常兆山 高硫型浅成低温

Vein 脉状
Alteration – Geometry 蚀变体的几何形态
Vertical 垂直体 Sub-horizontal 近水平状
Summiteville, USA
Vertical; Faultcontrolled
Quartz latite porphyry 石英安粗斑岩
Silicic – AA alteration 高硅高级泥化蚀变带
What is a HS deposit? 定义
Varied over time. Recently some proposed classification based on major sulphides 有过多次变动。 最近有人提议根据硫化物分类
à Mostly enargite – luzonite, hypogene covellite 硫砷铜矿四方硫砷铜矿或原生 铜蓝的大量存在
Tantahuatay, Peru
Epithermal gold deposits: production + reserves 浅成热液矿床的吨位－品位
低硫


高硫 中硫
LS subtype
与碱性岩有关的低硫矿床
Vi?
品位，克／吨
wenku.baidu.com
吨位，百万吨
Location of principal epithermal gold deposits 主要浅成热液矿床的分布
很高 Covellite 铜蓝 Digenite 蓝辉铜矿 高
Enargite 硫砷铜矿
Cerro Yanacocha open pit, Peru
What is a HS deposit? – diagnostic features 鉴定性特征
Alteration assemblage + ore mineral assemblage 蚀变矿物组合 和 矿石矿物组合 Alteration 蚀变: à Silicic (vuggy quartz/residual quartz) – pyrite 高硅蚀变（多孔状石英/残留石英） – 黄铁矿 à Advanced argillic (AA) alteration: hypogene quartz – alunite – pyrite 高级泥化蚀变（AA)：深成石英 – 明矾石组合 – 黄铁矿 Ore minerals: Enargite – luzonite, hypogene covellite 矿石矿物：硫砷铜矿 – 四方硫砷铜矿，深成铜蓝
High-sulfidation (HS) epithermal deposits 高硫化浅成低温热液矿床
Zhaoshan Chang Noel White Jeff Hedenquist Dave Cooke
10 X 2 km2 lithocap, Shuteen, Mongolia 蒙古Shuteen蚀变岩帽， 10 X 2 km2
只有硅和铝
Only Si and Al
SWIR spectral instruments 短波红外光谱仪器
PIMA
PNIRS
南京所生产
TerraSpec
Advanced argillic alteration – various textures 高级泥化蚀变的结构特征
Original texture preserved 保留原 岩结构
Pierina
Summitville
Summitville
Arribas et al., 2000
Silicic alteration 高硅蚀变
Not always ‘vuggy’ – depends on the protolith 不总是多孔状的 – 取决于原岩
Protolith = basalt 原岩是玄武岩
Einaudi, Hedenquist and Inan, 2003 Sulfidation states 硫化态
很高 Covellite 铜蓝 Digenite 蓝辉铜矿 高
Enargite 硫砷铜矿
Cerro Yanacocha open pit, Peru
What is a HS deposit? 定义
Alunite
Breccia 角砾状
Patchy – wormy (Gusano) 斑杂状－蠕虫状
AA alteration – textures 高级泥化蚀变的结构特征
Alunite 明矾石 Massive silicic 致密硅质
Vein 脉状
Plumosealunite vein 羽状明矾石脉 Quartzalunite 石英 - 明矾石
Alunite 明矾石
Quartz 石英
Intergrowth of quartz and alunite 石英和明矾石交生
Advanced argillic alteration – various textures and mineralogy 高级泥化蚀变的结构特征
Wormy 蠕虫状
Alunite, pyrophyllite, diaspore, topaz 明矾石，叶 腊石，水铝石， 黄玉
Andesite安山岩
by Arribas, 1995
500m
Lithocap 蚀变岩帽
Silicic – AA alteration 高硅 -高级泥化蚀变带
Lepanto, Philippines 菲律宾Lepanto矿
Zhaoshan.chang@jcu.edu.au
2 November 2011, Beijing, China
Photo Courtesy of Danilo Marcos, Gold Fields
Holiday and Cooke (2007)
High-sulfidation (HS) epithermal deposits 高硫化浅成低温热液矿床
低硫 中硫 高硫 Arribas et al. (2000)
Why explore for HS deposits? 重要性
- Significant Au-Cu resources - Some Pb-Zn under right geological conditions - Potential for linked, deeper porphyry deposits - 金－铜资源量大 - 合适的地质条件下可有铅锌 - 深部可能有斑岩型矿床
Kandite Group Kaolinite Dickite Halloysite Nacrite Pyrophyllite Diaspore Topaz Zunyite Dumortierite Corundum Andalusite Cordierite 高岭石 迪开石 埃洛石 珍珠陶土 叶腊石 水铝石 黄玉 氯黄晶 蓝线石 刚玉 红柱石 堇青石 Al2Si2O5(OH)4 Al2Si2O5(OH)4 Al2Si2O5(OH)4 Al2Si2O5(OH)4 Al2Si4O10(OH)2 AlO(OH) Al2SiO4(F,OH)2 Al13Si5O20(OH,F)18Cl Al6.5-7BO3(SiO4)3(O,OH)3 Al2O3 Al2SiO5 Mg2Al4Si5O18
APS: aluminium phosphate sulphate 铝磷硫酸盐
Hedenquist et al., 2000; Seedorf et al., 2005
Characteristics – Alteration 蚀变特征
Intermediate argillic: pyrite + (illite，illite/smecitite or smectite) ± chlorite 中级泥化：黄铁矿 + (伊利石、伊利石/蒙脱石混层矿物或蒙脱石) ± 绿泥石 Argillic: kaolinite 泥化：高岭石 Propylitic: chlorite ± epidote ± actinolite ± albite ± calcite ± pyrite 青磐岩化：绿泥石 ± 绿帘石 ± 阳起石 ± 钠长石 ± 方解石 ± 黄铁矿
Different people use these terms in different ways – read their definitions 注意同样的术语常被不同的人用来表达不同的意思 – 看具体的定义
Hedenquist et al., 2000; Seedorf et al., 2005
Free gold in weathered HS deposit; Yanacocha, Peru
Characteristics – Alteration 蚀变特征
Silicic: >95 wt% SiO2, residual/vuggy quartz, trace rutile, zircon 高硅蚀变： >95 wt% SiO2, 残留/多孔状石英，微量金红石，锆石 Advanced argillic: Quartz + pyrite + (alunite-APS and/or pyrophyllite) ± diaspore ± dickite ± kaolinite ± zunyite (F) ± topaz (F) ± cordierite (Mg) ± dumorterite (B) ± corundum ± andalusite 高级泥化蚀变：石英 + 黄铁矿 + (明矾石和/或叶腊 石) ± 水铝石 ± 迪开石 ± 高岭石 ± 氟氯黄晶 ± 黄玉 ± 蓝线石 ± 堇青石 ± 刚玉 ± 红柱石
Baguio, Philippines
AA alteration 高级泥化蚀变
Alunite 明矾石
Al > Fe Fe > Al
Alunite supergroup, include 3 groups, > 40 minerals 明矾石超族包括三个矿物 族，４０多种矿物
Alunite group 明矾石族矿物
Alunite 明矾石 KAl3(SO4)2(OH)6 Natroalunite 钠矾石 NaAl3(SO4)2(OH)6 Huangite 钙矾石 CaAl6(SO4)4(OH)12
黄氏石，为纪念黄蕴慧女士命名 After Ms. HUANG Yunhui Jambor, 1999
Other minerals in AA alteration 高级泥化蚀变中的其他矿物
Silicic alteration 高硅蚀变
Typically vuggy (“vuggy quartz”), if the protolith has phenocrysts or clasts 经常是多孔状的，如果原岩有斑 晶或角砾
Matrix also changed; fine quartz now 基质 也已改变为极细粒石英
Not practical: 不实用 à Ores: small volume, hard to find 矿体体 积小，难寻找 à Not helpful to exploration 对勘探 没有帮助
Einaudi, Hedenquist and Inan, 2003 Einaudi, Hedenquist and Inan, 2003 Sulfidation states 硫化态 Sulfidation states 硫化态
- Definition 定义 - Characteristics 特征 - Alteration: mineralogy and textures 蚀变：矿物和结构 - Lithocap 蚀变岩帽 - Mineralization: mineralogy and textures 矿化: 矿物和结构 - Genesis - Exploration 成因 勘探
Quartz – alunite 石英 – 明矾石
Open space filling 充填 开放空间 Alunite 明矾石
Vug-filling 充填孔洞
Alunite 明矾石
Alunite 明矾石
Advanced argillic alteration – various textures and mineralogy 高级泥化蚀变的结构特征