共查询到20条相似文献,搜索用时 10 毫秒
1.
《Journal of Structural Geology》1999,21(8-9):985-993
Displacement distributions along fault surfaces are a record of the processes of fault nucleation, slip, linkage, and propagation. Because several disparate processes can collectively influence the fault displacements, the relative contributions of these processes can be challenging, but are therefore necessary, to decipher. Continued advances in the mechanics of discontinuous slip surfaces in rock masses, when combined with appropriate field studies, should determine the roles of cohesive end zones, fault interaction, and propagation direction in shaping the displacement distributions. Studies of faults on other planetary surfaces provide a window into the role of a broad range of environmental conditions that can influence the faulting process. More inroads need to be made into traditional strain-based classes in structural geology so that mechanically sound concepts of fault analysis can become better utilized in the curriculum and by the non-specialist geological community. 相似文献
2.
进入21世纪的勘查地球化学 总被引:19,自引:5,他引:19
勘查地球化学是20世纪中叶诞生的年轻的地学分支,它仍处于发展的初期阶段。它的概念、理论与方法都还在不断发展与创新。本文回顾了勘查地球化学自诞生之日发展至今的一些重大历史事件,指出90年代勘查地球化学正面临重大转折,预测进入21世纪勘查地球化学将在解决人类资源与环境的重大问题上发挥巨大作用。其新的发展趋势应是以全球眼光和从地球演化全过程的观点来研究元素的分布、富集、分散与迁移。中国在这方面已走在全世界前面。中国勘查地球化学家应和国上有超前意识的学者一道作出巨大努力,以促成这种新的研究趋势加速发展,早日成为勘查地球化学在21世纪发展的主流。 相似文献
3.
论新时期地下水开发利用与管理的新使命 总被引:5,自引:0,他引:5
1994年本文作者曾在本刊发表文章 ,论述了地下水研究面临的历史转变。面对新世纪创造新辉煌的期盼 ,时过七年 ,在人类已跨入新世纪 ,面临创造新辉煌的形势下 ,地下水战线也应有新的作为、新的进展。本文论述了新时期在地下水开发利用与管理领域面临的应有转变和主要任务 :( 1)地下水开发与经营的指导思想要从比较放任 ,转变到高效利用与永续经营 ;( 2 )在三水统观统管联合运用中要把地下水作为珍贵后备水资源和抗旱的救命水加以对待 ;( 3)要把保护水质不受污染作为地下水管理的突出任务 ,要在重点地区建立地下水保护带 ;( 4)要建立和完善包括水位、水质动态观测在内的水环境综合观测网站 ,加强对地下水的全面观测 ;( 5 )要认真总结 5 0年来的地下水开发利用及管理工作 ,制定未来 30年的地下水事业发展规划 ;( 6 )要完善地下水开发利用保护法规 ;( 7)理顺地下水专业人才的培养渠道 ,认真培养地下水领域的高级专门人才 ;( 8)加强信息网建设 ,办好《地下水》刊物 ,在不断提高地下水科技水平的同时 ,重视科普宣传 相似文献
4.
6.
The exponential development of radio-astronomy methods (sensitivity, resolution, depth of surveys, etc) has led to the need for new methods aimed at distinguishing weak signals in the midst of numerous background signals, as has long been the case for radio astronomy at meter wavelengths. Centimeter-wavelength data accumulated with existing radio telescopes (such as the RATAN-600 reflector—the largest radio telescope in Russia) are presented, and expected problems for major new radio telescopes of the 21st century, such as the Square Kilometer Array, are discussed. The effectiveness of using certain tested methods to derive astrophysically important results through reasonable statistical processing of large datasets is shown. In experiments conducted with RATAN-600, these methods lead to an enhancement in sensitivity by an order of magnitude compared with the sensitivity of a resolving element. 相似文献
7.
8.
Asit K. Biswas Dr. 《GeoJournal》1991,24(4):341-345
Many arid and semi-arid countries are feeling water crisis already at present, and the problem will become more serious in the 21st century. Global water consumption will increase, 10-fold during this century, and the increasing trend will continue well into the 21st century. This Presidential Address to the International Water Reserves Association discusses the reasons for the water crisis, and the major water issues of the 21st century. Among those issues are water conservation and efficient use of water, water pricing and cost recovery, social and environmental considerations, institutional responses to better management, management of international water bodies and proper analytical frameworks. 相似文献
9.
Paleoanalogues of global warming in the 21st century 总被引:1,自引:0,他引:1
On the basis of landscape-climatic reconstructions for warming periods in the past, likely scenarios of future global warming
have been developed for various warming levels that might be reached during the current century. The paleoanalogue of global
warming by 0.7–1°C is the Holocene climatic optimum (5.5–6 ka B.P.) and that by 1.7–2°C is the last interglacial optimum (about
125 ka B.P.). The complex analysis concerning response of the principal ecosystem components to the expected warming signifies
that there will not be any shifts of vegetation zones during the 21st century; reconstruction will touch only the internal
structure of vegetable associations and broadening of interzonal ecotones. 相似文献
10.
11.
12.
Yong-Woong Kim 《GeoJournal》2001,53(1):5-15
In the early stages of economic development in Korea, national territorial planning was used as a policy tool to guide spatial structure and to provide physical infrastructure for urban and industrial development. Such a top-down approach was inevitable because Korea maintained the centralized political and government system until the early 1990s. Circumstances, however, have changed recently since the 1990s with progress in democratization and localization. In addition, forces of globalization are making significant impacts on the parameters of national territorial planning. Reflecting these changes in both internal and external conditions, the Fourth National Territorial Plan (2000–2020) has adopted a different approach from the past three territorial plans. This paper reviews the socio-economic background that necessitated such changes in approaches to national territorial planning. A major thrust of the Fourth Plan, a focus on emergent or anticipated planning issues in Korea, is discussed. Finally, the paper examines the rationale for long-term strategic planning in the highly fluctuating situation facing Korean society in the new century. 相似文献
13.
Ranching and the new global range: Amazônia in the 21st century 总被引:1,自引:0,他引:1
Robert Walker John Browder Cynthia Simmons Marcellus Caldas Sergio de Zen 《Geoforum》2009,40(5):732-745
This paper seeks to understand how the Brazilian Amazon, which many thought unsuitable for agricultural development, has yielded to a dynamic cattle economy in only a few decades. It does so by embedding the Thunian model of location rents within the regime of capital accumulation that has driven the Brazilian economy since the mid-20th century. The paper addresses policies that have created location rents in Amazônia, the effect of these rents on land managers, and the spatial implications of their behavior on forests. Thus, the paper connects macro-processes and structures to agents on the ground, in providing a political ecological explanation relevant to land change science. The policy discussion focuses on reductions in transportation costs, improvements in animal health, and monetary and trade reforms. To illustrate the impact of policy, the paper presents data on the geography of Amazonian herd expansion, on the growth of Amazonian exports, and on the profitability of the region’s cattle economy. It follows the empirical presentation with more abstract consideration of the spatial relations between cattle ranching and soy farming, and implications for deforestation. The paper concludes on a speculative note by considering the likelihood of forest transition in the region, given the transformation of Amazônia into a global resource frontier. 相似文献
14.
《Russian Geology and Geophysics》2014,55(5-6):534-543
The study provides an overview of key trends underlying the long-term and medium-term scenarios in the world energy outlook and prospects of fossil fuel resource depletion in the 21st century. 相似文献
15.
16.
17.
18.
面临21世纪的中国地下水模拟问题 总被引:43,自引:3,他引:40
本文在扼要介绍了我国地下水模拟的发展历程和现状后,着重探讨了面向21世纪中国地下水模拟发展中存在的几个带全局性的关键总是及对其对策; 相似文献
19.
二十一世纪初地质工作的若干思考 总被引:3,自引:0,他引:3
经济全球化、世界范围内经济结构的调整和高新技术的飞速发展,使21世纪成为一个充满机遇和挑战的世纪。按照我国经济社会发展的总体部署,从21世纪伊始,我国要实现“十五”计划、第三步发展战略所确定的目标,到21世纪中叶,人均国民生产总值要达到中等发达国家水平,人民生活比较富裕,基本实现现代化。这一目标必须在实施可持续发展的总体要求下实现,任务十分艰巨。面对新的形势,地质工作者承担着十分繁重的历史使命。如何做好新世纪初的地质工作,使地质工作既能满足国民经济建设和社会发展的需要,又能实现自身的健康发展,是… 相似文献
20.
生态环境地质学——21世纪新兴的地球学科 总被引:7,自引:2,他引:5
环境地质学研究人为地质活动所引起的灾害,地质环境学研究自然环境对人类的影响,两者是完全不同的学科。生态环境地质学应用生物学、环境学和地质学的原理和知识,解决由于人类利用和开发自然环境而引起的问题。生态环境地质学牵涉到分类学、生态学、生物化学、环境化学、沉积学、第四纪地质学和地球化学的研究,涉及到由于人为的地质作用而引起的元素重新迁移、重新富集和重新沉积的过程,对于生命和人类的健康是非常重要的,还涉及到国家和地区经济的可持续发展。生态环境地质学的研究包括下列内容:(1)生态环境地质可容负荷研究;(2)监测研究;(3)预警研究;(4)修复研究;(5)实验研究;(6)虚拟研究。 相似文献