CAJ | 학술논문

赛什塘铜矿位于东昆仑造山带东端的鄂拉山地区,是中国西部重要的矽卡岩型铜矿之一。矽卡岩形成于印支期石英闪长岩与中—下三叠统地层Tb21-2岩性段的接触带,矿体主要呈似层状、透镜状产于外接触带矽卡岩中。Tb21-2岩性段由中性火山岩、大理岩及变质粉砂岩构成,其中变安山质凝灰岩及安山岩与铜矿化有着密切的空间关系。岩相学研究表明,含铜矽卡岩的形成经历了矽卡岩阶段、退化蚀变阶段、石英-硫化物阶段及石英-碳酸盐阶段。矽卡岩阶段形成石榴子石、辉石及硅灰石,退化蚀变阶段则形成绿帘石、角闪石及磁铁矿,石英-硫化物阶段大量金属硫化物发生沉淀。电子探针分析表明,石榴子石与辉石矿物组分分别为Gro0.00~91.00And7.02~100.00(Pyr+Alm+Spe)0.00~4.27与Di12.80~98.08Hd2.41~79.80(Jo+Jd+Opx)0.00~13.47,表明其属于典型的钙矽卡岩类。空间上,靠近石英闪长岩与安山岩接触带处,钙铝榴石和绿帘石更富集,而向大理岩的一侧以钙铁榴石为主,并常见硅灰石及含Mn的钙铁辉石。矿物学特征及矿物成分的变化显示：从矽卡岩阶段到石英-硫化物阶段,流体性质呈幕式的变化,成矿流体至少经历了2次氧化还原性质的转变,这种变化可能与成矿流体中大气降水的不断加入有关。赛什塘铜矿属于矽卡岩型矿床,以石英闪长岩为主的岩浆活动携带了大量的热量及流体,侵入到中—下三叠统地层中,与围岩地层发生物质交换的同时,引起了大理岩、变质粉砂岩与中性火山岩之间的双交代作用,是导致矽卡岩和矿体形成的重要机制。
새십당동광위우동곤륜조산대동단적악랍산지구,시중국서부중요적석잡암형동광지일。석잡암형성우인지기석영섬장암여중—하삼첩통지층Tb21-2암성단적접촉대,광체주요정사층상、투경상산우외접촉대석잡암중。Tb21-2암성단유중성화산암、대리암급변질분사암구성,기중변안산질응회암급안산암여동광화유착밀절적공간관계。암상학연구표명,함동석잡암적형성경력료석잡암계단、퇴화식변계단、석영-류화물계단급석영-탄산염계단。석잡암계단형성석류자석、휘석급규회석,퇴화식변계단칙형성록렴석、각섬석급자철광,석영-류화물계단대량금속류화물발생침정。전자탐침분석표명,석류자석여휘석광물조분분별위Gro0.00~91.00And7.02~100.00(Pyr+Alm+Spe)0.00~4.27여Di12.80~98.08Hd2.41~79.80(Jo+Jd+Opx)0.00~13.47,표명기속우전형적개석잡암류。공간상,고근석영섬장암여안산암접촉대처,개려류석화록렴석경부집,이향대리암적일측이개철류석위주,병상견규회석급함Mn적개철휘석。광물학특정급광물성분적변화현시：종석잡암계단도석영-류화물계단,류체성질정막식적변화,성광류체지소경력료2차양화환원성질적전변,저충변화가능여성광류체중대기강수적불단가입유관。새십당동광속우석잡암형광상,이석영섬장암위주적암장활동휴대료대량적열량급류체,침입도중—하삼첩통지층중,여위암지층발생물질교환적동시,인기료대리암、변질분사암여중성화산암지간적쌍교대작용,시도치석잡암화광체형성적중요궤제。
The Saishitang copper deposit is an important skarn deposit located in the Southeast of Ngola Mountain Area, Eastern margin of East Kunlun orogenic belt. The skarn occurs along the contact between Indosinian quartz diorite and middle-lower Triassic Tb21-2 lithologic section. The ore bodies which are stratoid or lenticular mainly occur in exoskarn. The Tb21-2 lithologic section consists of intermediate volcanic rocks, marble and metamorphic siltstone. Cu mineralization is adjacent to the metamorphic andesitic tuff and andesite spatially. Petrography studies of Cu-bearing skarn show four stages of skarn formation and ore development, including skarn stage, retrograde alteration stage, quartz-sulfide stage and quartz-carbonate stage. Skarn stage consists of garnet, pyroxene and wollastonite and retrograde alteration stage dominates by epidote, amphibole and magnetite. In quartz-sulfide stage a large amount of sulfides were precipitated. Electron microprobe analysis shows that components of garnet and pyroxene are Gro0.00~91.00And7.02~100.00(Pyr+Alm+Spe)0.00~4.27 and Di12.80~91.75Hd2.41~79.80(Jo+Jd+Opx)0.00~13.47, respectively. The result indicates that the skarn in Saishitang deposit belongs to typical calcic skarn. High concentrations of grossular and epidote are found in skarns located closer to the contact between quartz diorite and andesite. Andradite is richer near the marble with wollastonite and Mn-bearing hedenbergite. Mineralogical characteristics and compositional variations suggest:from skarn stage to quartz-sulfide stage, the property of fluid changed episodically with two redox fluctuations at least, probably resulting from the influx of meteoric waters in ore-forming fluid. Saishitang copper deposit is a skarn deposit. The quartz diorite-dominated intrusions carrying plenty of heat and fluids intrude into middle-lower Triassic strata. The materials exchange between intrusions and wall rocks may be the mechanism of the development of skarn and ore bodies in Saishitang deposit, accompanying the bimetasomatism between marble and metamorphic siltstone and intermediate volcanic rocks.