混合稀释剂法测定岩石样品中Sr-Nd同位素组成——以新疆松喀尔苏铜(金)矿区含矿花岗斑岩为例
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摘要
混合稀释剂法是测定地质样品中放射性同位素组成的重要手段,具有样品用量少、测试精度和灵敏度高等优点。应用混合稀释剂法获取了新疆东准噶尔松喀尔苏铜(金)矿区含矿花岗斑岩的Sr-Nd同位素数据,其中,含矿斑岩样品初始87Sr/86Sr值(ISr)较低且比较分散,变化范围为0.70268~0.71004,均低于大陆地壳ISr平均值(0.719);εNd值较高且为正值,变化范围为+3.8~+8.3,并具有非常年轻二阶段Nd模式年龄,t2DM值在0.4~0.8 Ga之间。Sr、Nd同位素组成与新疆北部富碱侵入岩相似,其源区很有可能是由于幔源岩浆的底侵作用添加到下地壳中,地壳停留时间较短的新生年轻地壳与幔源岩浆发生了源区混合。东准噶尔卡拉麦里成矿带晚石炭世加厚岩石圈的拆沉导致大规模的幔源岩浆底侵作用,碰撞后的伸展环境为成矿物质的向上运移提供了通道,形成了以多金属矿为主的成矿带。
Mixing diluents method was an extremely important way in identifying the composition of radioactive isotopes in rock samples,and it had the advantage of less samples,higher test precision and sensitivity.Therefore, mixing diluents method was applied to obtain date about the Sr-Nd isotopic composition of ore-bearing porphyry in the Songkaersu copper(gold) deposit mining area in eastern Junggar.The 87Sr/86Sr(ISr)initial value was relatively low and decentralized with the range of 0.70268 to 0.71004,which was lower than the average ISrvalue(0.719)in crust.Additionally,the εNdvalue was high and positive with the range of +3.8~+8.3 as well very young two-stage Nd model ages,and the t2DMvalue was between 0.4~0.8 Ga.Sr-Nd isotopic composition was similar to the alkali rich intrusive rock in northern Xinjiang.Its source area was likely to be due to the effect of bottom of invasion of the mantle-derived magma adding to the lower crust,and the newborn and young crust with shorter crustal residence time mixed with mantle-derived magma.The delamination of upset the late carboniferous to the lithosphere in east Carboniferous resulted in large bottom of invasion mantle-derived magma.The stretching environment after collision provided the ore-forming materials of upward migration channel,and formed metallogenic belt which was mainly with polymetallic ore.
Mixing diluents method was an extremely important way in identifying the composition of radioactive isotopes in rock samples,and it had the advantage of less samples,higher test precision and sensitivity.Therefore, mixing diluents method was applied to obtain date about the Sr-Nd isotopic composition of ore-bearing porphyry in the Songkaersu copper(gold) deposit mining area in eastern Junggar.The 87Sr/86Sr(ISr)initial value was relatively low and decentralized with the range of 0.70268 to 0.71004,which was lower than the average ISrvalue(0.719)in crust.Additionally,the εNdvalue was high and positive with the range of +3.8~+8.3 as well very young two-stage Nd model ages,and the t2DMvalue was between 0.4~0.8 Ga.Sr-Nd isotopic composition was similar to the alkali rich intrusive rock in northern Xinjiang.Its source area was likely to be due to the effect of bottom of invasion of the mantle-derived magma adding to the lower crust,and the newborn and young crust with shorter crustal residence time mixed with mantle-derived magma.The delamination of upset the late carboniferous to the lithosphere in east Carboniferous resulted in large bottom of invasion mantle-derived magma.The stretching environment after collision provided the ore-forming materials of upward migration channel,and formed metallogenic belt which was mainly with polymetallic ore.
引文
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[26]王德滋,沈渭洲.中国东南部花岗岩成因与地壳演化[J].地学前缘,2003,10(3):209-220.
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[29]李献华,周汉文,刘颖,等.粤西阳春中生代钾玄质侵入岩及其构造意义:Ⅱ.微量元素和Sr-Nd同位素地球化学[J].地球化学,2001,30(1):57-65.
[30]邱检生,胡建,McInnes B I A,等.广东龙窝花岗闪长质岩体的年代学、地球化学及岩石成因[J].岩石学报,2004,20(6):1363-1374.
[31]王中刚,赵振华,于学元.新疆北部富碱侵入岩带地质地球化学特征及其成因[G]//涂光炽.新疆北部固体地球科学新进展.北京:科学出版社,1993:169-172.
[32]赵振华,王中刚,邹天人,等.新疆乌伦古富碱侵入岩成因探讨[J].地球化学,1996,25(3):205-220.
[33]Chen Y,Hu A,Zhang G,et al.Zircon U-Pb age of gramnitic gneiss on Duku highway in westem Tianshan of China and its geological implications[J].Chinese Science Bulletin,2000,45(7):649-653
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[35]Xiao Y,Zhang H F,Shi J A,et al.Late Paleozoic magmatic record of East Junggar,NW China and its significance:Implication from zircon U-Pb dating and Hf istope[J].Gondwana Research,2011,20(2/3):532-542.
[36]Su Y P,Zheng J P,Griffin W L.Geochemistry and geochronologyofCarboniferousvolcanicrocksintheeasternJunggar terrane,NW China:Implicaiton for a tectonic transition[J].Gondwana Research,2012,22(3/4):1009-1029.
[37]HanBF,WangSG,JahnBM,etal.Depleted-mantle source for the Ulungur River A-type granites from North Xinjiang,China:Geochemistry and Nd-Sr isotopic evidence,and implications for Phanerozoic crustal growth[J].Chemical Geology,1997,138(3/4):135-159.
[38]伍建机,陈斌.西准噶尔庙尔沟后碰撞花岗岩微量元素和Nd-Sr同位素特征及成因[J].新疆地质,2004,22(1):29-36.
[39]苏玉平,唐红峰,刘丛强,等.新疆东准噶尔苏吉泉铝质A型花岗岩的确立及其初步研究[J].岩石矿物学杂志,2006,25(3):175-184.
[40]Chen B,Jahn B M.Genesis of post-collisional granitoids and basement nature of Junggar Terrane,NW China:Nd-Sr isotopeand traceelement evidence[J].Journal of Asian Earth Sciences,2004,23(5):691-703.
[41]侯增谦,潘小菲,杨志明,等.初论大陆环境斑岩铜矿[J].现代地质,2007,21(2):332-351.
[2]杨进辉,周新华.胶东地区玲珑金矿矿石和载金矿物Rb-Sr等时线年龄与成矿时代[J].科学通报,2000,45(14):1547-1553.
[3]韩以贵,李向辉,张世红,等.豫西祁雨沟金矿单颗粒和碎裂状黄铁矿Rb-Sr等时线定年[J].科学通报,2007,52(11):1307-1311.
[4]刘远华,杨贵才,张轮,等.西秦岭阳山超大型金矿床花岗岩岩石地球化学特征[J].黄金科学技术,2010,18(6):1-7.
[5]胡西顺,原莲肖,朱红周,等.陕西龙头沟金矿床的地质地球化学特征及成因探讨[J].黄金科学技术,2010,18(2):1-5.
[6]应汉龙.云南大坪金矿床围岩蚀变和同位素地球化学特征[J].黄金科学技术,1998,6(4):14-23.
[7]黄雪飞,张宝林,李晓利,等.电气石研究进展及其找矿意义[J].黄金科学技术,2012,20(3):56-65.
[8]祁进平,宋要斌,李双庆,等.河南省栾川县西沟铅锌银矿物铷—锶同位素组成特征[J].岩石学报,2009,25(11):2843-2854.
[9]李科.山东沂南金铜铁矿床同位素地球化学研究[D].北京:中国地质大学,2009.
[10]王银喜,顾连兴,张遵忠,等.东天山晚石炭世大石头群流纹岩Sr-Nd-Pb同位素地球化学研究[J].岩石学报,2007,23(7):1749-1755.
[11]李秋立,陈福坤,王秀丽,等.超低本底化学流程和单颗粒云母Rb-Sr等时线定年[J].科学通报,2006,51(3):321-325.
[12]濮巍,赵葵东,凌洪飞,等.新一代高精度高灵敏度的表面热电离质谱仪(Triton TI)的Nd同位素测定[J].地球学报,2004,25(2):271-274.
[13]应汉龙,刘秉光.云南老王寨金矿床微量元素和同位素组成及对成矿物质来源的限定[J].黄金科学技术,2000,8(2):15-20.
[14]何国琦,成守德,徐新,等.中国新疆及邻区大地构造图(1∶250万)[M].北京:地质出版社,2004.
[15]胡霭琴,王中刚,涂光炽.新疆北部地壳演化及成岩成矿规律[M].北京:科学出版社,1997.
[16]赵振华,沈远超,涂光炽.新疆金属矿产资源的基础研究[M].北京:科学出版社,2001:75-105.
[17]赵霞,贾承造,张光亚,等.准噶尔盆地陆东—五彩湾地区石炭系中、基性火山岩地球化学及其形成环境[J].地学前缘,2008,15(2):272-279.
[18]吴小奇,刘德良,李振生.卡拉麦里缝合带后碰撞期火山活动[J].地学前缘,2009,16(3):220-230.
[19]Liew T C,Hofmann A W.Precambrian crustal components,plutonic associations,plate environment of the Hercynian Fold Belt of central Europe:Indications from a Nd and Sr isotopic study[J].Contributions to Mineralogy and Petrology,1988,98(2):129-138.
[20]李献华,赵振华,桂训唐.华南前寒武纪地壳形成时代的Sm-Nd和锆石U-Pb同位素制约[J].地球化学,1991,20(3):255-264.
[21]周新华,蒋荣华,陈焕疆,等.上海金山群斜长角闪岩Sm-Nd和Ar-Ar同位素年龄测定[J].岩石学报,1993,9(4):418-421.
[22]Faure G.Principles of Isotope Geology(2nd Edition)[M].New York:John Wiley and Sons,1986:567.
[23]廖启林,戴塔根.新疆北部浅成低温热液型金矿床成矿地球化学特征初探[J].地质地球化学,2000,28(2):19-25.
[24]沈渭洲,凌洪飞,李武显,等.中国东南部花岗岩类的Nd模式年龄与地壳演化[J].中国科学(D辑),2000,30(5):471-478.
[25]沈渭洲,凌洪飞,孙涛.华南晚中生代花岗岩—火成岩Sr、Nd同位素地球化学[M]//周新民.南岭地区晚中生代花岗岩成因与岩石圈动力学演化.北京:科学出版社,2007:123-160.
[26]王德滋,沈渭洲.中国东南部花岗岩成因与地壳演化[J].地学前缘,2003,10(3):209-220.
[27]Chen J F,Jahn B M.Crustal evolution of southeastern China:Nd and Sr isotopic evidence[J].Tectonophysics,1998,284(1/2):101-133.
[28]郭新生,陈江峰,张巽,等.桂东南富钾岩浆杂岩的Nd同位素组成:华南中生代地幔物质上涌事件[J].岩石学报,2001,17(1):19-27.
[29]李献华,周汉文,刘颖,等.粤西阳春中生代钾玄质侵入岩及其构造意义:Ⅱ.微量元素和Sr-Nd同位素地球化学[J].地球化学,2001,30(1):57-65.
[30]邱检生,胡建,McInnes B I A,等.广东龙窝花岗闪长质岩体的年代学、地球化学及岩石成因[J].岩石学报,2004,20(6):1363-1374.
[31]王中刚,赵振华,于学元.新疆北部富碱侵入岩带地质地球化学特征及其成因[G]//涂光炽.新疆北部固体地球科学新进展.北京:科学出版社,1993:169-172.
[32]赵振华,王中刚,邹天人,等.新疆乌伦古富碱侵入岩成因探讨[J].地球化学,1996,25(3):205-220.
[33]Chen Y,Hu A,Zhang G,et al.Zircon U-Pb age of gramnitic gneiss on Duku highway in westem Tianshan of China and its geological implications[J].Chinese Science Bulletin,2000,45(7):649-653
[34]谭佳奕,吴润江,张元元,等.东准噶尔卡拉麦里地区巴塔玛依内山组火山岩特征和年代确定[J].岩石学报,2009,25(3):539-546.
[35]Xiao Y,Zhang H F,Shi J A,et al.Late Paleozoic magmatic record of East Junggar,NW China and its significance:Implication from zircon U-Pb dating and Hf istope[J].Gondwana Research,2011,20(2/3):532-542.
[36]Su Y P,Zheng J P,Griffin W L.Geochemistry and geochronologyofCarboniferousvolcanicrocksintheeasternJunggar terrane,NW China:Implicaiton for a tectonic transition[J].Gondwana Research,2012,22(3/4):1009-1029.
[37]HanBF,WangSG,JahnBM,etal.Depleted-mantle source for the Ulungur River A-type granites from North Xinjiang,China:Geochemistry and Nd-Sr isotopic evidence,and implications for Phanerozoic crustal growth[J].Chemical Geology,1997,138(3/4):135-159.
[38]伍建机,陈斌.西准噶尔庙尔沟后碰撞花岗岩微量元素和Nd-Sr同位素特征及成因[J].新疆地质,2004,22(1):29-36.
[39]苏玉平,唐红峰,刘丛强,等.新疆东准噶尔苏吉泉铝质A型花岗岩的确立及其初步研究[J].岩石矿物学杂志,2006,25(3):175-184.
[40]Chen B,Jahn B M.Genesis of post-collisional granitoids and basement nature of Junggar Terrane,NW China:Nd-Sr isotopeand traceelement evidence[J].Journal of Asian Earth Sciences,2004,23(5):691-703.
[41]侯增谦,潘小菲,杨志明,等.初论大陆环境斑岩铜矿[J].现代地质,2007,21(2):332-351.