《斑岩型矿床课件.pptx》由会员分享，可在线阅读，更多相关《斑岩型矿床课件.pptx（46页珍藏版）》请在三一办公上搜索。
1、,Vuggy Quartz, Peru,Calc-Alkalic PCD,Advanced Argillic and Silicic Alteration, FSE, Philippines,Calc-Alkalic PCD,Advanced Argillic Alteration高级泥化蚀变,From Garwin, 2000,Potassic and Propylitic Alteration - Batu Hijau,What characterises propylitic alteration?,Weakly to moderately developed secondary alt
2、eration assemblage that typically preserves primary rock texturesCan occur as pervasive or selectively pervasive replacements, or as vein halosAssociated veins have similar mineralogies,Epidote, Baja California, Mexico. Image fromjohnbetts-fineminerals,Alteration Zonation蚀变分带,蚀变分带,矿化分带,青盘岩化,石英绢云岩化,钾
3、化,边缘带,低黄铁矿壳,边缘带,矿壳,低品位矿,黄铁矿壳,Alteration Zoning 蚀变分带,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
4、(1970) model,South American porphyry model,potassic,potassic,potassic,phyllic,propylitic,propylitic,wallrocks,wallrocks,Alteration Overprinting 蚀变叠加,Modified after Gustafson and Hunt 1975,outline,Characteristics 特征Classification 分类Distribution 分布Geodynamic settings 动力学背景Intrusions 侵入岩Hydrothermal al
5、teration and mineralization 热液蚀变和矿化,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,11,000E,E26 - Cu & Au Grades,10,800E,10,600E,11,200E,200 m,+,+,+,+,+,+,+,+,+,+,+,+,+,+,+,+,+,+,+,+,+,+,+,+,+,+,+,+,+,+,+,+,+,+,+,+,+,+,+,+,+,+,+,+,+,+,+
6、,+,0.5 - 1 g/t Au,2 % Cu,1- 2 % Cu,0.5 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 deposit 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
7、 gold in qz-mt vein, Ridgeway, NSW 石英磁铁矿脉不含金,Cu, Au and quartz veins, Grasberg铜、金和石英脉, Grasberg,Kavaleris, 1994,Gold and magnetite, Grasberg, Indonesia金和磁铁矿,Kavaleris, 1994,A veins: These are typically granular quartz-K-feldspar-anhydrite-sulfide veins that generally lack internal symmetry, and are
8、irregular and discontinuous,“A” veins,“B” veins,“D” veins,Vein Types (Gustafson and Hunt, 1975),B veins: These transitional quartz veins occupy continuous planar fractures, contain molybdenite, and lack K-feldspar and associated alteration halos,D veins: Late sulfide veins contain pyrite and lesser
9、bornite, chalcopyrite, enargite硫砷铜矿, tennantite, sphalerite and gl, with quartz-anhydrite gangue and phyllic alteration halos,Supergene Mineralisation次生成矿作用,Boyongan, Philippines,Idealised supergene enrichment blanket 次生矿床富集层位理想模式,From Titley, 1982,EnrichmentBlanket,次生矿化,深成矿化,青盘岩化,低品位核,钾化,青盘岩化高岭土化,高
10、岭土绢云母,低黄铁矿化带,黄铁矿化带,淋滤盖层,Examples of Fe minerals in leached caps 淋滤盖层中的Fe矿实例,Cuajone, Peru,Overburden覆盖层,Hematitic 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, Bolivia,Goethitic leached capabo
11、ve a pyritic Sn-Agporphyry system, Bolivia含Sn-Ag黄铁矿 斑岩体系上的针铁矿淋滤层,含Ag-Au的富黄铁矿浅成热液矿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 hem
12、atite, goethite and jarosite will produce gradational colors as shown in the standard 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
13、矿,Goethite 针铁矿,Jarosite 黄钾铁钒,Limonites 褐铁矿:,From Peterson and Chavez (2019).,Neotocite 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 i
14、n 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 fractures from oxidation of chalcocite, Escondida, Chile,Antlerite 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）：,2FeS2 (黄铁矿) + 7O2 + H2O 2FeSO4 + 2H2SO42FeSO4 + O2 + 2H2SO4 2Fe2(SO4)3 + 2H2OFe2(SO4)3 +
15、6H2O 2Fe(OH)3（胶体） + 3H2SO4,Fe(OH)3脱水形成褐铁矿（针铁矿、水针铁矿、水赤铁矿），构成“铁帽”,CuFeS2 (黄铜矿) + O2 + H2O CuSO4 + FeSO4 + H2SO42CuSO4 + 2CaCO3 + 5H2O Cu2CO3(OH)2 (孔雀石) + 2CaSO42H2O + CO2,近潜水面以下的还原带：,CuSO4 + 5CuFeS2 + 8H2O 8Cu2S + 5FeSO4 + 8H2SO4,含铜量,黄铜矿,辉铜矿,34.6 %,79.8 %,CuSO4 + 4FeS2 + 4H2O 7CuS + 4FeSO4 + 4H2SO4,含铜
16、量,黄铁矿,铜蓝,0 %,66.5 %,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” supergene enrichment,若次生硫化物进一步氧化（潜水面下降）：,4Cu2S + 9O2 2Cu2O + 4CuSO4,含铜量,辉铜矿,赤铜矿,79.8 %,88.8 %,4Cu2S + 2O2 Cu + CuSO4,含铜量,辉铜矿,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“次生氧化富集作用” supergene enrichment,outline,Characteristics 特征Classification 分类Distributi
17、on 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,基本事实,矿床多位于汇聚板块的边界，与钙碱性岩浆作用密切相关含矿斑岩体常与同源火山岩密切共生，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入环境过渡带深度范围内矿床附近岩石中铜含量通常很低同位素研究表明，S主要来自地幔；含矿流体早期主要为岩浆水，晚期有大气降水的参与,Felsicmagma,Volatilemigration
18、,Tectonic trigger (e.g., ridge subduction),Multiple phases of intrusive activity one or more of 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
19、the mineralizing intrusion (multiple seismic events),Fluid exsolution may be triggered by mafic magma underplating of felsic magma chamber,Porphyry ore genesis,Mafic magma (?),Episodic fluid accumulation and release,Several kms,斑岩型铜矿床成因的板块构造摸式（Sillitoe, 1972 ）,洋陆碰撞造山带（安第斯带）斑岩铜矿成因示意图,陆陆碰撞造山带（地中海沿岸）斑岩
20、铜矿成因示意图,岩性：黑云母二长花岗斑岩,侵入年龄：57-26 Ma,矿带的Cu储量: 10106 t,玉龙：6.5106 t 杂那尕：3.2105 t 莽总：6.7105 t 多霞松多：8.9105 t 马拉松多：1.01106 t,Gu et al., 2019, Mineralogy and Petrology, 78: 1-20,Potassic stage,Phyllic stage,Propylitic stage,Gu et al., 2019, Mineralogy and Petrology, 78: 1-20,Gu et al., 2019, Mineralogy and
21、Petrology, 78: 1-20,Major genetic classes: Magmatic-hydrothermal Volcanic-hydrothermal Hydrothermal brecciasTectonic,Breccias in Magmatic - Hydrothermal Systems,Polymict tourmaline breccia, Sierra Gorda, Chile,Generated by explosive fluid release from crystallising porphyryAngular clasts -implies li
22、mited clast transport & abrasion 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 breccias,Tourmaline-chalcopyrite cement, Rio Blanco,Sulfide Mineralisation Styles 硫化物矿化类型,Clast alteration蚀变碎屑,Vein脉,Cement胶结物,Tourmaline breccia, Ro Bla
23、nco, Chile,Hydrothermal cement 热液胶结Alteration of matrix 岩石蚀变Alteration of clasts 碎屑蚀变Cross-cutting veins 交切脉体,2 - 5 km paleodepth 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
24、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,Breccias in Hydrothermal Systems 热液体系中的角砾岩,Capillitas diatreme, Fallon Negro district, Argentina,Volcanic-Hydrothermal Breccias Natures Drillholes,Sericite-chlorite altered po
25、lymict matrix-rich breccia, Acupan Gold Mine, Philippines,Chalcopyrite clast in polymictic matrix-rich breccia, Amacan, Philippines,Late-stage diatreme breccia at Acupan Au-Ag mine, Philippines,outline,Exploration 勘探,Porphyry deposit discoveries since 1992,Map source: gebco,Pebble East,RekoDiq,Toki
26、cluster,Inca de Oro,Resolution,Antapaccay,La Colosa,Spence,Galeno,La Fortuna,Oyu Tolgoi,Cadia,BoyonganBayugo,Xietongmen,Mt Bini,E48,Marsden,Tampakan,More discoveries have been made in covered geological settings than in the paste.g., SpenceTokiCadia EastPebble EastHugo DummettThese covered deposits
27、are mostly being discovered in near-mine (brownfields) areas rather than virgin (greenfields) areas,Porphyry discoveries since 1992,Biotite alteration halo in albite-sericite altered quzrtz monzonite porphyry, E48, NSW,Exploration 勘探活动,Aeromagnetics - North Parkes, NSW,Gravity - North Parkes, NSW,Ex
28、plore near known systems thoroughly在查明系统附近进行全面勘查,Geochemistry: soil, stream, rock chip, RAB地球化学：土壤，水系，岩石碎片，RAB,Geophysics: aeromagnetics, 等地球物理：航磁,Regional-scale structures区域尺度构造,Exploration 勘探活动,Exploration Drilling - Cadia Far East, NSW,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,xiexie!,谢谢！,
