内蒙古呼伦西白地区铌稀土多金属矿成矿特征及找矿标志     

胡二红  贺中银  张善明  吕新彪  阮班晓  赵鹏彬  孙浩  纪鹏飞  何世明  苏波  刘婷 《中国地质》2020,47(2):300-314

北山成矿带东缘的内蒙古呼伦西白地区近年来发现了多处铌稀土矿床(点),矿床(点)产于二叠纪二长花岗岩外接触带上,矿体赋存于滨浅海相碳酸盐岩-变碎屑岩内,其形态、产状、规模受构造-岩浆活动控制,并与磁异常对应,其中灰石山东北铌稀土矿区Nb2O5品位0.02%～0.56%、平均0.11%,REO品位0.13%～2.63%,平均0.93%,辉森乌拉西铌金矿区Nb2O5品位0.01%～0.1%,与白云鄂博Nb-REE-Fe超大型矿床特征类似,成矿潜力巨大。结合区域地质背景及铌稀土多金属矿成矿特征,初步认为区内该类型矿床的找矿标志为:二叠系滨浅海相碳酸盐岩-变碎屑岩地层、构造挤压形成的虚脱空间或韧-脆性转换部位、二叠纪二长花岗岩外接触带、放射性异常梯度带-磁异常位置、岩石蚀变(褐铁矿化、硅化、碳酸盐化等)和石英细网脉发育地段。对该地区铌稀土多金属矿成矿特征和找矿标志的研究有利于拓展北山地区三稀矿产的找矿思路,也可为此类矿产的找矿方向提供借鉴。  相似文献   

2007-2016年四川省土壤干旱时空动态分析     

陈艾琳  戴晓爱  张诗琪  周旋 《山地学报》2020,38(1):31-41

四川作为农业大省,旱灾是导致农业减产最主要的因素。通过遥感和GIS手段进行四川省土壤干旱程度的时空分析,提高干旱的空间可视化程度,加强干旱监测的时效性尤为重要。本研究基于四川省2007—2016年逐季度的MODIS数据和1961—2011年40个气象站的月降水资料,采用温度植被干旱指数(TVDI)计算得到四川省干旱等级分布情况,辅以标准化降雨指数(SPI)进行相关性分析,并通过线性回归、反距离权重空间插值、GIS空间分析模型重建等方法,分析近十年来四川省地区以季度为时间尺度的土壤干旱时空变化特征,制作各时相土壤干旱分布图展示其微变化。结果表明:(1)在月时间尺度上,SPI-1与TVDI呈中等至强负相关关系,即TVDI值越小,SPI值越大,干旱程度越轻;验证结果表明TVDI都能够较好地对四川省的干旱空间分布状况进行反映。(2)四川省各区域、各季节干旱分布不均:空间上,干旱频发的区域集中在四川盆地及攀西南部区域。时间上,在春季,四川盆地区域的土壤干旱程度大致呈现加剧—持续—减缓的趋势;夏季,四川盆地的干旱变化趋势是加剧—减缓—加剧;秋季,四川盆地的干旱变化趋势是加剧—减缓—持续减缓;冬季,全川干旱程度变化不明显。本文的研究结果对四川省开展农业防灾减灾,引导农业灌溉具有指导意义。  相似文献   

2017年西藏米林6.9级地震前的热红外异常分析          下载免费PDF全文

张丽峰  王培玲  张朋涛  孙玺皓 《地震工程学报》2020,42(2):360-367

以小波变换和功率谱估计为研究方法,使用中国静止气象卫星热红外亮温数据,研究了2017年11月18日西藏米林MS6.9地震前的热辐射情况。结果发现震前4个月出现热红外异常,其后续演化方向与相关区域的断裂走向非常一致。在8月10日左右异常面积达最大,相对功率谱大于6倍的面积约为20万km^2,9月20日左右消失。分析相同频率2016年同期数据,结果显示在震中周围并未出现显著异常。时序曲线分析表明在8月12日相对功率谱达到峰值,为平均值的20倍,98天后米林地震发生;从7月4日到9月7日,地震当年相对功率谱偏离背景值和标准差,持续时间为65天。西藏地区的强震热红外异常表现出与地热资源分布较为一致的特征及特征周期相对较长的特点,为判定西藏地区的震情积累了一些经验。  相似文献   

Analysis of Gravity Changes before and after the Akto MS6.7 Earthquake in 2016     

Ailixiati Yushan  Liu Daiqin  Li Jie  Li Rui  Abudutayier Yasen  Sun Xiaoxu  Zhu Zhiguo  Li Guirong  Chen Li 《中国地震研究》2018,32(3):377-387

This paper analyzes the characteristics of time sequence changes of gravity points near the epicenter, different changes of measuring lines and gravity changes of measuring areas in point-line-area manner respectively with the 5-period mobile gravity data through densified observation by the South Xinjiang Observation Network after the 2015-2016 Akto earthquake in Xinjiang. The gravity observation results before the earthquake indicate that the Wuqia-Bulungkol area near the epicenter presented the trend of gravity value increasing since 2015, but the gravity value decreased half a year before the earthquake, and witnessed a high gradient zone of gravity changes during some periods before the earthquake. The gravity observation results after the earthquake show that there is a trend of opposite changes in gravity difference on the northern and southern sides of Bulunkou, and good correspondence exists between the characteristics of gravity field changes near the epicenter before and after the earthquake and the geologic structure distribution in the area.  相似文献   

A New Wavelet Method for Identification of Eddies and Assessment of Incidents on Islands of the Eastern Caribbean     

Jason D. Tambie  Madiha Farag-Miller  Keith Miller  Bheshem Ramlal  Michael Sutherland 《Marine Geodesy》2019,42(3):227-245

Using two dimensional continuous wavelet transforms, a novel method for identification of mesoscale eddies is presented to facilitate extraction of characteristics for area, amplitude, type, and location from maps of sea level anomalies. In comparison with the previously established growing method for eddy identification, it is found that the wavelet method identifies more than twice the number of eddies and is particularly better at resolving small eddies down to the 0.25 degree resolution of the data. Such research into eddy identification and tracking is significant to the assessment of eddies with potential to impact on coastlines of small islands. The method is applied to the identification of eddies on tracks towards islands of the Eastern Caribbean over 23?years. Spatial and temporal variation in rate of occurrence and magnitude is established. For Barbados there is an average of 9 anticyclonic incidents a year with maximum amplitude of typically 0.22?m in the dry seasons and 0.16?m in the wet seasons. Seasonal variation is reversed for the other islands with twice the number of anticyclonic incidents having maximum amplitudes of about 0.20?m annually.  相似文献   

Indoor localization for pedestrians with real-time capability using multi-sensor smartphones     

Catia Real Ehrlich 《地球空间信息科学学报》2019,22(2):73-88

ABSTRACT

The localization of persons or objects usually refers to a position determined in a spatial reference system. Outdoors, this is usually accomplished with Global Navigation Satellite Systems (GNSS). However, the automatic positioning of people in GNSS-free environments, especially inside of buildings (indoors) poses a huge challenge. Indoors, satellite signals are attenuated, shielded or reflected by building components (e.g. walls or ceilings). For selected applications, the automatic indoor positioning is possible based on different technologies (e.g. WiFi, RFID, or UWB). However, a standard solution is still not available. Many indoor positioning systems are only suitable for specific applications or are deployed under certain conditions, e.g. additional infrastructures or sensor technologies. Smartphones, as popular cost-effective multi-sensor systems, is a promising indoor localization platform for the mass-market and is increasingly coming into focus. Today’s devices are equipped with a variety of sensors that can be used for indoor positioning. In this contribution, an approach to smartphone-based pedestrian indoor localization is presented. The novelty of this approach refers to a holistic, real-time pedestrian localization inside of buildings based on multi-sensor smartphones and easy-to-install local positioning systems. For this purpose, the barometric altitude is estimated in order to derive the floor on which the user is located. The 2D position is determined subsequently using the principle of pedestrian dead reckoning based on user's movements extracted from the smartphone sensors. In order to minimize the strong error accumulation in the localization caused by various sensor errors, additional information is integrated into the position estimation. The building model is used to identify permissible (e.g. rooms, passageways) and impermissible (e.g. walls) building areas for the pedestrian. Several technologies contributing to higher precision and robustness are also included. For the fusion of different linear and non-linear data, an advanced algorithm based on the Sequential Monte Carlo method is presented.  相似文献   

2011~2020年勘查地球化学数据处理研究进展     

左仁广  王健  熊义辉  王子烨 《矿物岩石地球化学通报》2021,40(1):81-93

我国建立了包含海量数据的高质量的勘查地球化学数据库,为矿产勘查、环境评价和地质调查等提供了重要的数据支撑。如何高效处理勘查地球化学数据,并从中发掘和识别深层次信息一直是勘查地球化学学科研究的热点和前沿领域。本文在系统调研国内外学者过去十年发表的论著基础上,对勘查地球化学数据处理方法进行分析与对比,从勘查地球化学数据库建设、地球化学异常识别及其不确定性评价等方面概述了我国近十年来在该领域取得的主要研究进展,包括:(1)分形与多重分形模型由于考虑了地球化学空间模式的复杂性和尺度不变性,在全球范围内得到极大的发展和推广,我国学者引领了基于分形与多重分形的勘查地球化学数据处理;(2)机器学习和大数据思维开始在该领域启蒙,并迅速得到关注,正在成为研究热点和前沿领域,我国学者率先开展基于机器学习算法的勘查地球化学大数据挖掘研究;(3)我国学者需要进一步加强勘查地球化学数据缺失值处理以及成分数据闭合效应研究。今后该领域应进一步加强对弱缓地球化学异常识别、异常不确定性评价以及异常识别与其形成机理相结合等方面的研究。  相似文献   

Structural characteristics of the KPR-CBR triple-junction inferred from gravity and magnetic interpretations,Philippine Sea Plate     

《China Geology》2021,4(4):541-552

The intersection of the Kyushu-Palau Ridge (KPR) and the Central Basin Rift (CBR) of the West Philippine Basin (WPB) is a relic of a trench-trench-rift (TTR) type triple-junction, which preserves some pivotal information on the cessation of the seafloor spreading of the WPB, the emplacement and disintegration of the proto-Izu-Bonin-Mariana (IBM) Arc, and the transition from initial rifting to steady-state spreading of the Parece Vela Basin (PVB). However, the structural characteristics of this triple-junction have not been thoroughly understood. In this paper, using the newly acquired multi-beam bathymetric, gravity, and magnetic data obtained by the Qingdao Institute of Marine Geology, China Geological Survey, the authors depict the topographic, gravity, and magnetic characteristics of the triple-junction and adjacent region. Calculations including the upward continuations and total horizontal derivatives of gravity anomaly are also performed to highlight the major structural features and discontinuities. Based on these works, the morphological and structural features and their formation mechanisms are analyzed. The results show that the last episode amagmatic extension along the CBR led to the formation of a deep rift valley, which extends eastward and incised the KPR. The morphological and structural fabrics of the KPR near and to the south of the triple-junction are consistent with those of the western PVB, manifesting as a series of NNE-SSW- and N-S-trending ridges and troughs, which were produced by the extensional faults associated with the initial rifting of the PVB. The superposition of the above two reasons induced the prominent discontinuity of the KPR in deep and shallow crustal structures between 15°N–15°30′N and 13°30′N–14°N. Combined with previous authors’ results, we propose that the stress produced by the early spreading of the PVB transmitted westward and promoted the final stage amagmatic extension of the CBR. The eastward propagation of the CBR destroyed the KPR, of which the magmatism had decayed or ceased at that time. The destruction mechanism of the KPR associated with the rifting of the PVB varies along strike the KPR. Adjacent to the triple-junction, the KPR was destroyed mainly due to the oblique intersection of the PVB rifting center. Whereas south of the triple-junction, the KPR was destroyed by the E-W-directional extensional faulting on its whole width.©2021 China Geology Editorial Office.  相似文献   

东亚夏季环流多齿轮耦合特征及其对中国夏季降水异常的影响分析     

庞轶舒  祝从文  马振峰  秦宁生 《大气科学》2019,43(4):875-894

东亚夏季风成员的相互作用,构成了东亚夏季风高、低层环流的“多齿轮耦合”形态。本文利用多变量主成分分析（MV-EOF）等方法诊断分析了东亚夏季风多齿轮耦合的变化特征、耦合机制、时间稳定性、空间稳定特征及其对中国夏季降水的影响机制,并在此基础上构建了典型多齿轮耦合形态影响夏季降水的概念模型。结果表明,多齿轮耦合受到垂直温、压场的强迫和青藏高原大地形的影响,主要表现在年际变化上（周期为2～6年）。其前两个模态稳定地反映了东亚夏季风成员典型联动作用。在第一模态中,北方气旋、南亚高压和西太平洋副热带高压为主要耦合系统。其中北方气旋为正压结构,在高层通过南侧偏西气流与南亚高压耦合,南亚高压则通过中纬东部地区下沉辐散气流与西太平洋副热带高压联动。当该耦合模态增强时,有利于中国夏季降水呈自北向南“＋－＋－”分布。第二模态主要反映中高纬气旋、东亚副热带西风气流、南亚高压、西北太平洋反气旋系统和西太平洋副热带高压耦合特征。其中,中高纬气旋和西北太平洋反气旋为正压系统,两者通过其间的东南气流联动。气旋系统在高层通过南侧西风与东亚副热带西风急流和南亚高压联动。反气旋在中低层通过南侧的偏东气流影响副热带高压强度和面积。当该耦合模态增强时,中国黄河以北及河套地区降水偏多,黄河以南降水偏少。  相似文献   

A DIAGNOSTIC ANALYSIS OF AIR TEMPERATURE ANOMALY MODE OVER CHINA IN 2009/2010 WINTER BASED ON GENERALIZED EQUILIBRIUM FEEDBACK ASSESSMENT (GEFA) METHOD     

江志红  吴燕珠  刘征宇  温娜  赵灿 《热带气象学报(英文版)》2015,21(2):121-130

By using the observed monthly mean data over 160 stations of China and NCAR/NCEP reanalysis data, the generalized equilibrium feedback assessment(GEFA) method, combined with the methods of EOF analysis, correlation and composite analysis, is used to explore the influence of different SST modes on a wintertime air temperature pattern in which it is cold in the northeast and warm in the southwest in China. The results show that the 2009/2010 winter air temperature oscillation mode between the northern and southern part of China is closely related to the corresponding sea surface temperature anomalies(SSTA) and its associated atmospheric circulation anomalies. Exhibiting warming in Northeast China and cooling in Southwest China, the mode is significantly forced by the El Nio mode and the North Atlantic SSTA mode, which have three poles. Under the influence of SSTA modes, the surface northerly flow transported cold air to North and Northeast China, resulting in low temperatures in the regions. Meanwhile, the mid-latitude westerlies intensify and the polar cold air stays in high latitudes and cannot affect the Southwest China, resulting in the warming there.  相似文献