【作者】 张学书；

【导师】 秦德先；

【作者基本信息】 昆明理工大学 ， 矿产普查与勘探， 2006， 博士

【摘要】 论文主要从金平—黑水河裂谷地质特征、演化和成矿系列以及玄武岩（科马提岩—玄武岩组合）、基性—超基性侵入岩的岩石学、岩石化学特征、稀土元素和微量元素、同位素地球化学特征及铂族元素地球化学特征等方面论述了本裂谷带内的基性—超基性岩浆岩与峨眉山大火成岩省玄武岩之间的成因联系，并从金平—黑水河白马寨及版福Ni-Cu-（PGE）矿床的野外地质特征、矿石特征、矿床地球化学（稀土、微量元素及铂族元素）及同位素定年等方面论述了裂谷内岩浆型铜镍硫化物矿床与ELIP岩浆岩之间成因演化关系及其在后期区域构造变质作用中的热液改造成矿作用特征，总结了裂谷带内岩浆型铜镍硫化物矿床的岩浆熔离分异演化成矿模式及热液改造成矿模式，并总结了该类矿床的综合勘查找矿模式，对区内工作程度较高的金平地区岩浆型铜镍硫化物矿床进行了远景成矿预测。岩浆型矿床主要有两种类型，即氧化物型矿床和硫化物型矿床，前者主要为与基性—超基性岩（主要为层状杂岩体）有关的Cr、V、Ti和Fe矿床，如攀枝花钒钛磁铁矿型矿床，而岩浆型铜镍硫化物矿床是铜、镍和铂族元素及其它稀有贵金属如金、银等的重要工业矿床类型；岩浆型铜镍硫化物矿床一般产于构造相对较稳定的地台区和地盾区或活动性克拉通边缘裂谷带中，其矿床的形成与地幔成因的基性—超基性岩有关，通常其成矿时代较老。金平—黑水河裂谷（盐源—丽江—大理—金平—黑水河扬子克拉通西缘古生代裂谷的一部分）内与地幔熔离分异成因的基性—超基性岩有关的铜镍硫化物矿床属于显生宙以来的岩浆型铜镍硫化物矿床的比较典型的代表。金平—黑水河地区在晚古生代—三叠纪早期为—大陆边缘裂谷，位于扬子克拉通西南边缘，处于扬子克拉通与东印支板块的结合部分（图3-3）。在空间上，该裂谷沿扬子克拉通西缘的哀牢山变质带西南侧呈北西向延伸，向北西与大理—丽江裂陷相接，其西界为哀牢山—藤条河（-越南马江）深断裂（俯冲带）；时间演化上自早奥陶世（或寒武纪晚期）开始形成至三叠纪封闭结束。裂谷在演化的早期表现为被动大陆边缘裂谷的特征，岩浆作用微弱；中期表现为活动大陆边缘裂陷的特征，岩浆活动强烈，尤以晚二叠世的峨眉期基性岩浆喷发及相伴的基性—超基性岩浆侵入作用最为强烈；晚期裂谷内的岩浆活动微弱，仅发育有厚度不大的流纹斑岩，以被动接受陆源碎屑沉积为主。在成矿作用上，裂谷带内的矿产按其产出的地质环境及其成矿特征可划分为4个成矿系列组合、8个成矿系列、17个矿床类型（表4-1）。金平—黑水河裂谷的二叠纪玄武岩以金平县城东南大老塘一带厚度最大，达4536米，且以熔岩占绝对优势，并大致划分为自火山角砾岩、斑状或杏仁状玄武岩、致密块状玄武岩、粗玄岩至主要为玄武质凝灰岩的两个火山喷发旋回。区内基性—超基性侵入岩成群成带集中分布于新交里—营盘街—白马寨岩带及蒋家坪—牛栏冲岩带中。往南至越南境内，晚二叠世玄武岩主要分布于黑水河裂谷带的边部，而稍年轻一些的晚二叠世—早三叠世的高镁超镁铁—镁铁质侵入岩分布于裂谷中的轴部位置。金平地区与越南黑水河地区二叠纪玄武岩在岩石化学成份上既有相似性，亦存在明显的差异，岩石化学成份上两地均表现为低钛、低碱、且Na₂O＞K₂O的含量特征，均属亚碱性拉斑质玄武岩。但越南黑水河裂谷地区玄武岩（科马提岩）较金平地区玄武岩具有更低的TiO₂、Na₂O、K₂O及较低的P₂O₅、Al₂O₃含量和更高的MgO含量及Mg#指数（Mg#=82.22-92.58）。金平玄武岩Mg#=45.33-65.85，与峨眉山玄武岩更为接近。总体上，金平玄武岩与峨眉山玄武岩区攀西岩区特征相似（低镁低钛），而黑水河玄武岩与盐源—丽江岩区玄武岩的高镁低钛特征相吻合，反映出金平—黑水河裂谷玄武岩系与峨眉山玄武岩具有相似的成因环境。金平—黑水河裂谷金平地区玄武岩与峨眉山微量元素原始地幔标准化配分特征（图3-12，图3-13）的总体变化趋势相似，均表现出右倾型的原始地幔标准化配分曲线；但峨眉山玄武岩具有相对较高的Nb、Ta、Ti、Zr、Hf、Th等高场强元素及较高的强不相容元素含量，为富集型地幔部分熔融的产物；而金平—黑水河裂谷玄武岩却表现出较高的Th含量、较低的Nb、Ta、Ti元素含量特征，而且虽然金平和黑水河地区玄武岩的稀土元素原始地幔标准化曲线特征不同，但其微量元素的原始地幔标准化曲线特征却非常相似，均表现为异常低的Rb含量、P严重亏损、Hf轻微富集的特点（图3-12），与峨眉山玄武岩异常低的Rb含量、较高的P含量和Ti含量（多数为高钛）所表现出的微弱的地壳混染特征（图3-13）不同，显示金平—黑水河裂谷玄武岩具一定程度的地壳混染。金平地区玄武岩稀土总量∑REE=102.48-288.15ppm，稀土含量变化较大；∑Ce／∑Y为1.23-4.05，（La／Yb）_N为3.03-13.4，岩石的（La／Lu）_N比值在2.95-12.93之间，轻稀土富集；δEu为0.94-1.1，稀土分布模式无明显的Eu异常，稀土配分曲线为典型的右倾轻稀土富集型（图3-14，上图）。黑水河地区科马提岩—玄武岩稀土总量极低，∑REE=24.47-45.16，稀土元素分异特征不明显，∑Ce／ZY=0.34-0.84，（La／Yb）_N=0.34-1.87，且多数小于1，（La／Lu）_N=0.33-2.01，多数小于1，略显重稀土富集特征，原始地幔标准化曲线显示轻、重稀土无明显分异，δEu值在0.75-1.52之间，略显Eu正异常特征（图3-14，下图）。金平玄武岩铅同位素组成除²⁰⁸Pb／²⁰⁴Pb略高外，变化范围总体上与红海地幔柱成因玄武岩及峨眉山玄武岩区永胜及宾川地区的玄武岩相似，但金平玄武岩Pb同位素组成在一定程度上偏离Pb同位素组成C组分范围，只有少数样品Pb同位素组成与C组分接近，表明金平玄武岩岩浆受到了地壳物质的混染。金平—黑水河裂谷玄武岩的⁸⁷Sr／⁸⁶Sr的初始比值（表3-7）表明其与峨眉山玄武岩主体及红海、西伯利亚、夏威夷地幔热柱玄武岩相似，暗示其岩浆源区特征的相似性。金平、永胜及宾川玄武岩的¹⁴³Nd／¹⁴⁴Nd对⁸⁷Sr／⁸⁶Sr的投影图中的投影点表明（图3-15），金平地区玄武岩与永胜及宾川地区玄武岩相类似，原始岩浆可能来源于富集型地幔区，并受到了大陆地壳的混染作用。金平玄武岩的¹⁴³Nd／¹⁴⁴Nd值在0.512269-0.512725之间，反映出玄武岩具壳源或混染壳源的特征；而黑水河玄武岩的¹⁴³Nd／¹⁴⁴Nd值在0.512158—0.513184之间，暗示以幔源为主的源区特征；黑水河地区玄武岩—科马提岩系，除少数样品外，其ε_Nd值均大于0，且其数值较大，暗示其岩浆源于强烈亏损的地幔源区，而峨眉山玄武岩的ε_Nd多数小于0，少数大于0，显示其岩浆虽源于地幔，但经历了较强烈的幔—壳交代作用、地壳物质的同化混染程度较大；金平玄武岩的ε_Nd值除个别样品外，均为负值，暗示其岩浆源于富集型地幔。而越南黑水河版福地区的玄武岩¹⁴³Nd／¹⁴⁴Nd比值普遍较金平地区及永胜、宾川地区玄武岩的比值高，而且其ε_Nd值多为较大的正值，表明其来源主要为亏损的地幔源区，受地壳混染作用的影响较小。金平—黑水河裂谷及峨眉山玄武岩的高场强元素特征比值表明不同地区、不同类型峨眉山玄武岩的ω（Ta）／ω（Hf）的平均值（表3-9）均在0.3以上，ω（Nb）／ω（Zr）比值除少数苦橄岩外，均大于0.1，与地幔热柱成因玄武岩一致[ω（Ta）／ω（Hf）＞0.3，ω（Nb）／ω（Zr）＞0.1]，峨眉山玄武岩分布区自西向东，岩石的ω（Ta）／ω（Hf）值呈现逐渐减小的趋势，表明峨眉山玄武岩西部较东部更多地保留了地幔热柱成因岩浆的地球化学特征。相比较之下，除ω（Nb）／ω（Zr）与峨眉山及地幔热柱成因玄武岩一致外，金平—黑水河裂谷玄武岩表现出更为富集Th、相对亏损Ta的特征，ω（Th）／ω（Ta）比值高于、ω（Ta）／ω（Hf）比值低于峨眉山玄武岩及地幔热柱成因玄武岩（表3-9），各比值与大陆板内拉张带或初始裂谷玄武岩特征极为一致，表明金平—黑水河裂谷玄武岩较之于峨眉山玄武岩及典型地幔柱成因玄武岩具有更强烈的地壳成份混染作用及其岩浆源区更为富集Th的特征。而且ω（Th）／ω（Ta）比值特点显示峨眉山玄武岩主体部分的岩浆主要起源于原始地幔，部分熔融程度不高，地壳混染微弱；而在空间上远离峨眉山玄武岩主体的金平—黑水河裂谷玄武岩表明岩浆经历了较强烈的地壳混染作用。金平—黑水河裂谷玄武岩的Nb／Zr比值及Zr-Zr／Y投影图（图3-16）显示金平玄武岩形成于板内环境，黑水河玄武岩—科马提岩主要属洋中脊环境，少数属岛弧环境，表明两个玄武岩浆中心的裂陷深度不同，金平可能属浅槽盆相，而黑水河则可能达到深槽盆相的环境，但后者并没有发展形成大洋型地壳。Sm／Eu-Sr（Rb）相关投影图（图3-20c，d）表明，金平地区玄武岩以辉石、橄榄石的分离结晶作用为主，这一特征与金平玄武岩的主要斑晶成分为辉石、橄榄石相吻合，但总体上的分离结晶程度较低：Sm／Eu比值相对跳跃较大可能反映存在一定程度的地壳混染。金平玄武岩的铂族元素的分异程度不高，铂族元素配分模式表现为不明显的Pt-Pd型，具有Ru-Os型与Pt-Pd型的过渡特征，原始地幔标准化的配分模式为向左陡倾斜型．具较陡的正斜率。金平—黑水河裂谷六大类含矿镁铁岩—超镁铁岩侵入岩的岩石化学特征均表现为亚碱性、属低钛拉斑玄武岩系列和铁质基性—超基性岩的特征；金平地区二叠纪玄武岩与镁铁质—超镁铁质岩及铜镍矿石之间具有相同的稀土元素、微量元素和铂族元素地球化学特征，即相似的稀土元素配分模式（右倾轻稀土富集型）、铂族元素含量及配分模式（较低的丰度值、较大的Pd／Ir比值，为左倾Pt-Pd富集型配分模式）以及相同的微量元素原始地幔标准化配分模式及相同的元素含量特征，表明其间存在成因及时空演化上的必然的联系。分布于黑水河裂谷轴部的超基性—基性岩（侵入相）与分布于其周边区域的苦橄岩—玄武岩（喷出相）亦表现出相同的元素变化特征，即两者均表现出较高的Mg、Ni、Co、Cr、Yb和Lu含量及较低的Ti、Fe、Ca、Na、K、Rb、Sr、V、Nb、Ta、zr和LREE含量特征。金平—黑水河裂谷铜镍成矿带处于扬子克拉通西缘峨眉大火成岩成矿省的西南缘。含矿岩体与相邻地区类似矿床的含矿岩体形成时代基本接近（表4-30），含矿岩体主要为铁质超基性岩系列的橄榄岩—辉石岩组合，沉积围岩中多数含有碳质页岩（板岩）并发育较强烈的具有沉积特征的黄铁矿化，分异好的岩体含矿性较好，含矿岩体规模均较小。金平—黑水河裂谷代表性岩浆型铜镍硫化物（铂族）矿床（白马寨及版福）的基本地质特征相似，均以分异超基性岩为赋矿围岩，矿化主要产于岩体的底部或中心部位，以浸染状及块状矿石为主，矿石的矿物成份基本相同，均以磁黄铁矿、黄铁矿、镍黄铁矿及黄铜矿为主，所不同的是版福铜镍矿床的矿石中含有较多的金属硫砷化物、碲化物、锑化物及铂族矿物，而白马寨矿床中该类矿物成份十分罕见。金平白马寨铜镍矿与其它矿床的显著差别在于其铜镍极为富集（1号块状富矿占总镍储量的67.8％，平均品位达Ni：3.68％，Cu：1.99％），而相对贫铂族元素，岩体分异极好，块状富镍矿石位于岩体中心，但各类矿石含铂族元素极微（不同类型矿石Pt+Pd平均品位为0.02-0.15g／t），矿石伴生金、银含量亦较低（表4-32）。越南黑水河版福铜镍矿床矿石组合、矿石自然类型及矿体基本特征上与其它类似矿床相似，但由于岩体分异较差，未出现底部块状矿石，矿石以浸染状矿石及沿接触构造破碎带形成的脉状矿体中的块状矿石为主，矿石的硫化矿物的硫同位素组成与陨石硫同位素组成相近，成矿过程中来自围岩中硫的混染作用不强，矿石中硫主要来自科马提岩浆本身。白马寨岩体含硫总平均值为11.114％，远高于超基性岩平均硫含量值(2850×10^-6)，而且白马寨岩体自辉长岩至橄榄岩，其硫含量成倍增加，表明晚期熔浆是高度富硫的。除白马寨矿区以外，金平地区其它岩体的硫含量总体均较超基性岩平均值（0.285％）高，而且玄武岩的平均含硫量亦高于超基性岩平均值，表明金平地区基性—超基性岩所代表的初始岩浆房是富集硫的。白马寨铜镍硫化物矿体矿石的δ²¹S值变化范围为6.68-7.59‰，与辉石岩、沉积围岩及外围的玄武岩均具有相似的硫同位素组成特征，即均富集重硫，矿石硫来源与玄武岩、侵入岩及沉积围岩相似。Sr同位素表明有地壳物质的混染并对成矿有一定作用。金平白马寨铜镍矿床及版福铜镍矿床在矿石化学成分上的特征基本一致（表4-32），表现为Cu-Ni富集、相对贫铂钯、伴生金银亦较低的特点，Ni:Cu:Co的比值较高，Pt+Pd含量低—极微，并且Pt／（Pt+Pd）比值亦较低（＜0.5），Pt的富集程度不明显；相比之下，在区域上，金宝山Pt-Pd富集程度高而铜镍含量极低，杨柳坪铜镍矿床的Cu-Ni及Pt-Pd均有不同程度的富集。白马寨铜镍矿矿石具有轻稀土富集及弱的Eu负异常特征，并且各类矿石和弱矿化辉长岩与喀拉通克、杨柳坪铜镍矿的浸染状和块状矿石的稀土元素原始地幔标准化配分曲线特征一致，含量高于球粒陨石值10-50倍，但喀拉通克及杨柳坪铜镍矿矿石的稀土总量比白马寨矿块状矿石更高（图4-32A）。白马寨含矿橄榄岩相对富集轻稀土元素。杨柳坪玄武岩、红格侵入岩及金平玄武岩都表现出具有相似的REE的配分模式曲线（图4-328）。白马寨矿区基性—超基性岩的Sr、Nd同位素表明岩浆有来自地壳成分的混染，黑水河地区版福基性—超基性岩的Nd同位素特征表明其受地壳混染程度较小。金平—黑水河裂谷成矿带南北两段含矿岩体母岩浆存在一定的差别，但在各自的区域内，侵入相岩体与喷发相熔岩之间存在成因演化上的关联关系，金平地区含矿岩体岩石组合为橄榄岩-辉石岩-辉长岩组合（白马寨、营盘街）、辉石岩—辉长岩—辉绿岩组合（牛栏冲、蒋家坪）等，岩石为拉斑玄武岩浆系列。南段越南黑水河版福含矿岩体为纯橄岩—橄榄岩组合，喷发相的岩石为玄武岩—科马提岩组合，岩石为科马提质拉斑玄武岩浆系列（详见第三章）。金平—黑水河裂谷岩浆型硫化Cu-Ni-PGE矿床形成于扬子克拉通西南缘晚古生代拉张环境，含矿超镁铁岩—镁铁岩在空间上常沿一定构造岩浆带分段集中成群分布，矿床（点）在岩带中呈单点状分段重现的形式出现，单个岩体常由不同岩相的岩石组成，岩石分异特征明显，其中以白马寨矿床的含矿岩体最为典型，按各岩相在空间上的分布规律，至少存在五类分异岩浆和矿浆，即最早期的辉长岩岩浆、中期的辉石岩浆、中晚期的橄辉岩（辉橄岩岩浆）和晚期的橄榄岩岩浆以及最后侵入的硫化物高度富化的矿浆。白马寨周围尚分布有具不同程度矿化的同类岩体，其中的矿化可能为与白马寨含矿岩体所代表的统一岩浆房中分流出去的部分含矿岩浆或富矿矿浆在不同部位侵入就位的结果，随着分流出去的程度的不同，则有可能在其外围形成一定规模的铜镍矿化。而黑水河地区，由现有出露岩体判断，岩体分异并不强烈。在自岩浆源演化形成中间富化岩浆房的过程中，可能由于构造作用的影响，导致岩浆房分化、分离形成了数个次级的子岩浆房，部分子岩浆房可能只继承了母岩浆房中含矿性较低的中上部岩浆成分，从而导致岩体分异程度及矿化强度的差别，其综合成矿模式如图4-34所示。白马寨和版福矿床铜镍硫化物的富集机理均以深部熔离分异成矿作用为主，但存在较大的差异，前者矿石矿物以镍铜的硫化物为主，铂族元素含量甚微，无铂族独立矿物（铂族元素赋存于黄铜矿及镍黄铁矿中）；后者的热液叠加成矿作用较强，矿石中除镍铜的硫化物外，尚含有较多的硫盐矿物、碲化物、Ni-Co的硫砷化物及等轴铋碲钯矿等矿物。但金平地区的铜镍矿床与基性—超基性侵入岩有关的气化热液与热液叠加成矿作用较为发育，岩浆气化热液作用多造成围岩的接触交代及热变质作用，热液的叠加成矿作用主要表现在对铜及铂族元素的成矿作用上，矿石中常见镍黄铁矿呈不规则状或条状与黄铜矿和碳酸盐矿物组成细脉状矿化，矿石中普遍见到黄铜矿交代磁黄铁矿及镍黄铁矿的现象，海绵陨铁状矿石与致密块状矿石接触处附近常见前者被后者交代而形成交代假象的混染状矿石以及浸染状矿石对造岩矿物的交代作用等等，这些都是岩浆热液叠加作用的结果。黑云母、绿泥石及角闪石与硫化矿物共生产出亦表明存在挥发份的气液活动（图版Ⅵ-1，Ⅵ-2）。一般情况下，经改造形成的矿石趋向于富集Cu、Au、Ag和Pd等；白马寨矿床一些硫化矿石相对富集Cu、Pd和Au的特征反映了热液流体的成矿作用。并且Ar-Ar法同位素测定的坪年龄值在160-170 Ma之间，亦佐证了矿床的热液改造成矿作用。此外岩浆热液叠加成矿作用还形成了一些规模较小但较富的脉状铜镍矿体，如金平白马寨营盘街—蚂蝗沟岩群中靠近围岩接触带附近的脉状铜镍矿化，同时岩浆叠加作用还造成了早期浸染矿化的进一步富集，特别是热液叠加成矿作用还可能是Pt、Pd等元素富集的主要成矿作用，黑水河版福地区铂族元素的独立矿物、硫盐矿物和碲化物以及脉状矿体中的与石英共生产出的不规则网脉状硫化矿物矿化等均是热液叠加成矿作用的结果。白马寨及版福矿床的热液活化改造成矿作用可能与岩浆期后（指基性—超基性岩浆作用期后，下同）的区域构造热事件有关，但很显然，白马寨矿床的热液活动并没有完全改变硫化矿体特别是块状矿体的完整性，区域性的构造运动及热事件仅仅影响到了矿体边缘部分，在矿体的边缘形成角砾岩化的硫化矿石或造成矿体的局部破坏，而这又进一步加速了热液流体的带入并造成交代型浸染状矿石和造岩矿物间的填隙硫化矿化（即部分所谓的海绵陨铁状矿石）（图版Ⅶ-1—Ⅶ-5）。除正常的磁黄铁矿—镍黄铁矿—黄铜矿矿物组合外，一些硫化物矿物相中的某些微量金属如Bi和Pb等常以外来矿物相的形式产出（如派克矿（斜硫锑铋镍矿）等），亦表明构造—热液改造成矿作用的存在。热液改造成矿作用的可能作用模式如图4-35所示。在第一种情况下（左图）：块状硫化矿体产生了变形，其边部的裂隙及角砾化作用利于热液流体的带入，并对矿石及含矿围岩进行改造；在第二种情况下（右图）：岩浆成因块状硫化矿体为岩浆型浸染状矿体所覆盖，当块状—浸染状矿体产生变形时，热液流体沿渗透性最好的浸染状矿体地段渗入对矿体进行改造。更多还原

【Abstract】 The paper has been focused on the genetic relation between the mafic-ultramafic magmatism in the Jinping-Song Da rift and the basaltic magmatism of Emeishan Large Igneous Province from the viewpoints of the geology of the rift, petrology, petrochemistry, REE and trace elements geochemistry, elements isotope and PGE geochemistry of basalts（kamatiite-basalts associations） and mafic-ultramafic intrusions, and whereas more study works have been concentrated on the characteristics of magmatic Cu-Ni（PGE） sulfide deposits and its genetic evolution relation with the ELIP magmatism and its hydrothermaUy modified features during post-Permian tectonothermal events based on field observation, the discussions over the ore features and ore deposit geochemistry（REE, trace elements and PGE geochemistry） and Ar-Ar dating of ore. The metallogenic model of magmatic liquation and differentiation and hydrothermally modification and comprehensive exploration model based on the advanced studies over the typical magmatic Cu-Ni（PGE） deposit of the Baimazhai and Ban Phuc deposits, in the Jinping-Song Da rift have been summarized in the paper, and mineralization Target areas have also been put forward for the magmatic Cu-Ni（PGE） sulfide deposits.Magmatic ore deposits are of two types: 1) Oxide ore deposits, which are the Cr, V, Ti and Fe deposits,genetically related to mafic-ultramafic（mainly layered） complex, such as the Panzhihua V-Ti magnetite deposit; 2) Sulfide ore deposits, which are the Ni, Cu, Co and PGE and associated Au and Ag deposits genetically related mantle-plume sourced mafic-ultramafic intrusions swarms. Magmatic sulfide Ni-Cu（PGE） deposits are generally situated in the stable platform and shield area, or in the rift in active margin of Craton area, and generally has older mineralization age. The Jinping-Song Da rift is actually south part of the Yanyuan—Lijiang—Dali—Jinping—Song Da Paleozoic rift as whole. The magmatic sulfide Ni-Cu（PGE） deposits, i.e. the Baimazhai and Ban Phuc deposit in the Jinping—Song Da rift are the typical magmatic sulfide ore deposit hosted by the Phanerozoic mafic-ultramafic intrusions rocks which genetically related to the magmatic liquation and differentiation in the mantle plume acting area.Jinping-Song Da area is a continental marginal rift which developed during the late Paleozoic era-early Triassic period and located in the junction between the SW margin of Yangtze craton and the east India-China plate（Fig.3-3）. Spatially, the rift extends northwestward along SW side of the Ailaoshan metamorphic belts which situated in the SW margin of the Yangtze craton, it meets the Dali—Lijiang taphrogenic trough which is also located in the west margin of Yangtze craton, the Ailaoshan—Tentiaohe—Da Ma（Vietnam） suture zone forms its west boundary. Temporally, the rift started to be opened in the early Ordovician period（or late Cambrian period） and ended in the Triassic period. In its early stage of evolution, it exhibits the property of the passive continental margin with weak magmatism; in its middle evolution stage, it displays the features of the active continental margin with strong magmatism, especially it featured by the Emeishan basaltic eruption of the late Permian age and associated mafic-ultramafic intrusions. In the late stage of rift evolution, it is a passively sedimentary basin with continental source materials deposition and being of very weak magmatic activities only with thin rhyolite porphyry. Metallogenically, the mineral deposits in the rift can be categorized as 4 metallogenic series groups and 8 metallogenic series and 17 types of deposits（Table4-1）.The late Permian basalts in the Jinping-Song Da rift present the thickest lava of up to 4536m in the Dalaotang profile, SE of the Jinping town. The rocks are dominant by lave, and the volcanic sequence can be divided into two erupting cycles with each begins with volcanic breccia, porphyric and amygdaloidal basalts, via massive basalt and trachybasalt, ended in basaltic tuff. The mafic and ultramafic intrusions occur in swarms and clusters or in belts as the Xinanli-Yinpanjie-Baimazhai intrusions belt and the Jiangjiaping-Niulanchong intrusions belt. To Vietnam in the south, the late Permian basalts mainly distributed in the fringe area of the Song Da rift, whereas the younger mafic-ultamafic intrusions with high MgO of the late Permian to the early Triassic age are distributed in the axis area of the rift.Both the Permian basalts in Jinping and in Song Da area in Vietnam share some petrochemical similarity and also some difference. Both have the petrochemical characteristics of the low Ti, low alkine, and content of Na₂O>K₂O, and both are belonging to the petrological series of sub-alkine, tholeiitic basalts. But in Song Da area, Vietnam, basalt（komatiite） exhibits extremely lower contents of TiO₂, Na₂O, K₂O and lower P₂O₅ and Al₂O₃ and higher MgO content and higher Mg# ratios(（Mg#=82.22-92.58）. The Mg# ratios of basalts in Jinping area is at the range from 45.33 to 65.85, which is more close to that of Emeishan basalts. In general, Basalts in Jinping area is similar to that in Panxi rift of the ELIP in petrology and petrochemical characteristics （low MgO and low TiO₂ content）, while basalt in Song Da area, south section of the Jinping-Song Da rift, is similar in its high MgO and low TiO₂ content with that in the Yanyuan—Lijiang are of the ELIP, suggesting the similar genetic tectonic context of the basalts in the Jinping-Song Da rift and the basalts in the remaining area of ELIP. Basalts in Jinping section of the Jinping-Song Da rift exhibits a general similar variation trend in the primitive mantle normalized distribution patterns of trace elements with that of the ELIP basalts as whole（Fig.3-12 and Fig.3-13）, both display a right-dipping type of the primitive mantle normalized pattern of the trace elements. Whereas the ELIP basalt have higher contents of HFSE elements such as Nb、Ta、Ti、Zr, Hf、Th etc. and higher contents of strongly incompatible elements, which is the products of partly melting from enriched mantle. But the basalts in the Jinping-Song Da rift show high Th content and low Nb, Ta ant Ti contents, and furthermore basalts from Jinping area and Song Da area share exact same distribution pattern of primitive mantle normalized trace elements, and both present extremely low content of Rb and strongly depleted P content and slightly enriched Hf contents over the primitive mantle value, although they have different distribution of primitive normalized REE elements（Fig.3-12）, which are different with elements contents characteristics of the extremely low Rb content and high P and Ti contents of the ELIP basalt as whole showing weak contamination with substances from crust（Fig.3-13）, while the features of trace elements disclose that basalts in Jinping-Song Da rift have contamination with materials from crust to some extent.The REE value characteristics of basalts in Jinping area are as follows:∑REE=102.48-288.15ppm;∑Ce/∑Y=1.23-4.05; （La/Yb）_N=3.03-13.4; （La/Lu）_N=2.95-12.93;δEu=0.94-1.1; which show the variable value of REE with LREE enriched and without apparent Eu anomaly, the primitive mantle normalized distribution pattern is typical right-dipping LREE enriched model.（Upper diagram of Fig. 3-14）.The REE value characteristics of basalt-kamatiite series in Song Da area are as follows:∑REE=24.47-45.16ppm;∑Ce/∑Y=0.34-0.84; （La/Yb）_N=0.34-1.87; （La/Lu）_N=0.33-2.01, commonly lower than 1;δEu=0.75-1.52, mostly lower than 1, which show the extremely low REE values with badly differentiated REE and slightly enriched HREE values with slightly positive Eu anomaly, there no significant differentiation of the REE from the primitive mantle normalized distribution pattern （Lower diagram of Fig. 3-14）.Except for slightly higher ratio of ²⁰⁸Pb/²⁰⁴pb, the range of the Pb isotope value of basalts in Jinping area is generally similar with that Red Sea area, Yongsheng and Binchuan area of the ELIP, which are of mantle plume genesis. But the isotope values of Pb of basalts in Jinping area are at odds with that of the Common Pb Isotopic Value （C composition）, with only small number of samples being close to the C composition in Pb isotope value, which show that the basalts in Jinping area suffer contamination by materials from crust. The initial ratio of ⁸⁷Sr/⁸⁶Sr of basalts in the Jinping-Song Da rift （Table 3-7） indicate that it shares the similarity with that of the basalts in the main ELIP basalts and in Red Sea, Siberian and Hawaii which are genetically related to mantle plumes, suggestive of the similarity in the magma sources. From the diagram of ¹⁴³Nd/¹⁴⁴Nd versus ⁸⁷Sr/⁸⁶Sr（Fig. 3-15）, it is conclude that basalts in Jinping, Yongsheng area and Binchuan area are genetically similar with each other, the primary magma of basalts may come from enriched mantle and experience contamination by substances from crust.The ratios of ¹⁴³Nd/¹⁴⁴Nd of the basalts in Jinping area range from 0.512269-0.512725, suggesting the crust source or contaminated crust source of the magma, while the ratios of ¹⁴³Nd/¹⁴⁴Nd of basalts in the Song Da area range from 0.512158—0.513184, indicating the magma originates mainly from mantle. The ^εNd values of basalt-kamatiite association are mostly more than O, and in big value, except for minor sample, it suggest that the magma come from strongly deplete mantle origin, while for the ELIP basalts, most of the ^εNd value are less than O, with minor more than O, indicating the magma origin being from mantle, but suffer contamination and assimilation to a great extent, and experience strong metasomatic action between mantle and crust. Almost all of ^εNd values of basalts in Jinping area are minus value excepting individual sample, suggestive of enriched mantle origin. The ratios of ¹⁴³Nd/¹⁴⁴Nd of basalts in Ban Phuc area, Vietnam, are commonly higher than that of basalts in Jinping, Yongsheng and Binchuan area, and moreover the ^εNd of the basalts in Ban Phuc area are in big positive value, it is suggested that the magma of basalts in Ban Phuc area is come from depleted mantle source with little contamination by crust materials.The typical ratios of the HFSE elements of basalts in Jinping-Song Da rift and ELIP area indicate that all the average ratios ofω（Ta）/ω（Hf）（Table 3-9） are bigger than 0.3, and ratios ofω（Nb）/ω（Zr） are bigger than 0.1, except for minor picrite sample, which are in accordance with that of mantle-plume originated basalts. From the west to the east in the ELIP, the ratios ofω（Ta）/ω（Hf） of basalts showing gradually decreasing trend, suggesting that the basalts in west ELIP have more geochemical features of mantle plume originated magma than that in the east ELIEComparatively, basalts in the Jinping-Song Da rift are more rich in Th, and relatively deplete in Ta, higher ratios ofω（Th）/ω（Ta）（Table3-9）, lower ratios of （Ta）/ω（Hf） than that of basalts in ELIP or other mantle plume-related basalts, excepting that they all have similarity of ratios ofω（Nb）/ω（Zr）. All types of ratios of basalts in the Jinping-Song Da rift are in line with that of basalts in intraplate extension area or initial rifting area, suggestive of richer Th content in magma source and suffering more crustal contamination than that of ELIP and mantle plume related basalts. From the ratios ofω（Th）/ω（Ta）, it is indicated that the major part of the ELIP basalts originated mainly from primitive mantle with low grade of part melting and weak crustal contamination, while the origin magma of basalts in the Jinping-Song Da rift, which is spatially far away from the majority of the ELIP, experienced strong crustal contamination.The ratios of Nb/Zr and plots of Zr vs Zr/Y （Fig.3-16）show that the basalts in Jinping area in the Jinping-Song Da rift is originated in intraplate tectonic environment, and the basalts-komatiite association is mainly generated in mid-ocean ridge tectonic, with minor being in island arc, and these show that the two magma activity centers have different depth of rifting, The depth of rifting in the Jinping-Song Da rift probably reached to the shallow trough basin facies for Jinping section, and deep trough for the Song Da section, but the latter has not been developed to a stage forming the oceanic crust. The correlation diagrams of Sm/Eu vs Sr（Rb） （Fig.3-20c, d） show that the basalts in Jinping area is evolved mainly by the crystalline separation of pyroxene and olivine, which correspondent to that the phenocrystal minerals being mainly the pyroxene and olivine in basalts, but the basalts have a lower degree of crystalline separation, the variable Sm/Eu ratios reflects the crustal contamination to a certain extent.Differentiation degree of the PGE elements of the basalts in Jinping area is low and the its primitive mantle normalized patterns is of not-so-apparent Pt-Pd type, with the transition features of Ru-Os type and Pt-Pd type, steep left-dipping primitive mantle normalized distribution model with big positive slope.There are six categories of mineralized mafic-ultramafic intrusions in the Jinping-Song Da rift, all exhibit the characteristics of sub-alkaline, and fall into the types of low-Ti tholeiitic series and ferric mafic-ultramafic series. The Permian basalts and mafic-ultamafic intrusions and associated sulfide ores share geochemistry of REE and trace elements and PGE i.e. they all have the similar primitive mantle normalized REE distribution patterns（right-dipping light REE enriched distribution patterns）, and PGE contents and its primitive mantle normalized distribution patterns（tower abundance value, bigger Pd/Ir ratios and left-dipping Pt-Pd enriched distribution patterns）,and they all have the same primitive mantle normalized distribution spider diagrams and same elements abundance, which show there is an inevitable genetic relation between them in both the temporal and spatial evolution terms.There are also same REE and trace elements variations characteristics between the mafic and ultamafic intrusions distributed in the axis of the Song Da rift and the picrite-basalts association in the peripheral area, i.e. they all contain higher contents of Mg, Ni, Co, Cr, Yb, Lu and lower contents of Ti、Fe、Ca、Na、K、Rb、Sr、V、Nb、Ta、Zr and LREE.The magmatic Cu-Ni（PGE） sulfide metallogenic belt in the Jinping-Song Da rift is located in the SW margin of the ELIP metallogenic province which situated in the west margin of the Yangtze craton. The mineralized intrusions is generally emplaced in the same age as that of the intrusions of similar deposit in the adjacent area（Table 4-30）, with the ore-bearing intrusions being the peridotite-pyroxenite associations of the ferric ultamafic rock series, and most of the intrusions-hosting country rocks contains carbonaceous shale with large number of the sedimentary pyrite. The size of mineralized intrusion is at small scale, and the better the differentiation of the intrusions, the better the mineralization of the intrusions. The Baimazhai and Ban Phuc Ni-Cu（PGE） deposits, which are the typical magmatic Ni-Cu（PGE） deposit in the Jinping-Song Da rift, share similar basic geological characteristics. Their rnineralised intrusions are all the differentiated ultamafic rocks, the sulfide ores are mainly located in the bottom or the center of the intrusions, the ore types are mainly the disseminated and massive ore, both the two typical deposits are of the same mineralogy as the pyrrhotite, pyrite, pentlandite and chalcopyrite, what is different is that the ores in Ban Phuc deposit contains more metal arsenide, telluride, antimonide and PGE minerals than that in the Baimazhai deposit while they are very rare.The distinguish features of the Baimazhai Ni-Cu sulfide deposit in Jinping, lies in that it is extremely rich in Cu and Ni（the massive ore-body No.1 take up 67.8% of the total Ni reserve with average grade of 3.68% of nickel and 1.99% of Cu） and relatively poor in PGE, with the massive ore being located in the center of the extremely well-differentiated and mineralized intrusion, all types of ores containing very low PGE elements（the average Pt+Pd contents of different ores range from 0.02 to 0.15g/t） and also the associated gold and silver are also very low （Table 4-32）.As for the Ban Phuc Ni-Cu（PGE） sulfide deposit in the Song Da rift, it has similar basic geological features, ores associations and natural ore types with other deposits in the rift, but there is no bottom massive ores because of low grade of differentiation, the ore types are mainly the disseminated ore and massive ores in the veinlet ore body filled along the contact fracture zone. The sulfur isotope composition of the sulfides in the ores is close to that of the chondrite, there is not much sulfur mixture from country rocks during the ore-forming, the sulfur is mainly originated from the komatiite magma itself.The total average sulfur content in Baimazhai intrusions is 11.114%, which far higher than that of the global average ultramafic rocks（with sulfur content is 2850ppm）. And the sulfur contents increasing greatly in the order from gabbro to peridotite, which shows the sulfur enriched features of the magma in later stage. Except for the intrusions in the Baimazhai ore deposit, the sulfur contents（0.285%） of other intrusions and basalts located in the Jinping rift are also higher than that of the global ultramafic rocks, which suggestive of sulfur enrichment in the primitive magma indicated by the mafic-ultamafic intrusions in the Jinping area. And the sulfur isotope value of ores in Baimazhai Ni deposit ranges from 6.68-7.59‰which is similar with that of the pyroxenite, basalts and the sedimentary shale in the Jinping area in terms of the positive sulfur isotope composition, and it suggesting they have the same sulfur source and the sedimentary shale has supply some sulfur source for the mineralization. And the Sr isotope composition also shows the contamination materials from the crust（including the sulfur）.The chemical compositions of ores from both the Baimazhai and Ban Phuc Cu-Ni deposit are of similar basic geological features（Table4-32）, showing that is enrich in Cu and Nickel while poor in PGE and associated gold and silver, with higher Ni:Cu:Co ratio and extremely low contents of Pt+Pd value, and low Pt/（Pt+Pd） ratios（＜0.5）, it does not exhibit apparent enrichment of Pt. By comparison, the enrichment of Pt and Pd in the ores in the Jinbaoshan deposit is higher but with extremely low contents of Cu and Ni, while it shows Cu-Ni and Pt-Pd enrichments to some extent in the ores in the Yanliuping Cu-Ni sulfide deposit.Plots of chondrite-normalised REE（Fig.4-32A and B） shows the Baimazhai ores are slightly LREE enriched, with weak negative Eu anomalies. And the different types of ores and weakly mineralized gabbro in the Baimazhai deposit exhibit a similar primitive mantle normalized REE plots with that of the Kalangtoke and the Yangliuyping ores, the REE contents in Baimazhai deposit is 10-50 times chondrite values. But the total REE value of the ores in Kalangtoke and Yangliuping are higher than that of the massive ores（Fig.4-32A）. The peddotite in Baimazhai intrusion is relatively LREE-enriched. And what it is important that The Yangliuping basalts, Hongge intrusions and Jinping basalts all show similar REE patterns（Fig. 4-32B）.The Sr and Nd isotope compositions of the mafic-ultamafic intrusions in Baimazhai deposit indicate that the origin magma is contaminated with "materials from crust, while the Nd isotope composition of mafic-ultamafic intrusions in Ban Phuc deposit in the Song Da rift show that it was only slightly contaminated by crust matters.There are some apparent differences between the parent magmas of the mineralized mafic-ultamafic intrusions in the North（Jinping） section and south（Song Da） section, but intrusions and eruption in each area share genetic correlation with each other exhibited by the REE, trace elements and elements isotope geochemistry. There are two types of rock associations in the Jinping rift, i.e. the peridotite-pyroxenite-gabbro（Baimazhai Cu-Ni deposit and Yinpingjie Cu-Ni（PGE） deposit） and the pyroxenite-gabbro-diabase（Niulanchong and Jiangjiaping）, all these rocks are the tholeiitic series, while in the south section of the Song Da rift, the mineralized intrusions in Ban Phuc nickel deposit is the dunite-peridotite association, and the erupted rocks is the basalt-komatiite association, which belong to the komatiitic-tholeiitic series（please refer to Chapter 3 for the details）.The magmatic Cu-Ni（PGE） sulfide deposit in the Jinping-Song Da rift are formed in the late Paleozoic extension basin, ore-bearing mafic-ultramafic rocks occurs spatially in belts and swarms along structure zone, with ore deposits（occurrences） being located repeatedly in single deposits in different sections of the Jinping-Song Da rift. The single intrusion is composed of different rock facies with clear differentiation, the ore-bearing intrusions in Baimazhai deposit are the typical representatives among these intrusions, in which, there are at least five kinds of differentiated magma and ore magma decided by the spatial distribution of the different rock intrusions, i.e. the early gabbro magma, middle pyroxenite magma, middle-later olivine pyroxenite magma and pyroxene peridotite magma and the final sulfide highly enriched ore magma, there are other same types of intrusions with mineralization to different extent occurs in the surrounding area of the Baimazhai deposit, in which the mineralization is the results of part of the ore-bearing magma evolved from the unified ore magma represented by the ore-bearing intrusions in the Baimazhai deposit, the size of Cu-Ni mineralization depends on the amounts of the ore-magma evolved from the unified magma chamber. While in the Song Da area, the differentiated level of the intrusions are not so good by the known outcrops of the ultramafic rocks. During the formations of ore-enriched magma chamber evolved from the original magma source, several sub-sized magma chamber may be formed by the differentiations and liquation of the original magma due to regional tectonic events, and some sub-sized magma chamber may only inherit part of the magma from the middle-upper part of the parent magma chamber with low level of mineralization, which lead to the difference of the differentiation and mineralization of the intrusions. The comprehensive metallogenic model are showed in Fig.4-34.The enrich mechnism of the Cu-Ni sulfide in the Baimazhai and Ban Phuc nickel deposit is mainly evolved from the deep liquation and differentiation, but with great difference between each other, the former is mainly the Ni-Cu sulfide with rare PGE and no independent PGE minerals（which occurs in the chalcopyite and pyrite）; while the latter has strongly hydrothermal modification, except for the Ni-Cu sulfide, there are also a great number of sulfosalt, telluride, Ni-Co sulfur arsenide and michenefite etc. But there also exists the pneumatolytic hydrothermal and hydrothermal fluids modification related to the mafic-ultramafic intrusions in the Baimazhai Ni-Cu deposit in Jinping-Song Da rift, which indicated by the contact metasomatism and hydrothermal metamorphism, and the hosting rocks are commonly hydrothermally metamorphosed, i.e. hornfelisic alteration etc. The hydrothermally-modified metallogenesis is showed in the ore-formations of Cu and PGE mineralization, by which the veinlets consisting of irregular or banded pentlandite and chalcopyrite and carbonate in the ores. It is common that the prrhotitie and pentlandite are replaced by the chalcopyrite, and massive ores are replaced by sideroritic ores forming the psedomorphic mixed disseminated ores in the contact zone between them, and metasomatism of disseminated ore to the rock-forming minerals. The occurrence of biotite, chlorite and amphibole inter-grown with sulphides is additional evidence of volatile activity. In general, these modified ores tend to be enriched in Cu, Au and Pd as indicated by the ores in the Baimazhai nickel deposit. The hydrothermally modified metallogensis is also verified by the Ar-Ar dating which indicate the mineralization age range from 160-170Ma.In addition, some rich veinlet Cu-Ni ore-bodies with small size are formed due to the superimposed hydrothermally modification metallogenesis, for instance, the veinlet rich massive Cu-Ni sulfide ores are common in the contact zone between the Yingpanjie-Mahuanggou mafic-ultramafic intrusions swarm. And the hydrothermally modification also lead to the further enrichments of the early disseminated ores and the enrichments of PGE elements. While the independent PGE minerals, sulfosalt, tellurides and irregular networks of sulfide associated with quartz are the results of the hydrothermally modified metallogenesis.Hydrothermal remobilisation at Baimazhai is probably linked to post-magmatic tectonothermal events in the region. These events produced hydrothermal fluids that were focused hydrothermal fluids into suitable structures and the same fluids also modified existing mafic-ultramafic sulphide systems. No detailed structural data are available from the Baimazhai region, but limited field structural observations show that mylonites are present in the ASRR fault zone and an overturned anticline affects the sedimentary rocks that are intruded by the Baimazhai intrusions. At Baimazhai, there is convincing evidence of hydrothermal alteration of the intrusive rock, during which the silicate minerals have been pervasively replaced by hydrous phases（PhotoⅥ-1,Ⅵ-2）. The hydrothermal fluids may not have modified the entire body of massive sulphides, but it is possible that tectonic movements have affected its margins, forming zones of disrupted or brecciated sulphides. This would have facilitated the introduction of hydrothermal fluids resulting in disseminated and interstitial sulphide ores （PhotoⅦ-1—Ⅶ-5）. The "alteration-modified" sulphides are interpreted as an example of this tectonic and hydrothermal activity. This is also indicated by the presence of sulphide phases, other than the normal pyrrhotite-pentlandite-chalcopyrite assemblage, in which metal redistribution of certain trace elements such as Bi and Pb occurred to precipitate exotic sulphides （e.g. parkerite）. A schematic illustration of the model is shown in Fig.4-35. In this model we envisage two possibilities: 1) a massive sulphide body was deformed and its marginal zones disrupted and brecciated allowing access of hydrothermal fluids, which modified the sulphides and the host rock; 2) alternatively, a magmatic massive sulphide body was originally overlain by a zone of magmatic disseminated sulphides; upon deformation of the massive-disseminated sulphide system, hydothermal fluids penetrated the most permeable zones as represented by the disseminated zone. In both cases the contact between sulphides and wall rock is a zone of highest geochemical gradient as well as a favourable structural locale and the fluids are expected to be focused within this zone.更多还原