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41.
 A reasonable warmer winter index (IWWI) in the framework of the three equiprobability categories (i.e. warmer, normal and colder categories) is proposed based on the winter temperature data observed at 565 stations in China during 1956-2005, where IWWI is defined as the ratio of the station number of warmer category over the total number of stations. The results suggest that the trend of IWWI was consistent with that of the winter temperature on decadal time scale, and their rates of change were 10%/10 a and 0.4 ℃/10 a, respectively. It is found that only 13 warmer winter events in total were detected by IWWI over the past 50 years, and 85% of them occurred after 1986.  相似文献   
42.
Processes of initial collision and suturing between India and Asia   总被引:6,自引:0,他引:6  
The initial collision between Indian and Asian continents marked the starting point for transformation of land-sea thermal contrast, uplift of the Tibet-Himalaya orogen, and climate change in Asia. In this paper, we review the published literatures from the past 30 years in order to draw consensus on the processes of initial collision and suturing that took place between the Indian and Asian plates. Following a comparison of the different methods that have been used to constrain the initial timing of collision, we propose that the tectono-sedimentary response in the peripheral foreland basin provides the most sensitive index of this event, and that paleomagnetism presents independent evidence as an alternative, reliable, and quantitative research method. In contrast to previous studies that have suggested collision between India and Asia started in Pakistan between ca. 55 Ma and 50 Ma and progressively closed eastwards, more recent researches have indicated that this major event first occurred in the center of the Yarlung Tsangpo suture zone (YTSZ) between ca. 65 Ma and 63 Ma and then spreading both eastwards and westwards. While continental collision is a complicated process, including the processes of deformation, sedimentation, metamorphism, and magmatism, different researchers have tended to define the nature of this event based on their own understanding, an intuitive bias that has meant that its initial timing has remained controversial for decades. Here, we recommend the use of reconstructions of each geological event within the orogenic evolution sequence as this will allow interpretation of collision timing on the basis of multidisciplinary methods.  相似文献   
43.
Studies on the deep-seated xenoliths from global volcanoes reveal that the present petrological crust-mantle boundary between the lower crust and the upper mantle actually is a transitional layer from mainly mafic granulites to ultramafic spinel lher-zolites[1,2], i.e. a transitional zone distinctive from the seismological Moho[3]. Oceanic lithosphere crust- mantle transitional zone can be established from the study on the exposed ophiolites. However, as for the continental lithosphere, since …  相似文献   
44.
Shigenori  Maruyama  J. G. Liou  Ruyuan  Zhang 《Island Arc》1994,3(2):112-121
Abstract In the Triassic suture between the Sino-Korean and Yangtze cratons, the Dabie metamorphic Complex in central China includes three tectonic units: the northern Dabie migmatitic terrane, the central ultrahigh-P coesite- and diamond-bearing eclogite belt, and the southern high-P blueschist-eclogite belt. This complex is bounded to the north by a north-dipping normal fault with a Paleozoic accretionary complex and to the south by a north-dipping reverse fault with Yangtze basement plus its foreland fold-and-thrust sequence. Great differences in metamorphic pressure suggests that these units reached different depths during metamorphism and their juxtaposition occurred by wedge extrusion of subducted old continental fragments. These units were subsequently subjected to (i) Barrovian type regional metamorphism and deformation at shallow depths; (ii) intrusion of Cretaceous granitic plutons; and (iii) doming and segmentation into several blocks by normal and strike-slip faults. A new speculative model of tectonic exhumation of UHP rocks is proposed.  相似文献   
45.
在我国东部沿海修建地下水封石洞油库若干问题的探讨   总被引:2,自引:0,他引:2  
随着我国大陆架油、气田不断被发掘、开采,石油储运问题已指日可待。我国海岸线的基岩岸约占全长的2/3以上,其中,块状结晶岩体又占基岩岸的一半以上,这就给水封油库的布置提供了良好的基础。在油库的选择和兴建中,应加强对建库岩体和主要结构面、地应力及其分布的充分研究,以期能对洞库稳定问题、地下水位及水量的合理确定问题有所裨盖、  相似文献   
46.
唐爽  张晋瑞  姜灵  魏春景  初航 《地质学报》2023,97(3):705-724
位于内蒙古中西部地区的宝音图群,主要由云母片岩、斜长角闪岩、石英岩和大理岩等组成。其中云母片岩中发育典型的巴罗式递增变质带,目前对于该递增变质带的研究非常薄弱。本文对宝音图群的云母片岩开展了系统的岩相学、矿物化学、相平衡模拟以及锆石U-Pb年代学的研究。岩相学研究结果显示,三个云母片岩样品具有不同的峰期矿物组合,分别为石榴子石+白云母+黑云母+斜长石+石英,十字石+白云母+黑云母+斜长石+钛铁矿+石英,石榴子石+蓝晶石+白云母+黑云母+斜长石+钛铁矿+石英。此外,样品LS93和LS07存在晚期红柱石的叠加。相平衡模拟研究限定三个云母片岩的峰期温度压力分别为:577℃、0.73 GPa, 620℃、0.78 GPa和670℃、0.8 GPa,具有递增型特征,其峰期温度压力指示的地热梯度为18~20℃/km,为典型的中压相系;此外,三个样品的P-T轨迹均显示早期升温升压直至峰期阶段,随后降温降压的顺时针型,反映地壳加厚和后期抬升的演化过程。云母片岩中的锆石发育典型的变质边结构,变质边的Th/U=0.004~0.02,锆石U-Pb年代学结果显示该变质年龄为398±6 Ma,代表峰期或近峰期阶...  相似文献   
47.
From May 6 to June 2,1987,a huge forest fire broke out and raged for 28 days in Da Hinggan Lingregion in far Northeast China,causing heavy loss of life and property,which claims the biggest forest firedisaster in Chinese history.The fire drew attention of the whole of China and was also concerned by manyother countries.How were the meteorological satellites used in the detection of the forest fire?This paperelaborates the principles and methods of the fire detection using meteorological satellites,so that to sum upthe experience and to increase the ability of forest fire detection.  相似文献   
48.
??????????????????α?????GPS???ι???????????α?????????????????????????????????????????????????????????????????????????в??????????????????????????????????????????α???????????????????ι????????????α???????????????????Ч?????????????????????????????????Bayes?????????????????α?????????????????????????????????????????????????????????????????????????????????????????????Щ???????????????????????????????????????????????????GPS????????м??????????????????????????Ч???????????????????????????????????????  相似文献   
49.
搭载在中国新一代极轨卫星FY-3A上的微波湿度计对于大气湿度以及云雨分布特征具有较好的探测能力。利用其150GHz极化波段亮温和183-31GHz附近的水汽吸收波段亮温及其反演产品,对2008年7月22日襄樊特大暴雨中10:00-11:00强降水成因进行了分析。结果表明:襄樊10:00-11:00强降水产生时,微波湿度计5个波段亮温均处于低值区的大梯度带;极化比、极化差出现明显的大、小值分裂;微波湿度计的高频通道资料表明,襄樊处于深对流中心地带,正是这种深厚的对流系统导致了襄樊的强降水。  相似文献   
50.
巴黎能力建设委员会助力全球气候治理   总被引:1,自引:0,他引:1  
在全球气候治理中,能力建设涉及减缓、适应等多个方面.相对于发达国家,发展中国家在应对气候变化能力方面存在更多挑战,也亟待支持.巴黎能力建设委员会(PCCB)是《联合国气候变化框架公约》(以下简称公约)下属能力建设议题唯一的常设机构.在《巴黎协定》的授权下, PCCB于2016年成立,致力于解决发展中国家在实施和加强应对...  相似文献   
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