德兴铜矿是中国东部大陆环境最具代表性的大型斑岩铜矿,由朱砂红、铜厂及富家坞三大矿床组成,其中的铜厂矿体以富金而别具特色.在前人研究基础上,本文通过系统的野外观测、详细的岩芯编录和全面的岩相学研究,厘定了铜厂矿床的脉体类型和形成顺序,系统地开展了各类脉体的流体包裹体研究,查明了成矿流体的演化过程,再塑了岩浆-热液矿化过程.初步识别出德兴矿床3组脉体类型,分别记录了三个不同阶段的蚀变-成矿过程:早期A脉分为4类,形成于成矿早期斑岩尚未固结时,伴有大规模的钾化和黑云母化甚至磁铁矿化;中期B脉可分为7类,形成于斑岩体固结后的大规模裂隙事件发育期,B脉石英呈梳状对称生长、黄铁矿以中心线生长;后期D脉共有3类,发育于成矿晚期,系雨水大量加入和硫化物大量淀积产物.观察发现,所有A、B及D脉沉淀过程中,均伴随大量的岩浆流体出溶、热液蚀变、流体挥发等热液活动、各脉均捕获了同体系内富含的热液流体.详细显微镜鉴定表明,各类脉体的脉石矿物石英内发育的大部分包裹体与世界典型斑岩铜矿床的矿化特征相似,从成矿早期A脉到成矿晚期D脉包裹体的类型发生如下变化:早期以LVH(含单子晶或多子晶包裹体发育,包裹体中还见有金属硫化物)+富气相包裹体为主→中期以含单子晶包裹体+富气相包裹体为主,以及含有少量富液相包裹体→成矿晚期,以富液相包裹体+少量富气相包裹体.包裹体显微测温结果总体上指示了温度、压力及热液成分在各类脉体的形成过程的变化规律,从早期到晚期温度和盐度逐渐降低,热液成矿作用明显经历三个阶段:早期岩浆未完全固结,温度达到800～600℃以上,压力较高(140～50MPa),发生强烈的钾硅酸盐化;中期,由于岩浆冷凝结晶,岩体顶部围岩裂隙发育,静岩压力向静水压力发生转换,温度下降到450～550℃,压力陡然从55～40MPa下降至20MPa(B脉);而D脉形成时,发生大规模绿泥石-水云母化,温度下降至350～375℃,压力完全降低至20MPa以下;最后,与成矿作用无关的热液活动了两次,峰值温度分别是320～300℃和180～200℃,形成了无矿碳酸盐脉、石英脉及黑云母. 在成矿过程中,成矿热液也从形成A/B脉时以岩浆热液为主,转变为形成D脉时以雨水、地下水为主.与世界典型斑岩型铜矿床相比,德兴斑岩铜矿床的蚀变-矿化系统基本一致,都由强硅酸盐蚀变带--青磐岩蚀变带--泥岩蚀变带等构成,在不同的蚀变阶段形成了具有特色的不规则形状A脉、脉石矿物梳状对称的B脉及粗颗粒大脉型D脉.德兴铜厂铜金矿各成矿阶段内主要成矿流体特征及其演化过程基本类似于世界典型斑岩矿床.但是,也存在不同之处,在铜厂铜金矿的A、B及D脉都发育了少量CO_2包裹体,表明德兴铜厂成矿过程中CO_2参与成矿作用,世界其它斑岩型矿床或没有报道发育 CO_2 包裹体(杨志明等,2008),或者仅在其中某个阶段发现了少量CO_2包裹体(Harris et al., 2004).CO_2包裹体参与成矿是否有特殊指示意义,须进一步的工作才能得出正确的结论.
德興銅礦是中國東部大陸環境最具代錶性的大型斑巖銅礦,由硃砂紅、銅廠及富傢塢三大礦床組成,其中的銅廠礦體以富金而彆具特色.在前人研究基礎上,本文通過繫統的野外觀測、詳細的巖芯編錄和全麵的巖相學研究,釐定瞭銅廠礦床的脈體類型和形成順序,繫統地開展瞭各類脈體的流體包裹體研究,查明瞭成礦流體的縯化過程,再塑瞭巖漿-熱液礦化過程.初步識彆齣德興礦床3組脈體類型,分彆記錄瞭三箇不同階段的蝕變-成礦過程:早期A脈分為4類,形成于成礦早期斑巖尚未固結時,伴有大規模的鉀化和黑雲母化甚至磁鐵礦化;中期B脈可分為7類,形成于斑巖體固結後的大規模裂隙事件髮育期,B脈石英呈梳狀對稱生長、黃鐵礦以中心線生長;後期D脈共有3類,髮育于成礦晚期,繫雨水大量加入和硫化物大量澱積產物.觀察髮現,所有A、B及D脈沉澱過程中,均伴隨大量的巖漿流體齣溶、熱液蝕變、流體揮髮等熱液活動、各脈均捕穫瞭同體繫內富含的熱液流體.詳細顯微鏡鑒定錶明,各類脈體的脈石礦物石英內髮育的大部分包裹體與世界典型斑巖銅礦床的礦化特徵相似,從成礦早期A脈到成礦晚期D脈包裹體的類型髮生如下變化:早期以LVH(含單子晶或多子晶包裹體髮育,包裹體中還見有金屬硫化物)+富氣相包裹體為主→中期以含單子晶包裹體+富氣相包裹體為主,以及含有少量富液相包裹體→成礦晚期,以富液相包裹體+少量富氣相包裹體.包裹體顯微測溫結果總體上指示瞭溫度、壓力及熱液成分在各類脈體的形成過程的變化規律,從早期到晚期溫度和鹽度逐漸降低,熱液成礦作用明顯經歷三箇階段:早期巖漿未完全固結,溫度達到800～600℃以上,壓力較高(140～50MPa),髮生彊烈的鉀硅痠鹽化;中期,由于巖漿冷凝結晶,巖體頂部圍巖裂隙髮育,靜巖壓力嚮靜水壓力髮生轉換,溫度下降到450～550℃,壓力陡然從55～40MPa下降至20MPa(B脈);而D脈形成時,髮生大規模綠泥石-水雲母化,溫度下降至350～375℃,壓力完全降低至20MPa以下;最後,與成礦作用無關的熱液活動瞭兩次,峰值溫度分彆是320～300℃和180～200℃,形成瞭無礦碳痠鹽脈、石英脈及黑雲母. 在成礦過程中,成礦熱液也從形成A/B脈時以巖漿熱液為主,轉變為形成D脈時以雨水、地下水為主.與世界典型斑巖型銅礦床相比,德興斑巖銅礦床的蝕變-礦化繫統基本一緻,都由彊硅痠鹽蝕變帶--青磐巖蝕變帶--泥巖蝕變帶等構成,在不同的蝕變階段形成瞭具有特色的不規則形狀A脈、脈石礦物梳狀對稱的B脈及粗顆粒大脈型D脈.德興銅廠銅金礦各成礦階段內主要成礦流體特徵及其縯化過程基本類似于世界典型斑巖礦床.但是,也存在不同之處,在銅廠銅金礦的A、B及D脈都髮育瞭少量CO_2包裹體,錶明德興銅廠成礦過程中CO_2參與成礦作用,世界其它斑巖型礦床或沒有報道髮育 CO_2 包裹體(楊誌明等,2008),或者僅在其中某箇階段髮現瞭少量CO_2包裹體(Harris et al., 2004).CO_2包裹體參與成礦是否有特殊指示意義,鬚進一步的工作纔能得齣正確的結論.
덕흥동광시중국동부대륙배경최구대표성적대형반암동광,유주사홍、동엄급부가오삼대광상조성,기중적동엄광체이부금이별구특색.재전인연구기출상,본문통과계통적야외관측、상세적암심편록화전면적암상학연구,전정료동엄광상적맥체류형화형성순서,계통지개전료각류맥체적류체포과체연구,사명료성광류체적연화과정,재소료암장-열액광화과정.초보식별출덕흥광상3조맥체류형,분별기록료삼개불동계단적식변-성광과정:조기A맥분위4류,형성우성광조기반암상미고결시,반유대규모적갑화화흑운모화심지자철광화;중기B맥가분위7류,형성우반암체고결후적대규모렬극사건발육기,B맥석영정소상대칭생장、황철광이중심선생장;후기D맥공유3류,발육우성광만기,계우수대량가입화류화물대량정적산물.관찰발현,소유A、B급D맥침정과정중,균반수대량적암장류체출용、열액식변、류체휘발등열액활동、각맥균포획료동체계내부함적열액류체.상세현미경감정표명,각류맥체적맥석광물석영내발육적대부분포과체여세계전형반암동광상적광화특정상사,종성광조기A맥도성광만기D맥포과체적류형발생여하변화:조기이LVH(함단자정혹다자정포과체발육,포과체중환견유금속류화물)+부기상포과체위주→중기이함단자정포과체+부기상포과체위주,이급함유소량부액상포과체→성광만기,이부액상포과체+소량부기상포과체.포과체현미측온결과총체상지시료온도、압력급열액성분재각류맥체적형성과정적변화규률,종조기도만기온도화염도축점강저,열액성광작용명현경력삼개계단:조기암장미완전고결,온도체도800～600℃이상,압력교고(140～50MPa),발생강렬적갑규산염화;중기,유우암장냉응결정,암체정부위암렬극발육,정암압력향정수압력발생전환,온도하강도450～550℃,압력두연종55～40MPa하강지20MPa(B맥);이D맥형성시,발생대규모록니석-수운모화,온도하강지350～375℃,압력완전강저지20MPa이하;최후,여성광작용무관적열액활동료량차,봉치온도분별시320～300℃화180～200℃,형성료무광탄산염맥、석영맥급흑운모. 재성광과정중,성광열액야종형성A/B맥시이암장열액위주,전변위형성D맥시이우수、지하수위주.여세계전형반암형동광상상비,덕흥반암동광상적식변-광화계통기본일치,도유강규산염식변대--청반암식변대--니암식변대등구성,재불동적식변계단형성료구유특색적불규칙형상A맥、맥석광물소상대칭적B맥급조과립대맥형D맥.덕흥동엄동금광각성광계단내주요성광류체특정급기연화과정기본유사우세계전형반암광상.단시,야존재불동지처,재동엄동금광적A、B급D맥도발육료소량CO_2포과체,표명덕흥동엄성광과정중CO_2삼여성광작용,세계기타반암형광상혹몰유보도발육 CO_2 포과체(양지명등,2008),혹자부재기중모개계단발현료소량CO_2포과체(Harris et al., 2004).CO_2포과체삼여성광시부유특수지시의의,수진일보적공작재능득출정학적결론.
Dexing copper deposit, known for rich gold, is the most typical continental porphyry deposit in the east of China. Based on systematic field observation of whole ore body and cataloging of core rock, alteration-mineralization system of Dexing Tongchang porphyry copper-gold deposit is clearly studid to Distinguish the order of mineral veins formation and to implement the microthermometere of fluid inclusions in the veins in this paper. According to the behavior of fluid inclusions of different mineralization stages and the result of microthermometer, the characteristics of ore-forming fluid of alteration-mineralization system of Dexing Tongchang porphyry copper-gold deposit are completely recognized. Dexing Tongchang porphyry copper-gold deposit was formed by multi-stages of alteration and mineralizaiton from early to the end. In the early stage, the four A-type veins were formd when the porphyry rock is not completely solidified so that the veins are irregluar or unclearly bordered with wall rock or porphyry rock and large-scale of K-feldspar alteration, biotite alteration and even magnetitization. In the middle stage, the seven B-type veins where symmetrical pectinate quartzs or chlorite are vertical to the vein wall and metal minerals are as their centerline, were largely formed when most of the ore minerals including the chalcopyrite, molybdenite, bornite and so on were formed contemporaneously. At the post-minerlization stage, three D-type veins with or without alterated Hydromica halo and the lastest hypothermal carbnate-quartz veins and biotite veins were fromed when the mineralizaiton system was opened and meteoric water and undergrand water infused into the open fissure. Mineralization and alteration system of Dexing Tongchang copper-gold deposit is similar to that worldwide typical porphyry deposit, showing that A-type Veins and K-silicification occurred on the boundary between wallrock and granodiorite porphyry, B- and D- veins and propylitization occurred outspreading along the wallrock and granodiorite porphyry near to the boundary,and the latest carbonate, quartz and biotite veins and argillization were spliced above or out of the propylitization belt. Fluid inclusions of differt veins varied with the ore-forming process that there were mainly LVH (one or moe daugther metal mineral or transparent minerals are contained in the fluid inclusions)and VL (more than 50% vaper in volume) types of inclusion in the early A-type veins, lots of LVH and VL and little of LV fluid inclusions in the B-type veins at middle stages, and VL and LV (less than or equal to 50% vaper in volume) fluid inclusions in the latest D-type veins. The behavior fluind inclusions in the temperature-mearsuring process and the result of microthermometer have been use to evalute the conditions of different mineralization stages. In the early stage, when porphyry magma still unsolidified, the A-type veins are formed at the 600～800℃ and 120～50MPa or even above them; at the middle stage, the B-type veins are formed when the static rock pressure (55MPa) transferred to the static water pressure (20MPa); and at the latest stage, the temperature and pressure totally decrease to 350～375℃. After the mineralization of Tongchang deposit, two hydrothermal activation without mineralization overprinted on the former mineralization veins, respectively under 320～300℃ and 180～200℃. The hydrothermal fluid varied from magma fluid as A- and B- veins fromed to meteoric water or ground water as the D-type veins were formed. However, there are CO_2-bearing fluid inclusions hosted in Dexing Tongchang copper-gold deposit, which are never found in other porphyry deposits, or only little in one ore-forming stage in some porphyry deposit. Thus may represents abnormal on its metallogeny of Dexing Tongchang porphyry Cu deposit.
