安庆铜矿床典型矽卡岩矿物形成过程数值模拟
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摘要
安庆铜矿床位于长江中下游成矿带内安庆-贵池矿集区,为典型的矽卡岩型矿床。为了更好地理解安庆铜铁矿床矽卡岩成因及矽卡岩成岩过程对后续成矿的影响,文章基于矿区地质条件、矿物学特征和矿床学相关研究成果,利用数值模拟方法开展定量化研究。模拟结果验证了安庆矽卡岩型矿床是以双交代作用为主形成的。其中,Mg来自碳酸盐岩地层,主要从外带向内带方向迁移,因此外接触带相对富集透辉石。而侵入体中的含Fe热液则从岩体向碳酸盐岩一侧扩散,因此内接触带相对富集石榴石。岩体一侧形成的矽卡岩孔隙度较碳酸盐岩地层大,从而使得更多的含矿热液进入孔隙通道中,继续形成矽卡岩矿物;另一方面,岩体一侧的矽卡岩隔离了含矿热液与碳酸盐岩的直接接触,使得含Fe热液保持一定的活性,有利于后期磁铁矿的形成。同时,这种矽卡岩正反馈的结果为后期磁铁矿的形成提供了一个有利的场地。模拟结果可以提高对安庆铜铁矿床矽卡岩成岩过程的理解。
Anqing copper deposit is located in Anqing-Guichi mineralization zone in the middle and lower reaches of the Yangtze River. It is a typical skarn type deposit. In order to better understand the genesis of skarn in Anqing copper-iron deposit and the influence of skarn diagenesis on subsequent mineralization, the geological features, mineralogical features and diagenetic geochemical processes of this area are considered by computer simulation. The simulation results show that the skarn deposits in Anqing are mainly formed by bimetasomatism. Among them, Mg comes from carbonate strata and migrates mainly from outer belt to inner belt, so the outer contact zone is relatively rich in diopside. The Fe-bearing hydrothermal solution in the intruder diffuses from the rock mass to the carbonate rock side, so the inner contact zone is relatively rich in garnet. The porosity of the skarn formed on the side of the rock mass is larger than that of the carbonate formation, so more hydrothermal fluid enters the pore channels and continues to form skarn. On the other hand, the skarn on the side of the rock mass isolates the direct contact between the hydrothermal solution and carbonate rocks, thus the hydrothermal fluid maintains a certain activity and flows to the far reaction front of the carbonate rocks and continues to form skarn. At the same time, the results of positive feedback of skarn provide a favorable site for the formation of magnetite. These results can improve the understanding of skarn diagenesis in Anqing copper-iron deposit.
Anqing copper deposit is located in Anqing-Guichi mineralization zone in the middle and lower reaches of the Yangtze River. It is a typical skarn type deposit. In order to better understand the genesis of skarn in Anqing copper-iron deposit and the influence of skarn diagenesis on subsequent mineralization, the geological features, mineralogical features and diagenetic geochemical processes of this area are considered by computer simulation. The simulation results show that the skarn deposits in Anqing are mainly formed by bimetasomatism. Among them, Mg comes from carbonate strata and migrates mainly from outer belt to inner belt, so the outer contact zone is relatively rich in diopside. The Fe-bearing hydrothermal solution in the intruder diffuses from the rock mass to the carbonate rock side, so the inner contact zone is relatively rich in garnet. The porosity of the skarn formed on the side of the rock mass is larger than that of the carbonate formation, so more hydrothermal fluid enters the pore channels and continues to form skarn. On the other hand, the skarn on the side of the rock mass isolates the direct contact between the hydrothermal solution and carbonate rocks, thus the hydrothermal fluid maintains a certain activity and flows to the far reaction front of the carbonate rocks and continues to form skarn. At the same time, the results of positive feedback of skarn provide a favorable site for the formation of magnetite. These results can improve the understanding of skarn diagenesis in Anqing copper-iron deposit.
引文
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[11] 束学福.安庆夕卡岩型铁铜矿床地质地球化学特征及铁质来源研究[J].矿物岩石地球化学通报,2004,24(3):219-224.
[12] 张智宇,杜杨松,向文帅,等.安徽安庆铜铁矿床成因:矿床地质特征与元素地球化学约束[J].岩石学报,2012,28(11):3739-3756.
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[21] SUN T,LIU L.Delineating the complexity of Cu-Mo mineralization in a porphyry intrusion by computational and fractal modeling:a case study of the Chehugou deposit in the Chifeng district,Inner Mongolia,China[J].Journal of Geochemical Exploration,2014,144:128-143.
[22] LIU L,WAN C,ZHAO C,et al.Geodynamic constraints on orebody localization in the Anqing orefield,China:computational modeling and facilitating predictive exploration of deep deposits[J].Ore Geology Reviews,2011,43(1):249-263.
[23] 贾蔡,袁峰,张明明,等.宁芜盆地白象山铁矿床成矿作用过程数值模拟[J].岩石学报,2014,30(4):1031-1040.
[24] LIU L,LI J,ZHAO R,et al.3D modeling of the porphyry-related Dawangding gold deposit in south China:implications for ore genesis and resources evaluation[J].Journal of Geochemical Exploration,2016,164:164-185.
[25] 姚鹏,李金高,顾雪祥,等.从REE和硅同位素特征探讨西藏甲马矿床层状夕卡岩成因[J].岩石矿物学杂志,2006,25(4):305-313.
[26] 於崇文.热液成矿作用动力学[M].北京:中国地质大学出版社,1993.
[27] 杨光树,温汉捷,胡瑞忠,等.安庆夕卡岩型铁铜矿床流体包裹体研究[J].地球化学,2008,37(1):27-36.
[28] FOURNIER R O.Hydrothermal processes related to movement of fluid from plastic into brittle rock in the magmatic-epithermal environment[J].Economic Geology,1999,94(8):1193-1211.
[29] HENLEY R W,BRINK F J,KING P L,et al.High temperature gas-solid reactions in calc-silicate Cu-Au skarn formation; Ertsberg,Papua Province,Indonesia[J].Contributions to Mineralogy & Petrology,2017,172(11/12):106.
[30] ZOU Y,LIU Y,DI T,et al.Finite difference modeling of metallogenic processes in the Hutouya Pb-Zn deposit,Qinghai,China: Implications for hydrothermal mineralization[J].Ore Geology Reviews,2017,91:463-466.
[31] 刘晓东.安徽月山矿田成矿流体系统研究[D].合肥:合肥工业大学,2000.
[32] BORISOVA E A,ADLDER P M.Deposition in porous media and clogging on the field scale.[J].Physical Review E Statistical Nonlinear & Soft Matter Physics,2005,71(2):2839-2858.
[33] 滕传耀.安徽安庆铜铁矿床矽卡岩成矿作用研究[D].北京:中国地质大学,2013.
[34] MEINERT L D,DIPPLE G M,NICOLESCU S.World Skarn Deposits[M]//Economic Geology 100th Anniversary Volume.[S.l.]:Society of Economic Geologists, Inc.,2005:299-336.
[35] 向文帅.安徽省安庆铜铁矿床特征及成因[D].北京:中国地质大学,2010.
[36] LIANGMING L,ZHIMING S,CHONBIN Z,et al.The controlling mechanism of ore formation due to flow-focusing dilation spaces in skarn ore deposits and its significance for deep-ore exploration:examples from the Tongling-Anqing district[J].Acta Petrologica Sinica,2008,24(8):1848-1856.
[37] ORD A,HOBBS B E,ZHANG Y,et al.Geodynamic modelling of the Century deposit,Mt Isa Province,Queensland[J].Journal of the Geological Society of Australia,2002,49(6):1011-1039.
[38] ZHAO C,LIN G,HOBBS B E,et al.Finite element modelling of reactive fluids mixing and mineralization in pore-fluid saturated hydrothermal/sedimentary basins[J].Engineering Computations,2002,19(3):364-387.
[39] MEINERT L D.Skarns and skarn deposits[J].Geoscience Canada,1992,19(4):145-162.
[40] SEWARD T M, BARNES H L.Metal transport by hydrothermal ore fluids [M]//BAENES H L.Geochemisty of Hydrothermal Ore Deposits.3rd ed.New York: John wiley & Sons,1997:435-486.
[41] 刘悟辉,徐文炘,戴塔根,等.湖南柿竹园钨锡多金属矿田野鸡尾矿床同位素地球化学研究[J].岩石学报,2006,22(10):2517-2524.
[42] REED M H, SPYCHER N F.Boiling,cooling,and oxidation in epithermal systems: a numerical modeling approach [J].Reviews in Economic Geology,1985,2:249-272.
[43] ZHOU T F,YUAN F,YUE S C,et al.Geochemistry and evolution of ore-forming fluids of the Yueshan Cu-Au skarn-and vein-type deposits,Anhui Province,South China[J].Ore Geology Reviews,2007,31(1/2/3/4):279-303.
[44] 卢焕章.流体不混溶性和流体包裹体[J].岩石学报,2011,27(5):1253-1261.
[2] 周涛发,岳书仓,袁峰.安徽月山矿田成岩成矿作用[M].北京:地质出版社,2005.
[3] 周涛发,岳书仓.安徽月山矿田铜矿床的形成机制[J].长春地质学院学报,1997,19(3):310-316.
[4] 周涛发,岳书仓.长江中下游铜、金矿床成矿流体系统的形成条件及机理[J].北京大学学报(自然科学版),2000,36(5):697-707.
[5] 董玉翠,张智宇,杜杨松,等.安徽安庆铜铁矿床成矿流体演化特征及其成矿意义[J].高校地质学报,2013,19(2):245-258.
[6] 周涛发,岳书仓.安徽月山地区闪长岩类地质地球化学研究[J].火山地质与矿产,1995,16(3):20-30.
[7] 周涛发,岳书仓.月山地区铜矿床氢氧同位素地球化学研究[J].合肥工业大学学报(自然科学版),1996,19(1):120-126.
[8] 袁峰,周涛发,刘晓东,等.安徽安庆铜矿床稀土元素地球化学研究[J].中国稀土学报,2002,20(3):199-202.
[9] 王训诚,周育才.安徽省安庆铜铁矿床地质特征及成因探讨[J].地质与勘探 1995,31(3):16.
[10] 滕传耀,杜杨松,张智宇,等.安徽安庆铜铁矿床矽卡岩岩相学和矿物学特征及意义[J].矿物岩石,2012,32(3):40-50.
[11] 束学福.安庆夕卡岩型铁铜矿床地质地球化学特征及铁质来源研究[J].矿物岩石地球化学通报,2004,24(3):219-224.
[12] 张智宇,杜杨松,向文帅,等.安徽安庆铜铁矿床成因:矿床地质特征与元素地球化学约束[J].岩石学报,2012,28(11):3739-3756.
[13] HOBBS B E,ZHANY Y,ORD A,et al.Application of coupled deformation,fluid flow,thermal and chemical modelling to predictive mineral exploration[J].Journal of Geochemical Exploration,2000,69/70:505-509.
[14] ZHAO C,ORD A,HOBBS B E.Fundamentals of computational geoscience[M].Berlin Heidelberg: Springer-Verlag,2009.
[15] ZHAO C,REID L B,REGENAUER-LIEB K.Some fundamental issues in computational hydrodynamics of mineralization: a review[J].Journal of Geochemical Exploration,2012,112(1):21-34.
[16] ORD A,HOBBS B E,ZhANG Y,et al.Geodynamic modelling of the century deposit,Mt Isa Province,Queensland[J].Journal of the Geological Society of Australia,2015,49(6):1011-1039.
[17] SCHARDT C,LARGE R R.New insights into the genesis of volcanic-hosted massive sulfide deposits on the seafloor from numerical modeling studies[J].Ore Geology Reviews,2009,35(3/4):333-351.
[18] ORD A,HOBBS B E,LESTER D R.The mechanics of hydrothermal systems: I.Ore systems as chemical reactors[J].Ore Geology Reviews,2012,49(8):1-44.
[19] LIU L,ZHAO Y,ZHAO C.Coupled geodynamics in the formation of Cu skarn deposits in the Tongling-Anqing district,China:computational modeling and implications for exploration[J].Journal of Geochemical Exploration,2010,106(1/2/3):146-155.
[20] WEIS P,DRIESNER T,HEINRICH C A.Porphyry-copper ore shells form at stable pressure-temperature fronts within dynamic fluid plumes[J].Science,2012,338(6114):1613-1616.
[21] SUN T,LIU L.Delineating the complexity of Cu-Mo mineralization in a porphyry intrusion by computational and fractal modeling:a case study of the Chehugou deposit in the Chifeng district,Inner Mongolia,China[J].Journal of Geochemical Exploration,2014,144:128-143.
[22] LIU L,WAN C,ZHAO C,et al.Geodynamic constraints on orebody localization in the Anqing orefield,China:computational modeling and facilitating predictive exploration of deep deposits[J].Ore Geology Reviews,2011,43(1):249-263.
[23] 贾蔡,袁峰,张明明,等.宁芜盆地白象山铁矿床成矿作用过程数值模拟[J].岩石学报,2014,30(4):1031-1040.
[24] LIU L,LI J,ZHAO R,et al.3D modeling of the porphyry-related Dawangding gold deposit in south China:implications for ore genesis and resources evaluation[J].Journal of Geochemical Exploration,2016,164:164-185.
[25] 姚鹏,李金高,顾雪祥,等.从REE和硅同位素特征探讨西藏甲马矿床层状夕卡岩成因[J].岩石矿物学杂志,2006,25(4):305-313.
[26] 於崇文.热液成矿作用动力学[M].北京:中国地质大学出版社,1993.
[27] 杨光树,温汉捷,胡瑞忠,等.安庆夕卡岩型铁铜矿床流体包裹体研究[J].地球化学,2008,37(1):27-36.
[28] FOURNIER R O.Hydrothermal processes related to movement of fluid from plastic into brittle rock in the magmatic-epithermal environment[J].Economic Geology,1999,94(8):1193-1211.
[29] HENLEY R W,BRINK F J,KING P L,et al.High temperature gas-solid reactions in calc-silicate Cu-Au skarn formation; Ertsberg,Papua Province,Indonesia[J].Contributions to Mineralogy & Petrology,2017,172(11/12):106.
[30] ZOU Y,LIU Y,DI T,et al.Finite difference modeling of metallogenic processes in the Hutouya Pb-Zn deposit,Qinghai,China: Implications for hydrothermal mineralization[J].Ore Geology Reviews,2017,91:463-466.
[31] 刘晓东.安徽月山矿田成矿流体系统研究[D].合肥:合肥工业大学,2000.
[32] BORISOVA E A,ADLDER P M.Deposition in porous media and clogging on the field scale.[J].Physical Review E Statistical Nonlinear & Soft Matter Physics,2005,71(2):2839-2858.
[33] 滕传耀.安徽安庆铜铁矿床矽卡岩成矿作用研究[D].北京:中国地质大学,2013.
[34] MEINERT L D,DIPPLE G M,NICOLESCU S.World Skarn Deposits[M]//Economic Geology 100th Anniversary Volume.[S.l.]:Society of Economic Geologists, Inc.,2005:299-336.
[35] 向文帅.安徽省安庆铜铁矿床特征及成因[D].北京:中国地质大学,2010.
[36] LIANGMING L,ZHIMING S,CHONBIN Z,et al.The controlling mechanism of ore formation due to flow-focusing dilation spaces in skarn ore deposits and its significance for deep-ore exploration:examples from the Tongling-Anqing district[J].Acta Petrologica Sinica,2008,24(8):1848-1856.
[37] ORD A,HOBBS B E,ZHANG Y,et al.Geodynamic modelling of the Century deposit,Mt Isa Province,Queensland[J].Journal of the Geological Society of Australia,2002,49(6):1011-1039.
[38] ZHAO C,LIN G,HOBBS B E,et al.Finite element modelling of reactive fluids mixing and mineralization in pore-fluid saturated hydrothermal/sedimentary basins[J].Engineering Computations,2002,19(3):364-387.
[39] MEINERT L D.Skarns and skarn deposits[J].Geoscience Canada,1992,19(4):145-162.
[40] SEWARD T M, BARNES H L.Metal transport by hydrothermal ore fluids [M]//BAENES H L.Geochemisty of Hydrothermal Ore Deposits.3rd ed.New York: John wiley & Sons,1997:435-486.
[41] 刘悟辉,徐文炘,戴塔根,等.湖南柿竹园钨锡多金属矿田野鸡尾矿床同位素地球化学研究[J].岩石学报,2006,22(10):2517-2524.
[42] REED M H, SPYCHER N F.Boiling,cooling,and oxidation in epithermal systems: a numerical modeling approach [J].Reviews in Economic Geology,1985,2:249-272.
[43] ZHOU T F,YUAN F,YUE S C,et al.Geochemistry and evolution of ore-forming fluids of the Yueshan Cu-Au skarn-and vein-type deposits,Anhui Province,South China[J].Ore Geology Reviews,2007,31(1/2/3/4):279-303.
[44] 卢焕章.流体不混溶性和流体包裹体[J].岩石学报,2011,27(5):1253-1261.