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排序方式: 共有237条查询结果,搜索用时 31 毫秒
1.
山东玲珑金矿床成矿流体地球化学特征 总被引:3,自引:0,他引:3
玲珑金矿床第一成矿阶段与含金黄铁矿共生的石英中主要发育4种类型的原生流体包裹体:Ⅰ气液两相,Ⅱ含CO2三相,ⅢCO2,Ⅳ单液相包裹体。流体包裹体成分激光拉曼光谱分析及测温结果显示:①Ⅰa型包体,气液比10%~15%,均一温度为162.7~235.6℃,w(NaCl)(盐度)为4.65%~7.59%,气相平均摩尔分数为:H2O 96.48%,CO22.4%;②Ⅰb型包体,气液比30%~45%,均一温度266.9~349.2℃,w(NaCl)为10.8%~13.4%,气相平均摩尔分数为H2O 69.75%,CO224.74%;③Ⅱ型含CO2包体,CO2相所占比例为20%~90%,其均一温度为193.5~321.6℃,w(NaCl)2.9%~5.3%,CO2相中,H2O的摩尔分数为27.72%,CO2为70.6%。包裹体成分分析及测温结果综合研究认为,玲珑金矿成矿过程中存在大气降水热液与地幔来源流体的混合作用,前者与从流体中分离出的富CO2流体混合,以不同比例被捕获形成Ⅱ型包体;而与分异出CO2后的CO2不饱和地幔流体混合,被捕获形成Ⅰb型包体。两种流体混合导致的含矿热液物化条件变化对金的沉淀成矿具有重要意义。 相似文献
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The extensive territory of the ancient (Hellenistic to Byzantine) city of Sagalassos (SW Turkey) offered a rich variety in natural mineral resources. The frequent occurrence of iron slag in the excavations at the site proved the local working of metal. A geochemical prospection campaign was done in the territory of the ancient city in order to identify or discard the city and its territory as a self-sustaining metallurgical centre. Secondly, the geochemical impact of ancient metallurgy was investigated. Geochemical anomalies identified in stream sediments are explained by the presence of mineralised deposits and ancient metal working. Mg, Cr, Co and Ni anomalies point to chromite and chrysotile-magnetite deposits related to the basic rocks of the Lycian nappes in the area. Fe, V and Ti anomalies indicate the presence of iron mineralisations, which have been worked for iron production in ancient times. Finally, the association of P, Cu, Pb, Mn, As and Ag anomalies are an indicator of human activity at archaeological sites. Within the framework of this geochemical prospection, a metal working site apart from the city of Sagalassos was identified. Here, ore was both extracted and processed to workable iron. 相似文献
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Claude Boutron Kevin Rosman Carlo Barbante Michael Bolshov Freddy Adams Sungmin Hong Christophe Ferrari 《Comptes Rendus Geoscience》2004,336(10):847-867
The investigation of the occurrence of lead in dated snow and ice from Greenland and Antarctica has played a major role in our understanding of the history of the pollution of the atmosphere of our planet by this metal. Such studies have however proved to be very demanding, mainly because of the extreme purity of polar snow and ice. Reliable measurements can be obtained only if ultra-clean and highly sensitive procedures are used, as pioneered by Clair Patterson. The Greenland data show evidence of large-scale pollution of the atmosphere of the Northern Hemisphere for lead as early as two millennia ago during Greco–Roman times, especially because of mining and smelting activities in southern Spain. It peaked at the end of the 1960s, with lead concentrations in snow about 200 times higher than natural values, before declining during recent times because of the fall in the use of leaded gasoline. Lead pollution in Antarctica was already significant at the end of the 19th century as a consequence of whaling activities, the traffic of coal-powered ships crossing the Cape Horn, and mining activities in South America, South Africa and Australia. After declining because of the opening of the Panama Canal, the great economic depression and World War II, it reached a maximum during the 1980s, with lead concentrations 20 times higher than natural values. Other studies focus on past natural variations of lead in ancient ice dated from the last climatic cycles. To cite this article: C. Boutron et al., C. R. Geoscience 336 (2004). 相似文献
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WILLIAM A. KOELSCH 《Geographical review》2004,94(4):502-518
ABSTRACT. Strabo of Amasia (ca. 64 B.c.‐ca. A.D. 23) wrote the first comprehensive geography of the world known to the Greeks and Romans. Interest in Strabo and his Geography, which survives nearly intact in seventeen books, has fluctuated over the centuries among both classicists and historians of geography. After some historical background on Strabo and his reception, this essay considers the contribution of two significant recent English‐language treatments, as well as Strabo's Geography itself, and suggests ways in which the Strabonic model may have renewed relevance to the geographer's task of interpreting the oikoumene in the contemporary world. 相似文献
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Jia Xia 《Engineering Geology》2005,78(3-4):209-214
The ancient gravel stratum near Nanjing, China, is a major stratum of Cenozoic age along the middle–lower reaches of the Yangtze River. This paper first presents a typical geological profile and material composition of the ancient gravel stratum, and then discusses its geologic origin, soil–rock-forming processes, engineering mechanical properties, and their relations. These analyses are useful for city planning, geotechnical engineering, construction, and characterization of the geological environment in the Nanjing area. 相似文献
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The ancient landslide has endured long-term slope evolution which results in its complicated material and special rock-soil properties. The risk of ancient landslide reactivation is substantially increasing due to the increase of intensified human engineering activities and the frequency of extreme weather events. Many ancient landslides have been reactivated all over the world and led to serious fatalities and severe damage to many important engineering facilities such as transportation and hydropower engineering projects. On the basis of the analysis of the research situation about the ancient landslides at home and abroad, the main research advances were summarized including the regional developing laws and recognizing of the ancient landslides, the mechanics properties of ancient landslide body and related sliding zone, reactivation mechanism of ancient landslides, reactivating process and modeling analysis of ancient landslides, early recognization of ancient landslide reactivation, etc. To meet the demands of disaster prevention and reduction, three key scientific issues were put forward to be solved: ①automaticaly establishing the methodology and identification criterions for recognition of ancient landslide; ②revealing the reactivation mechanism of ancient landslide based on a new strength theory; ③establishing the early rapid recognition method and predictive model for ancient landslide reactivation. Solving the above mentioned scientific theory and methodology will facilitate the planning and site selection of major projects as well as the disaster prevention and reduction in ancient landslide developing areas. 相似文献
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Cultural tourism routes can reveal and protect cultural tourism heritage by means of cultural tourism in the “time category” and the “space category”. The construction of an evaluation system for cultural tourism routes and the evaluation, scoring and grading of existing and potential cultural tourism routes are the key to the protection of heritage, history and culture along these routes, and the key to encouraging the standardization, branding and sustainable development of various formats on the routes. Yunnan cultural tourism routes are diverse and rich in resources, and their developmental foundation is good. However, the tourism development and cultural development activities occur along separate lines and there is a lack of unified management. Therefore, it is necessary to conduct research on information collection, information analysis, problem diagnosis and improvement of status in the local practices of Yunnan cultural tourism routes, and to guide the sustainable development of Yunnan cultural tourism routes. Based on the advanced experience of COE (Council of Europe), UNESCO WHC (United Nations Educational, Scientific and Cultural Organization, World Heritage Committee) and ICOMOS(International Council on Monuments and Sites), this paper comprehensively analyzes the decisive criteria for line evaluation by interpreting and summarizing the connotations of cultural tourism routes, and determines that the evaluation of cultural tourism routes should include lines. Five aspects―the theme, the participating subject, the object itself, related activities and multi-party value―are used to construct a five-component model. At the same time, based on the consumer utility function, a complete route evaluation and hierarchical system is constructed. Then, taking the Ancient Tea-horse Road cultural tourism route as an example and using the expert scoring method and the analytic hierarchy process, the actual scores and grades of the Ancient Tea-horse Road cultural tourism route are determined, and countermeasures and suggestions for its sustainable development are proposed. The paper also verifies the applicability and practicability of the evaluation system, and promotes and improves the feedback evaluation system. The aim is to at promote and widely apply the evaluation system of cultural tourism routes, realizing the transformation from individual cases to joint cases, and promoting the standardization and sustainable development of cultural tourism routes. 相似文献
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下蜀组在长江下游分布很广,与农副业生产关系密切,是许多大型工程建筑的地基持力层。虽然几十年来许多地层古生物学工作者做了大量的研究,使之成为晚新生界的典型层位,但对其成因和代表的环境等尚存在分歧看法。本文讨论一例五十年代可能发现于下蜀组底部的、近年来生境研究得十分清楚的生物化石,认为下蜀组沉积初期的环境可能是温湿、低平、多水域的,沉积成因类型可能是水成的。在生物证据不多的情况下,哪怕增加一点点说明问题的生物线索都显得异常珍贵,因为往往生物反映的环境面貌比较地全面和具体。 相似文献