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川南煤系硫铁矿矿山地质环境现状分析 总被引:1,自引:0,他引:1
着重分析当前川南煤系硫铁矿的矿山地质环境现状,以及硫铁矿山普遍存在的一些地质环境问题,旨在引起社会各方面对矿山地质环境保护的重视。 相似文献
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新疆库鲁克塔格前寒武纪地块岩浆热事件及构造演化 总被引:3,自引:0,他引:3
库鲁克塔格地块是新疆前寒武系出露较全、保存较完好地块。通过对前人岩浆活动定年工作总结,进行岩石地球化学特征及构造环境分析,构建库鲁克塔格岩浆活动序列及构造演化格架。库鲁克塔格地块前后经历了4次构造岩浆运动,前3次较强烈,具区域变质、变形、岩浆侵入及地形隆起特征,第4次构造运动主要为隆起和沉积缺失。具体划分为7个阶段:古太古代陆核形成阶段(3.6~3.3 Ga);陆壳增生改造阶段(2.6~2.3 Ga);古元古代陆壳改造阶段(2.1~1.8 Ga);中元古代晚期—新元古代早期造山运动阶段(1.1~0.86 Ga);新元古代中期造山后伸展阶段(830~800 Ma);新元古代中晚期陆内裂解阶段(770~630 Ma)和显生宙造陆运动。 相似文献
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我国热带亚热带部分地区花岗岩和片麻岩中黑云母风化研究 总被引:5,自引:0,他引:5
综合应用X射线衍射、扫描电镜、透射电镜及偏光显微镜等技术手段研究了我国热带、亚热带部分地区花岗岩和片麻岩中黑云母的风化现象。结果表明,化学风化产物主要有黑云母/蛭石不规则间层矿物、水黑云母、蛭石、0.7nm埃洛石及铁的氢氧化物(氧化物)等。影响黑云母风化及次生产物形成的主要因素包括黑云母的晶体结构和化学成分、气候、风化壳母岩的矿物成分等。 相似文献
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地质调查和年代学资料表明,研究区内早燕山期侵入岩为一套中性—酸性双峰式岩系。通过岩石学、矿物学和地球化学方面的研究,对该岩系的成分演化特征、形成的构造环境进行了较细致的论述,得出该岩系是一个具不连续演化特点的钙碱性岩系,形成于破坏性板块边缘的张性环境,相当于Ⅰ型花岗岩系,属于环太平洋岩浆作用的内容。 相似文献
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Yangyang Feng Zuohai Feng Wei Fu Zhiqiang Kang Jian Jiang Along Guo Xi Wang Meng Feng Chunzeng Wang 《Resource Geology》2019,69(4):430-447
The Xinlu Sn‐polymetallic ore field is located in the western Nanling Polymetallic Belt in northeastern Guangxi, South China, where a number of typical skarn‐, hydrothermal vein‐type tin deposits have developed. There are two types of Sn deposits: skarn‐type and sulfide‐quartz vein‐type. The tin mineralizations mainly occur on the south side of the Guposhan granitic complex pluton and within its outer contact zone. To constrain the Sn mineralization age and further understand its genetic links to the Guposhan granitic complex, a series of geochronological works has been conducted at the Liuheao deposit of the ore field using high‐precision zircon SHRIMP U‐Pb, molybdenite Re‐Os, and muscovite Ar‐Ar dating methods. The results show that the biotite‐monzogranite, which is part of the Xinlu intrusive unit of the Guposhan complex pluton, has a SHRIMP U‐Pb zircon age of 161.0 ± 1.5 Ma. The skarn‐type ore has a 40Ar‐39Ar muscovite plateau age of 160 ± 2 Ma (same as its isochron age), and the sulfide‐quartz vein‐type ore yields an Re‐Os molybdenite isochron age of 154.4 ± 3.5 Ma. The magmatic‐hydrothermal geochronological sequence demonstrated that the hydrothermal mineralization took place immediately following the emplacement of the monzogranite, with the skarn metasomatic mineralization stage predating the sulfide mineralization stage. Geochronologically, we have compared this ore field with 26 typical Sn deposits distributed along the Nanling Polymetallic Belt, leading to the suggestion of the magmatic‐metallogenic processes in the Xinlu ore field (ca. 161–154 Ma) as a component of the Early Yanshanian large‐scale Sn‐polymetallic mineralization event (peaked at 160–150 Ma) in the Nanling Range of South China. Petrogenesis of Sn‐producing granite and Sn‐polymetallic mineralization were probably caused by crust–mantle interaction as a result of significant lithospheric extension and thinning in South China in the Late Jurassic. 相似文献
37.
Fei ZHENG Yuan YUAN Yihui DING Kexin LI Xianghui FANG Yuheng ZHAO Yue SUN Jiang ZHU Zongjian KE Ji WANG Xiaolong JIA 《大气科学进展》2022,39(4):546-552
In the first half of winter 2020/21,China has experienced an extremely cold period across both northern and southern regions,with record-breaking low temperatures set in many stations of China.Meanwhile,a moderate La Ni?a event which exceeded both oceanic and atmospheric thresholds began in August 2020 and in a few months developed into its mature phase,just prior to the 2020/21 winter.In this report,the mid?high-latitude large-scale atmospheric circulation anomalies in the Northern Hemisphere,which were forced by the negative phase of Arctic Oscillation,a strengthened Siberian High,an intensified Ural High and a deepened East Asian Trough,are considered to be the direct reason for the frequent cold surges in winter 2020/21.At the same time,the synergistic effect of the warm Arctic and the cold tropical Pacific(La Ni?a)provided an indispensable background,at a hemispheric scale,to intensify the atmospheric circulation anomalies in middle-to-high latitudes.In the end,a most recent La Ni?a prediction is provided and the on-coming evolution of climate is discussed for the remaining part of the 2020/21 winter for the purpose of future decision-making and early warning. 相似文献
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Yangtze Delta floods and droughts of the last millennium: Abrupt changes and long term memory 总被引:6,自引:1,他引:6
Summary Climate variability and flood events in the Yangtze Delta, which is a low-lying terrain prone to flood hazards, storm tides and typhoons, are studied in terms of a trend and detrended fluctuation analysis of historical records. The data used in this paper were extracted from historical records such as local annuals and chronologies from 1000–1950 and supplemented by instrumental observations since 1950. The historical data includes frequencies of floods, droughts and maritime events on a decadal basis. Flood magnitudes increase during the transition from the medieval warm interval into the early Little Ice Age. Fluctuating climate changes of the Little Ice Age, which are characterised by arid climate events, are followed by wet and cold climate conditions with frequent flood hazards. For trend analysis, the Mann-Kendall test is applied to determine the changing trends of flood and drought frequency. Flood frequency during 1000–1950 shows a negative trend before 1600 A.D. and a positive trend thereafter; drought frequency increases after 1300. The detrended fluctuation analysis of the flood and drought frequencies reveals power law scaling up to centuries; this is related to long-term memory and is similar to the river Nile floods. 相似文献