河南省嵩县祁雨沟金矿区四号角砾岩筒金矿体空间定位模式

河南嵩县祁雨沟金矿区四号角砾岩筒是燕山晚期中酸性岩浆超浅成侵位而形成的隐爆-坍塌型角砾岩筒,第一期矿化形成受角砾岩筒形态制约的不规则状胶结物型金矿体,第二期矿化形成受断裂裂隙制约的脉状矿体。前者主要受角砾岩筒本身的形态制约,形成不规则状矿体;后者受制于剪切裂隙系统,形成含金石英-多金属硫化物脉状金矿体。两种不同的矿化类型在垂向上存在明显分带性。在490m中段以下主要为受角砾岩筒形态控制的不规则状胶结物型金矿体,490m中段以上则逐渐过渡为受叠加裂隙控制的脉状矿体。     

湖南水口山矿田老鸭巢爆破角砾岩特征及成因初探

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.     

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

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.     

高速铁路膏溶角砾岩深埋隧道支护荷载确定方法

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。     

Extensional rise and fall of a salt diapir in the Sørvestsnaget Basin,SW Barents Sea

Regional extension which initiates and promotes the rise of salt diapirs can also make diapirs fall once the supply of salt from its source is restricted. New observations on the 3D seismic data from a salt diapir in the Sørvestsnaget Basin suggest that salt moves until the end of the Eocene and is subtle to minor readjustments afterwards, revealing a more complex kinematics that previously described. Observations such as salt horns and sags and an antithetic fault linked to the western flank of the diapir suggest that salt syn-kinematics during Middle-Late Eocene included passive rising of the salt, followed by a fall. The salt horns are remnants of a taller salt diapir that, together with the indentation of the Middle-Late Eocene syn-kinematic sediment overburden above the salt, indicate diapiric fall due to restriction of salt supply by extension. Post-kinematic readjustments did not include diapiric reactivation by tectonic compression as previously thought, but minor salt rise by shortening due to gravity gliding after the tilting of the margin during Plio-Pleistocene glacial sediment loading and differential compaction of surrounding sediments. The salt diapir appears to be presently inactive and salt supply may have been restricted from its source already since Late Eocene.     

吉林省白山市金英金矿床地质特征及成因探讨

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.     

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

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.     

南海北部深水盆地流体活动系统及其成藏意义

根据高精度的3D和2D地震资料,对南海北部深水盆地的流体活动系统的类型、影响因素和它们之间的演化关系进行了研究.南海北部深水区存在着包括:泥火山、泥底辟、气烟囱、管状通道、多边形断层和构造断层等多种类型的流体活动系统.根据地震反射特征,可以把它们划分为断层有关的流体活动系统和柱状流体活动系统两大类.研究发现研究区内的流体活动系统主要受构造和沉积两方面的影响.并且,气烟囱、泥底辟和泥火山存在着单向演化的关系,可以从是否有沉积物参与运移及是否喷出海底将它们区分开来.最后,本文探讨了流体活动系统对深水油气和天然气水合物成藏的重要影响,建立了南海北部流体活动系统的存在模式.     

安徽宣城薛家村隐爆角砾岩的发现及其找矿意义

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。