CharacterandtypesofGoldDeposits--ZYC

1、 For Economic GeologistslLode (mesothermal or orogenic) gold deposits 中温热液（造山型）金矿床 脉矿床lCarlin gold deposits (Sediment-hosted, dissemianted deposits) 卡林型金矿(沉积岩容矿浸染状金矿床)l(Volcanic-associated) Epithermal gold deposits (火山作用相关的)浅成低温热液型金矿床lYoung placer deposits 年轻砂金矿床 lIntrusion-related deposits (Porphyr

2、y Skarn) 侵入相关金矿床lDeposits hosted by banded iron-formations 条带状铁矿容矿 lDeposits hosted by quartz-pebble conglomerate 角砾岩型金矿（石英砾石容矿金矿床，Witwatersrand型）outlineoutlineTypes of gold deposits世界黄金产量的世界黄金产量的11%11%卡林型卡林型铁氧化物铁氧化物铜金型铜金型造山型造山型夕卡夕卡岩型岩型斑斑岩岩型型浅成低温热液型浅成低温热液型古砾岩型古砾岩型Types of gold depositsoutlineoutline

3、Low sulfidationGeology of Orogenic Gold造山型金矿地质造山型金矿地质Richard J. GoldfarbOre Deposit Models & Exploration CourseCUGBNovember, 2009Ore Deposit Models & Exploration Course澳大利亚澳大利亚 伊尔冈地块的金矿伊尔冈地块的金矿Low Preservational Potential for Au Systems:Porphyry and Epithermal Au Deposits斑岩型和斑岩型和浅成低温浅成低温热液型金

4、热液型金矿床保留矿床保留下来的可下来的可能性较低能性较低斑岩型铜斑岩型铜金矿床金矿床浅成热液浅成热液金银矿床金银矿床造山带型金矿床造山带型金矿床Accretionary Forearcs - Sites of Massive Flow弧前增生楔弧前增生楔-大量流体活动的地区大量流体活动的地区大陆大陆洋脊洋脊弧后弧后增生地体增生地体陆弧陆弧弧后伸展区弧后伸展区造山带巨型金矿（据造山带巨型金矿（据GSC国际金矿数据库国际金矿数据库) Low-Sulfide 低硫化物含量低硫化物含量 Mesothermal 中温热液中温热液 Mother Lode 主矿脉主矿脉 Metamorphic 变质的变质的

5、 Orogenic 造山的造山的High Au/Ag ratios 区分区分 Low sulfidationLow sulfidation 低硫型低硫型Archean Lode Gold Deposits Greenstone belts of Archean cratons (Granitoid-Greenstone Terranes) 在花岗绿岩地体中的绿岩带在花岗绿岩地体中的绿岩带Yilgarn, Zimbabwe, South Africa?, Brazil, Kolar, Superior Yilgarn, 津巴布韦津巴布韦,南非南非? 巴西巴西, Kolar, SuperiorTh

6、oleiitic basalt, Dolerite, Ultramafic intrusions, BIF, Granitoid 拉斑玄武岩拉斑玄武岩, 辉绿辉绿岩岩, 超基性侵入岩超基性侵入岩, 条带状铁质建造条带状铁质建造, 花岗岩类花岗岩类Deposits in Proterozoic greenstone belts are relatively small and unimportant on a global scale. Phanerozoic Lode Gold Deposits 显生宙的脉状金矿显生宙的脉状金矿Accreted Oceanic Sequences; Conti

7、nental Margins 增生的海洋沉积序列；大陆边缘增生的海洋沉积序列；大陆边缘Graywacke, Slate, Basalt, Granitoids 硬砂岩硬砂岩, 板岩板岩, 玄武岩玄武岩, 花岗岩类花岗岩类Mother Lode, Russian Far East, Tasman, Central Asia (i.e., Kumtor, Muruntau), Alaska 主矿脉主矿脉, 俄国远东俄国远东, 塔斯曼塔斯曼, 中亚地区中亚地区(如如Kumtor, Muruntau), 阿拉斯加州阿拉斯加州Key Factors Controlling the Metallogene

8、sis of the Lode Gold Deposits1) Major structure主构造主构造2) Metamorphic grade变质程度变质程度3) Physical or chemical trap物理或化学圈闭物理或化学圈闭Spatial/Temporal Association with Granitoids与花岗岩类的时空联系与花岗岩类的时空联系There is no evidence that felsic intrusions directly contributed to the gold metallogenic event.1) Major structur

9、eGolden Mile (1,200 t)Spatial Association with Deep Crustal Faults 与地壳规模深大断裂的空间关系与地壳规模深大断裂的空间关系 1) Major structureFOCUS OF ORE FLUIDS: VARIATIONS IN STRIKE OF CRUSTAL-SCALE FAULTS 成矿流体的聚集成矿流体的聚集: 地壳规模断层走向发生变化的部位地壳规模断层走向发生变化的部位Shapes, orientations, and distribution of individual gold deposits are con

10、trolled by small-scale, second order structuresThe Jiacha lode gold deposit, southern TibetStructural Styles 构造样式构造样式Orogenic Gold Tonnages: Archean MM Settings造山带金矿吨位：太古代成熟地幔背景造山带金矿吨位：太古代成熟地幔背景(From R. Kerrich, 2009)GOLD-GREENSCHIST ASSOCIATION 金与绿片岩的联系金与绿片岩的联系2) Metamorphic grade GOLD-GREENSCHIST

11、ASSOCIATION 金与绿片岩的联系金与绿片岩的联系绿片岩绿片岩角闪岩角闪岩英闪岩岩床英闪岩岩床片麻岩片麻岩Temperature & PressureTemperatureDuctile to brittle transition: Space PressureGold Ore in Sulfides in Quartz Vein金金矿矿赋赋存存于于石英脉中的硫化物上石英脉中的硫化物上Gold Ore in Sulfidized Wallrocks adjacent to veins 金矿赋金矿赋存于硫化的围岩中存于硫化的围岩中3) Gold Ore Features 4) Go

12、ld Occurrences 金的产出状态金的产出状态Gold occurs in the native state, generally in small fractures in quartz but also in pyrite pyrrhotitearsenpyrite5) Mineralogy of Giants大型矿床的矿物学大型矿床的矿物学6) 6) 造山带造山带型金矿床（型金矿床（70t70t）的品位吨位图）的品位吨位图7) Visible Wallrock Alteration可以观察到的围岩蚀变可以观察到的围岩蚀变 sericitization, carbonization

13、, (de-)silicification, sulfidation 绢云母化、碳酸盐化、（去）硅化、硫化绢云母化、碳酸盐化、（去）硅化、硫化 discoloration, (bleached haloes; 10cm -10s m) 变色变色(漂白的晕带；大于漂白的晕带；大于10厘米到几十米厘米到几十米) chlorite + albite + CO2 + H2O + Au(HS)2 绿泥石绿泥石+钠长石钠长石+ CO2 + H2O + Au(HS)2sericite + Fe-Mg carbonates + sulfides + Au 绢云母绢云母+ Fe-Mg碳酸盐碳酸盐+ 硫化物硫化物

14、+ Aucarbonate spots 碳酸盐斑点碳酸盐斑点sulfide porphyroblasts (pyrite + arsenopyrite; 3 cm) 硫化物斑状变斑晶硫化物斑状变斑晶(黄铁矿黄铁矿+ 毒砂毒砂; 3 cm)Bierlein & Crowe, 2000Sericitic Alteration 绢云母化蚀变绢云母化蚀变Carbonization of Wallrocks 围岩围岩的碳酸盐化的碳酸盐化Hodgson,Gold 2000Sulfidation Sulfidation 硫化作用硫化作用7) Visible Wallrock Alteration from Groves, Ore Deposit Models绿片岩相绿片岩相角闪岩相角闪岩相Relative Lithogeochem Halos, Yilgarn CratonYilgarn克拉通中的岩石化学晕克拉通中的岩石化学晕Yilgarn (Southern Cross)Muruntau stockworksHIGH TEMPERATURE OROGENIC GOLD高温造山型金矿高