内蒙古科尔沁右翼中旗敖兰三队侵入体年龄及地球化学特征
Geochronology and geochemistry of the Aolansandui pluton in Horqin Right Wing Middle Banner of Inner Mongolia
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摘要: 内蒙古科尔沁右翼中旗敖兰三队侵入体的同位素年代学及岩石地球化学研究表明,敖兰三队侵入体巨晶正长花岗岩具有低Sr、高Yb型花岗岩特征,其LA-ICP-MS锆石206Pb/238U年龄加权平均值为220±1Ma,表明该侵入体是晚三叠世早期侵位形成的。岩石高硅、富碱、高铁镁比、贫钙、贫镁和低钛;稀土元素配分曲线呈现"海鸥式"分布特征,显示强烈的Eu负异常。微量元素特征显示较低的Sr、Ba含量,较高的Yb、Zr和Y含量,在微量元素原始地幔标准化蛛网图上显示明显的Sr、Ba和Ti的负异常。岩石具有高的Rb/Sr和Rb/Nb,显示出壳源岩浆的成分特征。综合分析表明,本区巨晶正长花岗岩为低压下地壳部分熔融的产物。根据(Y+Nb)-Rb、(Yb+Ta)-Rb、Nb-Y-Ce三角图解,并结合区域构造演化,认为巨晶正长花岗岩形成于造山后伸展的构造环境。在中-晚三叠世,内蒙古科尔沁右翼中旗地区构造体制经历了重要的转变,由挤压体制转变为造山后软流圈上涌、岩石圈减薄。Abstract: Geochronology and geochemistry of the Aolansandui pluton in Horqin Right Wing Middle Banner of Inner Mongolia were studied. Zircon U-Pb dating demonstrates that the weighted mean 206Pb/238U age for the zircons from the syenogranite is 220±1Ma, suggesting Late Triassic. The syenogranite belongs to low-Sr and high-Yb type granitoids. The syenogranite is characterized by high SiO2, high alkali, high TFeO/MgO ratios, and low CaO, low MgO and lower TiO2 values. The syenogranite is characterized by "sea-gull" REE patterns and significant negative Eu anomaly as well as depletion of Sr and Ba and enrichment of Yb, Zr and Y. The high Rb/Sr and Rb/Nb ratios of the rock indicate a crustal origin. Comprehensive analysis shows that the syenitegranite was formed by low pressure felsic crust partial melting. In (Y+Nb)-Rb, (Yb+Ta)-Rb, Nb-Y-Ce diagrams combined with regional tec-tonic evolution, the authors hold that the syenogranite was formed in a post-orogenic setting. In the Middle Late Triassic period, the regional tectonic regime in Horqin Right Wing Middle Banner of Inner Mongolia underwent significant changes, and experienced as-thenosphere upwelling after squeezing into the orogenic lithosphere and thinning.
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[1] 李兆鼐,权恒,李之彤,等. 中国东部中、新生代火成岩及其深部过程[M].北京:地质出版社, 2003:1-357.
[2] 吴福元,孙德有,林强. 东北地区显生宙花岗岩的成因与地壳增生[J].岩石学报,1999, 15(2):181-189.
[3] 李之彤,赵春荆. 吉黑东部晚三叠世岩浆活动及其与板块构造的关系[J].中国地质科学院院报,1988, 第18号:21-32.
[4] 吴福元,孙德有,李惠民,等. 松辽盆地基底岩石的锆石U-Pb年龄[J].科学通报,2000, 45(6):656-660.
[5] 吴福元,Wilde S,孙德有. 中国东部出露的最年轻侵入岩的锆石离子探针年龄[J]. 科学通报,2001, 46(12):1048-1052.
[6] 吴福元,杨进辉,柳小明. 辽东半岛中生代花岗质岩浆作用的年代学格架[J].高校地质学报,2005, 11(3):305-317.
[7] 吴福元,杨进辉,张艳斌,等. 辽西东南部中生代花岗岩时代[J]. 岩石学报,2006, 22(2):315-325.
[8] 葛文春,吴福元,周长勇,等. 大兴安岭北部塔河花岗岩体的时代及对额尔古纳地块构造属性的制约[J].科学通报,2005, 50(12):1239-1247.
[9] 葛文春,吴福元,周长勇,等. 大兴安岭中部乌兰浩特地区中生代花岗岩的锆石U-Pb年龄及地质意义[J].岩石学报,2005, 21(3):749-762.
[10] 葛文春,隋振民,吴福元,等. 大兴安岭东北部早古生代花岗岩锆石U-Pb年龄、Hf同位素特征及地质意义[J].岩石学报,2007, 23(2):423-440.
[11] 武广,陈衍景,孙丰月,等. 大兴安岭北端晚侏罗世花岗岩类地球化学及其地质和找矿意义[J].岩石学报,2008, 24(4):899-910.
[12] 武广,陈衍景,赵振华,等. 大兴安岭北端洛古河东花岗岩的地球化学、SHRIMP锆石U-Pb年龄和岩石成因[J].岩石学报,2009, 25(2):233-247.
[13] 隋振民,葛文春,吴福元,等. 大兴安岭北部察哈彦岩体的Hf同位素特征及其地质意义[J].吉林大学学报(地球科学版),2009, 39(5):849-856.
[14] 徐美君,许文良,王枫,等. 小兴安岭中部早侏罗世花岗质岩石的年代学与地球化学及其构造意义[J].岩石学报,2013, 29(2):354-368.
[15] 许文良,王枫,裴福萍,等. 中国东北中生代构造体制与区域成矿背景:来自中生代火山岩组合时空变化的制约[J].岩石学报, 2013, 29(2):339-353.
[16] 李之彤,赵春荆. 东北北部三叠纪A型花岗岩的初步研究[C]//中国地质科学院沈阳地质矿产研究所集刊,第1号,沈阳地质矿产研究所编.北京:地震出版社, 1992, 96-108.
[17] 秦克章,田中亮吏,李伟实,等. 满洲里地区印支期花岗岩Rb-Sr等时线年代学证据[J].岩石矿物学杂志,1998, 17(3):235-240.
[18] 吴福元,林强,葛文春,等. 张广才岭新华屯岩体的形成时代与成因研究[J].岩石矿物学杂志,1998, 17(3):226-234.
[19] Lu S T, Yang S G. The late Mesozic rifting in the northeastern Chi-na and the fault-rifting basins in East Asia[J]. Science in China(Se-ries B),1987, 21:185-195.
[20] 陈义贤,陈文寄,周新华,等. 辽西及邻区中生代火山岩-年代学、地球化学和构造背景[M].北京:地震局出版社, 1997:1-279.
[21] Wu F Y,Wilde S A,Zhang G L, et al. Geochronology and pet ro-genesis of post-orogenic Cu,Ni-bearing mafi-ultramafic intru-sions in Jilin,NE China[J]. Journal of Asian Earth Sciences,2004, 23:781-797.
[22] 付俊彧,宋维民,庞雪娇,等. 内蒙古科尔沁右翼中旗地区古生界疑源类化石及其时代[J].地质通报,2012, 31(9):1404-1409.
[23] Yan Mi C, Chi Q H. The Chemical Compositions of the Conti-nental Crust and Rocks in the Eastern Part of China[M].Beijing:Science Press, 2005:171.
[24] Hofmann A W. Chemical differentiation of the Erth:the relation-ship between mantle,continental crust,and oceanic crust[J]. Earth and Planetary Science Letters,1988, 90:297-314.
[25] 张旗,王焰,李承东,等. 花岗岩的Sr-Yb分类及其地质意义[J]. 岩石学报,2006, 22(9):2249-2269.
[26] 宋彪,张玉海,万渝生,等. 锆石SHRIMP样品靶制作、年龄测定及有关现象讨论[J]. 地质论评, 2002, 48(增刊):26-30.
[27] Ludwig K R.Isoplot-A plotting and regression program for radio-genic-isotope data[J]. US Geol. Survey Open-File Report,1994, 39:91-445.
[28] Whalen J B,Currie K L, Chappell B W. A-type granites:Geo-chemical characteristics,discrimination and petrogenesis[J].Contri-butions to Mineralogy and Petrology,1987, 95:407-419.
[29] 张旗,王焰,熊小林,等. 埃达克岩和花岗岩:挑战与机遇[M].北京:中国大地出版社, 2008:1-344.
[30] 贾小辉,王强,唐功建. A型花岗岩的研究进展及意义[J].大地构造与成矿学,2009, 33(3):465-480.
[31] Rapp R P, Watson E B. Dehydration melting of metabasalt at 8~32 kbar:Implications for continental growth and crust-mantle recy-cling[J].Journal of Petrology,1995, 36:891-931.
[32] Taylor S R, McLennan S M..The Continental Crust:Its Composi-tion and Evolution[M].London:Blackwell, 1985:57-72.
[33] Loiselle M C, Wones D R.Characteristics and origin of anorogenic granites[J].Geological Society of America Abstract Progressing, 1979, 11:468.
[34] Sylvester P J. Post-collisional alkaline granites[J].Journal of Geolo-gy,1989, 97:261-280.
[35] Eby G N. Chenical subdivision of the A-type granitoids:petroge-netic and tectonic implications[J].Geology,1992, 20:641-644.
[36] Whalen J B,Jenner G A,Longstaffe F J,et al. Geochemical and isotopic(O,Nd,Pb and Sr) constraints on A-type granite:Petro-genesis based on the Topsails igneous suite,Newfoundland Appala-chians[J]. Journal of Petrology,1996, 37:1463-1489.
[37] 洪大卫,王式光,韩宝福,等. 碱性花岗岩的构造环境分类及其鉴别标志[J].中国科学(B辑),1995, 25:418-426.
[38] Pearce J A,Harris N B W,Tindle A G. Trace element discrimina-tion diagrams for the tectonic interpretation of granitic rocks[J].J. Petrol.,1984, 25:956-983.
[39] 徐备, 陈斌. 内蒙古北部华北板块与西伯利亚板块之间中古生代造山带的结构及演化[J].中国科学(D辑),1997, 27(3):227-232.
[40] 邵济安.中朝板块北缘中段地壳演化[M].北京:北京大学出版社, 1991:1-136.
[41] Wang Q, Liu X Y. Paleoplate tectonics between Cathasia and Ang-araland in Inner Mongolia of China[J].Tectonics,1986, 5(7):1073-1088.
[42] Wu T R,He G Q, Zhang C.On Palazonic tectonics in the Alxa region,Inner Mongolia.China[J]. Acta Geologica Sinica,1998, 72(3):256-265.
[43] Chen B,Jahnb B M,Wilde S,et al. Two contrasting Paleozoic magmatic belts in northern Inner Mongolia,China:Petrogenesis and tectonic implications[J].Tectonophysics,2000, 328:157-182.
[44] 李锦轶,高立明,孙桂华,等. 内蒙古东部双井子中三叠世同碰撞壳源花岗岩及其对西伯利亚与中朝古板块碰撞时限的约束[J]. 岩石学报,2007, 23(3):565-582.
[45] 孙德有,吴福元,高山. 小兴安岭东部清水岩体的锆石激光探针U-Pb年龄测定[J].地球学报,2004, 25:213-218.
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