斑岩型矿床相关知识

中国大陆环境斑岩型矿床包括斑岩型Cu（-Mo、-Au）、斑岩型Mo、斑岩型Au和斑岩型Pb-Zn 等矿床类型,主要产出于青藏高原大陆碰撞带、东秦岭大陆碰撞带和中国东中部燕山期陆内环境,在地球动力学背景、深部作用过程、岩浆起源演化、流体与金属来源等方面与岩浆弧环境斑岩型矿床存在重要差异。

在大洋板块俯冲形成的岩浆弧,主要发育斑岩Cu-Au矿床或富金斑岩Cu矿（岛弧）和斑岩Cu-Mo及斑岩Mo矿床（陆缘弧）。

相比,在大陆碰撞带,晚碰撞构造转换环境发育斑岩Cu、Cu-Mo和Cu-Au矿床,矿床受斜交碰撞带的走滑断裂系统控制,后碰撞地壳伸展环境则主要发育斑岩Cu-Mo矿床,矿床受垂直于碰撞带的正断层系统控制;在陆内造山环境,早期发育斑岩Cu-Au矿床,晚期发育斑岩Pb-Zn矿床,它们主要沿古老的但再活化的岩石圈不连续带分布,受网格状断裂系统控制;在后造山（或非造山）伸展环境,则大量发育斑岩Mo矿和斑岩Au矿,它们则主要围绕大陆基底—克拉通（或地块）边缘分布,受再活化的岩石圈不连续带控制。

大陆环境斑岩Cu（-Mo,-Au）矿床的含矿斑岩多为高钾钙碱性和钾玄质,以高钾为特征,显示埃达克岩地球化学特性。

岩浆通常起源于加厚的新生镁铁质下地壳或拆沉的古老下地壳。

上地幔通过三种可能的方式向岩浆系统供给金属Cu（和Au）：①提供大批量的幔源岩浆并底垫于加厚下地壳底部,构成含Cu岩浆的源岩;②提供小批量的软流圈熔体交代和改造下地壳,并诱发其熔融;③与拆沉的下地壳岩浆熔体发生反应。

大陆环境含Mo岩浆系统高SiO2、高K2O,岩相以花岗斑岩为主,花岗闪长斑岩次之,既不同于Climax 型,又有别于石英二长斑岩型Mo矿床,岩浆起源于古老的下地壳。

金属Mo主要为就地熔出,部分萃取于上部地壳。

大陆环境含Pb-Zn花岗斑岩多属铝过饱和型,与S型花岗岩相当,以高δ18O（〉10‰）和高放射性Pb为特征,Sr-Nd-Pb同位素组成反映其来源于中下地壳的深熔作用,金属Pb-Zn主要来源于深融的壳层。

斑岩型矿床：分类、分布、动力学背景和侵入体Porphyry Deposits –Characteristics斑岩矿床的特征Large tonnage and low grade bulk mineable deposits大吨位低品位适于规模开采Large volumes of hydrothermal alteration大规模的热液蚀变Stockwork and breccia-hosted ore网脉状和角砾状矿石Related to porphyritic intrusions与斑状侵入体相关Supergene enrichment表生富集E27 Cu-Au porphyry, NSWCuMo (*10)Au (*10,000)钙碱性碱性高K 钙碱性岩浆中SiO2增加•早期形成的矿脉和蚀变矿物组合中磁铁矿含量递增•侵位深度的递减陆缘弧环境根据金属含量的分类Modified from Kesler (1973) and Thompson (1994)Modified from Blevin, 2003Magma Chemistry岩浆化学Cu -AuSn ±WMoWW -MoCu -MoSnIncreasing Fractionation结晶分异作用增强Increasing Oxidation氧化性增加Rb/SrFe 2O 3 /FeO10110010-110-110-210-3102101100103Metal endowment of intrusion-related deposits controlled by the magma’s:•oxidation state•compositional evolution •silica contentAnhydrite phenocryst with apatite inclusions, North Parkes, NSW与侵入岩有关矿床中金属总量受岩浆以下条件的控制•氧化态•成分演化•SiO 2含量Aktogay-Aiderly Cerro Colorado La Granja Radomiro Tomic Resolution Pima Cuajone Lone Star Morenci-Metcalf Rio Blanco –Los BroncesEl Teniente102030405060708090C o n t a i n e d c o p p e r m e t a l (M t )BehemothianSuper-giantOyu Tolgoi Grasberg Los Pelambres Cu-Mo deposits Chuquicamata Collahuasi Bingham Escondida El Salvador Cu-Au depositsButte Cananea Ray Cu-Au-Mo deposits204.3 Mt CuPebble Reko Diq Largest 25 PCDs -based on contained Cu (Mt)最大的25个PCD －根据Cu 金属量（Mt ）Location: Porphyry Cu-Mo Deposits位置：斑岩型Cu-Mo 矿床Porphyry Cu-MoNorthern ChileAktogay-AiderlySouthern PeruLa Granja ButteSW Arizona /SonoraCentral Chile Map source: 40080012001600200024002800GrasbergBingham Oyu Tolgoi Cadia district Kal'makyr Dalneye FSE/Lepanto Cerro Casale Panguna Ok Tedi Batu Hijau Minas Conga Tampakan Escondida El Teniente Galore Creek Alumbrera Frieda River Atlas Sar Cheshmeh Chuquicamata Sipilay G o l d (t o n n e s )Cu-Mo depositsCu-Au depositsCu-Au-Mo depositsPebble Reko Diq Kerr-S-M Largest 25 Au-rich PCD -contained Au (t)最大的25个富Au PCD –含Au （t ）Map source: Gold-rich porphyry copper districts富金斑岩铜矿地区Batu HijauAlmalyk Porphyry Cu-Au 斑岩型Cu-Au 矿床Oyu Tolgoi Cerro Colorado Bajo de la Alumbrera Minas CongaReko DiqCadiaPangunaPhilippinesPNG –Irian JayaGalore CreekDalneyeCerro CasaleLa EscondidaPorphyry Cu-Au-Mo斑岩型Cu-Au-Mo 矿床Bingham CanyonSar ChesmehPebbleEpochs of porphyry deposit formation斑岩型矿床的形成时期Calc-alkalic（钙碱性）High-K calc-alkalic（高K钙碱性）Alkalic（碱性）Magmatic affinity Tectonic Setting岩浆种类构造背景0100200300400500Age (Ma)Age (Ma)01002003004005001020Continental arc（陆缘弧）Island arc（岛弧）Collision zone（碰撞带）Arc of unknown type（不明类型弧）Data source: Kirkham & Dunne, 1999Compressional arc settings 05 km5 km PhilippineSeaBoholSeaL. MainitNImage courtesy of David Braxton and Anglo AmericanBoyongan/Bayugo Porphyry ComplexFore Arc 有利的地球动力学环境•Porphyry deposits emplaced within a narrow time interval斑岩型铜矿就位于一个很短的时间区间•Similar magma suites in each event在每期事件中呈现相近的岩浆组合•Similar metal suite in each event在每期事件中具有相似的金属组合•General relationship to subduction environment通常与俯冲环境有联系•Specific relationship to tectonic change与构造环境转变具有特定关系Porphyry Provinces斑岩省NazcaRidgeJuan Fernandez Ridge150 km BenioffcontourPeruChileTrenchLa Granja(10 Ma)Yanacocha (11 Ma)Minas Conga (20 Ma)Pierina(14.5 Ma)El Teniente (5 Ma)Cerro Casale(13.5 Ma)400 kmBajo de laAlumbrera(8-7 Ma)Río B lanco (6 Ma)Los Pelambres(10 Ma)7.8 cm/yrIncaPlateauNSouthAmericanPlateNazcaPlate Pascua-Lama(9–8 Ma)El Indio (8–5 Ma)80°W70°W60°W0°10°S20°N30°S40°S Ridge Subduction 海岭俯冲Triggered Miocene porphyry & HSmineralisation -central & northern Peru触发了中新世的斑岩和HS矿化—秘鲁中北部Triggered Late Miocene –Pliocene porphyry& HS mineralisation -Central Chile触发了晚中新世－上新世的斑岩和HS矿化－智利中部Source:/mgg/image/2minrelief.html菲律宾PhilippinesSource:/mgg/image /2minrelief.html200 km200 kmPhilippine PlateEurasian PlateMankayan district (2 –1 Ma)~8 Mt Cu & 37 Moz AuBaguio district (3 –1 Ma)~3 Mt Cu & 35 Moz AuMankayan district(2 –1 Ma)8 Mt Cu & 37 Moz AuaseismicScarborough RidgeImage courtesy of Paddy Waters, AngloAmerican (Philippines)Northern Luzon Tectonic Setting 吕宋岛北部构造背景Baguio district (3 –1 Ma)3 Mt Cu & 35 Moz AuSubducted part of Scarborough RidgeScarborough山岭的俯冲部分•Shallowing subduction angle使俯冲角度变小•Cessation of voluminous andesitic volcanism使大规模安山质火山作用停止•Thrust stacking & crustal thickening逆冲堆叠和地壳加厚•Giant earthquakes and propogation of deformation fronts强烈地震和变形前缘扩展•Formation of porphyry and epithermal deposits斑岩和浅成热液矿床的形成•Rapid uplift & exhumation快速隆升和剥蚀Cerro Aconcagua, ArgentinaRidge Subduction -Side Effects?海岭俯冲的副作用？Post-orogenic porphyry depositsCollision commenced ~65 MaPorphyries cluster at ~40, ~35, ~25 MaHabo造山后斑岩矿床碰撞起始于~65百万年斑岩集中形成于~40, ~35, ~25 MaXenolith of biotite quartz monzonitein QMP, North Parkes, NSW碱性PCD Intrusions侵入岩碱性PCD钙碱性PCD石英闪长斑岩,Far South East, Philippines石英二长斑岩North Parkes, NSW石英二长斑岩中有黑云母石英二长岩包体Intrusion Geometries侵入体形态QMP pipe, E27 Cu-Au PCD,North Parkes, NSWQMP 石英二长斑岩Biotite-altered trachyandesite 粗安岩被次生黑云母交代E27 open pit,North Parkes, NSWIntrusion Geometries侵入体形态Multi-phase intrusions多相侵入体•Multiple pipes, dykes or sills typicallycomprise mineralised intrusive complexes矿化侵入杂岩体通常由多个岩筒、岩墙或岩席组成•Only one or two intrusive phases createsignificant mineralisation只有一到两个侵入相产生重要矿化•A number of factors may affect anintrusion’s capacity to exsolve abundantvolatiles and metals, including:影响岩浆分出挥发份和金属能力的因素包括：•depth of emplacement侵位深度•volatile content挥发份含量•crystallisation history结晶史•seismic activity地震活动Early, high grade quartz monzonite porphyry cut by later, lower grade crystal-rich Quartz monzonite porphyry, North Parkes porphyry Cu-Au deposit, NSW3-D geology block modelDinkidi Stock (Wolfe, 2001)Multi-phase Intrusions多相侵入体侵入杂岩闪长岩二长闪长岩Dinkidi 岩珠二长岩二长岩脉岩Quan 斑岩正长岩石英碎屑角砾岩Biotite quartz monzonite xenolith in quartzmonzonite porphyry, NorthParkes, NSW 石英二长斑岩中的黑云母石英二长岩捕虏体NorthParkes, NSWMulti-phase intrusions多相侵入体黑云母蚀变粗面安山岩中的石英黄铜矿脉，被QMP 侵入体截断Truncated Veins被截断的矿脉Intrusion Geometries侵入体形态Laramide volcanic edificeLaramide Intrusive complexPC intrusionsArizona Cu-Mo PCDsOrdovician VolcanicsOrdovician Intrusive complexNorth Parkes Cu-Au PCDs•Plutons (deep) 岩体PCDPCD•Pipes 岩筒•Dykes (shallow) 岩墙EarlyLate •Stocks 岩株SubeconomicPCDSubeconomicPCDSections from Lang and Titley (1998) and Lickfold et al. (2003)E26E37E31E27E48E22E28Deposit Clusters矿床群Endeavour porphyry Cu-Au deposits, North Parkes, NSWYerington cross-section from Dilles et al. (2000)Batholithic Roots -Yerington, Nevada根部岩基Ann-Mason PCDMcArthur PCDMagmatic-Hydrothermal Transition Comb quartz layers (USTs) in intra-mineral monzonite,Ridgeway porphyry Cu-Au deposit, NSWVolatile accumulation -magmatic-hydrothermal transition挥发份聚集：岩浆－热液过渡成矿期二长岩中的梳状石英层二长岩中的梳状石英层3 cmUnidirectional solidification textures (USTs)单向固结结构（USTs ）Magmatic-Hydrothermal Transition岩浆－热液过渡Quartz USTs, North Parkes, NSW •Buoyant hydrothermal fluid migrates upwards through the melt and accumulates in the roof of the inwardly-crystallizing magma 热液流体向上运移，穿过熔体，聚集在向内结晶的岩浆房的顶部•Bands of distinctly prismatic crystals (e.g., qz, mt) grow downwards from the roof of the volatile pocket柱状晶体（如石英、磁铁矿）从挥发份囊的顶部向下生长；多批次形成多个带Volatile accumulationand UST growth挥发份聚积和UST结构的生长North Parkes, NSW (Lickfold et al. 2003)USTs Vein-dykesMagmatic-Hydrothermal Transition岩浆－热液过渡Felsic magma Volatile migration •Tectonic trigger (e.g., ridge subduction)大地构造引发•Multiple phases of intrusive activity –one or more of which efficientlyconcentrates and releases metals 多相侵入活动–其中的一或多期有效聚集和释放金属•Incompatible behaviour of metals and volatiles allows magmatictransport of metals and sulfur 金属和挥发份的不兼容性使得岩浆能搬运金属和硫•Cycles of volatile accumulation and release at the apex of the mineralizing intrusion (multipleseismic events)多周期挥发份聚积和释放发生在成矿岩体的顶部(多次地震)•Fluid exsolution may be triggered by mafic magma underplating of felsicmagma chamber 流体分离可以由长英质岩浆房下的镁铁质岩浆垫托诱发Porphyry ore genesis 斑岩矿床成因Mafic magma (?)Outflow and mineralisation Episodic fluid accumulation and releaseS e v e r a l k m s。

斑岩型矿床（POD）：特征、成矿与找矿葛良胜武警黄金地质研究所一、斑岩型矿床的分布及研究意义Porphyry Ore Deposits In the WorldPorphyry Deposits In Asia/ChinaPorphyry Ore Deposits 斑岩型矿床矿资源世界上的主要的Cu, Mo 矿资源的主要生产资源Au 的主要生产资源具有巨大经济意义的超大型矿床具有巨大经济意义的超大型矿床非常有意义的找矿靶区非常有意义的找矿靶区为什么斑岩型矿床这么重要?Bingham）：“在石英二长斑《经济地质学原理》最早使用“斑岩铜矿床”。

第一个斑岩铜矿地质模式：模式：圣马纽埃-卡拉闪长岩模式：形成主要与闪长岩类的无石英而缺少千枚岩时空相伴，矿体主要产于星散状—细网脉状及网状或带状概略对称②火山斑岩矿床（花岗40506070481216SiO 2(wt%)N a 2O + K 2O (w t %)800Cooke et al. 2006石英二长斑岩石英二长斑岩黑云母石英二长岩碱性钙碱性碱性如何确定？通常认为与成矿有关的花岗岩是I型花岗岩Characteristics of S & I Type GranitesI -TYPE15:50:35AuCu MoMoAu C u -A u Cu-Mo Cu-Mo-Au•Cu porphyry: Mo, Au •Mo (Climax) porphyry: Sn, W, py •Sn porphyry: W, Mo, Bi,Fluorite四、斑岩型矿床形成的地质构造环境裂谷型（西南天山等）俯冲型（华北板块北缘，中国东部）碰撞型（冈底斯-三江、秦岭-大别、天山-兴蒙）伸展型（长江中下游、华南）陆内型（华北板块）中国主要斑岩型矿床成矿带（区）中国著名的东秦岭斑岩钼矿带•金堆城•南泥湖•上房沟•雷门沟•石窑沟•三道庄、岩体）内蒙古毕力赫POD-Au流体出熔的典型标志•UST，单向（定向）固结结构，是初始出溶流体冷凝沉淀的产物，常早于G脉形成，一般由细圆齿状粗粒棱柱石英（梳状石英）与细晶（斑）岩交替成层组成。