金沙江弧—盆系时空结构及地史演化

金沙江结合带是一条古特提斯弧后洋盆消亡的俯冲消减杂岩带。弧后洋盆形成于早石碳世－早二叠世。晚泥盆世晚期已具有雏型,早二叠世是洋盆扩张的鼎盛时期,早二叠世 晚期向西俯冲,在金沙江结合带中形成３条消减杂岩带。金沙江弧－盆系于志留纪末在早古生代变质“软基底”的基础上开始生成、发展和演化,经历了泥盆纪弧后裂谷盆地阶段（Ｄ）、早石炭世－早二叠世的弧后洋盆阶段（Ｃ１－Ｐ１）、早二叠世晚期－晚二叠世的洋壳俯冲消     

青藏高原天然气水合物资源预测

青藏高原分布着中国规模最大的多年冻土带,发育有良好的中、新生代海相地层及海相、陆相盆地,为高原天然气水合物矿藏的形成创造了有利条件。本文根据陆上天然气水合物的形成条件,从多方面讨论了水合物形成的可能性及其矿藏有利的分布位置,认为青藏高原完全有条件形成天然气水合物矿藏,最有利的分布区是藏北地区含油气盆地储集层的露头区。对水合物矿藏的研究不但具有资源意义,而且还有潜在的环境意义。     

青藏高原中部中生代OIB型玄武岩的识别:年代学、地球化学及其构造环境

目前对青藏高中部的蛇绿岩类型、形成环境及其深部地幔源区特征还缺乏很好的约束。在区域地质调查基础上,本文展示了青藏高原中部龙木错—双湖缝合带嘎错玄武岩、班公湖—怒江缝合带多玛、塔仁本玄武岩及那曲盆地西侧中生代玄武岩的单斜辉石Ar-Ar测年、锆石SHRIMP定年和地球化学及Sr,Nd,Pb同位素数据,以约束形成这些玄武岩的时代、构造环境和地幔源区特征。目前的数据表明:1羌塘双湖嘎错枕状玄武岩单斜辉石的中温坪年龄为232.5±2.4Ma,可能指示嘎错玄武岩浆活动发生于中三叠世晚期,班公湖—怒江缝合带多玛枕状玄武岩、塔仁本玄武岩浆活动时代大约在早白垩世中晚期(110Ma左右);2在这些蛇绿混杂岩带中的玄武岩显示OIB而不是MORB型地球化学特征,双湖嘎错玄武岩的地球化学特征介于峨眉山高Ti玄武岩与夏威夷碱性玄武岩之间;中晚三叠世那曲嘎加组玄武岩的地球化学特征非常类似于夏威夷碱性玄武岩;班公湖—怒江缝合带内的早白垩世多玛玄武岩和塔仁本玄武岩的地球化学特征在很大程度上可比于夏威夷碱性玄武岩;3双湖嘎错OIB型玄武岩可能形成于以增生楔为基底的裂谷环境而不是以洋壳为基底的大洋板内环境,那曲嘎加组OIB型玄武岩很可能形成于以弧内—弧前沉积物为基底的陆棚—陆坡环境下的裂谷背景,塔仁本和多玛OIB型玄武岩形成于以洋壳为基底的洋岛环境,这表明班公湖—怒江洋壳在大约110Ma时尚未彻底消亡,可能暗示班公湖—怒江洋盆的关闭时间明显晚于晚侏罗世—早白垩世早期闭合的早期认识;4地球化学指标显示青藏高原中部中生代玄武岩未受到地壳物质或很少受到陆下岩石圈物质改造,一些相对新鲜样品的Nd,Pb组成似乎可以用来代表其地幔源区的成分特点,其高206Pb/204Pb比值(>18.5)指示羌塘双湖中晚三叠世嘎错玄武岩、班公湖—怒江缝合带早白垩世洋岛玄武岩所代表的中生代特提斯地幔很可能不具“Dupal”异常。然而,由于研究程度的限制和缺乏更多的可靠数据,这种观察还需要进一步确认。     

青藏高原区域地质调查中几个重大科学问题的思考

在世纪之交，中国地质调查局部署的青藏高原近百幅1：25万区域地质调查填图，取得了一系列重要新发现、新进展、新成果，神秘的青藏高原地质构造、结构、组成、演化等问题得到了进一步的认识和理解。喜马拉雅奠基于5．5亿年左右的泛非造山事件基底上，历经奥陶纪至泥盆纪台地沉积，并于石炭纪末转化为印度板块北缘的弧后伸展裂陷带；雅鲁藏布江蛇绿混杂岩带曾是特提斯大洋南侧与冈底斯古岛弧带相对应的中生代弧后扩张盆地；冈底斯带曾经历了晚古生代岛弧造山作用；班公湖-怒江带两侧大量地质特征重大差异表明，班公湖-怒江带是冈瓦纳大陆北界，是印度(滇藏)地层区和华南(羌塘-三江)地层区的分界，是新元古代Rodinia超大陆解体后显生宙特提斯大洋俯冲、消减、碰撞，最后消亡的遗迹。     

基于MapObjects的水准测量数据预处理程序设计

采用了MapObjects地理信息系统控件及VB编程语言,开发了一个水准测量数据预处理程序,实现了自动搜索测量路线、判断路线闭合差是否超限和显示水准测量路线图的功能。     

Seasonal fluctuation of Myxobolus gibelioi (Myxosporea) plasmodia in the gills of the farmed allogynogenetic gibel carp in China

ＩＮＴＲＯＤＵＣＴＩＯＮＭｙｘｏｓｐｏｒｅａｎｓａｒｅｖｅｒｙｃｏｍｍｏｎｐａｒａｓｉｔｅｓｏｆｆｉｓｈ .Ｔｈｅｉｒｓｅａｓｏｎａｌｆｌｕｃｔｕａｔｉｏｎｓｉｎｐｒｅｖａｌｅｎｃｅａｎｄｉｎｔｅｎｓｉｔｙｏｆｉｎｆｅｃｔｉｏｎｗｅｒｅｄｅｓｃｒｉｂｅｄｂｙｓｏｍｅａｕｔｈｏｒｓ (Ｍｉｔｃｈｅｌｌ,1 989;Ｓｉｔｊａ ＢｏｂａｄｉｌｌａａｎｄＡｌｖａｒｅｚ Ｐｅｌｌｉｔｅｒｏ,1 990 ;Ｃｏｎｅ ,1 994 ) .Ｈｏｗｅｖｅｒ,ａｌｍｏｓｔｎｏｒｅｌａｔｅｄｉｎｆｏｒｍａｔｉｏｎｉｓａｖａｉｌａｂｌｅｉｎＣｈｉｎ…     

Construction of two selectable markers for integrative/conjugative plasmids in Flavobacterium columnare

Flavobacterium columnare, the etiological agent of columnaris disease, is one of the most important and widespread bacterial pathogens of freshwater fish. In this study, we constructed two artificial selectable markers (chloramphenicol and spectinomycin resistance) for gene transfer in F. columnare. These two new artificial selectable markers, which were created by placing the chloramphenicol or spectinomycin resistance gene under the control of the native acs regulatory region of F. columnare, were functional in both F. columnare and Escherichia coli. The integrative/conjugative plasmids constructed by using these markers were introduced into F. columnare G4 via electroporation or conjugation. The integrated plasmid DNA was confirmed by Southern blotting and PCR analysis. These two markers can be employed in future investigations into gene deletion and the pathogenicity of virulence factors in F. columnare.     

MULTI-ARC BASIN SYSTEM OF THE KUNLUN OROGENICBELT AND PAN-CATHYSIAN CONTINENTAL ACCRETION

After Rodinia supercontinent was disintegrated in Late Proterozoic, an ocean, namely, Tethys Ocean, occurred between Gondwana continental group and Pan-Cathaysian continental group from Late Proterozoic to Mesozoic. From Early Paleozoic to Mesozoic, Tethys Ocean was subducted toward Pan-Cathaysian block group, which results in backarc expansion, arc-land collision and forearc accretion. When the backarc basin expands and reaches the small oceanic basin, ophiolite melange will be generated. As accretion had already occurred in the south of the continental margin in the earlier stage, the succeeding backarc expansion and the frontal arc position were migrated toward south correspondingly. Therefore, multiple ophiolite belts and magmatic rock belts occurred, and show a trend of decreasing age from north toward south. As the continental margin was split and migrated toward south and reached a high latitude position, i.e., with the shortening and subduction of oceanic crust, the sedimentary bodies at high latitude was accreted continuously toward low latitude area together with the formation of oceanic island, mixing of cold-type and warm-type organism was generated. Moreover, blocks split and separated from Pan-Cathaysian or Gondwana continental group cannot traverse the oceanic median ridge and joins with another continental block. As a result, the Kunlun belt on the SW margin of the Pan-Cathaysian land was resulted from the multi-arc orogenesis such as the backarc seabed expansion, arc-arc collision, arc-land collision oceanic bed, and the continuous southward accretion process.     

The petrochemistry characteristics and petrogenesis of peraluminous granite in Tibet

There are 61 major peraluminous granitic bodies in Tibet (TPGs) along the south of the Bangong Co-Gêrzê-Amdo-Nujiang suture, whose lithology includes tourmaline granite, muscovite granite and two-mica granite. The TPGs have SiO₂ = 65.7%−79.52%, K₂O + Na₂O = 2.20%−12.51%, K₂O/Na₂O = 0.49−1.04 and A/CNK = 1.04−1.38. Al₂O₃ gradually decreases and the other oxides disperse with the increase in SiO₂. The rock series is mainly calc-alk series with high potassium. It has typical characteristics of strongly peraluminous granite. Based on the aluminum saturation index and QAP plots, the peraluminous granite plot is mostly within the continental collision granite (CCG) field, indicating that the peraluminous granites in Tibet formed in a continental collisional setting. Ab-Or-Q-H₂O phase diagram indicates the pressure of 0.5 × 10⁸−2 × 10⁸ Pa in TPGs, from which it can be deduced that the forming temperature was under 700°C. The TPGs mainly occurred at the collision stage between two continental crust plates, and the original magma is rooted in the remelting from the upper crust. It is the S-type granite in petrogenesis. The South Gandise belt and the Lhagoi Kangri belt have similar characteristics, suggesting that the two belts have the same magma source and the same tectonic setting. Translated from Acta Geologica Sinica, 2006, 80(9): 1329–1341 [译自: 地质学报]