Pore-water response on seasonal environmental changes in intertidal sediments of the Weser Estuary,Germany     

J. Sagemann  F. Skowronek  A. Dahmke  H. D. Schulz 《Environmental Geology》1996,27(4):362-369

In order to determine time-dependent changes in estuarine pore-water chemistry and flux variations across the sediment-water interface, sediment cores of an intertidal mud flat in the Weser Estuary were taken monthly over a one-year period. Sediment temperature, pH, Eh, Cl^–, O₂, NO ₃ ^– , and SO ₄ ^2– pore-water concentrations were measured and showed variations that relate to the changes of surface temperature and estuarine water composition. Fick's first law was applied to quantify diffusive fluxes from concentration gradients in the diffusive boundary layer and in the pore water. Total nitrate fluxes were calculated from flux chamber experiments. Diffusive oxygen fluxes increased from 5 mmol m^–2 d^–1 in winter to 18 mmol m^–2 d^–1 in early summer, while nitrate fluxes into the sediment increased from 3 mmol m^–2 d^–1 in winter to 60 mmol m^–2 d^–1 in early summer. Oxygen and nitrate fluxes into the sediment correlated linearly to sediment temperature. Sulfate fluxes increased from 0.5 mmol m^–2 d^–1 in winter to 10 mmol m^–2 d^–1 in August and September. Converted into carbon fluxes, the sum of these oxidants ranged from 10 mmol m^–2 d^–1 in winter to 80 mmol m^–2 d^–1 in summer. An estimation of the upper limit of the annual nitrate flux into the sediment showed that about 10% of the 250,000 t of nitrate discharged annually by the river may be decomposed within the inner Weser Estuary.  相似文献   

Geotechnical study of landslides resulting from a highway construction in Jordan   总被引：1，自引：0，他引：1  

Abdallah I. Husein Malkawi  Salah A. Taqieddin 《Natural Hazards》1996,13(1):1-15

Landslides in Jordan have caused numerous problems during the past 40 years. The most critical slides occurred during the period of 1991/1992 after exceptional heavy rain and snowfall. Many disastrous landslides occurred along the newly reconstructed international highway that links Amman, Jerash and Irbid. Causes for these slides are attributed mainly to the lack of a comprehensive overview and geotechnical understanding of the problem.Many investigators have been interested in this problem of finding an adequate solution to such landslides in Jordan either by using theoretical analysis or by using computer software to solve the slope instability problems. A detailed study was conducted at the Jordan University of Science and Technology to investigate the potential causes and measures for this problem. Seven landslides along the mountainous section of this international highway were reviewed. One of these landslides was thoroughly investigated using a three-dimensional computer program called JUST-SLOPE introduced at the Jordan University of Science and Technology campus. Results of this study indicate that landslides at this site could have been predicted had this technique been applied prior to the occurrence of this slide.  相似文献   

青藏高原东北地区现代降水中δD与δ^18O的关系研究   总被引：11，自引：0，他引：11  

章新平  姚檀栋 《冰川冻土》1996,18(4):360-365

根据对取自青藏高原东北地区部分降水样中氢氧稳定同位素比率的分析，得到沱沱河站的大气水线（ＭＷＬ）为：δＤ＝８．２５δ＾１８Ｏ＋９．２２‰，与全球平均ＭＷＬ的差别较小；德令哈、西宁站的ＭＷＬ分别为：δＤ＝５．８６δ＾１８Ｏ－２７．２８‰和δＤ＝６．９６δ＾１８Ｏ－３０．１９‰，均与全球平均ＭＷＬ差别较大。这主要归因于水汽源地的非平衡蒸发和凝结物在非饱和大气中降落时的非平衡蒸发。上述地区的过量氘Ｅｘｄ  相似文献   

极谱催化波测定天然水中微量锗的研究     

甘树才  曹淑琴 《世界地质》1996,15(3):101-104

系统研究了Ｇｅ－ＡＲＳ－Ｈ２Ｃ２Ｏ４－Ｖ体系报道极谱催化波的影响因素，测定了Ｇｅ－ＡＲＳ－Ｈ２Ｃ２Ｏ４三元配合物的配合比为１：２：１。实验初步证明了该体系催化波为具有吸附性质的平行催化波。本法检出限为０．１４ｍｇ．ｍＬ＾－１，相对标准偏差小于９．８９％，标准回收率为９３．７０％－１０９．０％，０－５０ｍｇ．ｍＬ＾－１的锗具有良好的线性关系。  相似文献   

波,流联合作用下的近岸海底沙波稳定性研究进展   总被引：3，自引：0，他引：3  

程和琴  王宝灿 《地球科学进展》1996,11(4):367-371

近岸海底大型沙波是一种研究较为薄弱的地貌单元，但它的迁移对港口、航道和海底电缆及钻井平台、输油管道等海洋工程设施建设造成的危害极大。在综述目前国内外有关研究文献的基础上，概要地介绍了作者提出的一种较为简便、省力和有效的沙波迁移速率和沙波稳定性定量评价和预测方法，旨在提高航道通航能力和海洋工程建设的灾害防治和预测能力  相似文献   

应力波与可滑移岩石界面间的相互作用研究   总被引：10，自引：1，他引：10  

卢文波 《岩土力学》1996,17(3):70-75

研究了应力波与用节理刚度系数描述的线性滑移岩石界面间的相互作用，给出了其透、反射波幅的一般表达式。通过应力波垂直人射界面时的具体分析，反映出岩石界面的节理刚度对应力波传播的重要影响，并揭示了岩石界面对应力波的高频滤波作用。  相似文献   

水压与钻孔联合爆破拆除大型地面煤仓          下载免费PDF全文

李玉民  赵锦桥  孙文进 《探矿工程》1996,(6):47-48

分析了水压与钻孔联合爆破的特点，给出了设计方法及参数，实践表明，在坚固筒体内构筑物拆除中应用该技术可取得安全，快速解体破碎和定向倾倒的良好效果。  相似文献   

X射线荧光测井的井液效应及其校正     

伍岳  林玉飞 《铀矿地质》1996,12(1):41-47

本文从Ｘ射线的性质，以及Ｘ射线与物质作用的机理出发，对井液效应进行了研究，并对其影响过程进行模拟。在理想井液模型上，推导出Ｘ射线活度与钻孔参数的数理关系。在此基础上，进一步研究得到了能适应野外多变情况的井液效应校正公式（ＣＢＷＥ）和方法。  相似文献   

双频梯度测量探查井巷漏水水力联系     

张宗岭 《物探与化探》1996,20(5):374-377,383

介绍一种利用双频仪解决矿区井巷巷道中漏水水力联系的原理和方法。双频梯度测量法有抗干扰能力强、分辨率高、仪器轻便等特点,实践证明应用效果很好。  相似文献   

Early Ordovician Sea Level Changes in South China and Their Worldwide Correlation     

Wang Xiaofeng 《中国地质大学学报(英文版)》1996,(1)

INTRODUCTIONTheoaf~ansed~arewidelydistributedinSouthetna,fromtheYanalCratondPborminnorthtocontinentalmarginofsoutheastern~insouth.ThePreSentpaperdiscussesmainlytheEarlyOrdovidan(thehoeofHirmtodontussimplex~tothebaseofNemopagngraciliszone,Wangatal.,1992)sealeVelchangeSandtheirworldwidecorrelationbasedonasyntheticalstudyofseqUenCe,bioshatiglaphyandaretratigl'aphy.Thisapproachwillfillinthe~instudyoftheOrdovidanofChina,andimprovethesu~ionandCO~ionofbio--,litho--andcbronostheigraphy.Mea…  相似文献