广东河台整装勘查区百旁金矿成矿规律          下载免费PDF全文

邓卓辉 《地质找矿论丛》2019,34(4):510-515

百旁金矿是广东地质五队近年来新发现的一处中型蚀变糜棱岩型金矿。百旁金矿地处粤西—桂东成矿带东段NE向罗定—广宁断裂带北东端部位,矿体受糜棱岩带内面理、裂隙带控制;金矿化具明显的以硅化、硫化物为中心的对称性分布特征,金矿体具有平行斜列、侧伏的分布规律,表现为向NE向侧伏;区内金矿化富集主要与热液活动有关,燕山期的重熔花岗岩侵入的同时伴随有富含硫化物的含金热液充填在糜棱岩、断裂带内而成矿。  相似文献   

L波段雷达探空高度评估及其质量标识          下载免费PDF全文

雷勇  郭启云  钱媛  曹晓钟 《应用气象学报》2018,29(6):710-723

以美国NCEP FNL分析数据和我国GRAPES_GFS预报数据为背景场,对2016年7月1日-2017年6月30日北京探空站的L波段秒级探空位势高度（探空高度）从观测余差、平均偏差、标准偏差、概率密度分布、峰度系数、偏度系数、相关系数和均方根误差等参数进行误差分析。根据分析结果对探空高度进行质量标识,并根据质量标识的结果再次求解参数,评估质量标识效果。结果表明:探空高度质量较好,无论是基于NCEP FNL还是GRA-PES_GFS,探空高度的误差基本在±5 dagpm以内。探测高层的观测余差平均偏差和标准偏差表明基于GRAPES_GFS的评估优于NCEP FNL的评估。单一个例选取的可疑点和错误点阈值具有误差特征、自适应的特点。  相似文献   

Key signatures of turbidite and sandy debris and core examples in Liaohe Basin          下载免费PDF全文

Yang Ke  Zhu Xiao-Min  Liu Yu  Liu Xing-Zhou  Guo Feng 《古地理学报》1999,22(3):483-492

Gravity flow is a widely-distributed fluid type in nature. Various classification schemes of gravity flow are proposed by different researchers from different viewpoints. The scheme of turbidity flow and debris flow is adopted in this paper. The sedimentary characteristics of turbidite and sandy debrite are summarized and discussed to clarify most typical facies marks of these two rock types. The study shows that turbidite and sandy debris can be identified by the following typical characteristics during the outcrop and core observation: If the graded bedding is developed in sandstone,it should be identified as turbidite;if the muddy rip-up clast or no bedding structure(massive sandstone)is developed in sandstone,it should be identified as sandy debris. These characteristics are the most reliable signatures to distinguish turbidite and sandy debris. In addition,some other sedimentary structures such as deformation bedding,climbing ripple cross bedding,wavy bedding,parallel bedding,scouring surface,lithologic abrupt interface,and flute cast also have certain indicative significance. It is necessary to make a comprehensive judgment based on the sedimentary background,vertical combination of lithofacies,geophysics and other materials when these characteristics are presented in the study.  相似文献   

陆相盆地层序地层学研究中几个问题的探讨   总被引：17，自引：5，他引：12  

蔡希源  张明学 《现代地质》1999,13(3):287-290

将层序地层学理论应用于陆相盆地研究仍处于探索阶段。陆相盆地的层序界面、最大洪泛面和首次洪泛面的识别标志都有别于海相地层。依据层序地层学理论和对松辽盆地的探索性研究, 对陆相盆地提出了层序界面、最大洪泛面和首次洪泛面的识别标志。  相似文献   

A wind tunnel investigation of particle segregation,ripple formation and armouring within sand beds of systematically varied texture          下载免费PDF全文

Cheryl McKenna Neuman  ottO Bédard 《地球表面变化过程与地形》2017,42(5):749-762

This paper reports on a wind tunnel investigation of particle segregation, ripple formation and surface armouring within sand beds of systematically varied particle size distribution, from coarsely skewed to bimodal. By design, the system was closed with no external inputs of mass from an external particle feed. Particles too coarse to travel in saltation for the given range in wind speed were dyed red in order to distinguish them in optical images from finer sand particles, which could be entrained into the unidirectional airflow. A 3D laser scanner measured the changing bed topography at regular time intervals during 18 experiments involving varied combinations of wind speed and bed texture. Image classification techniques were used to investigate the coincident self‐organization of the two populations of particles, as distinguished by their colour. As soon as saltation commenced, some of the red particles segregated into thin discontinuous patches. Particle trapping and sheltering on these rough patches was strongly favoured, causing them to grow preferentially. During the earliest stages of formation, bedform growth coincided with: (i) rapid coarsening of the surface texture; and (ii) the merging of proto‐ripple ‘crests’ to generate larger rhythmic bedforms of lower frequency. Consistent with previous work, ripple size was observed to increase under stronger winds when not exceeding the threshold for entrainment of the coarse‐mode or red particles from the crest. With declining rates of mass transport and particle segregation as the bed surface armoured, and the consequent deceleration of ripple propagation through to the end of each experiment, all surfaces eventually attained a steady‐state morphometry. At saturation, the largest ripples developed on beds having the lowest initial concentration of red particles. Copyright © 2016 John Wiley & Sons, Ltd.  相似文献   

Experimental study of aeolian sand ripples in a wind tunnel   总被引：1，自引：0，他引：1       下载免费PDF全文

Hong Cheng  Chenchen Liu  Jifeng Li  Bo Liu  Zhongquan Zheng  Xueyong Zou  Liqiang Kang  Yi Fang 《地球表面变化过程与地形》2018,43(1):312-321

The topographic parameters and propagation velocity of aeolian sand ripples reflect complex erosion, transport, and deposition processes of sand on the land surface. In this study, three Nikon cameras located in the windward (0–1 m), middle (4.5–5.5 m), and downwind (9–10 m) zones of a 10 m long sand bed are used to continuously record changes in sand ripples. Based on the data extracted from these images, this study reaches the following conclusions. (1) The initial formation and full development times of sand ripples over a flatbed decrease with wind velocity. (2) The wavelengths of full development sand ripples are approximately twice the wavelengths of initially formed sand ripples. Both wavelengths increase linearly with friction velocity. During the developing stage of sand ripples, the wavelength increases linearly with time. (3) The propagation velocity of full development sand ripples is approximately 0.6 times that of the initially formed sand ripples. The propagation velocity of both initial and full development of sand ripples increase as power functions with respect to friction velocity. During the developing stage of sand ripples, the propagation velocity decreases with time following a power law. These results provide new information for understanding the formation and evolution of aeolian sand ripples and help improve numerical simulations. Copyright © 2017 John Wiley & Sons, Ltd.  相似文献   

基于水下多目标定位的目标识别和辨析处理     

任纪庆  程鹏飞  蔡艳辉  徐彦田 《测绘工程》2010,19(2):59-61

在水下多目标的定位过程中,对不同目标发射源的标识和分辨是非常关键的一部分。介绍一种方法,即在目标发射数据的文件头加上一个目标号进行标识。在数据处理中采用三级顺序的数据分离,层层提取,能够分辨出不同目标定位所需的数据。  相似文献   

浊积岩和砂质碎屑流岩关键识别标志及辽河盆地岩心实例^*     

杨棵  朱筱敏  刘宇  刘兴周  郭峰 《古地理学报》2020,22(3):483-492

重力流是自然界中广泛存在的一种流体形式,不同学者基于不同切入点往往会提出多种重力流的划分方案。采用浊流和碎屑流的二分方案,对浊积岩和砂质碎屑流岩的沉积特征展开综述和探讨,旨在进一步概括这2类岩石的沉积特征,明确具有指示意义的最典型相标志。研究表明,在野外露头和钻井岩心中,可以通过以下典型特征鉴别浊积岩和砂质碎屑流岩: 砂岩内若发育以正粒序为特征的递变层理,则应该将其认定为浊积岩;若砂岩内发育泥岩撕裂屑、漂浮状泥砾或不含任何层理构造(块状砂岩),则应该将其认定为砂质碎屑流岩。这些特征是鉴别浊积岩和砂质碎屑流岩最可靠的标志。此外,变形层理、爬升波纹交错层理、波状层理、平行纹层、冲刷侵蚀界面、岩性突变界面和槽模等沉积构造也具有一定指示意义,出现这些特征时需要结合沉积背景、岩相的垂向组合关系和地球物理等资料进行综合判断。  相似文献   

堆积阶地古老滑坡识别方法及其在线状工程地质勘察中的应用     

安玉科  樊江  马胜午  马建全  高娟  毛立军 《吉林大学学报(地球科学版)》2020,50(6):1787-1794

阶地型古老滑坡体形成后,长期受各种营力影响,导致古老滑坡地貌形态破坏严重甚至消失。目前遥感技术和普通工程地质调绘很难发现这些滑坡的存在,给工程建设和后期运营造成较大安全隐患。为准确识别形态特征不明显的古老滑坡体,从阶地物质结构特征演变入手,找到阶地受剪切破坏产生的典型物质结构特征,将地层结构错断、卵砾石异常定向排列、摩擦镜面和泥包粒的眼球构造等作为滑坡准确识别依据。首先采用沿沟谷进行工程地质测绘的纵横交错追踪法确定滑坡体纵向范围和滑面形状,再结合地貌特征推测各级、块滑坡平面范围和分布,最后用点状勘探工程验证和校正推测结论。可将其总结为由"地貌异常、沿沟追踪、面上推断、点状校验"组成的阶地型滑坡识别方法,即物质结构异常推断法。结合线状工程勘察设计各阶段工作特点,提出线状工程前期工作中阶地型滑坡识别步骤,并在临渭高速公路工程建设项目中取得成功应用。  相似文献   

东营凹陷现河地区沙三段震积岩特征及其意义   总被引：15，自引：3，他引：12  

魏垂高  张世奇  姜在兴  刘金华 《沉积学报》2006,24(6):798-805

在区域构造背景研究和岩芯观察的基础上,在东营凹陷现河地区沙三段地层中识别出震积岩。震积岩的主要标志是发育各种类型的软沉积变形构造,包括微阶梯状正断层、层内小褶皱、扭曲变形、振动液化砂岩脉、震塌岩等。通过对河152井、王59井、牛38井、牛22井等井岩芯的系统观察,发现由于构造和地震强度的不同,震积岩的垂向序列有所不同,并进一步研究了各种震积岩构造特征与地震强度的关系,研究表明不同的震积岩构造特征对应不同的地震强度,进一步确定了与古地震的关系。通过对本区储层分析,认为震积岩可以作为一种有效的储集空间。这些研究为东营凹陷构造演化研究、震积岩的识别和描述以及成藏提供了重要的地质理论依据,并可为该区古地震研究提供依据。   相似文献