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矿床产于区域性主干断裂旁侧、向斜轴部发育的断裂带中,严格受构造控制。混合岩化花岗岩与锡的形成、富集关系密切,是成矿的母岩。 相似文献
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实测了云南西部兰坪盆地云龙县城南沘江西岸下白垩统南新组剖面。通过野外实测资料以及岩石薄片的观察描述,综合分析了研究区南新组的岩石组合、沉积构造、剖面结构等特征,认为南新组自下而上主要为曲流河相和湖泊相,厚度较薄的土壤相常作为夹层与前两者交互出现。河流相可进一步识别划分出河道、边滩、河漫滩、天然堤等亚相;湖泊相则可分辨滨湖、浅湖、半深湖三种亚相;古土壤相可分为钙质土和潜育土两种类型。相序结构指示研究区在早白垩世南新组沉积期为一个由构造运动相对活跃到较为稳定的过程,岩相组合结合土壤相分析显示气候以亚热带干旱-半干旱为特征。 相似文献
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本文用振动光谱和电子顺磁共振谱研究了云龙锡矿锡石的谱学特征。根据红外光谱的谱形、吸收频率和吸收峰强度特征,将云龙锡矿锡石的红外光谱划分成两种类型:A型谱和B型谱。红外光谱特征的研究结合宏观地质特征的研究表明:氧化物阶段锡石的红外光谱为A型谱,硫化物阶段锡石的红外光谱为B型谱。随着锡石成分和结构的变化,锡石的拉曼光谱的谱型、振动频率也发生变化,反映了锡石的成矿条件的差异。云龙锡矿锡石的EPR谱研究表明,云龙锡石中含有呈类质同象进入锡石晶格的V~(4+),根据V~(4+)的稳定场研究,云龙锡石主要形成于相对碱性和偏还原的条件下。 相似文献
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兰坪盆地位于东特提斯构造域,是三江地区的重要成矿带和中国海相找钾的潜在地区之一。其中,云龙组发育厚层膏盐蒸发岩系,是盆地内的重要含盐层位。为了更好地理解兰坪盆地在特定时期的成盐成钾条件和钾盐成矿潜力,笔者等从地层年代、古气候环境以及碎屑岩和蒸发岩物源等方面对近些年来围绕云龙组的研究工作进行了总结梳理,获得以下主要结论和认识：① 多种同位素定年结果基本限定云龙组地层年代为白垩纪,但目前缺乏直接的精细年代学研究;② 古纬度演化表明盆地自晚三叠世以来长期处于副热带高压带内,云龙组沉积期间总体表现为炎热、高温特征,同时存在炎热干旱与温暖湿润交替的古气候环境;③ 云龙组蒸发岩物源以海水为主,而碎屑岩主要来自大陆上地壳再旋回造山带的长英质岩石,其碎屑锆石年龄谱可较好地与扬子、松潘—甘孜和南羌塘陆块以及盆地内部与周缘缝合带的岩浆岩对比;④ 兰坪盆地云龙组与蕴藏有中国大陆目前唯一固体钾盐矿的思茅盆地勐野井组具有可对比的沉积序列、地层年代、古气候和物源演化特征,指示了良好的海相成钾前景。下一步,开展建立在云龙组精细地层年代基础上的“气候—构造—物源”耦合关系研究,是深刻认识兰坪盆地钾盐成矿条件和资源潜力的关键。 相似文献
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YANG Jianwen LI Lei ZHANG Pengying YE Beng HE Yingwen CHEN Ji CHA Wenjian 《中国地震研究》2019,33(2):320-335
On the basis of the airgun source signals recorded by the stations from January, 2016 to June, 2017, we use cross-correlation detection technology to obtain the characteristics of the stable phase travel time change of each station. We used the Yunlong MS5.0 and Yangbi MS5.1 earthquakes as samples. According to regional characteristics, 13 stations with high signal-to-noise ratios and complete data were selected (including 3 fixed stations and 10 active source stations). They are divided into four regions, and on the basis of the GNSS baseline data, the characteristics of regional wave velocity changes before and after the earthquake are analyzed. The results show that the station phase travel time change and the regional stress characteristics represented by the GNSS baseline data have good correlation in the short-term. Due to different degrees of regional stress, there are differences in the travel time changes of different stations in the four regions. Before the Yunlong MS5.0 and Yangbi MS5.1 earthquakes, with regional stress adjustment, there is an upward trend in the travel time changes of related stations in the adjacent areas of up to 0.02s. The difference is that there are differences in the time nodes and duration of the travel time anomalies, and there is a reverse descent process after the Yangbi MS5.1 earthquake. There are different degrees of travel time fluctuations in the relevant stations before and after the two earthquakes, but the fluctuation range before and after the earthquake was small. Compared with the water level change of the reservoir, the adjustment of the regional stress is more likely to have a substantial impact on the travel time changes of the relevant stations. 相似文献
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云龙河地缝位于湖北省恩施市沭抚镇境内,区内特殊岩溶地貌等自然风光、生物物种多样性及土家族特殊的风俗习惯与文化等具有重要的旅游与科研价值。文章介绍云龙河地缝景区的特殊地貌景观与地质背景,提出对景区的保护措施。 相似文献
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