行LA-ICP-MS微区原位测定。结果显示,选择Si或Zr作内标,采用BCR-2G、ATHO-G、KL2-G和T1-G作外标时,Ti含量测定值与参考值之间差异均较大,因此它们不适合作外标物质。采用BHVO-2G作外标和Si作内标,NIST 610作外标和Zr作内标,Ti含量测定值与参考值之间的差异均小于4%,因此BHVO-2G和NIST 610可有条件地作为外标物质。选择Si还是Zr作内标,GSE-1G作外标时,Ti含量的测定值与参考值之间的差异均小于3%,说明GSE-1G是较为合适的外标物质。选用GSE-1G作为外标,Si作内标,对5个标准锆石中的Ti含量进行了测定,结果显示,Ti元素在锆石91500中分布不均匀,而在锆石GJ-1、M257、PENGLAI和MUDTANK中分布均匀。在Ti元素分布均匀的GJ-1、M257、PENGLAI和MUDTANK等4个锆石中,由于Ti的含量均小于5μg/g,不适合作为锆石中Ti元素测定用的外标物质,但可作为测定时的质量监控样品。 相似文献
3.
Polished and thin section examinations of samples from Indiana Coal Bed V (Springfield) have shown three sulfides to be present; namely pyrite, marcasite and sphalerite. Pyrite and marcasite are dominant forms whereas sphalerite is very minor. These sulfides appear to have formed in four distinct stages as judged on the basis of mineralogy and mineral texture. Pyrite occurs as framboids throughout the coal seam, as fibrous crystals in two horizons of the coal and in massive form as cleat fillings and cell fillings in fusinite and semi-fusinite. Marcasite occurs in spherical polycrystalline and twinned grains, as polycrystalline overgrowths on framboids, as cementing material for clusters of framboids, as blocky polycrystalline grains and with pyrite as cell fillings in fusinite and semi-fusinite. Sphalerite occurs exclusively as cell fillings in semi-fusinite. The paragenetic sequence indicates fluctuations in the overall coal bed chemistry. Individual sections display evidence of chemical variation on the micro scale. 相似文献
4.
喀斯特地区不同植被下小生境土壤矿物组成及有机碳含量空间异质性初步研究 总被引：4，自引：2，他引：2
通过对喀斯特地区乔木林、灌木林和草丛不同植被类型覆盖下的土面、石面、石缝、石沟、石洞、石槽和石坑7类小生境土壤样品分析测定,探讨了小生境土壤矿物组成及有机碳的空间异质性特征。结果表明:(1)不同植被类型下土壤矿物组成存在明显差异,即从草丛→灌木林→乔木林,小生境土壤中的石英、高岭石基本保持不变,但草丛土壤中的白云石矿物全部消失,灌木林、乔木林土壤中逐渐出现绿泥石;(2)随着植被正向演替,土壤有机碳含量显著增加,小生境土壤有机碳含量在不同植被类型条件下存在明显的异质性,表现为草丛>乔木林>灌木林。与此同时,以小生境土壤有机碳含量及变异系数为评价因子,分别对乔木林、灌木林及草丛中小生境有机碳进行聚类分析,结果显示,小生境微地貌特征是土壤有机碳含量及空间变异性的重要影响因子。对于土壤有机碳保护,草丛及灌木林区应以提高植被覆盖率为主;乔木林区则主要是保持现有良好的植被状况,减少人为干扰。 相似文献
5.
Lü Delin 《中国地质大学学报(英文版)》2001,12(4)
Since Dow (l972) proposed the concept of oil system atthe AAPG annual meeting in l972, after unremitting effol.tsand progressive perfection, it has become the petroleum systemaccepted by numerous geologists at present. The concept of pe-troleum system was introduced to our country in early l990s(I)ou, l999). In fact, as early as the 1960s, based on the hy-drocarbon exploration and development practice at Songliao ba-sin and Bohai Bay basin, some viewpoints similar to petroleumsystem have be… 相似文献
6.
滇池流域石漠化特征分析 总被引：2，自引：2，他引：0
位于云南省会昆明盆地内的滇池流域是滇中岩溶和石漠化较为发育的地区,石漠化总面积225.56 km2,占流域总面积的7.71%,占岩溶总面积32.69%。石漠化主要分布在望海山、大板桥—呈贡、黑林铺、海口、梁王山、上蒜片区,其中又以北东部的大板桥片区石漠化最为严重。石漠化已造成流域内水土流失加剧、可耕地面积减少、土壤涵养水源能力降低及生态环境恶化等危害。通过地面调查和ETM遥感解译,查清了流域内石漠化的发育分布与碳酸盐岩的岩性及其组合、岩溶作用、地形地貌、气象等自然因素、人为因素和工业污染关系密切。针对石漠化的形成原因,提出了生态修复、农田基本建设、水资源开发利用、农村能源建设、小集镇建设、土地合理利用等治理措施。 相似文献
7.
V. V. Seredin 《Geology of Ore Deposits》2007,49(1):1-30
Original data and a survey of the literature indicate that Au and Au-PGE mineralization are abundant in coal measures. Anomalous contents of noble metals have been established in basins with various types of basement, composed of granite, volcanic rocks, schist, and limestone. These basins are located in Au-and PGE-bearing ore districts, as well as at a considerable distance from known ore deposits and occurrences. Ore formation in coal-bearing basins may occur during sedimentation, peat accumulation, and diagenesis of organic matter or may be epigenetic. Noble metals are supplied to sedimentary basins as minerals that are transported by water and air and as ion species migrating along with surface and subsurface in-and exfiltration solutions of various chemical and genetic types. Ore mineralization concentrates in coal seams and host sedimentary beds of various grain size, including conglomerate, sand, and clay, as well as in zones of hydrothermal alteration superimposed on basement rocks and the sedimentary cover. The mode of occurrence of noble metals in coal basins is diverse as well (noble metal minerals, isomorphic admixtures in sulfides, and organic compounds). The data presented allow coal-bearing basins to be regarded as promising for economic noble metal mineralization fit for recovery as by-products in the course of coal mining. 相似文献
8.
本文采用电子探针、透射电镜和化学物相法,查明某古岩溶铀矿床中铀主要呈显微和超显微状沥青铀矿、铀石,其次呈分散吸附状和铀酰（次生）矿物形态存在;钼主要呈蓝钼矿、钼钙矿、钼华、钼铅矿等氧化物,其次呈胶硫钼矿等形态存在;铼主要呈吸附状,其次可能在黄铁矿中呈二硫化物包裹体形态产出。最后讨论了该三个元素赋存状态与该铀矿床形成地球化学环境之间的关系。 相似文献
9.
10.
J. Cassar M. Galea R. Grima K. Stroud A. Torpiano 《Environmental Earth Sciences》2011,63(7-8):1849-1860
The Maltese Megalithic Temples, constructed between the mid-fourth and mid-third millennia BC, are unique and are amongst the oldest stone buildings of such complexity in the world. They are of great local and international significance, embodying symbolic, educational and recreational values. These Temples are currently suffering from a series of severe problems associated with the deterioration of materials as well as structural problems, seen in a number of serious collapses in recent years. In 2000, it was decided that these vulnerable prehistoric structures needed to be protected from the direct impact of environmental factors by means of a temporary, open-sided shelter, conceived as a large parasol designed to be as light as possible, in visual as well as in physical terms. The erection of two of these shelters took place during 2008–2009. The performance of the shelters is currently being assessed by environmental monitoring which already indicates an improvement in conditions beneath the shelters when compared to conditions on site before sheltering. 相似文献
11.
SARS (Severe Acute Respiratory Syndrome) has been declared by WHO (World Health Organisation) as a global health threat. Within
a period of four to five months in 2003, the disease infected some 8,000 people in more than 25 countries and left 774 dead.
The many studies that have been done on the spread of SARS in Asia as well as countries as far flung as Germany and Canada
have focused on the global dimension of the infectious disease as well as the speed of its spread upon emergence in southern
China and then Hong Kong. Less attention has been paid to its spatial distribution at the national and local scales. This
discussion focuses on the spread of SARS at the national and local spatial scales. In the process, the study presents the
management of a hazard, in this case, an emerging infectious disease by national health care institutions such as the hospitals
that ultimately proved to have been wholly unprepared for coping with at least the health aspects of the outcome of a globalised
national agenda for growth and economic progress. 相似文献
12.
夏季草原与戈壁地表能量分析 总被引：1，自引：0，他引：1
利用野外试验资料，比较分析了夏季祁连山区草原和河西走廊张掖戈壁地表能量特征，并探讨了环境因素与地表能量特征的关系。结果表明，在夏季典型晴天，山区草原的净辐射、潜热通量大于戈壁，而感热、土壤热通量小于戈壁；山区草原净辐射、潜热通量的日变化大于戈壁；而感热、土壤热通量的日变化小于戈壁。在山区草原，晴天潜热通量是土壤热通量的三倍多，感热通量与土壤热通量差异很小，净辐射主要用于蒸发、蒸腾；在戈壁，晴天土壤热通量和感热通量是潜热通量的近两倍，净辐射主要用于加热地表，并通过地表加热下层土壤和地面大气。两地均存在能量不平衡现象，草原感热、潜热、土壤热通量之和小于净辐射，戈壁感热、潜热、土壤热通量之和大于净辐射，戈壁能量不平衡大于草原。导致山区草原和戈壁地表净辐射特征差异的主要因素是太阳辐射，导致山区草原和戈壁地表能量分量特征差异的主要因素是陆面植被和水分，根本因素是陆面水分。
相似文献
13.
Geochronology of anthropogenic pollutants in riparian wetland sediments of the Lippe River (Germany) 总被引：2，自引：0，他引：2
S. Heim J. Schwarzbauer A. Kronimus R. Littke C. Woda A. Mangini 《Organic Geochemistry》2004,35(11-12):1409
Anthropogenic pollutants were determined in a dated sediment core, collected from a riparian wetland of the Lippe River (Ruhr district, Germany). The historical trend in heavy metals, polycyclic aromatic hydrocarbons, organochlorines, polychlorinated biphenyls and linear alkylbenzenes as well as more recent contaminants such as industrial additives, organotins, synthetic musks, methyltriclosan and some other compounds were determined for the time period between 1930 and 1986. Emission sources, information on technical production and usage, as well as on the individual pollution pathways, with appropriate environmental stability, were considered in the interpretation of the sediment contamination over the past 50 years.Contaminants were analysed and interpreted according to two different criteria: (a) the origin of the main contaminants as related to mining and industrial activities as well as municipal sewage and agricultural effluents and (b) the pollution history. Due to a significant appearance of formerly missing contaminants in sediments deposited since 1970, we suggest classifying contaminants as either common (predating 1970) or modern (postdating 1970).In summary, the study provided a comprehensive reconstruction of the pollution history of the Lippe River system. 相似文献
14.
彝良县位于云南省东北部,为云南省七个地质灾害重点防治区的一部分。2003年的地质灾害调查显示,县域内有地质灾害236处,其中滑坡181处,不稳定斜坡9处,泥石流34处,地面塌陷12处,以滑坡和泥石流为主。综合研究分析结果表明,地质灾害的主要诱因除地质地理环境（地形地貌、降雨集中、岩溶作用、新构造运动强烈）等自然因素外,人类工程活动中的切坡过陡和采矿活动形成的巨大采空区也是主要诱发因素。在此基础上,根据各种影响因素的作用强度把彝良县划分为洛泽河—小米溪河高易发区、发达—洛旺中等易发区和低易发区（含小草坝亚区和龙街-奎香亚区）三个地质灾害区,并在灾害防治、协调管理、宣传教育等方面提出了一些有益的建议。 相似文献
15.
鄂尔多斯盆地东缘经过20 a的勘探开发,煤层气仍然没有实现产业化。随着勘探资料的不断丰富,有必要对该区进行煤层气有利区块的优选和重新认识。在前人研究基础上,首先将鄂尔多斯盆地东缘埋深1 500 m区域分为6个区块,选取煤层厚度、含气量、构造条件、水文条件、煤体结构、含气饱和度、储层压力梯度、渗透率和临界解吸压力与储层压力比9个参数作为区块优选指标,结合国内外及研究区实际情况制定了相应的评价临界值。将上述参数作为评价指标集合,以评价单元作为对象集,以有利、较有利和不利作为评级等级集合,然后运用模糊数学综合评判方法得到各评价单元的不同评价参数对评价等级的隶属度,并运用层次分析法确定了各指标的相对权重,最后得到了评价单元对评价等级的隶属度。根据最大隶属度原则,吴堡-柳林属于有利区,大宁-吉县和韩城属于较有利区,准格尔、府谷、河曲-临县属于不利区,吴堡-柳林的煤层气可采性好于大宁-吉县和韩城。因此,建议将吴堡-柳林、大宁-吉县和韩城定为研究区煤层气优先开发区块。 相似文献
16.
P. W. Uitterdijk Appel 《Mineralium Deposita》1994,29(4):341-352
Extensive scheelite-bearing calc-silicate zones with elevated contents of chromium, nickel, copper, zinc, yttrium and barium are found in Archaean supracrustal rocks of the Nuuk area, West Greenland. The calc-silicate zones are largely stratabound and occur in mafic and ultramafic metavolcanic rocks. The calc-silicates are interpreted as amphibolite facies metamorphosed alteration zones in komatiitic intrusive and extrusive rocks as well as in tholeiitic pillow lavas. The alteration which antedates the amphibolite facies metamorphism and the main deformation of the supracrustal rocks, presumably took place at the sea-floor or immediately below the sea-floor. The brines which caused the alteration were enriched in elements such as tungsten, boron, sulphur, iron, copper and zinc. The boron was precipitated as thin tourmalinites and the iron in massive to semi-massive sulphide bodies. The scheelite in the calc-silicates is mainly found as disseminated grains, as stringers and as veinlets. Rare veins up to 15 cm wide with massive scheelite are encountered. Channel sampling revealed grades up to 0.35% W over a width of 2.5 m. Highly anomalous bromine contents up to 418 ppm and equally anomalous chlorine/bromine ratios down to 3 have been found in scheelite-bearing calc-silicates. Somewhat similar anomalous bromine contents and Cl/Br ratios have been reported from serpentinites in the Outokumpu ore body, Finland. At Mount Isa, northern Australia and in the Antimony line in the Murchinson greenstone belt, southern Africa anomalous Cl/Br ratios have been observed. The possible role of bromine in the ore-forming processes is as yet poorly understood. 相似文献
17.
B. Cavalazzi A. Agangi R. Barbieri F. Franchi G. Gasparotto 《Geology of Ore Deposits》2014,56(5):395-408
This contribution is an updated review on sedimentary pyrite and on its role in well-consolidated research topics, such as the biogeochemical cycles and the studies on sediment-hosted ore deposit studies, as well as new frontiers of research, such as astrobiology. Textural and compositional information preserved in sedimentary pyrite from sediment-hosted ore deposits has contributed to elucidate their environment of forzmation. In particular, the content of redox-sensitive elements such as Ni, Co, Mo, and V has implications for defining the syn- and post-sedimentary conditions. In addition, the stable isotope compositions are useful indicators of the pathways of both biogenic and abiogenic pyrite formation. Despite the longstanding research on pyrite and the mechanism of its formation, there are still significant gaps in our knowledge. In this nonexhaustive review, we briefly touch on different current aspects of research on sedimentary pyrite, exemplifying how sedimentary pyrite remains relevant to geoscientists, and becomes more and more relevant in understanding some basic aspects of knowledge, such as the origin of life and the search for extraterrestrial life, as well as aspect of classical applied science, such as the implications for ore deposition. 相似文献
18.
Barbara Romanowicz 《Comptes Rendus Geoscience》2003,335(1):23-35
We present an overview of the present knowledge of the Earth's lower mantle 3D structure, as currently obtained owing to progress, in the last ten years, in seismic tomography as well as forward modelling of seismic travel times and waveforms. We discuss constraints that seismic modelling brings to the debate concerning major geodynamical questions, in particular the issue of global ‘1 layer’ or ‘2 layer’ circulation, of the missing geochemical reservoir, as well as of the role in global dynamics of the thermochemical boundary layer at the base of the mantle. 相似文献
19.
从以物理模型实验及理论解析为代表的植物消波研究手段与宏观和微观尺度下植物消波分析方法两个方面总结了国内外的研究现状和最新研究进展。对物理模型实验中的植物因子、水动力因子、植物模型制作和实验布置等要素以及理论解析模型进行归纳,分别阐述了以波高衰减和波能耗散为主要分析对象的植物消波分析方法,指出现有物理模型实验中植物几何比尺与波要素比尺难以统一和理论解析研究局限于二维情况等问题。综合考虑季节更替、植物摆动、波浪破碎、波浪随机性及非线性、潮流等因素是今后植物消波研究的重点突破方向。 相似文献
20.
笔者在工程地质实地调查和已有资料梳理的基础上,发现略阳城区工程地质的总体环境较差,褶皱构造和断裂构造明显,滑坡和崩塌等不良地质灾害现象严重。经分析提出了交通类工程施工中,避让和整治相结合的防治措施。 相似文献