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金属矿床地质的发展——纪念《矿床地质》创刊十周年 总被引：6，自引：1，他引：6
矿床知识来自矿业。有关矿石成因的争论曾引导到野外现场实际观察的良好趋向。20世纪中叶以来,先后应用先进的设备仪器以及如同位素和流体包裹体等对矿床进行研究;这不仅扩大了成矿作用的视野,而且更加深入洞察矿石的习性。然而,有关矿石成因与来源问题的争论仍在继续;不过进入了更深的层次。欲探索矿石形成的客观规律,最合理的方法是结合野外的现场观察进行室内的仔细研究。 相似文献
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全球气候变化及其对社会与自然系统产生的影响已日益受到全世界各国政府与广大民众的关注。与天气和气候有关的灾害给人类生命财产造成的损失日益增大,社会与生态系统似乎变得日趋脆弱。人们关心刚刚过去的20世纪的天气与气候发生了什么变化,更希望了解未来的21世纪,人类居住的地球会出现什么样的气候情景。根据一些国家和地区的观测记录、研究成果以及科学家们对气候变化的评估与预测展望,对全球气候变化问题进行概括。首先阐明20世纪地区性气候变化的事实;并根据政府间气候变化委员会(IPCC)科学技术报告中关于20世纪全球气候变化进行的总结性评估以及对21世纪全球气候变化的预测,作为阐述过去与未来全球气候变化的主要依据。同时,还介绍了一些科学家对IPCC关于全球气候变化的结论所持的不同观点或质疑。还就气候变化对社会与自然系统可能产生的影响略作论述。 相似文献
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A.M. Korjenkov K.Sh. Tabaldiev Al.V. Bobrovskii Ar.V. Bobrovskii E.M. Mamyrov L.A. Orlova 《Russian Geology and Geophysics》2009,50(1):63-69
We report a macroseismic study of a ruined medieval building, a small caravanserai located along the caravan way from the Talas valley to the Chatkal and Fergana valleys in Kyrgyzstan. The ruins document several events in which the caravanserai was destroyed, apparently during earthquakes, and was rebuilt or repaired. The earliest earthquake occurred soon after the building was put up, about 400 years ago, according to radiocarbon dating of charcoal, and another event shook the area between 400 and 50 years BP. After being damaged in the ultimate earthquake, in the middle of the 20th century, the building was eventually abandoned. 相似文献
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海潮从长江口沿江上溯,可达内陆600km以上的潮区界,为世界大河所少见。中国古人就对这一现象有所感知,在一些文学著作与地方志中可找到长江潮区界及其变化的信息。在公元3世纪末、4世纪初,长江的潮波已越过柴桑(今江西九江);在公元9世纪早期,长江枯水期的潮区界已经退到九江的湓浦口;在13世纪最后的十几年,长江潮区界下移至皖赣交界的小孤山附近。从公元9世纪早期到13世纪晚期的470年间,潮区界下移了64 km,年均为0.136km/a。20世纪中叶以来的学者普遍认为,长江的潮区界又下移至安徽铜陵的大通镇。可见,长江干流在尚未被大型水利工程截断以前,长江潮区界持续向下游移动。在13世纪末至20世纪中叶的670年中,长江潮区界下移170km,年均为0.254km/a,速率几乎是前一时期的2倍。分析表明,潮区界下移速率和三角洲向海的淤长有关,还可能受气候变化的重要影响。对比发现,在长江干流大型水利工程开始蓄水的几年后、九江站流量约8440m3/s的特大枯水时期,潮汐引起的水位上涨影响可达九江附近、即1100多年前中唐时代的潮区界位置。 相似文献
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The tide can now propagate upstream for more than 600 km from the Changjiang River estuary to hinterland,which is rare in the world. In China,information and records reflecting tidal limit and its movement in the Changjiang River can be found from some ancient books,literary works and local chronicles. At the end of the 3rd and the beginning of the 4th century AD, the tide limit of the Changjiang River reached the upstream of Chaisang(now named Jiujiang in Jiangxi Province). At the early 9th century,the tide limit in the dry season retreated to the Penpukou in Jiujiang. In the last ten years of the 13th century,the tidal limit moved back to the Xiaogushan Mountain near the border between Anhui Province and Jiangxi Province. By the middle of the 20th century,the modern researchers generally agreed that the tidal limit retreated to Datong in Anhui Province. Before the main stream of the Changjiang River was cut off by large-scale water conservancy projects,the tide limit had retreated seaward continuously. From the 3rd decade of the 9th century to the last decade of the 13th century,the tide limit moved downstream 64 km during the 470 years,with an average annual rate of 0.136km/a. During the 670 years from the end of the 13th century to the middle of the 20th century,the tide limit had moved downstream 170 km,with an average annual rate of 0.254 km/a,almost twice as much as that of the previous period. We suggest the climate change accounted for the different retreat rate of the tidal limit between the two periods discussed. In addition,a recent study found that during the extremely dry periods,when the discharge of Jiujiang station was about 8440 m3/s,the tidal limit reached near Jiujiang. In the years when the water conservancy project on the main stream of the Changjiang River began to store water,the tide limit actually returned to the previous position of the middle Tang Dynasty,i.e. 1100 years ago. 相似文献
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地球物理学的回顾与展望 总被引：13，自引：0，他引：13
简要回顾了 2 0世纪地球物理学的发展。指出 2 0世纪是地球物理学发展的重要历史阶段 ,在此期间实施的一系列大型的全球性的研究计划深化了人类对地球本体的认识 ,提供了有关资源、能源、灾害和环境的形成、分布与发展的深层过程和空间信息 ,扩大了人类对地球整体研究的视野 ,激励了对空间和地球 (包括大陆和海洋 )以及生态环境之间耦合的研究 ,并在造福人类的过程中取得了辉煌的成就。展望了 2 1世纪地球物理学的发展 ,认为 2 1世纪的地球物理学必将担负起地球科学中一系列重大科学问题的先导角色。在深化对地球本体和日地空间及其相互作用的认识 ,量化地球内部各圈的耦合和深部物质状态及物质组成的错综组构 ,解决水、资源、环境 (包括空间资源环境 )等问题中做出贡献。 相似文献
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基于湿地生态水文研究文献计量分析,透视国内外有关湿地水文、生态水文和水资源等领域的重大研究计划和重要学术会议,系统总结了湿地生态水文学发展历程,可分为萌芽起步阶段（20世纪50年代至80年代）、研究探索阶段（20世纪90年代）和快速发展阶段（21世纪以后）3个阶段,列举了重要代表性研究成果,并重点阐述了湿地生态水文学研究进展;基于对国际湿地生态水文学发展历程、研究进展及热点的综合分析,未来湿地生态水文学研究主要向基于"多要素、多过程、多尺度"的湿地生态水文相互作用机理及耦合机制、气候变化对湿地生态水文的影响机理及适应性调控、湿地"水文-生态-社会"耦合系统互作机理及互馈机制和基于湿地生态需水与水文服务的流域水资源综合管理等方向发展。最后,以国家重大需求为导向,提出了未来中国湿地生态水文学优先发展方向及建议。 相似文献
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Glaciers and volcanoes have been the trademark of Iceland for centuries. The glaciers now cover ≅10% of the country and the volcanic regions are covered by lava flows every 5–10 kyr on average. Naturalists have concentrated on these two aspects, making notes on volcanic eruptions and traveling along the glacier margins ever since the first settlement of Iceland in the ninth century in some of the earliest episodes of geological research. Systematic studies of the glaciers began in the latter half of the 18th century. Even earlier, features such as striations and moraines were discovered and described in locations remote from the contemporary glacier margins. These features were interpreted as the effect of a much more extensive ice sheet on the island. At the beginning of the 20th century the discussion of the origin of sediments was unseparable from the age problem. From 1910 to 1950 very few new data were presented on the glaciation history of Iceland. A few sporadic publications either accepted or rejected previous conclusions. Systematic geological mapping of the country started in the wake of World War II encouraged by the acceptance of the plate tectonic theory in the late sixties. One of the most important results of this revived mapping effort was the identification of interbedded sediments interpreted as glacial deposits. Around 1975 Iceland was known in the geological literature for preserving more numerous glacial deposits than found elsewhere on land in the northern hemisphere. Over the last few years, systematic lithofacies analysis of sediments interbedded within lava flows has been conducted with the aim of delineating the earliest glaciation of Iceland and the periodicity of glaciation through the Tertiary and Quaternary. The results show a gradual growth of ice from south-east towards the north and west during the Pliocene-Pleistocene transition interrupted by periods of recessions and intermittent ice-free conditions. 相似文献
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The geochemist, Vladimir Ivanovich Vernadsky has only recently become recognised internationally, despite being regarded as one of the greatest names in science of the 20th century in his homeland Russia. There are several reasons for his lack of renown in the west, but mainly because his most important work “The Biosphere” was only fully translated into English in 1997. This book and the ideas it contains are now becoming regarded as one of the pioneering works of the last century. It defines the biosphere as a unifying, holistic concept for the earth system at a time when reductionism was the driving motivation in scientific research. Above all, for earth scientists, Vernadsky regarded life as the driving geological force. However another, as yet unpublished work (in three volumes) entitled “The History of Natural Waters” also deserves similar attention. This book explores many concepts in hydrogeology, geochemistry, geofluid circulation and especially biology in which water is described as an integral part of the biosphere. 相似文献
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Some of the best records of continental vertebrates from the Cretaceous of Europe come from Romania, particularly two well-known occurrences of dwarfed and morphologically aberrant dinosaurs and other taxa that lived on islands (the Cornet and Haţeg Island faunas). Substantially less is known about those vertebrates living in the more stable, cratonic regions of Romania (and Eastern Europe as a whole), particularly during the earliest Cretaceous. We describe one of the few early Early Cretaceous fossils that have ever been found from these regions, the tooth of a large theropod dinosaur from Southern Dobrogea, which was discovered over a century ago but whose age and identification have been controversial. We identify the specimen as coming from the Valanginian stage of the Early Cretaceous, an incredibly poorly sampled interval in global dinosaur evolution, and as belonging to Carcharodontosauridae, a clade of derived, large-bodied apex predators whose earliest Cretaceous history is poorly known. Quantitative analyses demonstrate that the Romanian tooth shows affinities with a derived carcharodontosaurid subgroup, the Carcharodontosaurinae, which until now has been known solely from Gondwana. Our results suggest that this subgroup of colossal predators did not evolve vicariantly as Laurasia split from Gondwana, but originated earlier, perhaps in Europe. The carcharodontosaurine diversification may have been tied to a north-to-south trans-Tethyan dispersal that took place sometime between the Valanginian and the Aptian, illustrating the importance of palaeogeographic ties between these two realms during the largely mysterious early–mid Early Cretaceous. 相似文献
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地球深部与表层的相互作用 总被引：3，自引：1，他引：2
板块理论和全球变化是20世纪地球科学中的2大突破性进展.进入21世纪,地球系统科学进入将这两方面结合起来,探索地球深部和表层系统的相互作用,即"固体地球动力学与行星循环(planetary cycle)"的新阶段.根据最近国际综合大洋钻探计划关于2013年后学术新方向的讨论,从俯冲带加工厂、大洋中脊与巨型火成岩省3个方面进行介绍,提出我国打破传统的学科界限、迎接新方向的建议. 相似文献
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20世纪地球物理学的重要成就和21世纪的发展前沿 总被引：16，自引：1，他引：16
20世纪是地球物理学取得辉煌成就的重要历史时期。在这关键性的百年里实施了一系列大型且具全球性的研究计划。 2 1世纪必将在对地球本体的认识和解决水资源、矿产资源、自然灾害和环境 (包括空间环境 )方面继续作出新的重大贡献。只有深入研究地球内部物质与能量的交换 ,不同圈层的耦合及其深部动力过程才能深入探索地球系统的发展。为此 ,文中讨论三方面的问题 :(1)地球物理学的发展进程及其战略意义 ;(2 ) 2 0世纪地球物理学领域主要的重大成就 ;(3) 2 1世纪上、中叶地球物理学的发展前沿和导向。 相似文献
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实验岩石学通过高温高压实验来模拟地球内部状态,正演研究矿物、岩石及其组分的物理化学行为,与天然矿物和岩石样品反演研究相互补充. 从20世纪初美国卡内基研究所建立地球物理实验室算起,实验岩石学已经历了100多年的发展,在认识地球内部状态和过程以及矿物和岩石成因方面发挥了重要作用. 我国实验岩石学研究开展约50年,进入21世纪以来在实验平台和创新性研究成果方面取得了显著进步. 在学科发展趋势方面,实验岩石学表现出以下6方面的特点:（1）新的高温高压实验技术不断涌现;（2）实验与分析测试技术高度融合;（3）实验模拟与计算模拟相结合;（4）从热力学平衡扩展到动力学研究;（5）从干体系扩展到对挥发分和流体的深入研究;（6）应用场景从固体地球扩展到类地行星. 通过进一步开发或改进高温高压实验技术,加强与分析测试技术以及计算技术的结合,实验岩石学有望在破解地球内部流体的性质和作用、地幔演化和岩浆分异、变质反应速率和机制、类地行星形成与演化等重要科学问题方面作出关键贡献. 相似文献
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20世纪西北地区降水量变化特征 总被引：143，自引：17，他引：126
利用英国东安哥拉大学气候研究中心(CRU)的Hulme最新的1900-1998年的全球降水量资料,分析了20世纪西北地区降水量的变化特征.结果表明,20世纪西北地区降水量处于下降通道中,后期略有回升;西北地区东部和西部降水量的年代际变化有相反的趋势;20世纪后期西北地区中西部降水量有明显的增多趋势,东部降水量持续偏少,干旱连年发生. 相似文献
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Valdimar Kristinsson 《Geoforum》1973,4(1):53-62
The Vikings and other settlers of Iceland immigrated during the 10th century not only for political reasons but also because they were seeking more spacious lands and thus a better standard of living. They found what they were searching for, and they and their descendants for some hundreds of years did live a relatively prosperous life. Eventually in the 15th century they suffered a series of setbacks. Poor living conditions were nothing unusual for the Icelanders in late medieval Europe, but this coupled with both the cool climate and the lack of timber for housing and heating, and for boat and shipbuilding made their lot an especially hard one. The 18th century was the darkest one in Icelandic history, and those acquainted with the problems doubted that the little nation could survive. But then, beginning in the 19th century and rapidly increasing in the 20th century, the urban evolution came about and brought with it a measure of progress. As a result, most Icelanders now live in towns, with over fifty percent living in Reykjavik and its environs. The effects of rural migration is one problem that persists in spite of the fact that the average income is now similar in most areas. 相似文献
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Mary Ann Levine 《Geoarchaeology》2007,22(1):49-66
Although native copper has attracted the scholarly attention of both geologists and archaeologists since the middle of the 19th century, it is only recently that native copper studies have benefited from interdisciplinary research. This history of disciplinary solitude can be traced to the professionalization of the two fields in the early 20th century, an era in which crossdisciplinary communication began to wane. The effects of this phenomena resulted in the development of a model of aboriginal native copper procurement by archaeologists that did not take into account the geological literature, which had long identified numerous—rather than a single—source of native copper in North America. In this article, the author discusses how this disciplinary solitude developed and how it resulted in the creation of a dominant model for native copper procurement that constrained our understanding of aboriginal lifeways for generations. The author also considers how increasing collaboration between geologists and archaeologists since the 1970s has led to the reevaluation of an old model of native copper procurement that has been uncritically accepted by most archaeologists for over a century and a half. © 2007 Wiley Periodicals, Inc. 相似文献