湖南水口山矿田老鸭巢爆破角砾岩特征及成因初探     

程雄卫  汤静如  杜金亮  罗红波 《地质与资源》2012,21(2):239-243

老鸭巢铅锌金多金属矿床中的岩体超覆侵入时形成了一系列角砾岩,其中岩浆隐蔽爆破角砾岩就是矿床铅锌金矿体主要赋矿构造.隐蔽爆破角砾岩可分为隐爆角砾、震碎角砾、流化角砾.老鸭巢矿区广泛分布着晚三叠世-中侏罗世的古岩溶沉积体,这些沉积的孔隙度高且富含地下水.当岩浆超覆侵入此处时,由于外部环境发生急剧变化,岩浆减压、降温、二次沸腾,并不断析出流体,在局部圈闭环境下流体压力将逐渐增大;加之岩溶中地下水丰富,地下水不断的气化,使气体的压力骤然增大.在屏蔽作用良好的超覆部发生了爆破作用形成了隐爆角砾;在爆破的外部震碎带形成了震碎角砾;而爆破之后的流化作用则形成了流化角砾.通过对老鸭巢爆破角砾岩的特征的研究,结合爆破角砾岩形成的地层、构造、岩体等条件的分析来探讨隐蔽爆破角砾岩的形成过程.分析了老鸭巢铅锌金矿体与隐蔽爆破角砾岩的关系,为今后矿山找矿提供服务.  相似文献   

内蒙古东乌旗达勒廷查干铅锌银矿区东矿段隐爆角砾岩特征及其地质意义     

韩晓平 《地质与资源》2016,25(1):46-51

达勒廷查干铅锌银矿床位于大兴安岭中段查干敖包铁、铅、锌成矿带北东段,其赋矿围岩为上侏罗统满克头鄂博组与燕山期花岗斑岩中的超浅成酸性隐爆角砾岩体.角砾岩体从中心向外侧有较显著的岩石类型分带,中心部位为隐爆含角砾凝灰岩,向外角砾增大,逐渐过渡为震碎角砾岩.角砾岩蚀变强烈,主要为高岭土化、绿泥石化、绿帘石化、绢云母化、碳酸盐化,局部硅化强烈,并有明显的蚀变分带现象.矿体呈脉状,产于角砾岩体中.对本矿床隐爆角砾岩特征的研究可为矿区外围及深部找矿提供参考.  相似文献   

高速铁路膏溶角砾岩深埋隧道支护荷载确定方法   总被引：1，自引：0，他引：1  

何本国  朱永全  孙明磊  张志强  孙元国 《岩土力学》2013,34(3):827-832

合理的支护荷载确定方法是膏溶角砾岩深埋隧道设计和施工过程中的关键科学问题。以石太客运专线太行山隧道累计穿越4 410 m膏溶角砾岩地层为依托,通过现场支护荷载量测试验,统计得到初支围岩压力和二衬接触压力。采用泰沙基理论、比尔鲍曼理论、谢家烋理论、铁路隧道设计规范和普氏理论共5种方法分别计算围岩压力,并与现场实测值相比较。结果表明：围岩压力以竖向为主,泰沙基理论值与现场实测统计值最为接近;围岩压力在竖向、水平分布模式不同于传统计算方法,推荐竖向压力采用双峰型或均匀分布,水平压力采用折线型分布;初支和二次衬砌共同承担荷载,二衬分担比例为50.1%。研究成果可为高速铁路膏溶角砾岩以及类似地质条件深埋隧道修建提供参考。  相似文献   

吉林省白山市金英金矿床地质特征及成因探讨   总被引：1，自引：0，他引：1  

刘文香  满永路  王兴昌 《地质与资源》2009,18(4):279-283

金英金矿床产于叠加在先期存在的新元古界钓鱼台组石英砂岩与古元古界珍珠门组硅化白云质大理岩之间的不整合面附近的硅化构造角砾岩带中的F100断裂内,主要受区域性断裂F102及局部性断裂F100的联合控制.金英金矿形成的特殊环境和物化条件,使其具有独特的矿物组合和矿石结构构造,是我国目前发现的一种新类型金矿.金矿类型属于中生代造山带型金矿.  相似文献   

Ultramafic intrusion triggers hydrothermal explosions at Colle Fabbri (Spoleto, Umbria), Italy     

Francesco Stoppa  Gianluigi Rosatelli 《Journal of Volcanology and Geothermal Research》2009,187(1-2):85-92

The eroded Colle Fabbri volcano comprises intrusive and extrusive rocks which cover an area of about 10,000 m² in the Umbria region, Central Italy. The outcrop is located at the SW boundary of the Umbria Valley Graben (Umbria Region) on an N140 normal fault inside the Intramountain Ultra-Alkaline Province of carbonatite and melilitite rocks of central–southern Italy. A field survey of the outcrop allowed a reconstruction of igneous activity events of this unusual small-scale volcano. It is younger than 0.7 m.y. and rests on Lower Pleistocene conglomerates with intercalated clay beds. A palaeosoil marks the base of the volcanic sequence. It follows several metres of extrusive breccias composed of fragments of thermometamorphosed clay and travertine. Key features of these breccias are mud shells on blocks, plastic mud lumps, slumps, and mechanical injection from one layer into another, as well as plastic and vesiculated, micro-brecciated matrix. The breccias are cemented by a variety of silicate, sulphate, and sulphate–carbonate minerals deposited by intense hydrothermal circulation. The breccias are related to phreatic explosions triggered by the eruption of a superficial hydrothermal system. Up to 1 m thick sill and a dykelet swarm intrude the breccias. In the southern part of the outcrop there is a plug of melilitolitic composition which intrudes the breccias and deforms them upward. A variety of contact breccias is also scattered around the sill and the plug. In some places, hyaloclastite formed when melt invaded water pockets contained in the encasing rocks under hydrostatic pressure conditions. A thermal aureole, which moves up to 10 m away from the contact, is characterised by cordierite–trydimite association, thus indicating high-temperature (>>1000 °C) contact phenomena.  相似文献   

安徽宣城薛家村隐爆角砾岩的发现及其找矿意义     

洪大军  陈科夫  张旭  金敏 《华东地质》2019,(4):280-288

宣城茶亭铜金矿床是首次在皖东南地区发现的大型斑岩型铜金矿床,成矿岩体上部发育大规模与成矿有关的隐爆角砾岩。近期,在茶亭矿区西侧薛家村南部也发现了隐爆角砾岩,通过野外地质调查、室内综合分析及地球物理特征对比,证明角砾岩成分、矿化蚀变及矿物组合特征与茶亭铜金矿床的隐爆角砾岩类似;薛家村一带的CSAMT低阻、激电高极化、中等地磁、重力高特征也与茶亭矿区相似。茶亭矿区西部被三叠系覆盖,薛家村隐爆角砾岩的发现,指示茶亭矿区可能存在多次隐爆作用,对茶亭铜金矿床外围进一步找矿具有指导意义。  相似文献   

Predicting the uniaxial compressive strength and elastic modulus of a fault breccia from texture coefficient   总被引：1，自引：0，他引：1  

M. Alber  S. Kahraman 《Rock Mechanics and Rock Engineering》2009,42(1):117-127

  相似文献   

Sedimentology, petrography and geochemistry of a limestone breccia (Pietra di Billiemi) from north-west Sicily, Italy: implications for evolution of the Tethyan basins around the Triassic/Jurassic boundary     

GIOVANNA SCOPELLITI  RODOLFO NERI  ADRIANA BELLANCA  PIETRO DI STEFANO†  MARIO BARBIERI‡ 《Sedimentology》2009,56(2):591-607

In this study, the Pietra di Billiemi , a famous dimension stone, is investigated because it records the tectonic evolution of the south Tethys continental margin and preserves a record of major environmental changes occurring near the Triassic/Jurassic boundary. The Pietra di Billiemi is a grey, coarse-grained and clast-supported limestone breccia cropping out in an area of the Palermo Mountains representing a segment of the Apennine–Maghrebian chain in western Sicily. The rock consists of metre-sized to centimetre-sized angular clasts, derived from Upper Triassic sponge boundstones and rudstones, with a differently coloured, silt-grained matrix. Fitted fragments are observed commonly which suggest an in situ origin for the bulk of the breccia. The matrix is characterized by the absence of biogenic components and by variable mineralogy and geochemistry. Petrographic features and Sr-isotope values indicate that the most important and earliest fillings of the breccia consist of black matrix and white matrix temporally referable to Hettangian–Sinemurian times. Clotted micrite, carbonate fluorapatite and abundant pyrite, in addition to relatively high contents of redox-sensitive elements (V, Ni, Zn and S), are consistent with deposition in anoxic conditions that favoured microbial mediation for authigenic carbonate (calcite and dolomite) precipitation in the matrix. As a whole, the Billiemi breccia can be considered a product of tectonic fragmentation of a Tethyan carbonate platform edge around the Triassic/Jurassic boundary, formed when the drowned platform edge was covered by hemipelagic mudstones recording the anoxic conditions existing during Early Jurassic times.  相似文献   

切特木斯铜（银）矿地质特征研究——兼论伊斯基里克地区“鸡窝”状矿体成因     

肖力  李汉光  董刚  金宝义  唐明国  韩先菊 《矿产与地质》2009,23(4):329-334

在分析切特未斯铜（银）矿的地质特征、围岩蚀变特征、矿床成因基础上,通过与典型角砾岩型矿床和典型斑岩型矿床矿化特征、蚀变特征进行对比,认为该矿床成因类型为斑岩型。根据此类型矿床找矿标志和控制因素,结合区域地质条件研究对比,初步分析了找矿方向,圈定找矿远景区．  相似文献   

山西省代县滩上一带隐爆角砾岩地球物理和地球化学特征及其地质意义     

侯彦明  王云章  徐永婧  张雪梅 《现代地质》2019,33(4):727-737

隐爆角砾岩型金矿是国内外一种具有重要经济价值的矿床类型。在分析山西代县滩上隐爆角砾岩区的金多金属矿床地质背景、地球物理及地球化学特性的基础上,研究滩上一带隐爆角砾岩的岩石化学特征,发现该区金多金属矿体赋存部位位于岩体内、内外接触带及四集庄组岩组捕虏体中。研究认为,金多金属矿由石英斑岩中硫化物局部富集形成,其主要物质来源与滩上岩体之岩浆期后热液有关,黄铁矿化隐爆角砾岩为容矿岩石,断裂及其次级断裂、裂隙等构造活动为金矿体的形成提供了良好的导矿通道,燕山期中酸性浅成-超浅成岩浆活动为研究区成矿提供了大量含矿热液和成矿物质。  相似文献