钦-杭成矿带南段庞西垌断裂带热年代学证据
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摘要
庞西垌断裂带是钦-杭成矿带南段众多NE向韧性剪切带的其中一条,控制着一系列韧性剪切带型银金矿床的分布.对其进行热年代学研究有助于了解钦-杭成矿带南段NE向韧性剪切带的构造演化及其对伴生矿床的控制作用.获得的庞西垌断裂带内糜棱岩中两件白云母40 Ar/39 Ar总气体年龄分别为221.98±1.16Ma和223.77±1.16Ma.据此认为庞西垌断裂带在印支期发生韧性剪切活动,为伴生矿床的形成提供了有利空间;在同一糜棱岩样品中获得的磷灰石、锆石裂变径迹年龄分别为64.83±4.13Ma和75.69±2.88Ma,结合热史模拟结果可以得出,庞西垌断裂带在75~60Ma期间发生了快速冷却作用(6.2℃/Ma),与区域整体缓慢冷却过程(1.5℃/Ma)差别显著,据此推测庞西垌断裂带可能在约75~60Ma期间再次发生活动,而庞西垌银金矿床可能形成于晚白垩世.
The Pangxidong fault zone is one of many NE-strength ductile shear zones in the southern section of the Qin-Hang metallogenic belt and controls the distribution of a series of ductile shear zones related Ag-Au deposits.Study on its thermochronology is helpful to understand the tectonic evolution of the NE-trending ductile shear zone in the southern part of the QinHang metallogenic belt and its effect on the associated mineral deposits.A set of muscovite 40 Ar/39 Ar and fission track analysis were carried out in this paper.Two muscovite samples from the mylonite yielded 40 Ar/39 Ar isotopic total gas ages of 221.98±1.16 Ma and 223.77±1.16 Ma,respectively.It is interpreted that the ductile shearing happened in Pangxidong fault zone during the Indosinian period,which is believed to have provided favorable space for the formation of associated mineral deposits.Apatite and zircon fission track ages from the same mylonite sample yield 64.83±4.13 Ma and 75.69±2.88 Ma,respectively.Combined with the thermal history modeling results,it is shown that the fault zone had experienced a rapid cooling process during~75-60 Ma(6.2℃/Ma),which is much different from the slow cooling process of the Yunkai region(1.5℃/Ma).The re-sults suggest that the Pangxidong fault zone was active again during~75-60 Ma and the Pangxidong Ag-Au deposits possibly formed in the Late Cretaceous.
The Pangxidong fault zone is one of many NE-strength ductile shear zones in the southern section of the Qin-Hang metallogenic belt and controls the distribution of a series of ductile shear zones related Ag-Au deposits.Study on its thermochronology is helpful to understand the tectonic evolution of the NE-trending ductile shear zone in the southern part of the QinHang metallogenic belt and its effect on the associated mineral deposits.A set of muscovite 40 Ar/39 Ar and fission track analysis were carried out in this paper.Two muscovite samples from the mylonite yielded 40 Ar/39 Ar isotopic total gas ages of 221.98±1.16 Ma and 223.77±1.16 Ma,respectively.It is interpreted that the ductile shearing happened in Pangxidong fault zone during the Indosinian period,which is believed to have provided favorable space for the formation of associated mineral deposits.Apatite and zircon fission track ages from the same mylonite sample yield 64.83±4.13 Ma and 75.69±2.88 Ma,respectively.Combined with the thermal history modeling results,it is shown that the fault zone had experienced a rapid cooling process during~75-60 Ma(6.2℃/Ma),which is much different from the slow cooling process of the Yunkai region(1.5℃/Ma).The re-sults suggest that the Pangxidong fault zone was active again during~75-60 Ma and the Pangxidong Ag-Au deposits possibly formed in the Late Cretaceous.
引文
Cai,X.D.,Zhang,Y.H.,Han,Y.G.,2008.Advances in Ductile Shear Zones and Their Gold Mineralization Significance.China Mining Magazine,17(6):62-65,69(in Chinese with English abstract).
Ding,R.X.,Zou,H.P.,Lao,M.J.,et al.,2015.Indosinian Activity Records of Ductile Shear Zones in Southern Segment of Qin-Hang Combined Belt:A Case Study of Fangcheng-Lingshan Fault Zone.Earth Science Frontiers,22(2):79-85(in Chinese with English abstract).
Guenthner,W.R.,Reiners,P.W.,Ketcham,R.A.,et al.,2013.Helium Diffusion in Natural Zircon:Radiation Damage,Anisotropy,and the Interpretation of Zircon(U-Th)/He Thermochronology.American Journal of Science,313(3):145-198.https://doi.org/10.2475/03.2013.01
Hall,C.M.,Farrell,J.W.,1995.Laser 40 Ar/39 Ar Ages of Tephra from Indian Ocean Deep-Sea Sediments:Tie Points for the Astronomical and Geomagnetic Polarity Time Scales.Earth and Planetary Science Letters,133(3-4):327-338.https://doi.org/10.1016/0012-821x(95)00087-s
Han,K.Y.,Xu,K.J.,Gao,L.Z.,et al.,2017.U-Pb Age and Lu-Hf Isotope of Detrital Zircons from the MetaSedimentary Rocks in the Yunkai Region and Their Geological Significance.Acta Petrologica Sinica,33(9):2939-2956(in Chinese with English abstract).
Ketcham,R.A.,Carter,A.,Donelick,R.A.,et al.,2007.Improved Modeling of Fission-Track Annealing in Apatite.American Mineralogist,92(5-6):799-810.https://doi.org/10.2138/am.2007.2281
Li,X.M.,Wang,Y.J.,Tan,K.X.,et al.,2005.Meso-Cenozoic Uplifting and Exhumation on Yunkaidashan:Evidence from Fission Track Thermochronology.Chinese Science Bulletin,50(6):577-583(in Chinese).
Mapani,B.S.E.,Wilson,C.J.L.,1994.Structural Evolution and Gold Mineralization in the Scotchmans Fault Zone,Magdala Gold Mine,Stawell,Western Victoria,Australia.Economic Geology,89(3):566-583.https://doi.org/10.2113/gsecongeo.89.3.566
Mo,J.P.,Huang,J.,Feng,G.Y.,2009.Mineralization Mechanism Research of Shear Zone Gold Deposits in Northern Guangxi Province.Geology and Exploration,45(6):655-660(in Chinese with English abstract).
Samson,S.D.,Alexander Jr,E.C.,1987.Calibration of the Interlaboratory 40 Ar/39 Ar Dating Standard,MMhb-1.Chemical Geology:Isotope Geoscience Section,66(1-2):27-34.https://doi.org/10.1016/0168-9622(87)90025-x
Wang,C.H.,Zhang,C.Q.,Wang,Y.L.,et al.,2012.Chronological Research of the Hetai Gold Mine in Gaoyao County,Guangdong Province.Geotectonica et Metallogenia,36(3):427-433(in Chinese with English abstract).
Wang,H.N.,Yang,J.W.,Chen,H.Q.,1992.Geochemical Studies of the Pangxidong Silver Deposit in Guangdong Province.Mineral Deposits,11(2):179-187(in Chinese with English abstract).
Wang,Y.J.,Zhang,A.M.,Cawood,P.A.,et al.,2013.Geochronological,Geochemical and Nd-Hf-Os Isotopic Fingerprinting of an Early Neoproterozoic Arc-Back-Arc System in South China and Its Accretionary Assembly along the Margin of Rodinia.Precambrian Research,231:343-371.https://doi.org/10.1016/j.precamres.2013.03.020
Wang,Y.T.,Mao,J.W.,Li,X.F.,et al.,2004.Gold Mineralization Related to the Shear Zone.Earth Science Frontiers,11(2):393-400(in Chinese with English abstract).
Wang,Z.W.,Zhou,Y.Z.,2002.Geological Characterristics and Genesis of the Pangxidong-Jinshan Ag-Au Deposit in Yunkai Terrain,South China.Geotectonica et Metallogenia,26(2):193-198(in Chinese with English abstract).
Wang,Z.W.,Zhou,Y.Z.,Zhang,H.H.,et al.,1998.The Relationship between Late Yanshanian Magmatism and Association of Ore-Forming Elements in PangxidongJinshan Silver-Gold Metallogenic Belt,West Guangdong.Acta Petrologica et Mineralogica,17(2):97-103(in Chinese with English abstract).
Wang,Z.Y.,Wang,J.C.,Yin,Y.Q.,et al.,1998.Ore-Forming Law and Prospecting Area of Types of Au-Ag Deposits in Southeastern Guangxi.Guangxi Geology,11(3):27-33(in Chinese with English abstract).
Yang,Z.,Liu,R.,Wang,X.Y.,et al.,2014.Petrogenesis and Tectonic Significance of Late Yanshanian Granites in Yunkai Area,Southeast China:Evidence from Zircon U-Pb Ages and Hf Isotopes.Earth Science,39(9):1258-1276(in Chinese with English abstract).https://doi.org/10.3799/dqkx.2014.108
Yuan,W.M.,Wang,S.C.,Wang,L.F.,2000.Metallogenic Thermal History of the Wulonggou Gold Deposits in East Kunlun Mountains in the Light of Fission Track Thermochronology.Acta Geoscientia Sinica,21(4):389-395(in Chinese with English abstract).
Zhang,K.J.,Cai,J.X.,2009.NE-SW-Trending Hepu-Hetai Dextral Shear Zone in Southern China:Penetration of the Yunkai Promontory of South China into Indochina.Journal of Structural Geology,31(7):737-748.https://doi.org/10.1016/j.jsg.2009.04.012
Zheng,Y.,Zhou,Y.Z.,Wang,Y.J.,et al.,2016.A Fluid Inclusion Study of the Hetai Goldfield in the Qinzhou BayHangzhou Bay Metallogenic Belt,South China.Ore Geology Reviews,73:346-353.https://doi.org/10.13039/501100004613
Zhou,Y.Z.,Zeng,C.Y.,Li,H.Z.,et al.,2012.Geological Evolution and Ore-Prospecting Targets in Southern Segment of Qinzhou Bay-Hangzhou Bay Juncture Orogenic Belt,Southern China.Geological Bulletin of China,31(2):486-491(in Chinese with English abstract).
Zhou,Y.Z.,Zheng,Y.,Zeng,C.Y.,et al.,2015.On the Understanding of Qinzhou Bay-Hangzhou Bay Metallogenic Belt,South China.Earth Science Frontiers,22(2):1-6(in Chinese with English abstract).
蔡晓荻,张元厚,韩以贵,2008.含金剪切带型金矿床研究进展.中国矿业,17(6):62-65,69.
丁汝鑫,邹和平,劳妙姬,等,2015.钦-杭结合带南段韧性剪切带印支期活动记录:以防城-灵山断裂带为例.地学前缘,22(2):79-85.
韩坤英,许可娟,高林志,等,2017.云开地区变质沉积岩碎屑锆石U-Pb年龄、Lu-Hf同位素特征及其地质意义.岩石学报,33(9):2939-2956.
李小明,王岳军,谭凯旋,等,2005.云开地块中新生代隆升剥露作用的裂变径迹研究.科学通报,50(6):577-583.
莫江平,黄杰,冯国玉,2009.桂北地区剪切带型金矿成矿机理研究.地质与勘探,45(6):655-660.
王成辉,张长青,王永磊,等,2012.广东高要河台金矿同位素年代学研究.大地构造与成矿学,36(3):427-433.
王鹤年,杨建文,陈辉琪,1992.广东庞西洞银矿床的地球化学研究.矿床地质,11(2):179-187.
王义天,毛景文,李晓峰,等,2004.与剪切带相关的金成矿作用.地学前缘,11(2):393-400.
王正云,汪劲草,尹意求,等,1998.桂东南金银矿床类型成矿规律和找矿方向.广西地质,11(3):27-33.
王祖伟,周永章,2002.粤桂边境庞西垌-金山银金矿床特征与成因.大地构造与成矿学,26(2):193-198.
王祖伟,周永章,张海华,等,1998.粤西庞西垌-桂东南金山银金成矿带晚燕山期花岗岩的性质与成矿作用.岩石矿物学杂志,17(2):97-103.
杨振,刘锐,王新宇,等,2014.云开地区燕山晚期花岗岩的岩石成因及构造意义:锆石U-Pb年龄及Hf同位素证据.地球科学,39(9):1258-1276.https://doi.org/10.3799/dqkx.2014.108
袁万明,王世成,王兰芬,2000.东昆仑五龙沟金矿床成矿热历史的裂变径迹热年代学证据.地球学报,21(4):389-395.
周永章,曾长育,李红中,等,2012.钦州湾-杭州湾构造结合带(南段)地质演化和找矿方向.地质通报,31(2):486-491.
周永章,郑义,曾长育,等,2015.关于钦-杭成矿带的若干认识.地学前缘,22(2):1-6.
Ding,R.X.,Zou,H.P.,Lao,M.J.,et al.,2015.Indosinian Activity Records of Ductile Shear Zones in Southern Segment of Qin-Hang Combined Belt:A Case Study of Fangcheng-Lingshan Fault Zone.Earth Science Frontiers,22(2):79-85(in Chinese with English abstract).
Guenthner,W.R.,Reiners,P.W.,Ketcham,R.A.,et al.,2013.Helium Diffusion in Natural Zircon:Radiation Damage,Anisotropy,and the Interpretation of Zircon(U-Th)/He Thermochronology.American Journal of Science,313(3):145-198.https://doi.org/10.2475/03.2013.01
Hall,C.M.,Farrell,J.W.,1995.Laser 40 Ar/39 Ar Ages of Tephra from Indian Ocean Deep-Sea Sediments:Tie Points for the Astronomical and Geomagnetic Polarity Time Scales.Earth and Planetary Science Letters,133(3-4):327-338.https://doi.org/10.1016/0012-821x(95)00087-s
Han,K.Y.,Xu,K.J.,Gao,L.Z.,et al.,2017.U-Pb Age and Lu-Hf Isotope of Detrital Zircons from the MetaSedimentary Rocks in the Yunkai Region and Their Geological Significance.Acta Petrologica Sinica,33(9):2939-2956(in Chinese with English abstract).
Ketcham,R.A.,Carter,A.,Donelick,R.A.,et al.,2007.Improved Modeling of Fission-Track Annealing in Apatite.American Mineralogist,92(5-6):799-810.https://doi.org/10.2138/am.2007.2281
Li,X.M.,Wang,Y.J.,Tan,K.X.,et al.,2005.Meso-Cenozoic Uplifting and Exhumation on Yunkaidashan:Evidence from Fission Track Thermochronology.Chinese Science Bulletin,50(6):577-583(in Chinese).
Mapani,B.S.E.,Wilson,C.J.L.,1994.Structural Evolution and Gold Mineralization in the Scotchmans Fault Zone,Magdala Gold Mine,Stawell,Western Victoria,Australia.Economic Geology,89(3):566-583.https://doi.org/10.2113/gsecongeo.89.3.566
Mo,J.P.,Huang,J.,Feng,G.Y.,2009.Mineralization Mechanism Research of Shear Zone Gold Deposits in Northern Guangxi Province.Geology and Exploration,45(6):655-660(in Chinese with English abstract).
Samson,S.D.,Alexander Jr,E.C.,1987.Calibration of the Interlaboratory 40 Ar/39 Ar Dating Standard,MMhb-1.Chemical Geology:Isotope Geoscience Section,66(1-2):27-34.https://doi.org/10.1016/0168-9622(87)90025-x
Wang,C.H.,Zhang,C.Q.,Wang,Y.L.,et al.,2012.Chronological Research of the Hetai Gold Mine in Gaoyao County,Guangdong Province.Geotectonica et Metallogenia,36(3):427-433(in Chinese with English abstract).
Wang,H.N.,Yang,J.W.,Chen,H.Q.,1992.Geochemical Studies of the Pangxidong Silver Deposit in Guangdong Province.Mineral Deposits,11(2):179-187(in Chinese with English abstract).
Wang,Y.J.,Zhang,A.M.,Cawood,P.A.,et al.,2013.Geochronological,Geochemical and Nd-Hf-Os Isotopic Fingerprinting of an Early Neoproterozoic Arc-Back-Arc System in South China and Its Accretionary Assembly along the Margin of Rodinia.Precambrian Research,231:343-371.https://doi.org/10.1016/j.precamres.2013.03.020
Wang,Y.T.,Mao,J.W.,Li,X.F.,et al.,2004.Gold Mineralization Related to the Shear Zone.Earth Science Frontiers,11(2):393-400(in Chinese with English abstract).
Wang,Z.W.,Zhou,Y.Z.,2002.Geological Characterristics and Genesis of the Pangxidong-Jinshan Ag-Au Deposit in Yunkai Terrain,South China.Geotectonica et Metallogenia,26(2):193-198(in Chinese with English abstract).
Wang,Z.W.,Zhou,Y.Z.,Zhang,H.H.,et al.,1998.The Relationship between Late Yanshanian Magmatism and Association of Ore-Forming Elements in PangxidongJinshan Silver-Gold Metallogenic Belt,West Guangdong.Acta Petrologica et Mineralogica,17(2):97-103(in Chinese with English abstract).
Wang,Z.Y.,Wang,J.C.,Yin,Y.Q.,et al.,1998.Ore-Forming Law and Prospecting Area of Types of Au-Ag Deposits in Southeastern Guangxi.Guangxi Geology,11(3):27-33(in Chinese with English abstract).
Yang,Z.,Liu,R.,Wang,X.Y.,et al.,2014.Petrogenesis and Tectonic Significance of Late Yanshanian Granites in Yunkai Area,Southeast China:Evidence from Zircon U-Pb Ages and Hf Isotopes.Earth Science,39(9):1258-1276(in Chinese with English abstract).https://doi.org/10.3799/dqkx.2014.108
Yuan,W.M.,Wang,S.C.,Wang,L.F.,2000.Metallogenic Thermal History of the Wulonggou Gold Deposits in East Kunlun Mountains in the Light of Fission Track Thermochronology.Acta Geoscientia Sinica,21(4):389-395(in Chinese with English abstract).
Zhang,K.J.,Cai,J.X.,2009.NE-SW-Trending Hepu-Hetai Dextral Shear Zone in Southern China:Penetration of the Yunkai Promontory of South China into Indochina.Journal of Structural Geology,31(7):737-748.https://doi.org/10.1016/j.jsg.2009.04.012
Zheng,Y.,Zhou,Y.Z.,Wang,Y.J.,et al.,2016.A Fluid Inclusion Study of the Hetai Goldfield in the Qinzhou BayHangzhou Bay Metallogenic Belt,South China.Ore Geology Reviews,73:346-353.https://doi.org/10.13039/501100004613
Zhou,Y.Z.,Zeng,C.Y.,Li,H.Z.,et al.,2012.Geological Evolution and Ore-Prospecting Targets in Southern Segment of Qinzhou Bay-Hangzhou Bay Juncture Orogenic Belt,Southern China.Geological Bulletin of China,31(2):486-491(in Chinese with English abstract).
Zhou,Y.Z.,Zheng,Y.,Zeng,C.Y.,et al.,2015.On the Understanding of Qinzhou Bay-Hangzhou Bay Metallogenic Belt,South China.Earth Science Frontiers,22(2):1-6(in Chinese with English abstract).
蔡晓荻,张元厚,韩以贵,2008.含金剪切带型金矿床研究进展.中国矿业,17(6):62-65,69.
丁汝鑫,邹和平,劳妙姬,等,2015.钦-杭结合带南段韧性剪切带印支期活动记录:以防城-灵山断裂带为例.地学前缘,22(2):79-85.
韩坤英,许可娟,高林志,等,2017.云开地区变质沉积岩碎屑锆石U-Pb年龄、Lu-Hf同位素特征及其地质意义.岩石学报,33(9):2939-2956.
李小明,王岳军,谭凯旋,等,2005.云开地块中新生代隆升剥露作用的裂变径迹研究.科学通报,50(6):577-583.
莫江平,黄杰,冯国玉,2009.桂北地区剪切带型金矿成矿机理研究.地质与勘探,45(6):655-660.
王成辉,张长青,王永磊,等,2012.广东高要河台金矿同位素年代学研究.大地构造与成矿学,36(3):427-433.
王鹤年,杨建文,陈辉琪,1992.广东庞西洞银矿床的地球化学研究.矿床地质,11(2):179-187.
王义天,毛景文,李晓峰,等,2004.与剪切带相关的金成矿作用.地学前缘,11(2):393-400.
王正云,汪劲草,尹意求,等,1998.桂东南金银矿床类型成矿规律和找矿方向.广西地质,11(3):27-33.
王祖伟,周永章,2002.粤桂边境庞西垌-金山银金矿床特征与成因.大地构造与成矿学,26(2):193-198.
王祖伟,周永章,张海华,等,1998.粤西庞西垌-桂东南金山银金成矿带晚燕山期花岗岩的性质与成矿作用.岩石矿物学杂志,17(2):97-103.
杨振,刘锐,王新宇,等,2014.云开地区燕山晚期花岗岩的岩石成因及构造意义:锆石U-Pb年龄及Hf同位素证据.地球科学,39(9):1258-1276.https://doi.org/10.3799/dqkx.2014.108
袁万明,王世成,王兰芬,2000.东昆仑五龙沟金矿床成矿热历史的裂变径迹热年代学证据.地球学报,21(4):389-395.
周永章,曾长育,李红中,等,2012.钦州湾-杭州湾构造结合带(南段)地质演化和找矿方向.地质通报,31(2):486-491.
周永章,郑义,曾长育,等,2015.关于钦-杭成矿带的若干认识.地学前缘,22(2):1-6.