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1.
冀北丰宁—隆化深断裂带的基本特征和演化历史   总被引:3,自引:0,他引:3  
丰宁-隆化深断裂带系内蒙地轴南缘东南向大断裂的一部分,表现为一条复杂的构造-岩浆岩带,在漫长的物质历史时期中,先后经历了五台末期角闪岩相韧性逆冲、吕梁晚期绿片岩相脆-韧性斜冲、海西晚期绿片岩相韧-脆性斜冲及燕山中期脆性断裂活动等骤变阶段。深断裂带的演化特点为:垂向上由深层次→中层次→浅层次→表层次发展;构造变形则从固态流动变形向脆-韧性剪切变形、韧-脆性剪切变形到脆性变形演化。  相似文献   

2.
老湾金矿带受控于区域性龟(山)-梅(山)断裂在桐柏的出露部分——老湾脆-韧性剪切带。老湾脆-韧性剪切带为一右形走滑剪切断裂系统,它包括矿带南北两侧的边界断裂——老湾和松扒断裂及它们之间的次级剪切裂隙。老湾和松扒断裂为右形走滑性质的导岩、控岩断裂,它控制了区内岩浆热液产生和热液成矿体系的形成;次级剪切断裂位于两边界断裂之间的一系列次级脆性断裂,它们因几何形态、构造特征、滑移方式等方面的不同而具有分段性。其中上上河-彭家老庄段属区域右行走滑体系中R型张扭性断裂,老湾-盛老庄段主要为P型压扭性,其次为Y型张扭和T型张裂隙,二者同为Riedel剪切裂隙系统,组成一个由P和R连结的辫状右行走滑剪切带,它控制着老湾金矿带所有的矿脉带和矿(化)体。因而老湾金矿带断裂构造控矿模式为:一级边界断裂控岩,次级右行走滑剪切断裂带控矿.  相似文献   

3.
藏东地区新生代构造体系与成矿的关系   总被引:7,自引:0,他引:7       下载免费PDF全文
区域构造和微构造分析表明,新生代藏东地区构造应力场自印支燕山期的NE-SW向挤压向喜马拉雅山期的NNE-SSW向压扭性转变,表现在:(1)沿昌都地块两侧及古生代一中生代形成的深大断裂带发生了大规模的右旋走滑活动,伴重型较强的碎裂岩化、拉伸线埂和剑鞘褶皱等,沿主断裂两侧叠加一系列NW、NNW及NE向雁行式排列的褶皱和张扭性断裂;(2)在区域上,沿大规模右旋走滑断裂两侧形成一系列雁行式排列的第三系走滑拉分盆地;(3)新生代岩浆活动沿走滑断裂两侧的张扭性次级断裂有规律分布,新生代构造体制的转变造成大规模成矿流体与富集,使新生代成为本区最重要的成矿时期,而北澜沧江,妥坝、温泉断裂带及车所乡断裂带北段是该期矿产最有利的富集部位。  相似文献   

4.
黄栗树-庙集断裂带是扬子地块北东缘滁州-巢湖前陆褶皱冲断带根带的重要组成部分,以韧性、脆-韧性剪切带发育为特征,变形机制属简单剪切,主干断裂形成时差异应力在150MPa,应变速率在8×10-16/s左右.它的形成演化经历了逆冲→右行走滑→正断三个阶段,断裂带中段北部的分形值高于南部.断裂带西侧"扬子型"新太古代变质基底的发现及断裂带两侧燕山期中酸性岩体同位素地球化学特征的一致性,证明它不是大别造山带与扬子地块的界线.  相似文献   

5.
在粤西云浮珠川,高要大湾地区,吴川-四会和高要-惠来深断裂带最醒目的构造形迹分别是发育于震旦纪-泥盆纪浅变质岩系和加里东-印支期花岗岩中的风门凹、天湖凹韧性剪切带。风门凹韧性剪切带构造热事件形成于燕山中晚期;天湖凹韧性剪切带热事件形成于印支后者被前者切割成阶梯状或菱形状块。  相似文献   

6.
山东玲珑金矿的成矿流体特征   总被引:45,自引:3,他引:42  
卢焕章 Guha  J 《地球化学》1999,28(5):421-437
山东省玲珑地区是中国最大的金矿区之一,玲珑花岗岩位不部的前寒武纪地盾上,其中产有几十个有金矿矿化这个地区的基底由一套太石林粒岩和斜长角闪岩组成。玲玲花岗岩为片麻状黑云母花岗岩。其南缘是走向NE,倾向SE的破头青韧性剪切带。剪切带长数行政 千米,宽300-800m,且在其左边一出呈雁行状排列的次一级脆性性构造。  相似文献   

7.
辽宁丹东五龙金矿矿化类型及其构造控制机理   总被引:7,自引:1,他引:7  
吕贻峰  商维国 《现代地质》1994,8(3):309-316
位于辽宁丹东地区的五龙金矿受NE向剪切系统控制.在剪切带发展演化过程中,于不同阶段形成不同类型的金矿化。在早期韧性剪切带上升剥蚀阶段出现的NE向脆-韧性线状剪切带,控制同剪切带型金矿;叠加在韧性剪切带之上的NNE向一级断裂控制破碎带蚀变岩型金矿的形成和分布;沿SN向和NW向的二级断裂构造控制含金石英脉型金矿。  相似文献   

8.
镇沅老王寨构造蚀变岩型金矿矿床成因   总被引:4,自引:0,他引:4  
杨夕辉 《云南地质》2005,24(4):371-378
矿体产出受深大断裂派生的剪切断裂及脆—韧性剪切带控制明显,矿床形成具多期、多阶段和多源特征。通过对成矿流体和成矿机理的研究,笔者认为该矿床是较典型的构造蚀变岩型金矿床。  相似文献   

9.
陕西葫芦沟金矿成矿断裂的构造地球化学特征   总被引:1,自引:0,他引:1  
本区的成矿断裂是发育在太古代太华群中韧性剪切带之上的一系列脆-韧性、脆性剪滑断裂。在成矿过程中,不同类型断裂、不同类型构造岩带显示出不同的断裂动力蚀变特征和成矿元素组合。活化的金等元素在构造应力驱动下,于不同构造部位以不同形式沉淀并富集成矿,从而形成了蚀变岩型和石英脉型金矿体。  相似文献   

10.
西林河脆-韧性剪切带是区域上富尔河-古洞河岩石圈深断裂带的重要组成部分,总体走向330°,由东部、部和西部3条脆-韧性剪切断层带组成。东部带以脆性变形为主,延长约4km;中部带除脆性变形外兼有塑性变形,延长约5km,西部带以塑性变形为主,总延长5.5km。  相似文献   

11.
Komatiites are mantle-derived ultramafic volcanic rocks. Komatiites have been discovered in several States of India, notably in Karnataka. Studies on the distribution of trace-elements in the komatiites of India are very few. This paper proposes a simple, accurate, precise, rapid, and non-destructive wavelength-dispersive x-ray fluorescence (WDXRF) spectrometric technique for determining Sc, V, Cr, Co, Ni, Cu, Zn, Rb, Sr, Y, Zr, Nb, Ba, Pb, and Th in komatiites, and discusses the accuracy, precision, limits of detection, x-ray spectral-line interferences, inter-element effects, speed, advantages, and limitations of the technique. The accuracy of the technique is excellent (within 3%) for Sc, V, Cr, Co, Ni, Cu, Zn, Rb, Sr, Zr, Nb, Ba, Pb, and Th and very good (within 4%) for Y. The precision is also excellent (within 3%) for Sc, V, Cr, Co, Ni, Cu, Zn, Rb, Sr, Y, Zr, Nb, Ba, Pb, and Th. The limits of detection are: 1 ppm for Sc and V; 2 ppm for Cr, Co, and Ni; 3 ppm for Cu, Zn, Rb, and Sr; 4 ppm for Y and Zr; 6 ppm for Nb; 10 ppm for Ba; 13 ppm for Pb; and 14 ppm for Th. The time taken for determining Sc, V, Cr, Co, Ni, Cu, Zn, Rb, Sr, Y, Zr, Nb, Ba, Pb, and Th in a batch of 24 samples of komatiites, for a replication of four analyses per sample, by one operator, using a manual WDXRF spectrometer, is only 60 hours.  相似文献   

12.
本文拟定了一种以熔融法制备样片,用X射线荧光光谱测定硅酸盐类样品中Si、Fe、Al、Tj、Mn、Ca、Mg、K、Na、P等元素的分析方法。在对不同靶材X光管和分光晶体实验对比的基础上,选择了最佳的测量条件。该法具有快速、准确,测量范围广,检测限低,价格便宜等优点。经过近百个各种类型标样或管理样品的分析对比表明,本法不仅适用于硅酸盐类岩石样品的分析,还适用于铁矿、铝土矿、碳酸盐类岩矿样品以及水泥、耐火材料等样品的分析。  相似文献   

13.
最新的流行病学研究表明,空气中较高浓度的悬浮细颗粒可能对人类的健康有不利的影响。根据该项研究显示,由于心脏病、慢性呼吸问题和肺功能指标恶化而导致死亡率的升高与细尘粒子有关。这些研究结果已经促使欧盟于1999年4月出台了限制空气中二氧化硫、二氧化氮、氧化氮、铅和颗粒物含量的法案(1999/30/EC),对各项指标包括对可吸入PM10颗粒的浓度提出了新的限制性指标。PM10颗粒是指可以通过预分级器分离采集的气体动力学直径小于10μm的细颗粒。目前研究的兴趣重点逐步偏向PM2.5这些更细微颗粒物,PM2.5这种颗粒物对健康有明显的不利影响。在欧盟指令2008/50/EC中,对PM10和PM2.5都提  相似文献   

14.
This paper reports the first results of a study of 11 isotope systems (3He/4He, 40Ar/36Ar, 34S/32S, 65Cu/63Cu, 62Ni/60Ni, 87Sr/86Sr, 143Nd/144Nd, 206–208Pb/204Pb, Hf–Nd, U–Pb, and Re–Os) in the rocks and ores of the Cu–Ni–PGE deposits of the Norilsk ore district. Almost all the results were obtained at the Center of Isotopic Research of the Karpinskii All-Russia Research Institute of Geology. The use of a number of independent genetic isotopic signatures and comprehensive isotopic knowledge provided a methodic basis for the interpretation of approximately 5000 isotopic analyses of various elements. The presence of materials from two sources, crust and mantle, was detected in the composition of the rocks and ores. The contribution of the crustal source is especially significant in the paleofluids (gas–liquid microinclusions) of the ore-forming medium. Crustal solutions were probably a transport medium during ore formation. Air argon is dominant in the ores, which indicates a connection between the paleofluids and the atmosphere. This suggests intense groundwater circulation during the crystallization of ore minerals. The age of the rocks and ores of the Norilsk deposits was determined. The stage of orebody formation is restricted to a narrow age interval of 250 ± 10 Ma. An isotopic criterion was proposed for the ore-bearing potential of mafic intrusions in the Norilsk–Taimyr region. It includes several interrelated isotopic ratios of various elements: He, Ar, S, and others.  相似文献   

15.
Mining induced subsidence can significantly affect mining costs where major surface facilities and natural environment need to be protected. Overburden grout injection is a technology used to control coal mine subsidence by injecting the mine waste material extracted from the coal back into the inter-burden rock during longwall mining. The flowing slurry is here categorised as a nonlinear viscous cohesive (Bingham plastic) fluid. During longwall mining the grout slurry is pumped into the separated beds of the rock mass through a central vertical borehole, which is drilled deep into the inter-burden rock strata above the coal seam. However, a blockage can occur in the injection system when the slurry velocity falls below a certain critical threshold velocity, indicating a material phase change from cohesive-viscous to cohesive-frictional. In situ field injection tests through boreholes have been simulated at a smaller scale at the CSIRO laboratory in Brisbane by pumping the slurry through a radial disk (gap = 4 mm) from its centre. Laboratory experiments indicate a general, nonlinear, cohesive, viscous, frictional model for shear behaviour of the slurry, in which the material shear parameters are functions of the disk radial distance. Complete dimensional and dimensionless analytical solutions have been developed based on an approach related to Bingham–Herschel–Bulkley fluid mechanics. The derived formulae include relations for minimum pump pressure, local pressure and pressure gradient, wall shear stress, volume rate, velocity and velocity gradient. The theoretical results match the experimental measurements. The experiments covered slurries with maximum particle sizes of 0.5 to 2 mm with about 50% being larger than 100 µm. The viscosities at the various solids concentrations were measured with a standard torsion viscometer. This study differs from the previous research in several distinct aspects, namely, consideration of the variable shear parameters rather than fixed values, inclusion of total nonlinear behaviour, and implementation of a friction function to mimic behaviour of the deposited and consolidating stiff slurry, which can cause a significant pressure rise as a result of the increased shear resistance.  相似文献   

16.
本文介绍样品经四硼酸锂熔融制成玻璃小饼。采用Lachance模式和理论a系数来校正元素间的效应,由3080E型X-射线荧光谱仪和DF-350B数据处理系统完成硅酸盐中十三个项目的测定。  相似文献   

17.
岩石密度和超高压岩石折返速率   总被引:1,自引:3,他引:1  
在常温常压条件下对中国大陆科学钻CCSD主孔100-3000米岩心样品进行了密度测量,建立了密度连续剖面,并界定了不同超高压岩石的密度值。通过对比高温高压物性实验资料,岩石密度随着退变程度增强而降低,榴辉岩密度变化序列为3.52g/cm3→3.49g/cm3→3.07g/cm3→2.93g/cm3。超高压长英质岩石密度变化序列为3.00g/cm→2.80g/cm3→2.65g/cm3。上述实验资料是讨论不同折返阶段岩石所受浮力的基础,为研究折返速率大小提供了基本参数。本文通过折返板块运动平衡时,上浮力与粘滞力平衡这一关系式,定量研究了大陆俯冲板块的折返速率,认为密度差产生上浮力从而引起折返,温度对板块折返速率的影响最为显著;密度差大小、折返角度、折返板块大小对折返速率也有直接的影响。定量模拟分析表明,在温度高于850℃时,板块的折返速率可以超过100mm/a;当温度降至700℃时,折返速率则低于1.5mm/a。作者认为在折返早期,温度较高,板块快速折返至60-70km榴辉岩相深度;随着传导散热,温度降低,板块以较慢的速率折返至中下地壳。折返速率的估算表明,浮力是板块折返第一阶段(从>100km深部折返至<40km的中下地壳)的主要驱动力。  相似文献   

18.
The Kuskokwim River at Bethel, Alaska, drains a major mercury-antimony metallogenic province in its upper reaches and tributaries. Bethel (population 4000) is situated on the Kuskokwim floodplain and also draws its water supply from wells located in river-deposited sediment. A boring through overbank and floodplain sediment has provided material to establish a baseline datum for sediment-hosted heavy metals. Mercury (total), arsenic, antimony, and selenium contents were determined; aluminum was also determined and used as normalizing factor. The contents of the heavy metals were relatively constant with depth and do not reflect any potential enrichment from upstream contaminant sources.  相似文献   

19.
滇东南锡、银、铅、锌多金属矿床主要分布在个旧、白牛厂、都龙3个矿区,而滇东南较大的3个花岗岩体又分别出露在3个矿区或附近.花岗岩体均形成于燕山晚期,岩石化学、矿物成分相似,富含锡、银、铅、锌、钨、铜等成矿元素.矿床主金属元素组合与岩体之间的距离由远而近出现由锡、钨、(铍、铌、钽)→锡、钨、(铁)、铜、铟→锡、铅、锌、银、铟、(锑)有规律的变化.花岗岩浆是成矿物质来源和成矿热源.岩浆侵入初期使上覆地层隆起产生背斜(凹陷部位成向斜);同时使地层产生一系列裂隙、压性断层或层间断裂;岩浆侵入晚期,这些断层再次活动,表现为张性,岩浆产生的含矿热液沿由其活动所造成的断裂迁移、充填、交代、沉淀而形成矿床.  相似文献   

20.
Bellechester, Minnesota, is a small community of approximately 155 residents located on the county line between Goodhue and Wabasha counties in southeast Minnesota's karst region. Bellechester is served by a 21-year-old wastewater treatment facility (WWTF) consisting of three waste-stabilization ponds. On 28 April 1992 six sinkholes were discovered to have drained cell 2 of the WWTF resulting in the loss of approximately 8.7×106 1 of partially treated effluent and about 600 m3 of soil into previously undetected subsurface voids of unknown dimensions. In the week following the collapse, approximately 200 water wells located within a 5-km radius of the WWTF were sampled in an after-the-fact, emergency sampling program. Twelve samples with elevated fecal coliform levels, 18 samples with nitrate-nitrogen greater than the 10 mg/1 standard, and no samples with elevated chlorides were found. However, the elevated levels could not be unambiguously attributed to the WWTF collapse. This is the third WWTF to fail by sinkhole collapse in southeast Minnesota since 1974. All three collapsed lagoons have been located in similar geomorphic and stratigraphic settings. However, at least two lagoons have collapsed in the adjacent area in northeast Iowa, and these lagoons are located at different stratigraphic positions. Twenty-two WWTFs constructed in southeast Minnesota's karst region in the last 25 years have been identified as subject to potential sinkhole collapse. An unknown but significant number of manure storage lagoons, flood control structures, etc., have also been constructed in the karst region and are at risk. Public agencies are beginning to develop plans to deal with the risk associated with existing and future waste lagoons in this environment. The critical hydrogeologic parameters that can be used to prioritize the risk of collapse at existing facilities include: (1) the lithology of the first bedrock beneath each lagoon, (2) the thickness of surficial materials between the lagoon and the bedrock surface, (3) the presence and construction of liners (seepage rate), and (4) the proximity to existing sinkholes.  相似文献   

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