国际冻土工程研究进展——第五届冻土工程国际学术讨论会综述

2002年9月2～4日在俄罗斯雅库茨克市召开了第五届冻土工程国际学术讨论会,会议针对4个专题进行了讨论:土的物理和力学、多年冻土区工程建筑物的建筑和应用问题、开发有用矿床中的冻土问题和道路建筑.通过此文将国际上的一些最新研究动态给予介绍,给从事寒区工程研究的工作者以借鉴.     

Deposition of the Bear Gulch Limestone: a Carboniferous Plattenkalk from central Montana

The Carboniferous Bear Gulch Limestone of the central Montana Big Snowy Trough is a lithographic limestone analogous to the plattenkalk carbonates of the Mesozoic European/Middle Eastern Tethyan belt. It contains an excellently preserved chitinous and phosphatic marine fauna. Petrographic and field studies synthesized with palaeontological data provide insights into depositional history. Tectonic activity initiated development of small en echelon basins. Rims of these basins were sites of high primary productivity. Photosynthesis by subtidal cyanobacterial mats and algae caused in situ precipitation of micrite. Cyanobacteria and algae also provided a food source for benthic and nektonic organisms, which provided food for predators. Respiration in turn provided carbon dioxide for continued photosynthesis. Thus a balanced ecosystem evolved. Productivity in the water column used up available oxygen, resulting in dysaerobic to anaerobic conditions in the bottom waters and sediments. This plus high sedimentation rates of carbonate ooze transported downslope, aided in preservation of whole-body fossils. There are no likely modern analogues known for the Bear Gulch Limestone. However, comparisons with Mesozoic plattenkalke demonstrate that it is most closely analogous to those deposited in shallow water back-reef areas of the Tethyan carbonate platform, rather than to those deposited in the deeper water shelf-edge environment. This is in agreement with the water depth of roughly 40 m estimated for the Bear Gulch Limestone.     

9th International Symposium on Environmental Biogeochemistry

Reports

9th International Symposium on Environmental Biogeochemistry     

青藏铁路设计与建设——第六届国际冻土工程会议回顾

The 6^th International Symposium on Permafrost Engineering was successfully held in China in September 2004. About 150 scientists and engineers from 7 countries attended the symposium in Lanzhou on 5～7 September, and about 35 people from 6 countries participated in the field trip along the QinghaiTibet Highway/Railway on 8～13 September and the seminar in Lhasa on 14 September 2004. During the Symposium, the latest progress on permafrost engineering and the surveys, design and construction of the Qinghai-Tibet Railway were exchanged and inspected. Fifty-eight technical papers in English from the Symposium were published in the first volume of the Proceedings of the Symposium, as a supplement of the Journal of Glaciology and Geocryology, before the symposium. About 6 papers from the symposium are published in the second volume in the volume 27(1) of the Journal of the Glaciology and Geocryology, after the symposium. The Qinghai-Tibet Railway (QTR) under construction will traverse 632 km of permafrost, and the engineers are facing unprecedented engineering and environmental challenges. With the QTR under construction and to be completed in 2007, permafrost engineering has become the research focus of permafrost scientists and engineers in China. Many encouraging and promising achievements in permafrost engineering have been obtained during the past three years. However, there are still numerous engineering and environmental problems needing to be solved or resolved. In the discussions, some experts pointed out that methods, such as removal of snow cover on the embankments and toe areas, light-color embankments and side slope surfaces, awnings for shading the solar radiation, hairpin or tilted thermosyphons, could be applied to actively cool the roadbed of the QTR. Some new ideas on utilization of the natural cold reserves were proposed to protect the QTR permafrost roadbed from thawing. Many questions and answers on the survey, design, construction, operations, maintenance and environmental protection were exchanged in situ and in the Lhasa seminar with participation by some major railway designers, regulators and administrators.     

Jurassic--climate and biodiversity： The 6th International IGCP 506 Symposium

August was an intense and busy month for many geologists as the large 33rd IGC meeting was held in Oslo, Norway, from 6 to 14 August. Over 6,000 scientists from 113 countries contributed talks, posters and discussions at the IGC on a broad range of geo- logical topics. The congress was preceded and followed by as many as 30 fieldtrips coveting Scandinavian geology.     

为可持续利用而管理含水层补给—第四届国际地下水人工补给会议综述

１会议简况第四届国际地下水人工补给会议于２００２年９月２２－２６日在澳大利亚阿德莱德市举行。这是继１９８８年在美国加州Anaheim、１９９４年在美国佛罗里达州Orlando和１９９８年在荷兰Amsterdam召开的前３届会议之后,由国际水文地质学会（IAH）、联合国教科文组织（UNESCO）等组织主办的国际学术研讨会。来自２６个国家的１９７位正式代表出席了会议。其中,中国地质调查局１人、中国科学院３人。会议论文集收录了１００篇论文,反映了当代世界各国有关地下水人工补给研究的最新成果,由A．A．BALKEMA出版社在会前出版,…