New achievements of 1:50 000 regional geological survey of three sheets including Jingnan in Guizhou Province     

HE Yongzhong  QIAO Weitao  ZHANG Housong  XIANG Kunpeng  HE Xiao  AN Yayun 《中国地质调查》2014,7(4):54-59

In order to find out the distribution of strata, rock, paleontology and Carlin-type gold desposits in Southwestern Guizhou Province, the authors developed the 1:50 000 regional geological survey of Jingnan sheet, Bajie sheet and Pojiao sheet using the new methods of digital geological mapping, modern geological theory and test methods. The results show that the strata graphical units were clarified and divided, and that 18 informal mapping units were established according to rock associations as well as animal and plant fossils. Marine reptile fossils--Ichthyosaurid were first found in shelf facies of late Early Triassic at Northwestern Youjiang Basin. Marine reptile fossils--Nothosaurus were also found in platform-edge reefs facies of Middle Triassic. 11 new mineralization occurrences were discovered, including 9 gold mineralization occurrences, 1 molybdenum mineralization occurrence and 1 collophanite mineralization occurrence. This paper also delineated three metallogenic prospective areas and one target area. The research can provide useful information for geological and mineral investigations and researches in this area.  相似文献   

Strontium isotopic geochemistry of Tianqiao Pb-Zn deposit,Southwest China     

Song Dou  Jishun Liu  Jiaxi Zhou 《中国地球化学学报》2014,33(2):131-137

Tianqiao carbonate-hosted Pb-Zn deposit, controlled by NW-trending F37 thrust fault and NW-trending Tianqiao anticline, is located in the eastern part of Sichuan-Yunnan-Guizhou （SYG） Pb-Zn metallogenic province, southwestern Yangtze Block, southwest China. Ore bodies in this deposit are hosted in the Devonian-Carboniferous carbonate rocks, and ore minerals include sphalerite, galena and pyrite, while the gangue minerals are dominated by calcite and dolomite. Using high-precision solid thermal ionization mass spectrometry （TIMS）, this paper reports the strontium isotopic compositions （0.7119 to 0.7167） of sulfide samples from the Tianqiao deposit in order to trace the origin of hydrothermal fluids. Compared with the country rocks, the calculated 87Sr/86Sr200 Ma values of sulfide range from 0.7118 to 0.7130, higher than those of the age-corrected Devonian to Permian sedimentary rocks （0.7073 to 0.7101） and the Middle Permian Emeishan flood basalts （0.7078 to 0.7039）, but lower than those of the age-corrected Proterozoic basement rocks （such as the Kunyang and Huili Groups, 87Sr/86Sr200 Ma=0.7243 to 0.7288）. This implies a mixed strontium source between the older basement rocks and the younger cover sequences. Together with geologic and previous isotopic evidences, we considered that the fluids＇ mixing is a possible mechanism for sulfide precipitation in the Tianqiao deposit.  相似文献   

Distribution and controlling factors of selenium in weathered soil in Kaiyang County,Southwest China     

Haili Ren  Ruidong Yang 《中国地球化学学报》2014,33(3):300-309

Selenium is one of the life-related elements. Survey reveals that selenium enrichment in the studied strata from Kaiyang County is considered to be closely related to the following factors： regional black shale series in Ni- utitang Formation of Early Cambrian, strong adsorption of organic matter （OM）, magmatic hydrothermal migrate along the deep fault, mixing and migration of hydrothermal brine, regional uranium mineralization and presence of a great deal sulfides. For selenium enrichment in its weathered soil and crops, the reason responsible is sele- nium-enriched bedrock, which provides material sources for weathering profile and is considered as the main con- trolling factor of selenium content in the soil profile. After leaching and migrates downwards, organic carbon （OC） adsorption, iron-manganese layer adsorption, geochemical barrier role, selenium content in different profiles, there are mainly three types of distribution features： bottom enrichment type, top enrichment type and no significant en- richment type. Comprehensive analyses find that selenium enrichment area is mainly distributed in the Machang, Gaoyun-Fengsan-Guanpo, Baimadong, Chuandong-Hefeng-Shaoshang and Longgang-Gaozhai region, etc. Besides, around the east part of the county, in Huali and Yongxing selenium are relatively scarce.  相似文献   

气象灾害：全人类的共同敌人     

陈伟 《今日国土》2010,(3):26-29

气候异常远远超出一般意义上的气候问题和环境问题,是关系到全人类的发展问题。当各种气象灾害频繁地侵扰生态环境本来就日益脆弱的地球,并且动不动  相似文献   

西南地区持续性气候事件的未来变化预估   总被引：1，自引：0，他引：1  

胡祖恒  李永华  胡跃文  王勇 《气象科学》2020,40(6):829-837

利用RegCM4.0区域气候模式单向嵌套BCC_CSM1.1模式输出资料进行连续积分获得的模拟预估数据,对西南地区未来2025-2055年在两种温室气体排放情景下持续性干期和持续湿期事件的特征及其相对于历史基准期的变化进行了预估分析。结果表明,最长持续干期和湿期在RCP4.5和RCP8.5两种情景下的变化趋势不一致,RCP8.5情景下的最长湿期和持续湿期事件的发生频次相较RCP4.5并没有大幅增加,而是比RCP4.5情景具有更高的年际变率特征。相对于历史基准期,两种情景下的最长持续性气候事件的日数和发生频次在西南地区的东南部区域显著性增加,而在川西高原地区显著减少。对于持续干期发生的频次FCDD和最长持续湿期而言,四川中部以及四川、云南和贵州三省邻接处在RCP4.5情景下表现为显著增加的区域在RCP8.5情景下转变为显著减少。未来几十年西南地区持续性湿期和干期的分布特征可能更加趋于不均匀。  相似文献   

纵向岭谷区生态系统变化及西南跨境生态安全研究   总被引：73，自引：0，他引：73  

何大明  吴绍洪  彭华  杨志峰  欧晓昆  崔保山 《地球科学进展》2005,20(3):338-344

位于我国西南、以纵向山系和大河为主体特征的纵向岭谷区,其地表主要自然物质、能量输送和人类活动等,表现出明显的“通道—阻隔”作用,产生了复杂多样的关联效应：使其成为亚洲大陆主要的纵向生物走廊、避难所和我国与东南亚重要的生态廊道,拥有北半球除沙漠和海洋外的各类生态系统,是全球生物物种的高富集区和世界级基因库,但其生态脆弱、灾害频发;主导了区内多民族沿河谷分布、在山间盆地聚居的“大分散、小聚居”格局,其社会经济发展地域分异大。因此,该区一直是地学和生物学等研究地表复杂环境系统与生命系统演变规律的关键地区,在全球具有不可替代性;同时,该区资源富集,短期开发行为多、环境退化加剧、贫困普遍,保护与发展矛盾极为突出,在西部具有典型性和代表性。  相似文献   

西南地区云水量与可降水量比值的分布特征和变化趋势     

林丹  王维佳 《干旱气象》2013,(3):482-485,504

采用1980～2009年云水量和可降水量的NCEP逐月再分析资料,通过统计分析,研究30a来西南地区（云南、贵州、讴庆、四川）云水量与可降水量比值的时空分布特征和变化趋势。结果表明：（1）西南地区年、季17孟水量与可降水比值均具有明显的地区性差异,由西北向东南递减,高值区位于川西高原;（2）云水量与可降水比值年内分布不均匀,从2月到8月逐渐减小,9月至1月逐渐增大,同时,季节差异较大,夏季最小,冬季最大;（3）30a来,整个西南地区年、夏季和秋季云水量与可降水量比值呈显著减少趋势。  相似文献   

不同观测资料在西南地区数值预报中的应用   总被引：1，自引：0，他引：1  

张利红  何光碧  屠妮妮 《高原山地气象研究》2013,(3):18-23

利用3.4版WRF同化与预报系统开展自动站、探空、GPS大气可降水量和云迹风资料的同化对比试验,了解现有业务中已同化观测资料在新版系统中的应用效果,确定资料同化优选方案,为西南区域中心数值预报业务改进提供参考。试验表明:(1)自动站资料测站多、分布不均,对初猜场低层要素调整作用大,会减小温度、相对湿度误差;探空资料站点少、垂直信息丰富,对初猜场各层误差减小均有贡献;云迹风资料垂直分布不均,集中在对流层中高层,因此对初猜场的最大调整集中在中高层,会减小位势高度误差;GPS测站少,被剔除的比例高,对初猜场调整作用很小;(2)单独同化试验发现探空、云迹风资料有助于该地区降水预报改进,而自动站和GPS资料对降水预报有负作用;(3)同时同化探空、云迹风资料有利于西南地区降水预报准确率提高,尤其对大降水中心预报。  相似文献   

黔金丝猴缘何独居梵净山     

张加常 《气象知识》2013,(6):38-40

在我国西南地区的贵州省铜仁市梵净山国家级自然保护区,居住着比“国宝”大熊猫还珍稀的世界濒危物种——黔金丝猴,其数量之少,被称为“世界独生子”。据科学考察,目前全世界黔金丝猴的数量仅有700多只。  相似文献   

中国西南地区东部秋季干旱的环流特征及其成因分析   总被引：2，自引：0，他引：2  

沙天阳  徐海明  邹松佐 《南京气象学院学报》2013,(5):593-603

利用1961--2010年NCEP／NCAR再分析资料和全国753站月平均降水资料,研究了我国西南地区东部秋季干旱的环流特征及其成因。结果表明,西南地区东部秋季降水存在明显的年际和年代际变化。其中,年代际变化主要表现为,在20世纪80年代中后期,降水存在由多转少的突变;降水量年际变化则与苏门答腊一西太平洋和热带东太平洋的海温分布存在很好的关系。当苏门答腊一西太平洋和东太平洋海温呈现“＋-”异常分布时,引起大气热源的异常,加强哈德莱环流,同时,在南海及孟加拉湾附近激发出异常气旋性环流,而西南地区东部则处于南海气旋性环流外围异常偏北气流控制,削弱了孟加拉湾的水汽输送,从而造成西南地区东部的干旱。通过大气环流模式NCARCAM3．0（Community Atmosphere Model3．0）的海温异常试验,验证了上述观测结论。  相似文献