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1.
沉积物硼(B)同位素组成可以反映其地质成因及经历的地质过程,因此在许多领域的研究中都有较为广泛的应用。通过对位于柴达木盆地碱山背斜顶部的SG-1b钻孔沉积物(7.3~1.6 Ma)水溶组分的B同位素研究,发现钻孔沉积物B含量在38.55~172.3μg/g之间,平均含量为87.6μg/g;δ~(11)B值的变化范围在3.61‰~16.26‰之间,平均值为10.65‰,B含量与δ~(11)B值具有一定的正相关关系。进一步分析表明,受到碱山背斜构造隆升以及晚新生代以来气候干旱化的影响,柴西古湖逐渐咸化萎缩,沉积环境以及碳酸盐含量、粘土矿物含量及其矿物组合等也在发生变化,B含量和δ~(11)B值自钻孔底部向上的逐步增加以及后期的急剧增加,与水溶离子含量以及矿物和粒度等的变化一致,这说明柴达木盆地晚中新世以来湖泊沉积物的B含量和δ~(11)B值可以很好地反映研究区气候和湖水的演化过程,共同指示了研究区自7.3 Ma以来气候的持续干旱化和湖水盐度的逐步增加,以及3.3Ma以来干旱化和湖水浓缩过程的加剧。 相似文献
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辽宁南部瓦房店金刚石矿是国内最大的金刚石矿产区,现已发现4处金刚石成矿带、120个岩体。其中金伯利岩岩管24个、岩脉89个、可疑岩体7个,累计提交1221万克拉储量,占全国金刚石储量52%。本文主要对该矿床的金刚石母岩—金伯利岩的岩石地球化学特征进行了全面系统分析,发现金伯利岩中MgO、NiO、Cr 2O 3的含量与TiO 2、Al 2O 3、Na 2O、K 2O、CaO、P 2O 5等偏碱性组分呈正相关关系;Ni、Cr、Co含量与金刚石含量呈正相关,而Ti、Zr、Ba元素含量与金刚石含量呈负相关。通过对瓦房店矿区金刚石中石榴石及单斜辉石包裹体、橄榄石- 石榴石矿物对、石榴石微量元素、尖晶石- 橄榄石等多种地质温、压计归纳得出金刚石矿的来源深度为150~210 km,压力5~7 GPa,温度1083~1261℃,在上述温、压条件下,结合岩浆化学组成,估算金伯利岩具有低氧逸度(fO 2=2. 913×1. 01325×10-6Pa)的特点。结合野外勘查工作,总结了该矿床的地质特征、控矿构造、矿体空间分布规律等要素,认为NEE向和NE向断裂控制着金伯利岩体的展布方向和矿体形态。脉状金伯利岩体一般呈NEE 70°~80°方向展布,严格受NEE至近EW向的密集节理或裂隙控制。提出了金刚石母岩—金伯利岩是由源于上地幔岩浆,在一定的封闭条件下,受构造与岩性双重控制,多期性的爆发与侵入交替作用所形成,并建立了具有较高氧逸度和较高密度的流变性软流圈,通过渗滤熔体浸蚀岩石圈形成金刚石的理想成因模式,希望为下一步找矿工作提供参考。 相似文献
4.
The Glycerol Dialkyl Glycerol Tetraethers (GDGTs) occur ubiquitously in a wide range of environments, such as loess, peat, lake, soil, and ocean, which vary compositionally in response to environmental changes, and provide a series of biomarker proxies for paleoenvironmental reconstruction. This paper introduced the structures and biological sources of GDGTs, and reviewed the recent progresses of the application of the GDGTs proxies in the paleoenvironmental reconstruction of loess deposits. The main progresses include: The GDGTs proxies have been widely used in reconstructing the climate changes in loess deposits, and have established the temperature changes of last 800 ka for the Chinese Loess Plateau; Temperature variations in Chinese Loess Plateau displayed significant correlation with the Northern Hemisphere insolation, which may be also regulated by the surface vegetation conditions; and In the Chinese Loess Plateau, the increase in monsoon precipitation during the last deglaciation significantly lagged behind the rise of temperature. However, problems still exist in the current studies. For instance, the GDGTs-based temperature is likely overestimated, probably reflecting the temperature of warm season, and relationships between GDGT indices and climate factors are still unclear. In the future, the development of new proxies and more accurate regional calibrations based on the separation of 6- methyl GDGTs are expected to provide more reliable paleoenvironmental information, and will provide essential evidence for the evolution of hydrothermal pattern and mechanisms behind climate changes in different regions. 相似文献
5.
河北怀安朱家洼矿区位于华北板块北缘中段太古宙、元古宙、中生代金银铅锌铁硫铁矿成矿带,为火山热液型金多金属矿。为查明该区成矿规律,明确找矿方向,在区内开展了水系沉积物测量、土壤地球化学测量等工作。通过对元素分布、元素相关性、元素异常等特征研究表明,Au、Mo为本区主成矿元素;各元素异常平面分布具有分带性,高温元素W、Sn、Bi异常位于骆驼山火山机构中心,中低温元素Pb、Zn、As、Ag等异常分布于火山机构边部及周边围岩中,成矿元素Au、Mo异常主要位于火山机构西侧围岩中。异常查证发现金钼矿化体2条,金钼矿化受火山机构和北西向构造带控制。依据成矿地质条件、地球化学异常及查证成果认为,朱家洼矿区Au、Mo成矿潜力大,火山机构西侧围岩区是该区重点找矿地段。 相似文献
6.
基于中国企业海外R&D投资数据和零断尾负二项回归分析方法,探讨了1998—2015年中国企业R&D国际化的时空格局特征,并从东道国角度分析影响其区位选择的主要因素。结果表明:研究期内中国新建海外R&D机构数量快速扩张;海外R&D投资区域分布广泛,呈现分散和集聚并存的特征;以华为为例分析了典型中国企业海外R&D投资的空间布局特征,认为目前华为海外R&D投资呈现集中布局在欧洲,零散分布在亚洲、美洲、非洲的空间特征,主要是由其以全球技术升级和满足多样化的市场需求等R&D国际化的战略动机所决定。回归分析结果表明,中国企业对发达国家和发展中国家进行R&D投资的影响因素有共同点但也存在一定的差异:① 现阶段东道国的R&D需求不是影响中国企业对其进行R&D投资的主要因素;② 代表中国与东道国经济往来密切程度的关联要素是影响中国企业R&D投资的重要决策因素;③ 发达国家吸引中国企业对其进行R&D投资主要是因其创新能力强、R&D资源数量多,而政策及制度供给是影响中国企业对发展中国家进行R&D投资的主要因素;④ 地理距离对中国企业R&D“走出去”的阻碍作用主要体现在对发展中国家的R&D投资中。 相似文献
7.
China’s tourism industry has witnessed rapid progress in recent years, and is now an important part of global tourism in dealing with climate change. Within a framework of Pressure-State-Response (PSR), this paper focuses on the emission reduction pressure, carbon emission status, and responses of stakeholders in China’s tourism industry. Findings include: 1) The central government’s strategy and rapid growth of the industry scale exert rising pressure on China’s tourism to reduce carbon emissions. 2) Carbon emissions of China's tourism account for 13%-14.6% of global tourism, and about 3% of China’s emissions overall. Chinese tourists’ per capita carbon emission is lower than half of the global level. 3) The Chinese government attaches great importance to energy-saving and carbon emission reduction. In the tourism industry, documents, standards and other regulative measures have been issued to ensure that business practitioners set up green operational and managerial systems. In the field of tourism transportation, China's high-speed rail, new energy vehicles, and urban shared bicycles, have developed very rapidly in recent years, and they have effectively reduced the carbon emissions in traveling. Furthermore, this paper finds that Chinese tourists already have awareness and willingness for low-carbon tourism. 相似文献
8.
研究尼日尔三角洲东部深水区块发现,整个盆地从陆向洋具有3个大的构造分区:伸展拉张区、过渡区和挤压逆冲区。伸展区以大型同沉积断层伴生大量滚动背斜构造为特征,过渡区发育大量泥底辟构造,挤压区以复杂的逆冲叠瓦构造为主。通过分析形成机理,揭示东部深水转换带上M研究区构造特征,按构造的演化特征将该区构造分为泥底辟型、冲断-泥底辟混合型、逆冲型3种类型,提出研究区内的圈闭主要以构造-岩性圈闭为主,为尼日尔三角洲盆地深水勘探提供新的理论指导。 相似文献
9.
This paper presents an experimental study on the performance of a shear-sliding stud-type damper composed of multiple friction units with high-tension bolts and disc springs. A numerical evaluation of the response reduction effects achieved by the stud-type damper is also presented. In dynamic loading tests, the behavior of stud-type multiunit friction damper specimens was investigated. Three different full-scale damper specimens, which were composed of five, six, or seven friction units with two or four sliding surfaces, were incorporated into loading devices for testing. The stud-type friction dampers demonstrated stable rigid-plastic hysteresis loops without any remarkable decrease in the sliding force even when subjected to repetitive loading, in addition to showing no unstable behavior such as lateral buckling. The damper produced a total sliding force approximately proportional to the number of sliding surfaces and friction units. The total sliding force of the stud-type damper can thus be estimated by summing the contributions of each friction unit. In an earthquake response simulation, the control effects achieved by stud-type dampers incorporated into an analytical high-rise building model under various input waves, including long-period, long-duration and pulse-like ground motions, were evaluated. A satisfactory response reduction was obtained by installing the developed stud-type dampers into the main frame without negatively impacting usability and convenience in terms of building planning. 相似文献
10.
The temporal and spatial distributions of Antarctic sea ice play important roles in both the generation mechanisms and the signal characteristics of microseisms. This link paves the way for seismological investigations of Antarctic sea ice. Here we present an overview of the current state of seismological research about microseisms on Antarctic sea ice. We first briefly review satellite remote-sensing observations of Antarctic sea ice over the past 50 years. We then systematically expound upon the generation mechanisms and source distribution of microseisms in relation to seismic noise investigations of sea ice, and the characteristics of Antarctic microseisms and relationship with sea ice variations are further analyzed. We also analyze the continuous data recorded at seismic station BEAR in West Antarctica from 2011 to 2018 and compare the microseism observations with the corresponding satellite remote-sensing observations of Antarctic sea ice. Our results show that:(1) the microseisms from the coastal regions of West Antarctica exhibit clear seasonal variations, SFM with maximum intensities every April-May and minimum intensities around every October-November; while DFM intensities peak every February-March, and reach the minimum around every October. Comparatively, the strong seasonal periodicity of Antarctic sea ice in better agreement with the observed DFM; and (2) microseism decay is not synchronous with sea ice expansion since the microseism intensity is also linked to the source location, source intensity (e.g., ocean storms, ocean wave field), and other factors. Finally, we discuss the effect of Southern Annular Mode on Antarctic sea ice and microseisms, as well as the current limitations and potential of employing seismological investigations to elucidate Antarctic sea ice variations and climate change. 相似文献