Study of Panjin Wetlands Along Bohai Coast(Ⅱ):Ecological Water Requirement of Shuangtaizi Estuarine Wetland     

WANG Tieliang  ZHOU Linfei  ZHAO Be  YANG Peiqi 《中国海洋大学学报(英文版)》2009,8(2)

Shuangtaizi estuarine wetland along the Bohai Sea coast,the biggest bulrush wetland in the world,has been listed in ‘The Record of Important International Wetland Conservation District’. Taking the year of 2 000 as an example,the minimum,the most suitable and the maximum ecological water requirement of Shuangtaizi estuarine wetland are calculated in this paper based on both ecological theory and Geological Information System technology. In addition,the remote sensing technique is adopted in the data acquisi...  相似文献   

兰州台潮汐形变观测结果与景泰6.2级地震     

唐九安  杨嘉文  周志宇  常千军  白亚平  强科瑜  曹文祥 《大地测量与地球动力学》1992,(3)

本文介绍了兰州形变台水管倾斜仪和石英伸缩仪1987年初至1990年底观测资料的调和分析结果和各分量的年变化,分析了M_2波γ和α因子的月重复精度及其对非潮汐变化的监测能力和本区当前的构造活动特征,对异常变化与1990年10月20日甘肃景泰Ms6.2级地震之关系作了初步探讨。  相似文献   

Use of Mosses as Biomonitors of Major,Minor and Trace Element Deposition Around the Largest Thermal Power Plant in Serbia          下载免费PDF全文

Mirjana Ćujić  Snežana Dragović  Marko Sabovljević  Latinka Slavković‐Beškoski  Milan Kilibarda  Jelena Savović  Antonije Onjia 《洁净——土壤、空气、水》2014,42(1):5-11

  相似文献   

河南箕山登封岩群变质中基性火山岩的地球化学及年代学研究   总被引：1，自引：0，他引：1  

薛良伟  原振雷  赵太平  陶自强 《地球化学》2005,34(1):57-65

对登封岩群 TTG杂岩区内的斜长角闪质表壳岩包体以及绿岩区的变质中基性火山岩对比研究表明 ,其主元素、微量元素、稀土元素和同位素地球化学特征等指示该区的变质中基性火山岩同时同源 ,具有由拉斑玄武岩向钙碱性玄武岩演变的趋势.登封岩群上下部 2件 Sm Nd等时线年龄极为一致 ,可以合并为一条等时线 ,年龄为 (2 512± 19) Ma,ε Nd(t)=2.40± 0.16.综合分析认为 ,箕山地区的登封岩群稍晚于嵩山地区 ,是在新太古代末期一个非常短暂的时间内形成的 ,形成于类似现代岛弧的构造环境.  相似文献   

Dynamics of the circulation in the Sea of Marmara: numerical modeling experiments and observations from the Turkish straits system experiment   总被引：4，自引：3，他引：1  

Jacopo?ChiggiatoEmail author  Ewa?Jarosz  Jeffrey?W.?Book  James?Dykes  Lucio?Torrisi  Pierre-Marie?Poulain  Riccardo?Gerin  Jochen?Horstmann  ?ükrü?Be?iktepe 《Ocean Dynamics》2012,62(1):139-159

During September 2008 and February 2009, the NR/V Alliance extensively sampled the waters of the Sea of Marmara within the framework of the Turkish Straits System (TSS) experiment coordinated by the NATO Undersea Research Centre. The observational effort provided an opportunity to set up realistic numerical experiments for modeling the observed variability of the Marmara Sea upper layer circulation at mesoscale resolution over the entire basin during the trial period, complementing relevant features and forcing factors revealed by numerical model results with information acquired from in situ and remote sensing datasets. Numerical model solutions from realistic runs using the Regional Ocean Modeling System (ROMS) produce a general circulation in the Sea of Marmara that is consistent with previous knowledge of the circulation drawn from past hydrographic measurements, with a westward meandering current associated with a recurrent large anticyclone. Additional idealized numerical experiments illuminate the role various dynamics play in determining the Sea of Marmara circulation and pycnocline structure. Both the wind curl and the strait flows are found to strongly influence the strength and location of the main mesoscale features. Large displacements of the pycnocline depth were observed during the sea trials. These displacements can be interpreted as storm-driven upwelling/downwelling dynamics associated with northeasterly winds; however, lateral advection associated with flow from the Straits also played a role in some displacements.  相似文献   

Cosmogenic radionuclides and mineralogical properties of the Chelyabinsk (LL5) meteorite: What do we learn about the meteoroid?          下载免费PDF全文

Pavel P. Povinec  Matthias Laubenstein  A. J. Timothy Jull  Ludovic Ferrière  Franz Brandstätter  Ivan Sýkora  Jozef Masarik  Juraj Beňo  Andrej Kováčik  Dan Topa  Christian Koeberl 《Meteoritics & planetary science》2015,50(2):273-286

On February 15, 2013, after the observation of a brilliant fireball and a spectacular airburst over the southern Ural region (Russia), thousands of stones fell and were rapidly recovered, bringing some extremely fresh material for scientific investigations. We undertook a multidisciplinary study of a dozen stones of the Chelyabinsk meteorite, including petrographic and microprobe investigations to unravel intrinsic characteristics of this meteorite. We also study the short and long‐lived cosmogenic radionuclides to characterize the initial meteoroid size and exposure age. Petrographic observations, as well as the mineral compositions obtained by electron microprobe analyses, allow us to confirm the classification of the Chelyabinsk meteorite as an LL5 chondrite. The fragments studied, a few of which are impact melt rocks, contain abundant shock melt veins and melt pockets. It is likely that the catastrophic explosion and fragmentation of the Chelyabinsk meteoroid into thousands of stones was in part determined by the initial state of the meteoroid. The radionuclide results obtained show a wide range of concentrations of ¹⁴C, ²²Na, ²⁶Al, ⁵⁴Mn, ⁵⁷Co, ⁵⁸Co, and ⁶⁰Co, which indicate that the pre‐atmospheric object had a radius >5 m, consistent with other size estimates based on the magnitude of the airburst caused by the atmospheric entry and breakup of the Chelyabinsk meteoroid. Considering the observed ²⁶Al activities of the investigated samples, Monte Carlo simulations, and taking into account the ²⁶Al half‐life (0.717 Myr), the cosmic‐ray exposure age of the Chelyabinsk meteorite is estimated to be 1.2 ± 0.2 Myr. In contrast to the other radionuclides, ¹⁴C showed a very large range only consistent with most samples having been exposed to anthropogenic sources of ¹⁴C, which we associate with radioactive contamination of the Chelyabinsk region by past nuclear accidents and waste disposal, which has also been confirmed by elevated levels of anthropogenic ¹³⁷Cs and primordial ⁴⁰K in some of the Chelyabinsk fragments.  相似文献   

Review of To Interpret the Earth, Ten Ways to Be Wrong, by Stanley A. Schumm and Les poussères saharienes. Cycle sédimentaire et place dans les environments et paléoenvironments désetiques, by G. Coudé-Gaussen. John Libbey Eurotext     

To Interpret the Earth  Ten Ways to Be Wrong   《Quaternary Research》1993,39(3)

  相似文献   

In situ chemical dating of tectonothermal events in the French Variscan Belt     

Eugène Be Mezeme  Michel Faure  Alain Cocherie  Yan Chen 《地学学报》2005,17(5):420-426

In situ U–Th–Pb geochronology on monazite using Electron Probe Micro Analyser has been performed on migmatite in the southern French Variscan Massif Central in order to decipher its complex history. After the Early Visean (340 Ma) nappe stacking, the Cévennes area experienced a regional migmatization already dated 330–325 Ma in northern Cévennes. In these rocks two monazite populations are recognized on the basis of petrology texture and geochemistry. The oldest monazite generation that appears as inclusion in K-feldspar is dated at 331 ± 4 Ma. This age complies with that of the crustal melting experienced by the Cévennes metamorphic series. The youngest monazite generation is interstitial and gives an age of 320 ± 5 Ma. A hydrothermal origin, coeval with the peraluminous magmatism that predates the formation of the Late Carboniferous Velay Dome is proposed as a working hypothesis to account for the formation of this second monazite generation.  相似文献   

Structural,AMS and geochronological study of a laccolith emplaced during Late Variscan orogenic extension: the Rocles pluton (SE French Massif Central)     

E. Be Mezeme  M. Faure  Y. Chen  A. Cocherie  J-Y. Talbot 《International Journal of Earth Sciences》2007,96(2):215-228

In the southern French Massif Central, the Rocles leucogranite of Variscan age consists of three petrographic facies; textural analysis shows that they experienced the same subsolidus deformation. New chemical U-Th-Pb dating on monazite yielded 324 ± 4 Ma and 325 ± 5 Ma ages for muscovite-rich and biotite-rich facies respectively. AMS-study results agree with petrostructural observations. The magnetic planar and linear fabrics, which correspond to the preferred orientation of biotite and muscovite, are consistent with the foliation and lineation defined by the preferred mineral orientation. This fabric developed during pluton emplacement. The accordance of this granite foliation with that observed in the host rock, suggests that the Rocles pluton is a laccolith, but its present geometry resulted from post-emplacement southward tilting due to the uplift of the Late Carboniferous Velay dome. Restoration of the primary geometry of the pluton and its country-rocks to a flat-lying attitude places the granite lineation close to the trend measured in other plutons of the area. This restoration further supports the interpretation of the Rocles laccolith as a pluton emplaced along a tectonic contact reactivated during the late-orogenic collapse of the Variscan Belt.  相似文献   

精河——伊宁铁路工程沿线气象参数设计值研究     

马淑红  戈峰 《沙漠与绿洲气象(新疆气象)》2000,23(6):17-20

根据精河－－伊宁铁路沿线１６个气象观测站近４０年（１９６１～１９９８年）的气象资料,建立了铁路沿线无资料地区Ａ区冬季（１月）平均气温预测模式为ＴＡ１＝－３３．５２０１＋０．２０３３７６φ＋２．３０８８．９Ｈ。以概率模式预测该铁路沿线气温、日照时数、２４ｈ（０８～０８时）最大降水量不同概率设计值。由此提示了精何－－伊宁铁路沿线冬季（１月）平均气温、日照时数、２４ｈ（０８～０８时）最大降水量、各历时最大降水量的分布规律。这一研究成果已应用于该铁路工程设计中,将气象要素概率模式应用于西部大开发铁路工程建设中,在这气候研究领域沿属首次。  相似文献