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51.
山东沂沭断裂带早白垩世晚期恐龙足迹特征差异性*   总被引:1,自引:0,他引:1       下载免费PDF全文
近些年来,在山东沂沭断裂带南部地区(莒南、临沭、郯城和东海)的下白垩统上部大盛群中发现了大量的恐龙足迹化石,而这些化石反映的足迹类型、形态大小、足迹踩踏深度等方面都存在有差异性。研究发现,在足迹类型方面,莒南地区以兽脚类和鸟脚类恐龙足迹为主,临沭、郯城和东海地区以蜥脚类恐龙足迹为主。足迹大小方面,莒南地区的兽脚类足迹可划分为类型Ⅰ和类型Ⅱ两种类型,而东海地区的恐龙足迹主要属于类型Ⅱ,但是莒南地区大多数足迹的趾间角要小于东海地区的,这可能是由于兽脚类恐龙属种的不同所造成的;莒南地区鸟脚类足迹绝大多数要小于临沭地区的鸟脚类足迹;郯城地区的蜥脚类足迹较小,而莒南、临沭和东海地区大多数蜥脚类足迹的大小较为相似,个别临沭和莒南地区的蜥脚类恐龙足迹较大。足迹踩踏深度方面,临沭、东海和郯城地区的足迹相比莒南地区的足迹要稍深,这与足迹形成在不同湿度、黏度、颗粒度的沉积物表面上有密切联系。基于上述研究认为,在早白垩世晚期,沂沭断裂带内生活着种类繁盛,数量庞大的恐龙动物群,联系到沂沭断裂带东部诸城地区早白垩世早期地层中也发现有大量的以兽脚类为主的恐龙足迹化石,推断在早白垩世,沂沭断裂带及胶莱盆地当时为一个理想的恐龙生存、繁衍的栖息地。同时,山东早白垩世大量恐龙足迹化石的发现也为整个华北甚至东北亚地区晚中生代恐龙属种的分布、演化以及古地理研究提供了丰富的材料和信息。  相似文献   
52.
The tides and tidal energetics in the Indonesian seas are simulated using a three-dimensional finite volume coastal ocean model. The high-resolution coastline-fitted model is configured to better resolve the hydrodynamic processes around the numerous barrier islands. A large model domain is adopted to minimize the uncertainty adjacent to open boundaries. The model results with elevation assimilation based on a simple nudge scheme faithfully reproduced the general features of the barotropic tides in the Indonesian Seas. The mean root-mean-square errors between the observed and simulated tidal constants are 2.3, 1.1, 2.4, and 1.5 cm for M2, S2, K1, and O1, respectively. Analysis of the model solutions indicates that the semidiurnal tides in the Indonesian Seas are primarily dominated by the Indian Ocean, whereas the diurnal tides in this region are mainly influenced by the Pacific Ocean, which is consistent with previous studies. Examinations of tidal energy transport reveal that the tidal energy for both of the simulated tidal constituents are transported from the Indian Ocean into the IS mainly through the Lombok Strait and the Timor Sea, whereas only M2 energy enters the Banda Sea and continues northward. The tidal energy dissipates the most in the passages on both sides of Timor Island, with the maximum M2 and K1 tidal energy transport reaching about 750 and 650 kW m–1, respectively. The total energy losses of the four dominant constituents in the IS are nearly 338 GW, with the M2 constituent dissipating 240.8 GW. It is also shown that the bottom dissipation rate for the M2 tide is about 1–2 order of magnitudes larger than that of the other three tidal components in the Indonesian seas.  相似文献   
53.
This paper is a companion of a two-part papers on the development of a two-dimensional morphological model—CurWaC2D-Sed, based on next generation circulation solver. In this paper, the model developed in paper I is applied to the large-scale construction of near-harbor industrial zone with deep water harbor by reclamation in Caofeidian, Bohai Bay, which is a typical sandbar-lagoon bay-type tidal inlet system. Characteristics of tides, currents, waves and sediments in Caofeidian are firstly analyzed with field data from comprehensive field observations carried out in 2008. These data are then used for model calibration and validation, showing a good agreement between simulated results and field measurements for tides, currents and suspended sediments. The verified model is applied to study the effects of the construction of Caofeidian embankment and the on-going engineering scheme on hydrodynamics and sediment transports as compared with no constructions under three representative tide conditions and their combinations with normal and strong waves as well as on morphology evolution. The simulated results indicate that the present scheme leads to morphological changes in Caofeidian with acceptable rates of erosion and sedimentation. However, some attentions should be paid to erosion at offshore wharf in front of Caofedian foreland which may lead to potentially increasing landslide risks due to steep slope and sedimentation in Laogonggou creek.  相似文献   
54.
With the development of Chinese economies, air pollution is becoming more and more serious, which greatly affects the residents’ daily life and health. Meanwhile, China’s aging population is growing rapidly and bringing a number of social problems. We used the data of CHARLS and analyzed the relationships between air pollution and chronic diseases among the elderly in China. The results showed that air pollution had significant adverse effects on the health of the elderly, especially on diabetes and heart diseases. The subgroup analysis showed that female is more sensitive to air pollution than male, while different age groups are significantly sensitive to different chronic diseases.  相似文献   
55.
Through the analysis of original carbon isotopes in the blocks on the right bank of the Amu Darya River, Turkmenistan, it can be firstly concluded that the carbon dioxide (CO2) in the sour gas reservoirs belongs to the inorganic-origin gas. The origin of hydrogen sulfide (H2S) in the Amu Darya Right Bank Block is thermochemical sulfate reduction from the detailed analysis of hydrocarbon source rocks data, reservoir characteristics, vitrinite reflectance of organic matter, and sour gas content. Then, the factors affecting the distribution of sour gases in the Amu Darya Right Bank Block were investigated by the analysis of conventional sour gas distribution factors including geological structure, fracture and fault, caprock integrity, sedimentary facies, reservoir types, lithofacies, the source of sulfur and so on. The following basic findings were achieved: ① The basement rift in the study area is conductive to the distribution of CO2. The caprock integrity contributes to the concentration of CO2. The gas reservoirs in the biological dike reefs, patch reefs and overthrust zones usually have medium CO2 content. ② The geological structure and fracture caused the complexity of the distribution of H2S. The gypsum-salt rock in upper Jurassic-Tithonian is an important sulphur source, and the main hydrocarbon source rocks are also the major sulfur source of H2S gas reservoirs. Furthermore, the giant gypsum layers in the middle-upper Jurassic Callovian-Oxfordian and the upper Jurassic-Tithonian are conductive to preservation of H2S, and the small openings and holes in the reservoir is also correlative to the distribution of H2S. ③ The H2S in the study area is mostly distributed in the formations with the geothermal temperature of higher than 100 ℃. The open platform deep-water sedimentary facies are harmful to the formation of H2S. The patch reef and overthrust zones belong to the belts of low H2S content, however, the biological dike reef zones belong to the belts of medium-high H2S content. However, the origin and distribution factors of sour gases in natural gas reservoirs were obtained. At the same time, it was pointed out that more necessary and accurately quantitative research is still needed to determine the origin and distribution of acid gases in the Amu Darya Right Bank Block, Turkmenistan.  相似文献   
56.
Most of the current computing methods used to determine the magnetic field of a uniformly magnetized cuboid assume that the observation point is located in the upper half space without a source. However, such methods may generate analytical singularities for conditions of undulating terrain. Based on basic geomagnetic field theories, in this study an improved magnetic field expression is derived using an integration method of variable substitution, and all singularity problems for the entire space without a source are discussed and solved. This integration process is simpler than that of previous methods, and final integral results with a more uniform form. ΔT at all points in the source-free space can be calculated without requiring coordinate transformation; thus forward modeling is also simplified. Corresponding model tests indicate that the new magnetic field expression is more correct because there is no analytical singularity and can be used with undulating terrain.  相似文献   
57.
Strategic transformation of regionalization for agricultural comprehensive development (ACD) was presented by the Ministry of Finance of the People’s Republic of China (MOF) in 2014. The regionalization is the premise and basis of the sustainable development and improved competitiveness for agriculture. Based on the environmental resources related to agriculture, such as cropland, climate, water resources, terrain, geomorphology, patterns of the ACD projects, distribution of ecological planning, etc., we devised 13 indices using the geographic comprehensive regionalization method. The indices took into account a combination of dynamic and static, qualitative and quantitative, as well as agricultural and ecological factors. The strategic transformation of regionalization for the ACD in Ningxia Hui Autonomous Region of China was performed; seven types were included: prioritized regions, prioritized and restricted regions, protected regions, protected and restricted regions, restricted and prioritized regions, restricted and protected regions, and restricted regions. A further 24 subtypes were used based on locations and ecological zones. The regionalization results showed that prioritized regions were mainly in northern Ningxia, the most suitable area for agriculture. The protected and restricted regions were in central and southern Ningxia. In the central part, drought was the limiting factor for agriculture, and water conservation projects there should be supported. The ecological environment is fragile in southern Ningxia, so there is a need for ecologically sound agriculture to be developed in this region. Such regionalization could achieve two goals, namely agricultural conservation and eco-environmental protection. It was performed following the requirement for scientific regionalization to include three types of regions (prioritized regions, protected regions, and restricted regions), and was applied at the township scale in a provincial or autonomous region for the first time. The results provide both guidance for the strategic transformation of the ACD in Ningxia, and a reference for similar work in other provinces.  相似文献   
58.
安徽省庐枞盆地黄屯硫铁矿床地质特征及控矿因素分析   总被引:1,自引:0,他引:1  
黄屯硫铁矿位于庐枞中生代火山岩盆地的北东部边缘,矿体主要赋存于盖层龙门院组火山岩系与基底沉积地层接触部位的不整合面及其附近,成矿与次火山活动关系密切,属于次火山-热液矿床,成矿作用主要为热液充填交代方式。  相似文献   
59.
简要报道了新近首次在冀西北张家口尚义地区发现的恐龙足迹。野外地质调查发现,恐龙足迹赋存于尚义晚中生代盆地侏罗系—白垩系后城组顶部。恐龙行迹呈近东西向展布,由数十个足迹构成。初步研究表明,造迹者分别属于兽脚类和蜥脚类恐龙,由西向东行进。足迹中包括兽脚类足迹70余个,组成数个行迹;蜥脚类足迹15个,构成1列行迹。蜥脚类足迹特征显示其可能属于游泳状的行迹。华北北部土城子组/后城组发育于燕辽生物群—热河生物群更替演化时期(晚侏罗世—早白垩世早期),以往在该时期沉积物中罕见脊椎动物骨骼化石。近年来华北北部土城子组/后城组中频繁发现的恐龙足迹表明,燕辽生物群—热河生物群更替演化时期发育着以恐龙为代表的脊椎动物群。该发现将有助于进一步了解土城子组/后城组沉积时期恐龙属种的多样性及其生物古地理环境。晚侏罗世—早白垩世早期沉积古地理和古生态环境及其与恐龙动物群发育的研究有助于揭示陆地生物群更替演化和环境的关系。  相似文献   
60.
An abrupt ice and snow storm disaster which occurred in the spring of 2008 se-verely destroyed forests over a surprisingly large portion of southern China.A transect crossing Jinggang Mountain-Jitai Basin-Yushan Mountain-Wuyi Mountain was selected as the study area.The authors integrated field data collected in two field surveys to analyze the impacts of the disturbance on forests.The following results were obtained.(1) The extent of damage to plantations along the transect decreased in the order of slash pine > masson pine > mixed plantation > Chinese fir.Slash pine is an introduced species from southern America which is characterized by fast growth,low wood quality and rich oleoresin,and showed a damage rate of 61.3% of samples,of which 70.4% cannot recover naturally.Masson pine is the native pioneer species of forests with harder wood,and 52.5% were damaged due to turpentine,of which 60.9% cannot recovery naturally.Chinese fir is a local tree species and samples showed a rate of 46% and a relative rate of 32.5%,lower than the mixed plantation.(2) From west to east along the transect,we can see that evergreen broad-leaved forest of the western transect on Jinggang Mountain showed the lightest damage extent,and a Cryp-tomeria plantation at an altitude of 700 m was severely destroyed while Chinese fir showed light damage below 700 m and relatively severe damage above 900 m.Masson pine and slash pine in the central transect in Jitai Basin were damaged severely due to turpentine ac-tivities,and closed natural secondary deciduous broad-leaved forest was damaged severely due to high ice and snow accumulation on intertwined shrubs.Masson pine aerial-seeding plantations below 400 m along the eastern transect in Xingguo and Ningdu counties were nearly undamaged for small tree sizes,and Chinese fir at 500-900 m altitude showed a lighter damage extent.However,masson pine which was distributed above 400 m and planted in the 1960s,was severely damaged due to turpentine.  相似文献   
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