湖南仁里稀有金属矿田206号锂辉石伟晶岩脉地球化学特征及成矿时代

湖南仁里稀有金属矿田是中国近年来新发现的一处重要的花岗伟晶岩型铌、钽、锂等稀有金属矿产地,文章针对矿田含锂伟晶岩地球化学特征、成矿时代及其与花岗岩的关系,选取传梓源锂铌钽矿床内规模最大的206号锂辉石伟晶岩脉开展地球化学和白云母Ar-Ar定年工作,并与区内其他伟晶岩、花岗岩的地球化学特征、成岩时代对比分析.传梓源206号锂辉石伟晶岩属高分异稀有金属伟晶岩,形成时代为(135.4±1.4)Ma,岩石地球化学表现为高硅、高铝、低钙、相对富碱、钙碱性及过铝质特征;稀土元素总量很低,以轻稀土元素为主;微量元素富集Cs、Rb、U、Ta、Nb、Zr、Hf,相对亏损Ba、Ti,Zr/Hf、Nb/Ta比值低且集中.幕阜山地区稀有金属成矿可分为2期:第1期稀有金属成矿时代约145 Ma,与燕山早期岩浆活动有关;第2期稀有金属成矿时代135～125 Ma,为主成矿期,该期稀有金属伟晶岩与燕山晚期的二云母二长花岗岩存在成因联系,两者为同源岩浆连续结晶分异过程中不同阶段的产物.稀有金属富集成矿经历了岩浆-热液两阶段作用,Be、Nb、Ta、Li、Rb、Cs等稀有元素的富集多发生于岩浆结晶分异晚期,热液作用使Ta、Li、Rb、Cs再次富集.     

Flood-prone area mapping using machine learning techniques: a case study of Quang Binh province,Vietnam

Natural Hazards - Vietnam’s central coastal region is the most vulnerable and always at flood risk, severely affecting people’s livelihoods and socio-economic development. In...     

湖南仁里稀有金属矿田36号伟晶岩地球化学特征、成矿时代及其意义

位于幕阜山岩体西南缘的仁里稀有金属矿田是近年来华南地区新发现的一处重要花岗伟晶岩型稀有金属矿产地,铌钽矿体赋存于岩体内外接触带伟晶岩中,具有明显成矿分带性.文章选取仁里矿床岩体内接触带36号伟晶岩脉为研究对象,开展伟晶岩的地球化学及云母Ar-Ar年代学研究,探讨其与花岗岩围岩成因关系及岩体内接触带伟晶岩的成岩成矿时代,以丰富仁里矿田稀有金属成矿作用研究.研究表明,36号伟晶岩具高硅(w(SiO2)为72.87％～76.21％)、高铝(w(Al2O3)为13.69％～15.14％)、低钙镁铁、相对富碱(w(Na2O+K2O)为6.59％～8.33％)、(高钾)钙碱性及过铝质特征;微量元素总体富集Nb、Ta、Hf、U等高场强元素(HFSE),相对亏损Ba、Sr等离子亲石元素(LILE);稀土元素总量(ΣREE)13.95×10-6～71.63×10-6,轻稀土元素富集,重稀土元素亏损,具壳源特征.白云母Ar-Ar坪年龄为早白垩世(136.6±1.4)Ma,成矿作用发生于仁里矿田稀有金属大规模成矿的早阶段.地球化学及矿物学特征显示,36号伟晶岩与花岗岩围岩具有良好的演化关系,结合野外观察现象及成岩年龄,认为36号伟晶岩为花岗质岩浆侵位后残余岩浆结晶分异的产物,母岩为中粗粒片麻状黑云母二长花岗岩.     

硬土软岩滑坡近水平滑移的离心机模型试验研究

中国西北地区存在大量的新近纪硬土软岩滑坡灾害,为研究该类滑坡的变形特征,开展两组离心机模型试验模拟滑带劣化引起滑坡变形破坏的全过程,获取模型坡体土压及位移的实时变化曲线。研究表明,当软弱带强度降低时,硬土软岩滑坡的上部滑体呈块体状滑动,在快速运动滑动过程中,滑体呈现块状平移,不会彻底解体、液化;硬土软岩滑坡中前部出现水平应力集中,导致下伏滑带塑性流动变形,诱发其中前部上覆滑体的水平运动,并向滑坡后缘扩展,最终形成多级水平滑动。     

面向知识服务的地质资料管理转型研究

针对传统地质资料服务方式单一、数据共享困难等问题,提出了地质资料管理的转型方案.对面向知识服务的地质资料知识组织方式、知识检索以及知识管理理念如何指导地质资料服务等方面进行了探讨.以地质数据本体构建、基于关联数据技术的地质资料语义化组织以及基于地质大数据的知识检索模型搭建为转型手段,介绍了促进地质资料转型升级的语义化描...     

巴芬湾西部和格陵兰岛东部大气经向热量输送协同变化对夏季北极海冰的影响

利用欧洲中心气候再分析资料和美国国家冰雪数据中心北极海冰面积资料,分析了夏季北极海冰面积与前期大气经向热量输送年际变化的联系。结果表明：6月北半球中高纬大气的经向热量输送以瞬变热量形式为主,其中巴芬湾西部（B区）和格陵兰岛东部（G区）是瞬变热量向极区传输的两个通道,二者之间存在反位相的协同变化,且这种协同变化与夏季北极海冰面积变化密切相关。可能的机制为：6月,AD、AO和NAO三种北极大气环流型能够引起巴芬湾西部和格陵兰岛东部瞬变热量输送的协同变化,这种协同变化通过涡旋动力作用激发夏季极区大气表现为AD异常,同时影响途经区域的气温,从而通过热动力作用影响夏季北极海冰。将向极区输送的热量称为暖输送,从极区输出的热量为冷输送,则上述两个区域的瞬变热量协同输送可分为三种情况：B暖G冷、B冷G暖、B和G均冷,而B和G均暖的情况十分罕见。当B区向极区输入、G区输出热量时,有利于太平洋扇区和喀拉海的海冰偏少;当G区输入、B区输出热量时,利于喀拉海和拉普捷夫海海冰偏少;当B区和G区均输出热量时,利于波佛特海南部、喀拉海和拉普捷夫海海冰偏多,反之则相反。     

ALMA observations of the circumstellar envelope around EP Aqr

Atacama Large Millimetre/sub-millimetre Array(ALMA) observations of CO(1–0) and CO(2–1) emissions from the circumstellar envelope of the asymptotic giant branch(AGB) star EP Aqr have been made with four times better spatial resolution than previously available. They are analysed with emphasis on the de-projection in space of the effective emissivity and flux of matter using as input a prescribed configuration of the velocity field, assumed to be radial. The data are found to display an intrinsic axisymmetry with respect to an axis making a small angle with respect to the line of sight. A broad range of wind configurations, from prolate(bipolar) to oblate(equatorial) has been studied and found to be accompanied by significant equatorial emission. Qualitatively, the effective emissivity is enhanced near the equator to produce the central narrow component observed in the Doppler velocity spectra and its dependence on star latitude generally follows that of the wind velocity with the exception of an omni-present depression near the poles. In particular, large equatorial expansion velocities produce a flared disc or a ring of effective emissivity and mass loss. The effect on the determination of the orientation of the star axis of radial velocity gradients, and possibly competing rotation and expansion in the equatorial disc, is discussed. In general,the flux of matter is found to reach a broad maximum at distances of the order of 500 AU from the star.Arguments are given that may be used to favour one wind velocity distribution over another. As a result of the improved quality of the data, a deeper understanding of the constraints imposed on morphology and kinematics has been obtained.     

CNS+GNSS+INS船载高精度实时定位定姿算法改进研究

天文导航(CNS)、卫星导航(GNSS)和惯性导航(INS) 3种系统组合可提供高精度的定位定姿结果。实际工程中因INS长时间误差累积,以及系统硬件传输存在不可忽略的时间延迟,导致INS提供给CNS的预报粗姿态误差较大,恶劣海况下难以保障快速搜星,造成天文导航可靠性下降、姿态测量精度较低的问题。为此,本文提出了一种CNS+GNSS+INS高精度信息融合实时定位定姿框架,引入了等角速度外推措施,有效地解决了惯导信息延迟问题。通过高精度转台模拟恶劣海况下载体大角速度摇摆,验证了本文提出的改进算法的有效性。试验结果表明,该算法架构简单,性能可靠,显著提高了恶劣环境下星敏感器的快速、准确搜星能力,保障了三组合姿态测量的精度和可用性。     

Mining spatial associations between daily activities and health using EMA–GPS data

The geographical explicit ecological momentary assessment (GEMA) data collection platform provides extremely rich geospatial datasets and is very promising to gain behavior insights linking mobility, activities, and health. However, the task of analyzing these large datasets effectively is not straightforward, because they often involve a large multivariable dimension and rich qualitative data formats. Responding to the call for innovative analytic approaches in GIScience, this article advocates the use of spatial association rule mining (SARM) to extract frequent associations among daily activities, daily mobility, and health, including both physical health (e.g. pain) and mental health (e.g. happiness). This inductive mining approach works robustly with large datasets and is suitable for both qualitative and quantitative studies. A novel visualization technique to analyze the mined rules is also developed and presented.     

华南石炭纪中期白云岩地层分布及其形成模式

石炭纪是地质演化历史上重要的时期,发生了全球规模的海西造山运动,晚古生代大冰期（LPIA）达到峰值,全球海平面频繁波动,导致古气候和古环境的剧烈变化。在华南,石炭纪中期,浅水碳酸盐岩台地相区广泛发育一套白云岩沉积。本文系统总结华南3个主要碳酸盐台地内白云岩的厚度及时代,识别出白云岩时空分布的差异性。结合石炭纪中期全球气候环境特征,认为冰期兴盛引发了全球海平面下降,导致华南各沉积盆地形成利于白云岩化的环境,白云岩得以发育。而白云岩时空分布的差异性可能与各沉积盆地独特的构造演化以及不同成岩模式有关。中下扬子碳酸盐岩台地白云岩的形成模式主要为萨勃哈模式和成岩早期浅埋藏的渗透回流模式,形成相对较薄的白云岩沉积;中南部和西南部碳酸盐岩台地白云岩的形成模式为渗透回流模式,成岩规模较大,沉积较厚。