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861.
安徽铜陵朝山金矿床稳定同位素、稀土元素地球化学研究 总被引:14,自引:0,他引:14
朝山金矿床位于安徽铜陵狮子山矿田,属于矽卡岩型金矿床,侵入岩体为白芒山辉石二长闪长岩体。成矿过程包括矽卡岩阶段、石英-硫化物阶段和碳酸盐阶段3个主要成矿阶段。文章通过对朝山金矿床的氢、氧、碳、硫、硅同位素组成和稀土元素地球化学特征的研究,探讨成矿溶液中水、碳、硅和硫的来源以及成矿溶液的演化问题。研究表明,成矿热液早期以岩浆热液为主,随着成矿过程的进行,加入的大气降水比重越来越大,到晚期可能主要以大气降水为主。该矿床矿石中方解石的碳、氧同位素组成与矿区大理岩的碳、氧同位素组成明显不同,其δ^13 Cv-PDB、δ^18OV-SMOW值分别为-4.5~-5.3‰、13.9~14.0‰,与岩浆作用形成的CO2的碳、氧同位素组成一致,表明矿石中方解石的碳、氧来源于岩浆作用。硅和硫具深部岩浆或岩浆热液来源的特点。 相似文献
862.
Three sampling cross sections along the south path starting from the Tropics through the vapor passage in the Yunnan-Guizhou Plateau to the middle-low reaches of the Yangtze River, the north path from West China, via North China, to Japan under the westerlies, and the plateau path from South Asia over the Himalayas to the northern Tibetan Plateau, are set up, based on the IAEA (International Atomic Energy Agency)/WMO global survey network and sampling sites on the Tibetan Plateau. The variations, and the relationship with precipitation and temperature, of the δ^18 O in precipitation along the three cross sections are analyzed and compared. Along the south path, the seasonal differences of mean δ^18 O in precipitation are small at the stations located in the Tropics, but increase markedly from Bangkok towards the north, with the 51so in the rainy season smaller than inthe dry season. The δ^18 O sovalues in precipitation fluctuate on the whole, which shows that there are different vapor sources. Along the north path, the seasonal differences of the mean δ^18 O in precipitation for the stations in the west of Zhengzhou are all greater than in the east of Zhengzhou. During the cold half of the year, the mean δ^18 O in precipitation reaches its minimum at Uriimqi with the lowest temperature due to the wide, cold high pressure over Mongolia, then increases gradually with longitude, and remains at roughly the same level at the stations eastward from Zhengzhou. During the warm half of the year, the δ^18 O values in precipitation are lower in the east than in the west, markedly influenced by the summer monsoon over East Asia. Along the plateau path, the mean δ^18 O values in precipitation in the rainy season are correspondingly high in the southern parts of the Indian subcontinent, and then decrease gradually with latitude. A sharp depletion of the stable isotopic compositions in precipitation takes place due to the very strong rainout of the stable isotopic compositions in vapor in the process of lifting over the southern slope of the Himalayas. The low level of the δ^18 O in precipitation is from Nyalam to the Tanggula Mountains during the rainy season,but δ^18 O increases persistently with increasing latitude from the Tanggula Mountains to the northern Tibetan Plateau because of the replenishment of vapor with relatively heavy stable isotopic compositions originating from the inner plateau. During the dry season, the mean δ^18 O values in precipitation basically decrease along the path from the south to the north. Generally, the mean δ^18 O in precipitation during the rainy season is lower than in the dry season for the regions controlled by the monsoons over South Asia or the plateau, and opposite for the regions without a monsoon or with a weak monsoon. 相似文献
863.
864.
本文扼要介绍了PMOE行星历表研究当前的进展和工作 ,给出了PMOE2 0 0 2与DE40 5历表的比较。 相似文献
865.
866.
滑雪旅游开发布局影响因素与对策研究——以内蒙古自治区滑雪旅游开发为例 总被引:3,自引:1,他引:3
滑雪度假旅游成为欧美山地旅游开发的主要形式。近十几年来,山地滑雪旅游在中国迅速发展,并成为东北一些地方旅游产品的主打品牌。本文从滑雪旅游开发布局影响因素研究出发,通过对中国滑雪旅游市场的需求与供给这对矛盾的全面分析,对照发达国家的滑雪旅游开展状况,总结出中国目前比较缺乏中高端的旅游滑雪场所。据此,作者提出内蒙古应以发展中高端滑雪旅游作为切入点,以阿尔山国际滑雪场为主,建立山地型滑雪网络和滑雪天堂的旅游形象。这些重要结论,对内蒙古发展冰雪旅游业、突破冬季无旅游、延长旅游季节性等方面有重要的指导意义。 相似文献
867.
以纽约、洛杉矶、芝加哥为核心的美国三大都市旅游带,是伴随着美国城市化的形成而出现的。在美国三大都市旅游带的发展进程中,城市郊区化起了积极的联结与推进作用。某种意义上说,是郊区化的出现导致了多中心城市空间结构的形成和巨型城市带的兴起,进而促进了大都市旅游带的形成。比较美国三大都市旅游带与我国沿海大都市旅游带的发展,美国作为城市化高度发达国家,在城市化的进程中,城市空间规模的扩张、城市数量的增多和城市经济规模的扩大,推动了都市旅游带的发展。美国都市旅游带的生成特征与生长机理对我国沿海都市旅游带发展具有一定的启示。 相似文献
868.
在郯庐断裂带的安丘—夏庄箕状盆地的古近纪朱壁店组厚层冲积层中,发育许多震积岩层。它们是由地震液化、地震裂隙充填、振动塌落、地震断裂和地震沉陷作用而形成的震积岩组合。通过野外观测、室内鉴定和比较地震地质学研究,鉴别出了液化砂岩脉、液化砂岩墙、液化砂岩团块、裂隙充填砂砾岩墙、震塌岩、地震成因层内断裂及地震沉陷构造等震积岩构造。根据震积岩构造的特征和有关的研究成果,本文建立了由A、B和C3个震积岩单元组成的震积岩序列。水饱和砂受强烈振动液化作用形成A单元;随后,由砂砾层或砂层的地震裂隙充填和震动塌落而形成B单元;最后,由层内断裂作用及地面沉陷作用生成C单元;该序列的3个单元反映了厚层冲积物的地震作用全过程。 相似文献
869.
在黄河源区两岸的第二级阶地砂砾层和基座中发现了两种不同形态的冰楔假型群。一种是发育在阶地砂砾石层的冰楔假型,其特点宽而浅,底部边界呈圆滑锅状,深约0.5~0.9m,宽0.8~1.4m;另一种是发育在第二级阶地基座的基岩中,以窄深倒三角状为特点,其底部尖锐,深约0.7~2.0m,宽为0.3~1.0m。前者形成于全新世中期(5.69±0.43kaB.P.,5.43±0.41kaB.P.),后者形成于末次冰期的冰消期(13.49±1.43kaB.P.)。另外,还在洪积的砂砾石层中发现了规模较大的冻融褶皱(宽3~4m),其时代晚于39.83±3.84kaB.P.,也是末次冰期的产物。根据冰楔假型的对比研究,在全新世的中期(约5.5kaB.P.前后)和冰消期,黄河源区的降温幅度达6~7℃。尤其值得注意的是全新世中期的冰楔假型形成,表明了大暖期气温的不稳定性。 相似文献
870.
Origin of natural sulphur-bearing immiscible inclusions and H2S in oolite gas reservoir, Eastern Sichuan 总被引:1,自引:0,他引:1
Liu Dehan Xiao Xianming Xiong Yongqiang Geng Ansong Tian Hui Peng Pingan Shen Jiagui Wang Yunpeng 《中国科学D辑(英文版)》2006,49(3):242-257
Based on results of microscopic observation and laser Raman analysis about fluid inclusions, multiple special forms of immiscible
inclusions that contain sulphur, liquid hydrocarbon, bitumen, etc. were discovered in samples collected from the H2S gas reservoir-containing carbonates in the Lower Triassic Feixianguan Formation in the Jinzhu-Luojia area, Kai County, Sichuan
Province. Based on the lithology and burial history of the strata involved as well as measurement results of homogenization
temperature of fluid inclusions, bitumen reflectivity, etc., it is concluded that the H2S in the gas reservoir resulted from the thermal reaction between hydrocarbons in reservoir and CaSO4 in the gypsum-bearing dolostone section at the high temperature (140°C–17°C) oil-cracked gas formation stage in Late Cretaceous.
Thereafter, research on a great number of immiscible inclusions in the reservoir reveals that elemental sulphur resulted from
oxidation of part of the earlier-formed H2S and further reaction between sulphates, hydrocarbons and H2S in geological fluids in H2S-bearing gas reservoir at a temperature of 86°C–89°C and a pressure of 340×105Pa and during the regional uplift stage as characterized by temperature decrease and pressure decrease in Tertiary. Meanwhile,
gypsum, anhydrite and calcite formed at this stage would trap particles like elemental sulphur and result in a variety of
special forms of immiscible inclusions, and these inclusions would contain information concerning the complexity of the fluids
in the reservoir and the origin of H2S and natural sulphur in the gas reservoir. 相似文献