山东平邑卓家庄金矿金品位的分形结构特征及意义   总被引：8，自引：0，他引：8  

曾庆栋  郑晓廷 《地质与勘探》2000,36(3):43-45,47

卓家庄金矿为隐爆角砾岩型金矿床,主要矿石类型可分为４种：矿浆胶结隐爆角砾岩矿石、热液胶结隐爆角砾岩矿石、熔浆胶结隐爆角砾岩矿石、凝灰质胶结隐爆角砾岩矿石。金品位分形结构研究表明,该矿床具有多次分形结构及规律性变化特点,反映了多次矿化叠加的特点,并预示了深部矿化的存在。  相似文献   

Fluids double-fracturing genetic mechanism and mineralization of gold-copper of the breccia pipe at Qibaoshan in Shandong Province   总被引：9，自引：0，他引：9  

XU Xingwang  CAI Xinping  QIN Dajun  WANG Jie  LIANG Guanghe  Zhang Xiaoyun  LIU Lijin 《中国科学D辑(英文版)》2000,43(2):113-121

After studying the characteristics and special texture of the fluidogenous tectonics, mineral assemblage in the cemented vein between breccia and their special distribution, and stress analyzing the joint structures in and around the breccia pipe, it is found that the observed phenomena are caused by a new tectonic dynamic mechanics of fluid—double-fracturing caused by temperature and pressure of fluids and pulsating expansion. Under the actions of thermal stress and the pressure of fluids, thermal cracks and joints that developed along parts of the thermal cracks formed systematically in the rocks. Under these conditions, up-arching fracture zones that pulsatively expanded upward and cylindrical pressing breccia body were formed. Rocks at the peak of the pyramidal fractures zone break down instantly. Where the difference between pressure of fluids and the overburden pressure exceeded greatly the competence of the rocks, fluid junctions occurred and the velocity of the fluid flow increased as a result. Explosive body expanded upward in the shape of an inverse cone, cone-like explosive breccia body and cover-like shattering breccia body located on the upper part of the breccia pipe were ultimately formed. Gold-rich fluids were enriched and mineralized near the boiling surface in the lower part of the inverse cone-like explosive breccia body where temperature and pressure decreased rapidly, while copper-rich fluids were enriched and mineralized in the junction area where temperature and pressure were relatively high.  相似文献   

钠长石花岗岩中雪球结构形成机理的研究   总被引：5，自引：0，他引：5  

李福春  朱金初  金章东  李晓峰 《岩石矿物学杂志》2000,19(1):27-35

在某些富锂、氟含稀有金属花岗岩的石英和钾长石斑晶中常见 (半 )雪球结构。雪球结构的产出特征、雪球体中钠长石的电子探针分析结果以及其他间接证据都说明 ,雪球结构是在岩浆结晶分异过程中形成的。对矿物结晶顺序、石英和钠长石的生长速率以及固相线温度的研究表明 ,富锂、氟、钠的花岗质残余岩浆完全具备形成雪球结构的条件。岩浆熔体中较高的Na2 O/K2 O比值和F、H2 O含量在雪球结构的形成过程中起着重要的作用 :F的高含量使岩浆固相线温度降低 ,岩浆得以充分分异演化 ,形成接近端员组分的钾长石和钠长石 ;Na2 O/K2 O比值较大使钠长石首先结晶 ;较高的F和H2 O含量使岩浆粘度降低 ,石英的生长速率相对加快并逐渐包裹钠长石形成雪球结构。  相似文献   

Puziwan Gold Deposit in Shanxi, China: A Special Linear Cryptoexplosive Breccia Type Gold Deposit   总被引：1，自引：0，他引：1  

YAN Fengzeng Gold Headquarters  State Economic  Trade Commission  P.O. Box:  Beijing 《《地质学报》英文版》2000,74(3)

The Puziwan gold deposit is a special linear cryptoexplosive breccia type deposit found in northeastern Shanxi, China, in recent years. The deposit is located in a secondary metallogenic. belt of the most famous Au-Ag polymetallic metallogenic belt along the north margin of the North China platform. The secondary metallogenic belt is a synmagmatic tension-shear fault-fracture belt of ENE linear trend. The Indosinian cryptoexplosive breccia body, quartz monzonitic porphyry (beschtauite breccia), quartz monzonite (243.7 Ma, K-Ar), Yanshanian granite-porphyry (105±6 Ma, Rb-Sr) and orebodies mostly occur as dykes or veins and short lenses along the structural fracture belt. The orebodies are emplaced in the fractured cryptoexplosive breccia body in the tectonomagmatic belt and their attitude is consistent with that of the breccia body. The orebodies have two types: one is shallow-seated thick and big ones, which are short-lenticular in plan and wedge-shaped in cross section, shallow buried, large in size a  相似文献   

香炉碗子金矿区次火山岩及其地球化学特征     

冯守忠 《地质与资源》2000,9(3):155-159

香炉碗子金矿区分布的次火山岩是由花岗质岩浆沿东西向脆-韧性剪切带上升到地壳浅部隐爆而成,隐爆角砾岩体与霏细岩脉来自同一岩浆源,为同一岩浆活动不同演化阶段的产物,隐爆角砾岩体(脉)、霏细岩脉在时间上、空间上、成因上与金矿形成关系密切.稀土元素、微量元素、同位素等地球化学特征显示出成矿物质和成矿热液与隐爆角砾岩、霏细岩同源,成岩与成矿是同一岩浆作用不同阶段的产物.东西向脆-韧性剪切带内隐爆角砾岩体(脉)、霏细岩脉的存在是区内重要的找矿标志.  相似文献   

The metahyaloclastitic matrix of a unique metavolcanic block reveals subduction in the Somozas Mélange (Cabo Ortegal Complex,NW Iberia): tectonic implications for the assembly of Pangea          下载免费PDF全文

I. Novo‐Fernández  A. Garcia‐Casco  R. Arenas  R. Díez Fernández 《Journal of Metamorphic Geology》2016,34(9):963-985

The allochthonous Cabo Ortegal Complex (NW Iberian Massif) contains a ~500 m thick serpentinite‐matrix mélange located in the lowest structural position, the Somozas Mélange. The mélange occurs at the leading edge of a thick nappe pile constituted by a variety of terranes transported to the East (present‐day coordinates; NW Iberian allochthonous complexes), with continental and oceanic affinities, and represents a Variscan suture. Among other types of metaigneous (calcalkaline suite dated at 527–499 Ma) and metasedimentary blocks, it contains close‐packed pillow‐lavas and broken pillow‐breccias with a metahyaloclastitic matrix formed by muscovite–paragonite–margarite–garnet–chlorite–kyanite–hematite–epidote–quartz–rutile. Pseudosection modelling in the MnCNTKFMASHO system indicates metamorphic peak conditions of ~17.5–18 kbar and ~550 °C followed by near‐isothermal decompression. This P–T evolution indicates subduction/accretion of an arc‐derived section of peri‐Gondwanan transitional crust. Subduction below the Variscan orogenic wedge evolved to continental collision with important dextral component. Closure of the remaining oceanic peri‐Gondwanan domain and associated release of fluid led to hydration of the overlying mantle wedge and the formation of a low‐viscosity subduction channel, where return flow formed the mélange. The submarine metavolcanic rocks were deformed and detached from the subducting transitional crust and eventually incorporated into the subduction channel, where they experienced fast exhumation. Due to the cryptic nature of the high‐P metamorphism preserved in its tectonic blocks, the significance of the Somozas Mélange had remained elusive, but it is made clear here for the first time as an important tectonic boundary within the Variscan Orogen formed during the late stages of the continental convergence leading to the assembly of Pangea.  相似文献   

Qiyugou auriferous breccia pipes:A low-sulphidation epithermal system linked with transition of tectonic regime from collisional compression to extension,Xiong'ershan,Henan,China     

ZHANG Yuanhou  ZHANG Shihong  Pirajno Franco 《世界地质(英文版)》2021,24(1):23-42

The Xiong’ershan area,as a part of a metallogenic province in cetral China,contains substantial Leimengou porphyry molybdenite deposit,Qiyugou breccia gold deposits and vein gold deposit occurred in fault zone,as well as previously refer to as orogenic gold deposit.Around or nearby the Mesozoic porphyry granite,the typical porphyry deposit,much more breccia pipes and breccia gold deposit are developed in the area.In this paper we focus on reporting preliminary results obtained from field,petrographic work on the Leimengou porphyry molybdenite and the Qiyugou breccia gold deposit,as well as laser Raman microspectroscopy and microprobe analyses carried out on samples from the Au-bearing Qiyugou breccia pipes.An adularia-calcite assemblage is reported in these breccia gold deposits.Two stages of hydrothermal alteration,pervasive and vein,are identified.The first stage consists of the alteration of the breccia clasts and rock flour by actinolite,green biotite,epidote,chlorite and minor sericite.This hydrothermal activity is likely to relate to the molybdenite mineralisation episode.The second stage is characterised by quartz veining and adularia and calcite filling open-spaces.Vein ores associated with quartz,sericite,and minor calcite alteration occur in NE-trending fault that cut the first stage of alteration.The adularia-calcite alteration is genetically associated with gold mineralization.The adularia-calcite assemblage in the area suggest that the Qiyugou pipes are of low-sulphidation epithermal in nature.The Qiyugou breccia pipes are coeval and spatially associated with the nearby Leimengou porphyry Mo deposit,which together conform to an alkalic mineralising system.We propose a model for the development and evolution of the breccia pipes in conjunction with a model that describes the genesis of the porphyry Mo and auriferous breccia pipes as a unified magmatic-hydrothermal system,which is linked with transition from collisional compressional to extensional geodynamic regime.  相似文献   

内蒙古自治区额济纳旗呼伦西白金矿成矿地质条件及找矿模式     

杨富林  娄晨  刘雁青  李万忠  徐海山 《西北地质》2011,44(1):61-68

额济纳旗呼伦西白金矿床位于呼伦西白-珠斯楞反＂S＂型弧形构造的西端,北西向断裂规模较大,既是主要的控岩、控矿构造,也是热液活动的主要通道;后期叠加的北东向次级构造（与次火山岩活动或岩体的深部隐爆作用有关）是本区重要的储矿构造。矿体赋存在侏罗纪斑状黑云母花岗岩、正长斑岩内或与地层接触的内外带的不同构造部位,成矿物质主要来源于该期次火山岩活动,属于岩浆期后热液碎裂蚀变型、次火山岩型（或岩浆隐爆角砾岩型）金矿床。矿区内已发现的13条金矿脉产出环境可分为两种类型：一种是岩体内部或与围岩的内接触带,另一种是外接触带中的破碎带（或薄弱带）。与金矿形成关系密切的蚀变主要为硅化、黄铁矿化、黄铜矿化,含金品位与这些金属硫化物（或其氧化物）的含量呈正相关关系。在分析矿床的成矿地质条件的基础上,初步建立了该矿床的成矿模式,总结了综合找矿标志。  相似文献   

Neoproterozoic high-pressure/low-temperature metamorphic rocks in the Avalon terrane, southern New Brunswick, Canada     

C. E. White  S. M. Barr  R. A. Jamieson  P. H. Reynolds 《Journal of Metamorphic Geology》2001,19(5):519-530

High‐P/low‐T metamorphic rocks of the Hammondvale metamorphic suite (HMS) are exposed in an area of 10 km² on the NW margin of the Caledonian (Avalon) terrane in southern New Brunswick, Canada. The HMS is in faulted contact on the SE with c. 560–550 Ma volcanic and sedimentary rocks and co‐magmatic plutonic units of the Caledonian terrane. The HMS consists of albite‐ and garnet‐porphyroblastic mica schist, with minor marble, calc‐silicate rocks and quartzite. Pressure and temperature estimates from metamorphic assemblages in the mica schist and calc‐silicate rocks using TWQ indicate that peak pressure conditions were 12.4 kbar at 430 °C. Peak temperature conditions were 580 °C at 9.0 kbar. ⁴⁰Ar/³⁹Ar muscovite ages from three samples range up to 618–615 Ma, a minimum age for high‐P/low‐T metamorphism in this unit. These ages indicate that the HMS is related to the c. 625–600 Ma subduction‐generated volcanic and plutonic units exposed to the SE in the Caledonian terrane. The ages are also similar to those obtained from detrital muscovite in a Neoproterozoic‐Cambrian sedimentary sequence in the Caledonian terrane, suggesting that the HMS was exposed by latest Neoproterozoic time and supplied detritus to the sedimentary units. The HMS is interpreted to represent a fragment of an accretionary complex, similar to the Sanbagawa Belt in Japan. It confirms the presence of a major cryptic suture between the Avalon terrane sensu stricto and the now‐adjacent Brookville terrane.  相似文献   

黔西南戈塘金矿成因再认识          下载免费PDF全文

毛彬吉  冉瑞德  况顺达  吴治君  赵明峰  王小洪 《地质找矿论丛》2018,33(2):168-175

文章通过对戈塘金矿硅质角砾岩的地质特征、地球化学特征综合分析,认为矿区的角砾硅化灰岩、硅化黏土岩等蚀变地质体为热液成因,其中硅质来源可分为成岩期与成矿期:成岩期硅质来自热泉型生物沉积;成矿期硅质来自成矿流体。成矿流体是来源于深部流体与天水、地层建造水的混合作用形成的混合流体。根据矿石结构构造特征及含金蚀变地质体产状特征,结合在戈塘地区茅口组底部及以下地层中新近发现呈筒状产出的含金蚀变角砾岩,认为戈塘金矿矿区含金角砾岩具有隐爆角砾岩的特征,得出戈塘金矿成因类型可能为隐爆角砾岩型金矿的新认识。此认识可供黔西南金矿成矿理论研究、探讨新的找矿方向和成矿预测提供参考。  相似文献