斑岩型矿床-02-共46页PPT资料课件.pptx

1、Advanced Argillic Alteration高级泥化蚀变From Garwin, 2000What characterises propylitic alteration? Weakly to moderately developed secondary alteration assemblage that typically preserves primary rock textures Can occur as pervasive or selectively pervasive replacements, or as vein halos Associated veins h

2、ave similar mineralogiesEpidote, Baja California, Mexico. Image fromjohnbetts-finemineralsEpidoteCa2(Al,Fe3+)3Si3O12(OH) Alteration Zonation蚀变分带蚀变分带蚀变分带矿化分带矿化分带青盘岩化青盘岩化石英绢云岩化石英绢云岩化钾化钾化边缘带边缘带低黄铁矿壳低黄铁矿壳边缘带边缘带矿壳矿壳低品位矿低品位矿黄铁矿壳黄铁矿壳Alteration Zoning 蚀变分带Silicic 硅化硅化Potassic钾化钾化Propylitic青磐岩化青磐岩化 Advanced

3、argillic高级泥化高级泥化Phyllic and argillic绢英岩化和泥化绢英岩化和泥化 Phyllic alteration can be produced by magmatic-hydrothermal fluids绢英岩化蚀变由岩浆热液流体产生 The phyllic alteration zone can cut through potassic alteration zones, and be independently mineralised绢英岩化蚀变可以切穿钾化，独立形成矿化。Alteration Zoning 蚀变分带Lowell and Guilbert (1

4、970) modelSouth American porphyry modelphyllicpropyliticpropyliticwallrockswallrocksAlteration Overprinting 蚀变叠加Modified after Gustafson and Hunt 1975outline Characteristics 特征 Classification 分类 Distribution 分布 Geodynamic settings 动力学背景 Intrusions 侵入岩 Hydrothermal alteration and mineralization 热液蚀变和

5、矿化Main ore minerals: chalcopyrite, bornite, gold, molybdenite 主要矿石矿物：黄铜矿、斑铜矿、金、辉钼矿Hypogene Mineralization 深成成矿作用11,000EE26 - Cu & Au Grades10,800E10,600E11,200E200 m+2 g/t Au1 - 2 g/t Au0.5 - 1 g/t Au2 % Cu1- 2 % Cu0.5 1 % Cu Gangue: qz, or, anh, mt, bt ser py 脉石：石英、正长石、硬石膏、磁铁矿、黑云母绢云母黄铁矿 Within depo

6、sit zonation 在矿化带内: low pyrite, Cu-rich core 贫黄铁矿、富铜内核, outer pyrite-rich halo 富黄铁矿外带 Cu-Au rich core surrounded by Mo-rich zone & outer pyrite halo有些矿床内核富Cu-Au，核外环绕着中性富钼带和黄铁矿外带Free gold in qz-mt vein, Ridgeway, NSW 石英磁铁矿脉不含金石英磁铁矿脉不含金Cu, Au and quartz veins, Grasberg铜、金和石英脉, GrasbergKavaleris, 1994G

7、old and magnetite, Grasberg, Indonesia金和磁铁矿Kavaleris, 1994A veins: These are typically granular quartz-K-feldspar-anhydrite-sulfide veins that generally lack internal symmetry, and are irregular and discontinuous“A” veins“B” veins“D” veinsVein Types (Gustafson and Hunt, 1975)B veins: These transitio

8、nal quartz veins occupy continuous planar fractures, contain molybdenite, and lack K-feldspar and associated alteration halosD veins: Late sulfide veins contain pyrite and lesser bornite, chalcopyrite, enargite硫砷铜矿, tennantite, sphalerite and gl, with quartz-anhydrite gangue and phyllic alteration h

9、alos Supergene Mineralisation次生成矿作用Idealised supergene enrichment blanket 次生矿床富集层位理想模式From Titley, 1982EnrichmentBlanket次生矿化次生矿化深成矿化深成矿化青盘岩化青盘岩化低品位核低品位核钾化钾化青盘岩化青盘岩化高岭土化高岭土化高岭土高岭土绢云母绢云母低黄铁矿化带低黄铁矿化带黄铁矿化带黄铁矿化带淋滤盖层淋滤盖层Examples of Fe minerals in leached caps 淋滤盖层中的Fe矿实例Cuajone, PeruOverburden覆盖层Hematitic

10、 cap赤铁矿盖层Chalcocite ore辉铜矿矿石Examples of Fe minerals in leached caps 淋滤盖层中的Fe矿实例Jarositic leached cap in ahighly pyritic Ag-Au bearingepithermal system, BoliviaGoethitic leached capabove a pyritic Sn-Agporphyry system, Bolivia含含Sn-Ag黄铁矿黄铁矿 斑岩体系斑岩体系上的针铁矿淋滤层上的针铁矿淋滤层含含Ag-Au的富黄铁矿浅成热的富黄铁矿浅成热液矿床中的黄钾铁钒淋滤层液矿

11、床中的黄钾铁钒淋滤层Identifying residuals minerals in leached caps 淋滤盖层中的残留矿的鉴别 Iron oxide characterization chart for comparing smudges from leached outcrops and drill holes intervals氧化铁特征图，用于对比经淋滤的露头与钻孔中的颜色差异 Mixtures of red hematite, goethite and jarosite will produce gradational colors as shown in the stan

12、dard box用红色赤铁矿、针铁矿及黄钾铁矾进行混合，会产生象标准图标中一样的颜色等级 Note that the standard smudges are derived from leached capping environments and represents XRD analyzed end-member iron oxides 注意，标准影像来自淋滤层环境，代表经XRD分析了的铁氧化物的一个端元Hematite 赤铁矿Goethite 针铁矿Jarosite 黄钾铁钒Limonites 褐铁矿:-From Peterson and Chavez (2019). Neotocit

13、e on fractures in phyllic altered quartz monzonite porphyry, Quellaveco, Peru绢英岩蚀变石英二长斑岩裂隙中的硅锰矿Brochantite along oxidised qtz-cp veins in quartz monzonite porphyry Quellaveco, Peru氧化脉中的水胆矾Examples of Cu minerals in leached caps 淋滤盖层中的Cu矿Examples of Cu minerals in leached caps淋滤盖层中的Cu矿石Azurite on fra

14、ctures from oxidation of chalcocite, Escondida, ChileAntlerite 块铜矿Turquoise 绿松石azurite蓝铜矿Native Cu自然铜，近地表氧化带（潜水面以上）：近地表氧化带（潜水面以上）：2FeS2 (黄铁矿黄铁矿) + 7O2 + H2O 2FeSO4 + 2H2SO42FeSO4 + O2 + 2H2SO4 2Fe2(SO4)3 + 2H2OFe2(SO4)3 + 6H2O 2Fe(OH)3（胶体）（胶体） + 3H2SO4Fe(OH)3脱水形成褐铁矿（针铁矿、水针铁矿、脱水形成褐铁矿（针铁矿、水针铁矿、水赤铁矿），构

15、成水赤铁矿），构成“铁帽铁帽”CuFeS2 (黄铜矿黄铜矿) + O2 + H2O CuSO4 + FeSO4 + H2SO42CuSO4 + 2CaCO3 + 5H2O Cu2CO3(OH)2 (孔雀石孔雀石) + 2CaSO42H2O + CO2近潜水面以下的还原带：近潜水面以下的还原带：CuSO4 + 5CuFeS2 + 8H2O 8Cu2S + 5FeSO4 + 8H2SO4含铜量含铜量黄铜矿黄铜矿辉铜矿辉铜矿34.6 %79.8 %CuSO4 + 4FeS2 + 4H2O 7CuS + 4FeSO4 + 4H2SO4含铜量含铜量黄铁矿黄铁矿铜蓝铜蓝0 %66.5 %上述过程使原生矿石

16、的品位大大提高，即所谓的上述过程使原生矿石的品位大大提高，即所谓的“次生硫化物富集作用次生硫化物富集作用” supergene enrichment 若次生硫化物进一步氧化若次生硫化物进一步氧化（潜水面下降）（潜水面下降）：4Cu2S + 9O2 2Cu2O + 4CuSO4含铜量含铜量辉铜矿辉铜矿赤铜矿赤铜矿79.8 %88.8 %4Cu2S + 2O2 Cu + CuSO4含铜量含铜量辉铜矿辉铜矿自然铜自然铜79.8 %100 %上述过程使矿石的品位进一步提高，即所谓的上述过程使矿石的品位进一步提高，即所谓的“次生氧化富集作用次生氧化富集作用” supergene enrichment o

17、utline Characteristics 特征 Classification 分类 Distribution 分布 Geodynamic settings 动力学背景 Intrusions 侵入岩 Hydrothermal alteration and mineralization 热液蚀变和矿化 Porphyry ore genesis 斑岩矿床成因斑岩型矿床的成因认识斑岩型矿床的成因认识基本事实基本事实l 矿床多位于汇聚板块的边界，与矿床多位于汇聚板块的边界，与钙碱性岩浆作用密切相关钙碱性岩浆作用密切相关l 含矿斑岩体常与同源火山岩密切含矿斑岩体常与同源火山岩密切共生，在深部往往与大岩

18、基相连，共生，在深部往往与大岩基相连，表明斑岩体形成于喷发环境与侵表明斑岩体形成于喷发环境与侵入环境过渡带深度范围内入环境过渡带深度范围内l 矿床附近岩石中铜含量通常很低矿床附近岩石中铜含量通常很低l 同位素研究表明，同位素研究表明，S主要来自地主要来自地幔；含矿流体早期主要为岩浆水，幔；含矿流体早期主要为岩浆水，晚期有大气降水的参与晚期有大气降水的参与FelsicmagmaVolatilemigration Tectonic trigger (e.g., ridge subduction) Multiple phases of intrusive activity one or more o

19、f which efficiently concentrates and releases metals Incompatible behaviour of metals and volatiles allows magmatic transport of metals and sulfur Cycles of volatile accumulation and release at the apex of the mineralizing intrusion (multiple seismic events) Fluid exsolution may be triggered by mafi

20、c magma underplating of felsic magma chamber Porphyry ore genesisMafic magma (?)Outflow and mineralisationEpisodic fluid accumulation and releaseSeveral kms斑岩型铜矿床成因的板块构造摸式斑岩型铜矿床成因的板块构造摸式（Sillitoe, 1972 ）洋洋 陆碰撞造山带（安第斯带）斑岩铜矿成因示意图陆碰撞造山带（安第斯带）斑岩铜矿成因示意图 陆陆 陆碰撞造山带（地中海沿岸）斑岩铜矿成因示意图陆碰撞造山带（地中海沿岸）斑岩铜矿成因示意图 岩性岩

21、性：黑云母黑云母二长花岗斑岩二长花岗斑岩侵入年龄：侵入年龄：57-26 Ma矿带的矿带的Cu储量储量: 10106 t 玉龙：玉龙：6.5106 t 杂那尕：杂那尕：3.2105 t 莽总：莽总：6.7105 t 多霞松多：多霞松多：8.9105 t 马拉松多：马拉松多：1.01106 t Gu et al., 2019, Mineralogy and Petrology, 78: 1-20Potassic stagePhyllic stagePropylitic stageGu et al., 2019, Mineralogy and Petrology, 78: 1-20Gu et al.

22、, 2019, Mineralogy and Petrology, 78: 1-20Major genetic classes: Magmatic-hydrothermal Volcanic-hydrothermal Hydrothermal breccias TectonicBreccias in Magmatic - Hydrothermal SystemsGenerated by explosive fluid release from crystallising porphyryAngular clasts -implies limited clast transport & abra

23、sion 棱角状碎屑High temperature alteration rinds (clasts) and altered matrix蚀变边/岩石Sulfide cement硫化物胶结Magmatic-hydrothermal brecciasSulfide Mineralisation Styles 硫化物矿化类型硫化物矿化类型Maar-diatreme breccia complex角砾岩体角砾岩体Late intrusion into active hydrothermal system后期侵入至后期侵入至活动的热液活动的热液系统系统2 - 5 km paleodepth 古深度

24、古深度2 Phreatomagmatic breccias岩浆蒸气作用角砾岩Clastic matrix & milled clasts 碎屑状基质和粉碎的碎屑丰富Surficial and subsurface deposits 在地表及地下均有角砾岩形成Bedded and massive breccias 条带状、块状构造的角砾岩相Venting of volatiles to surface 地表挥发份气孔 death of a porphyry deposit 斑岩矿床的消逝 shortcut to the epithermal environment 形成浅成环境的捷径Brecci

25、as in Hydrothermal Systems 热液体系中的角砾岩Capillitas diatreme, Fallon Negro district, ArgentinaVolcanic-Hydrothermal Breccias Natures Drillholes Chalcopyrite clast in polymictic matrix-rich breccia, Amacan, PhilippinesLate-stage diatreme breccia at Acupan Au-Ag mine, Philippines outline Exploration 勘探Porp

26、hyry deposit discoveries since 1992Map source: gebcoPebble EastRekoDiqToki clusterInca de OroResolutionAntapaccayLa ColosaSpenceGalenoLa FortunaOyu TolgoiCadiaBoyonganBayugoXietongmenMt BiniE48MarsdenTampakan More discoveries have been made in covered geological settings than in the past e.g., Spenc

27、e Toki Cadia East Pebble East Hugo Dummett These covered deposits are mostly being discovered in near-mine (brownfields) areas rather than virgin (greenfields) areasPorphyry discoveries since 1992Biotite alteration halo in albite-sericite altered quzrtz monzonite porphyry, E48, NSWExploration 勘探活动Exploration 勘探活动Intrusive geochemistry and geochronology 岩体地球化学和年代学 Drilling 钻探Breccias 角砾岩Alteration mapping 蚀变填图