赣东北地区的区域成矿特征和成矿谱系   总被引：1，自引：0，他引：1  

王长明  吴淦国  张达  罗平  狄永军  余心起 《世界地质》2010,29(4):588-600

赣东北地区位于扬子、华夏两大构造单元复合部位,中、新生代受到北北东向滨西太平洋构造--成矿域强烈叠加作用,成矿地质条件优越、成矿期次多、成矿强度大、矿床类型多样。近年来区内找矿工作有了新突破,对内生金属矿床区域成矿规律的认识也有了新的进展。对照其大地构造单元笔者将赣东北地区划分成2个成矿带,7个成矿亚带,总结了4个主要成矿期,归纳出4大主要成矿系列,构建了区域矿床成矿谱系。  相似文献   

Research progress in volcanology in the Neapolitan area, southern Italy: a review and some alternative views   总被引：1，自引：0，他引：1  

Benedetto De Vivo  Paola Petrosino  Annamaria Lima  Giuseppe Rolandi  Harvey E. Belkin 《Mineralogy and Petrology》2010,99(1-2):1-28

Comprehensive reviews are given for the major volcanic systems that occur in the greater metropolitan area of Naples, southern Italy; Mt. Somma-Vesuvius to the east and the Campi Flegrei volcanic system to the west. Also included in the review is a detailed discussion of the large, highly explosive Campania Volcanic Zone (CVZ) ignimbrite events. These volcanic areas have been studied for more than 100 years, yet significant differences of opinion exist related to fundamental issues of origin and distribution. We present some alternative views related to petrogenesis on some issues based on more than 25 years of research. The relationship between risk assessment and management that impacts the threatened society or culture and the past and ongoing fundamental volcanological research is an essential part of the science. Countries with limited resources may be forced to accept an increased risk but even highly industrialized societies may not be able to completely eliminate deaths from volcanic eruptions. Scientific studies of the hazardous regions should be comprehensive and include reasonable alternative interpretations as this information reveals the level of confidence that must be conveyed to the public officials. The authors review the state of the art of risk assessment and management of the volcanic hazards in the Neapolitan region in light of the review of research.  相似文献   

Recent Developments in the Analysis of the Black Mat Layer and Cosmic Impact at 12.8 ka     

William C. Mahaney  Leslie Keiser  David H. Krinsley  Allen West  Randy Dirszowsky  Chris C.R. Allen  Pedro Costa 《Geografiska Annaler: Series A, Physical Geography》2014,96(1):99-111

Recent analyses of sediment samples from “black mat” sites in South America and Europe support previous interpretations of an ET impact event that reversed the Late Glacial demise of LGM ice during the Bølling Allerød warming, resulting in a resurgence of ice termed the Younger Dryas (YD) cooling episode. The breakup or impact of a cosmic vehicle at the YD boundary coincides with the onset of a 1‐kyr long interval of glacial resurgence, one of the most studied events of the Late Pleistocene. New analytical databases reveal a corpus of data indicating that the cosmic impact was a real event, most possibly a cosmic airburst from Earth's encounter with the Taurid Complex comet or unknown asteroid, an event that led to cosmic fragments exploding interhemispherically over widely dispersed areas, including the northern Andes of Venezuela and the Alps on the Italian/French frontier. While the databases in the two areas differ somewhat, the overall interpretation is that microtextural evidence in weathering rinds and in sands of associated paleosols and glaciofluvial deposits carry undeniable attributes of melted glassy carbon and Fe spherules, planar deformation features, shock‐melted and contorted quartz, occasional transition and platinum metals, and brecciated and impacted minerals of diverse lithologies. In concert with other black mat localities in the Western USA, the Netherlands, coastal France, Syria, Central Asia, Peru, Argentina and Mexico, it appears that a widespread cosmic impact by an asteroid or comet is responsible for deposition of the black mat at the onset of the YD glacial event. Whether or not the impact caused a 1‐kyr interval of glacial climate depends upon whether or not the Earth had multiple centuries‐long episodic encounters with the Taurid Complex or asteroid remnants; impact‐related changes in microclimates sustained climatic forcing sufficient to maintain positive mass balances in the reformed ice; and/or inertia in the Atlantic thermohaline circulation system persisted for 1 kyr.  相似文献   

基于Android的电力规划信息系统设计与实现     

付仲良  周达  陈伟  翁宝凤 《地理信息世界》2014,(6)

智能移动终端的飞速发展为电力规划信息在移动平台的展示提供了新的机遇。本文针对离线式移动GIS的特点和优势,结合电力信息系统移动客户端的建设情况,从移动GIS的架构、应用模式、数据组织方案、移动GIS关键技术及实现等方面进行了探讨建立一个基于Android的电力规划信息系统。  相似文献   

基于潜标测量的海洋环境噪声谱特性分析   总被引：3，自引：1，他引：2  

笪良龙  王超  卢晓亭  韩梅  邓小花 《海洋学报》2014,36(5):54-60

利用海洋环境噪声测量潜标系统对南海典型海域开展了为期3个月的海洋环境噪声测量,16通道海洋环境噪声测量系统每小时测量两分钟噪声信号。数据处理结果表明,800~5 000Hz范围内,噪声谱与风速相关性最好,且风速越大相关性越好,噪声谱与风速的相关性好于与浪高的相关性。风关噪声谱级在海水中部基本不随接收深度发生变化,但由于测量水听器阵长度未能覆盖整个水深,因此未给出海面和海底处谱级变化规律。在400Hz以上的高频段整个风速范围内噪声谱级都随风速发生变化,且噪声谱级与对数风速具有很好的线性关系。  相似文献   

基于灰色关联与模糊数学的重力式挡土墙震害评估     

梁力丹  郑达  巨能攀  李俊杰 《工程地质学报》2014,22(6):1234-1240

龙门山地区强震荷载导致大量已建边坡支挡结构严重受损,如何对震区受损挡土墙进行震害评估成为亟待解决的技术难点。本文首先通过对研究区挡土墙的震害分析,总结出其主要破坏模式包括滑移破坏、沉降破坏、倾覆破坏、墙身破坏以及越顶破坏5类。然后根据全面性、重要性以及科学性原则对影响震害评价的因子进行定性分析和分类,并结合挡墙的破坏模式,综合分析得到挡土墙安全评估的敏感性因子和一般因子。将震害范围60%作为挡墙评价的敏感性因子,而一般因子分为两级共10个指标,包括:滑移距离,沉降深度,倾斜角度,裂缝数量,裂缝长度比,开裂深度比,开裂宽度,错动距离,垮塌范围,覆盖范围。最后,采用灰色关联分析与模糊数学理论相结合的方法构建挡土墙震害评估体系,从而变事后处理为事先预防,为灾后恢复重建服务。  相似文献   

Experimental study of poromechanical behavior of saturated claystone under triaxial compression   总被引：1，自引：1，他引：0  

Da Wei Hu  Fan Zhang  Jian Fu Shao 《Acta Geotechnica》2014,9(2):207-214

This paper presents experimental results of drained and undrained triaxial compression tests of saturated Meuse–Haute/Marne claystone. The emphasis is to study the evolution of pore pressure with growth of microcracks and the effect of pore pressure on mechanical behavior. Basic mechanical responses are first investigated through drained triaxial compression tests, showing nonlinear stress strain relations, volumetric dilatancy and pressure sensitivity. In undrained triaxial compression tests, the pore pressure exhibits a transition from increase to decrease due to the transition from volumetric compressibility to dilatancy caused by the growth of microcracks. The failure surfaces, determined by total stress and Terzaghi’s effective stress under undrained condition, are compared with the one under drained condition.  相似文献   

Iron ore mining promotes iron enrichment in sediments of the Gualaxo do Norte River basin,Minas Gerais State,Brazil     

Aline Sueli de Lima Rodrigues  Guilherme Malafaia  Adivane Terezinha Costa  Hermínio Arias Nalini Júnior 《Environmental Earth Sciences》2014,71(9):4177-4186

The objective of the present study is to assess the influence of iron ore mining on Fe concentrations in fluvial sediments of the Gualaxo do Norte River basin (Minas Gerais State, Brazil). Initially background values were determined for Fe by means of the boxplot representation, the iterative 2σ technique and the calculated distribution function, using geochemical data obtained for alluvial terraces. Geochronologic analyses in carbonaceous materials attested for the proposed background values. After that, chemical analyses of active drainage sediments collected along the entire basin were carried out and a geochemical map of the study area was prepared. The mean background value for Fe is relatively high (8.2 wt %), when compared to the Fe concentration in the Earth’s crust (5.6 wt %). Such background value is strongly associated with the geological characteristics of the region. It was observed that most of the high Fe concentrations were detected in active sediments collected in the main river of the basin and not in its tributaries. This suggests that Fe enrichment is not only linked to the local geology but also to possible increase resulting from accidental leakage of iron ore mining tailings from containment dams and lakes upstream. It is suggested that measures that help stop or minimize such impact be adopted. The large capacity of Fe to adsorb and form complexes with toxic metals implicates in environmental hazards that may not be restricted only to the Gualaxo do Norte river basin, but may affect the other basins downstream.  相似文献   

Technical and public approaches to involve dredging stakeholders and citizens in the development of a port area     

L. Cutroneo  F. Massa  M. Castellano  G. Canepa  S. Costa  P. Povero  S. Tucci  M. Capello 《Environmental Earth Sciences》2014,72(8):3159-3171

  相似文献   

酒东盆地红山地区下白垩统新民堡群灰白色蚀变带特征及其与铀成矿的关系     

郭长林  耿海军  何大鹏  李万华  陈云杰  李斌 《铀矿地质》2014,(5):283-286

研究区位于酒东盆地东北缘红山地区。通过对下白垩统新民堡群后生氧化改造作用的研究,认为灰白色弱氧化、强水解蚀变带是层间氧化带的一部分。铁和有机质是沉积岩中常见的色素,当含氧水进入目的层砂体时,砂体中的有机质、低价铁(Fe2+)等化合物被氧化,导致岩石褪色;同时氧化作用导致砂岩中长石水解,形成以高岭石为主的白色黏土矿物,使岩石增白。增白与褪色的双重作用是砂岩总体上变白的重要原因,其所形成的灰白色蚀变岩位于强氧化的紫红色-黄色蚀变亚带与灰色原生岩石带之间的一定范围内。铀矿化(体)产在弱氧化、强水解灰白色砂岩与原生灰色砂岩界面附近偏灰色岩石一侧[1-2]。灰白色蚀变带与铀成矿关系密切,可作为区域性白垩系砂岩型铀矿的找矿标志之一。  相似文献