Polarization Anomaly Characteristics and Prospecting in Ag-Pb-Zn Polymetallic Ore Deposit in Changtuxili Area of Inner Mongolia     

MA Yixing  HE Peng  LIU Zhujian 《《地质学报》英文版》2019,93(Z2):442-443

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Application of S Anomaly to Evaluation of Deep Metallogenic Potential     

TANG Shixin  MA Shengming 《《地质学报》英文版》2019,93(Z2):444-444

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Babu (SW China)‐Cao Bang (NE Vietnam) Ophiolite Complex: Implications for Tectonic Evolution between South China and the Indochina Block     

MA Tianshou  WANG Lixing  GE Guangfu  DAI Chunzheng  YU Hao 《《地质学报》英文版》2019,93(Z2):34-36

The convergence process between South China and the Indochina Block is still controversial. A large number of igneous rocks scattered along the current China‐Vietnam border provide a good opportunity to investigate the tectonic evolution. Babu ophiolites, cropping out in the southeastern Yunnan province (SW China), consist primarily of metaperidotite, serpentinite, pillow basalt (metabasalt), gabbro, metadiabase. Most of them are fault contacted and strongly sheared, especially between metaperidotite/serpentinite and metabasalt. U‐Pb zircon analyses yield an Early Permian formation age of ～278 Ma. Basalts and metagabbros show light rare earth elements (LREEs)‐depleted and heavy rare earth elements (HREEs)‐flat REE patterns, and large ion lithophile elements (LILEs)‐depleted primitive‐normalized spider diagrams without Nb‐Ta anomalies, which is similar to N‐MORB. Metaperidotites have low initial ¹⁸⁷Os/¹⁸⁸Os (0.122‐0.126) and γOs values, and indicate that they were derived from a depleted mantle source. Relative low (⁸⁷Sr/⁸⁶Sr)i and high εNd(t) values of basalts and metagabbros also support their DMM origin. The petrological, geochemical and isotope characteristics suggest that Babu ophiolites were N‐MORB‐type and represent remnants of an Early Permian oceanic crust. Mafic‐ultramafic rocks exposed in Cao Bang area (NE Vietnam) have recently been considered as dismembered Paleotethyan ophiolites instead of were genetically linked to the Emeishan Large Igneous Province. U‐Pb zircon analyses suggest an Early‐Middle Permian age (274 ±18 Ma) for the formation of ultramafic rocks. Both whole rock geochemistry and Cr‐spinel mineral chemistry show MORB‐like characteristics. Field observations suggest that Babu and Cao Bang ophiolite complex structurally overlie Middle‐Triassic deposits, and form a tectonic mélange zone. It developed from the subduction of a Paleotethyan subsidiary ocean basin between the South China and Indochina blocks until their collision..  相似文献   

Rb-Sr Isotopic Age of Sphalerites from Qingchengzi Stratiform Pb-Zn Ores and Its Implication for the Ore Forming Process     

MA Yubo  XING Shuwen  ZHANG Zengjie  WANG Yan  ZHANG Yong 《《地质学报》英文版》2014,88(Z2):996-998

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Characteristics of Makeng Iron Deposit in Southwestern Fujian Province,Implications for the Skarn Deposit of Magmatic Origin     

MA Shuai  DI Yongjun  ZHANG D  Vatuva ABSAI  YAN Pengcheng 《《地质学报》英文版》2014,88(Z2):576-577

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关中地区蒸发量变化特征分析          下载免费PDF全文

邓芳莲  妙娟利 《陕西气象》2017,(6):28-31

利用陕西关中地区22个代表站1980—2013年20cm口径蒸发皿所测的蒸发量资料,分析了关中地区全区及东、中、西部蒸发量的时间、空间变化特征及主要影响因子。结果表明:(1)关中全区及各区域月平均蒸发量最大值均出现在6月,最小值均出现在12月;东部月蒸发量明显大于中部和西部。(2)关中全区和各区域蒸发量均为夏季最多,春季次多,秋季第三,冬季最少,夏季和春季占年蒸发量的73%。(3)关中全区及各区域蒸发量年变化趋势基本一致,呈缓慢增加趋势,中部和西部增加趋势较东部和全区明显。(4)关中全区及各区域年际变化趋势是20世纪80年代、90年代蒸发量基本相当,年平均为1 000~1 400mm;21世纪以来蒸发量显著增加,年平均为1 600~1 930mm。(5)影响关中地区蒸发量的主导气象因子为气温、日照时数、降水量;蒸发量与气温、日照时数正相关,与降水量负相关。  相似文献   

ENSO与西北太平洋强TC相关关系年代际变化研究          下载免费PDF全文

陶丽  蓝玉峰  孔承承 《大气科学学报》2018,41(5):596-607

利用美国联合台风警报中心(Joint Typhoon Warning Center,JTWC),中国气象局(China Meteorological Administration,CMA)上海台风所,日本气象厅(Japan Meteorological Agency,JMA)的台风最佳路径资料以及美国NCAR/NCEP再分析资料等,深入研究厄尔尼诺—南方涛动(El Ni1o-Southern Oscillation,ENSO)与西北太平洋强热带气旋(Tropical Cyclone,TC),即1 min最大风速大于等于114 kn相关关系的变化。结果表明,ENSO与热带西北太平洋(Western North Pacific,WNP)强TC频数之间的相关关系存在明显年代际变化。在1960—1971年期间(前一阶段),强TC年频数与Ni1o3. 4(11月—次年1月平均)相关性较弱;而在1983—2014年期间(后一阶段)两者的相关性则为强的正相关。并且强TC的年频数、生命史以及生成位置在后一阶段El Ni1o和La Ni1a年之间的差异相比前一阶段都有明显的增大。进一步分析发现:热带太平洋海温异常(Sea Surface Temperature Anomaly,SSTA)的西移是造成后一阶段Ni1o3. 4指数与强TC年频数相关性提高的关键因素。在后一阶段的El Ni1o(La Ni1a)年,SSTA的西移使得WNP东南象限的相对湿度明显增加(减少),从而有利于(不利于) TC在此象限生成。又因为位于东南象限的TC比较容易发展成强TC,因此导致后一阶段的El Ni1o(La Ni1a)年有更多(更少)的强TC在西北太平洋的东南象限生成。  相似文献   

新形势下基层气象台如何做好公共气象服务   总被引：1，自引：0，他引：1       下载免费PDF全文

陈志超  杨家锋  妙娟利 《陕西气象》2017,(4):47-50

以山东省五莲县气象台为例,介绍当前县级气象机构综合改革试点单位公共气象服务的现状,分析了县级气象台公共气象服务在新时期的需求,提出基层公共气象服务的发展思路。  相似文献   

MDOS与OSSMO系统制作A文件的差异原因分析          下载免费PDF全文

张红娟  曾英  邓芳莲  妙娟利 《陕西气象》2016,(2):49-50

对比分析陕西省2015年1—4月MDOS与OSSMO两个系统制作的A文件,发现A文件不一致的原因主要为:当原始数据改动时,台站未按业务规定和流程在MDOS系统中做相应的修改,此类疑误信息占比为88.83%;两个系统特殊业务处理方式不一致造成A文件不一致的比例为6.06%;网络故障和参数设置错误原因占比分别为2.88%和2.23%。  相似文献   

Production of Pacific White Shrimp Polycultured with Swimming Crab at Different Densities,and Nutrient Budget in the Enclosure System     

ZHOU Yangen  BAO Weiyang  SU Yuepeng  HUANG Ming  WANG Xingqiang  YAN Binlun  MA Shen 《中国海洋大学学报(英文版)》2022,21(1):171-178

This study was to evaluate the effect of stocking densities on the nitrogen and phosphorus budgets for a polyculture of the crab Portunus trituberculatus and the Pacific white shrimp Litopenaeus vannamei.The shrimps(initial weight,0.012 g)were cultured at a density of 45 shrimp m^-2,and juvenile crabs(initial weight,0.024 g)were cultured at five densities of 0,3,6,9,and 12 crabs m^-2.The treatments were grouped as C0S45,C3S45,C6S45,C9S45,and C12S45,respectively.Water quality parameters,growth of shrimp and crabs,and nitrogen and phosphorus budget were measured.The results indicated that the shrimp performances in polyculture treatments C3S45 and C6S45 were superior to those in the crab-free treatment(C0S45).The crab in treatments C3S45 and C6S45 exhibited a significantly higher final mean weight and carapace width/length than those in treatments C9S45 and C12S45.The final size and survival of crabs had a negative correlation with the increasing crab stocking density.The contents of total phos-phorus and total nitrogen and the comprehensive contamination index values were higher in the C9S45 and C12S45 treatments than in the other treatments.The conversion ratios of nitrogen for crab and shrimp growth in treatment C3S45 were significantly higher than those in the crab-free treatment.These findings indicate that polyculturing shrimp with crabs at suitable densities can improve productivity,profitability,nutrient utilization,and the environmental quality.From the 60-day treatments,the optimal culture densi-ties were 3-6 crabs m^-2 and 45 shrimps m^-2.  相似文献