河南省陕县金矿找矿前景评价

崤山地区为陕县黄金主要产地,与其邻区小秦岭和熊耳山地区相比,金矿找矿、勘探、开发力度尚显不足。本文通过遥感地质综合解译,论证了崤山地区具有良好的金矿成矿地质条件,在此基础上采用“矿化有利度法”对崤山地区金矿成矿远景进行了综合信息定量预测,结果表明崤山地区具有良好的金矿找矿前景,需进一步加大找矿勘探力度。     

Research Progress in Cenozoic N-S Striking Rifts in Tibetan Plateau

The formation of the Cenozoic N-S striking rifts in the Tibetan Plateau is the consequence of continuous contraction after the India-Asia collision. Its formation and evolution are of great significance for understanding the growth of the Tibetan Plateau. In recent years, geochronology, structural geology, geochemistry and geophysical exploration have been used to study the onset timing, mechanism and evolution process of the N-S striking rifts, and the N-S striking rifts are related to the deep dynamics in Tibet. However, it is still difficult to reach a consensus on the understanding of the N-S striking rifts in the Tibetan Plateau. This paper summarized the research status and existing problems on the onset timing, mechanism and their relationship with the deep layer of the plateau: the main extension period of the N-S striking rifts is Miocene; mechanisms controlling its formation are complex and may be various in different periods; the N-S striking rifts have a close genetic relationship with potassium and ultrapotassic rocks in the plateau, and their distribution may be affected by high-conductivity and low-velocity bodies. Based on existing knowledge, more precise geochronological constraints, deep process detection, and numerical modeling will be the future development trends in the study of N-S striking rifts.     

Subsidence and exhumation of the Mesozoic Qiangtang Basin: Implications for the growth of the Tibetan plateau

The subsidence and exhumation histories of the Qiangtang Basin and their contributions to the early evolution of the Tibetan plateau are vigorously debated. This paper reconstructs the subsidence history of the Mesozoic Qiangtang Basin with 11 selected composite stratigraphic sections and constrains the first stage of cooling using apatite fission track data. Facies analysis, biostratigraphy, palaeo‐environment interpretation and palaeo‐water depth estimation are integrated to create 11 composite sections through the basin. Backstripped subsidence calculations combined with previous work on sediment provenance and timing of deformation show that the evolution of the Mesozoic Qiangtang Basin can be divided into two stages. From Late Triassic to Early Jurassic times, the North Qiangtang was a retro‐foreland basin. In contrast, the South Qiangtang was a collisional pro‐foreland basin. During Middle Jurassic‐Early Cretaceous times, the North Qiangtang is interpreted as a hinterland basin between the Jinsha orogen and the Central Uplift; the South Qiangtang was controlled by subduction of Meso‐Tethyan Ocean lithosphere and associated dynamic topography combined with loading from the Central Uplift. Detrital apatite fission track ages from Mesozoic sandstones concentrate in late Early to Late Cretaceous (120.9–84.1 Ma) and Paleocene–Eocene (65.4–40.1 Ma). Thermal history modelling results record Early Cretaceous rapid cooling; the termination of subsidence and onset of exhumation of the Mesozoic Qiangtang Basin suggest that the accumulation of crustal thickening in central Tibet probably initiated during Late Jurassic–Early Cretaceous times (150–130 Ma), involving underthrusting of both the Lhasa and Songpan–Ganze terranes beneath the Qiangtang terrane or the collision of Amdo terrane.     

中国企业本土并购双方的地理格局及其空间关联研究

借鉴已有理论与实证研究成果,综合运用GIS空间分析与计量模型等方法,重点分析省区空间尺度上中国本土并购双方企业的地理格局,从企业地域“根植性”视角探讨并购双方区位选择与空间关联的影响因素。研究结果表明：① 买方和标的企业在空间上呈现共同集聚特征,总体形成了与中国沿江沿海“T”形区域发展格局、“核心-边缘”城镇等级体系相似的地理格局;② 并购双方企业主要集聚于经济发达区域,虽然2010年代以来中西部省区企业参与并购投资事件有所增长,但省区间差异逐渐固化,北京、长三角、珠三角等大都市地区更多以买方角色主导企业跨区域并购,而中西部及资源型区域企业则多以并购标的角色为主;③ 企业并购投资行为根植于地方经济社会和制度环境,买方和标的企业的区位选择机制较为相似,并购双方更偏好集聚于证劵和金融市场繁荣、区域创新系统完善、经济和产业基础雄厚的区域。     

塔克拉玛干沙漠腹地秋季陆面过程特征

利用塔克拉玛干沙漠腹地塔中2014年10月的秋季涡动通量数据,分析了塔中秋季陆面过程通量变化特征。结果表明：（1）塔中秋季10月净辐射R_n、感热通量H、潜热通量LE、地表土壤热通量G₀峰值依次为273.0、141.6、5.0、105.0 W·m^-2,平均日总量依次为2.85、2.68、0.08、-0.57 MJ·m^-2,净辐射能量分配以感热能量输送为主。（2）不同典型天气下,净辐射日总量扬沙>晴天>阴天>降水;阴天、扬沙天气H随R_n不同程度削减而减少,降水天气潜热增多导致日变化特征有别于其他天气。（3）10月能量闭合率为79.0%,不同天气能量闭合率阴天>晴天>扬沙>降水,依次为86.8%、83.4%、79.4%、71.4%。（4）地表反照率晴天呈“U”型变化,阴天和扬沙天气地表反照率趋势变缓发生波动现象,降水天气波动较大,趋势先降低后回升。（5）月平均热通量日间为正值,夜间为负值。日间能量闭合率为73.9%,夜间为50.8%,存在较高的能量不闭合。     

水下电磁探测技术的发展现状

首先阐述了水下电磁探测技术的现实意义,之后介绍了国外水下电磁探测、预警系统的研究现状,以及电场传感器、磁场传感器的性能指标。通过对国内水下电磁探测技术的发展历程以及与国外的差距进行分析,指出未来水下电磁探测系统集成化、智能化、系统化、无人化、多元化和网络化的发展趋势。     

Information Detection of Seismic Debris Flow by UAV High-resolution Image Based on Transfer Learning

A large number of debris flow disasters (called Seismic debris flows) would occur after an earthquake, which can cause a great amount of damage. UAV low-altitude remote sensing technology has become a means of quickly obtaining disaster information as it has the advantage of convenience and timeliness, but the spectral information of the image is so scarce, making it difficult to accurately detect the information of earthquake debris flow disasters. Based on the above problems, a seismic debris flow detection method based on transfer learning (TL) mechanism is proposed. On the basis of the constructed seismic debris flow disaster database, the features acquired from the training of the convolutional neural network (CNN) are transferred to the disaster information detection of the seismic debris flow. The automatic detection of earthquake debris flow disaster information is then completed, and the results of object-oriented seismic debris flow disaster information detection are compared and analyzed with the detection results supported by transfer learning.     

拱形与矩形断面地铁车站结构地震反应比较研究

采用动力时程法开展了拱形与矩形断面地铁车站结构地震反应的研究,分析了拱形断面和矩形断面地铁车站结构的关键截面在地震作用下的内力及变形的差异。结果表明:相比于矩形断面车站结构,拱形断面车站结构顶板边缘处和侧墙顶端的弯矩明显减小,车站侧墙顶端和顶板边缘处因承受弯矩过大而发生破坏的可能降低;内柱截面的轴压比明显减小,且与侧墙的轴压比差异显著减小,受力分配更为合理;拱形车站结构顶、底板的相对位移、内柱和侧墙的位移角相对较小。在已模拟的工况下拱形车站内力分布形式更为合理,水平变形相对较小,更有利于抗震。     

江西相山矿田北部产铀花岗斑岩LA-ICP-MS锆石U-Pb定年及成因类型

相山铀矿田是中国迄今为止发现的最大的火山岩型铀矿床,其北部主要铀矿类型为花岗斑岩型铀矿床,铀成矿在时空和成因上与超淺成侵入相的花岗斑岩有关。前人多针对某一具体矿床含矿主岩开展工作,获得的花岗斑岩成岩年龄数据相差较大,影响了对相山花岗斑岩型铀矿的深入研究。选择相山北部横涧、游坊、沙洲、云际等铀矿床的含矿主岩——花岗斑岩系统开展野外地质调查、地球化学特征和LA-ICP-MS锆石U-Pb定年研究,以期厘定相山花岗斑岩型铀矿床含矿主岩的成岩时代和成因类型。花岗斑岩LA-ICP-MS锆石U-Pb定年结果显示,横涧、游坊、沙洲、云际的花岗斑岩206Pb/238U年龄加权平均值分别为135.6±1.3Ma(MSWD=0.45,n=26)、136.2±1.3Ma(MSWD=1.2,n=21)、133.4±11Ma(MSWD=0.67,n=24)及134.3±1.1Ma(MSWD=0.88,n=25),集中在132~137Ma之间,属于早白垩世。研究认为,相山北部花岗斑岩成因类型界于A型花岗岩与S型花岗岩之间的过渡型,为A-S型花岗岩。花岗斑岩岩浆起源于中元古代地壳,地壳物质作为主要成分参与了花岗斑岩的形成,同时有少量地幔物质的加入。花岗斑岩为板内构造界境下伸展体制的产物,可能是由于太平洋板块俯冲后,因板块后撤导致岩浆侵入作用的结果。     

一种面向对象的最优分割尺度计算模型

作为信息提取和分类的前提,面向对象的影像分割尺度参数的设置直接影响到提取和分类的精度。本文以GF-2影像数据为例,在已有分割理论和方法的基础上提出一种基于最优分割尺度的计算模型（OS模型）。该模型以主成分分析所得的主成分以及新建的归一化植被指数（normalized vegetation index,NDVI）特征层作为分割参考层,综合考虑均质因子的影响,构建加权尺度评价指数,插值拟合最优分割尺度。构建误差系数（E_c）对模型进行评价,结果表明：OS模型误差系数（E_c=1.15%）小于传统模型（E_c=3.28%）,且分割对象更均匀、与实际地物更接近。