粤东北新丰地区基性岩脉年代学及地球化学特征Geochronology and Geochemistry Characteristics of Mafic Dikes in Xinfeng,Northeast Guangdong
许汉森;黄建桦;李宏卫;林小明;
摘要(Abstract):
对粤东北新丰地区基性岩脉进行了年代学、元素地球化学研究。结果表明:新丰地区近SN向和NWW向基性岩脉的锆石U-Pb年龄分别为(148.6±4.1)Ma(MSWD=1.3)和(85.7±2.0)Ma(MSWD=1.4),成岩时代为晚侏罗世和晚白垩世。基性岩脉具低碱富钠、较高钛含量、富铁、中等镁含量和准铝质特征。稀土元素标准化曲线呈小角度右倾斜型,轻重稀土元素中等分馏、轻稀土元素富集。微量元素表现出富集Ba、Rb、K,亏损Ta、Nb、Zr、Hf和P等特征。晚侏罗世基性岩脉轻微Ce负异常(δCe=0.89~0.93)和弱Eu正异常(δEu=1.00~1.05),Th/Yb比值比较高,表明岩浆源区可能遭受过富Th俯冲流体交代。2组基性岩脉岩浆源区均来自地幔,可能经历了石榴石-尖晶石二辉橄榄岩的部分熔融,并发生了单斜辉石、Ti-Fe氧化物矿物的分离结晶作用。新丰地区基性岩脉具有大陆裂谷玄武岩特征,形成于陆内裂谷环境,但早期基性岩脉(148.6 Ma)较晚期(85.7 Ma)具有相对较浅的岩浆源区。
关键词(KeyWords): 粤东北;基性岩脉;年代学;地球化学
基金项目(Foundation): 中国地质调查局项目“广东1∶5万周陂公社、隆街公社、新丰县、马头等四幅区域地质矿产调查”(12120113063100)
作者(Author): 许汉森;黄建桦;李宏卫;林小明;
Email:
DOI: 10.19509/j.cnki.dzkq.2018.0302
参考文献(References):
- [1]王学成,饶冰.粤北贵东岩体内基性岩脉的成因研究[J].南京大学学报,1989,25(1):120-131.
- [2]李献华.万洋山-诸广山花岗岩复式岩基的岩浆活动时代与地壳运动[J].中国科学:化学生命科学地学,1990(7):747-755.
- [3]李献华,胡瑞忠,饶冰.粤北白垩纪基性岩脉的年代学和地球化学[J].地球化学,1997,26(2):14-31.
- [4]曹建劲,胡瑞忠,谢桂青,等.广东沿海地区基性岩脉地球化学及成因[J].岩石学报,2009,25(4):984-1000.
- [5]林小明,李宏卫,林杰春,等.广东1∶5万周陂公社、隆街公社、新丰县、马头幅区域地质矿产调查报告[R].广州:广东省地质调查院,2016.
- [6]Liu Y S,Hu Z C,Gao S,et al.In situ analysis of major and trace elements of anhydrous minerals by LA-ICP-MS without applying an internal standard[J].Chemical Geology,2008,257:34-43.
- [7]Liu Y,Gao S,Hu Z,et al.Continental and oceanic crust recycling-induced melt-peridotite interactions in the Trans-North China Orogen:U-Pb dating,Hf isotopes and trace elements in zircons of mantle xenoliths[J].Journal of Petrology,2010,55(51):537-571.
- [8]Liu Y,Hu Z,Zong K,et al.Reappraisement and refinement of zircon U-Pb isotope and trace element analyses by LA-ICP-MS[J].Chinese Science Bulletin,2010,55(15):1535-1546.
- [9]Andersen T.Correction of common Pb in U-Pb analyses that do not report 204Pb[J].Chemical Geology,2002,192:59-79.
- [10]Ludwig K R.ISOPLOT 3.00:A geochronological toolkit for microsoft excel[D].Berkeley,California:Berkeley Geochronology Center,2003.
- [11]Wiedenbeck M,Alle P,Corfu F,et al.Three natural zircon standards for U-Th-Pb,Lu-Hf,trace element and REE analyses[J].Geostandards and Geoanalytical Research,1995,19:1-23.
- [12]Sláma J,Ko2ler J,Condon D J,et al.Plesovice zircon-A new natural reference material for U-Pb and Hf isotopic microanalysis[J].Chemical Geology,2008,249:1-35.
- [13]Middlemost E A K.Naming materials in the magma/igneous rock system[J].Earth Science Reviews,1994,37(3/4):215-224.
- [14]李曙光,聂永红,郑双根.俯冲陆壳与上地幔的相互作用:I.大别山同碰撞镁铁-超镁铁岩的主要元素及痕量元素地球化学[J].中国科学:地球科学,1997,27(6):488-493.
- [15]Hirose K,Kushiro I.Partial melting of dry peridotites at high pressures:Determination of compositions of melts segregated from peridotite using aggregates of diamond[J].Earth and Planetary Science Letters,1993,114(4):477-489.
- [16]Walter M J.Melt extraction and compositional variability in mantle lithosphere[C]∥Holland H D.Treatise on Geochemistry.Volume 2.New York:Elsevier,2003:363-394.
- [17]朱昱升,侯广顺,杨进辉.鹤壁新生代玄武岩源区及成因:地球化学和Sr-Nd-Hf同位素证据[J].岩石学报,2012,28(12):4064-4076.
- [18]Falloon T J,Green D H,Hatton C J,et al.Anhydrous partial melting and depleted peridotite from 2to 30kb and application to basalt petrogenesis[J].Journal of Petrology,1988,29(6):1257-1282.
- [19]Fodor R V,Vetter S K.Rift-zone magmatism:Petrology of basaltic rocks transitional from CFB to MORB,southeastern Brazil margin[J].Contributions to Mineralogy&Petrology,1984,88(4):307-321.
- [20]Rapp R P,Watson E B.Dehydration melting of meatabasalt at8-32kbar:Implications for continental growth and crust-mantle recycling[J].Journal of Petrology,1995,36(4):891-931.
- [21]徐文雄,王树忠,黄国龙,等.诸广岩体南部基性岩脉的地球化学特征及成因[J].华东理工大学学报:自然科学版,2008,31(2):101-110.
- [22]Taylor S R,Mc Lennan S M.The continental crust:Its composition and evolution[M].Oxford:Blackwell Scientific,1985:1-312.
- [23]Stolz A J,Jochum K P,Spettel B,et al.Fluid-and melt-related enrichment in the subarc mantle:Evidence from Nb/Ta variations in island-arc basalts[J].Geology,1996,24(7):587-590.
- [24]Weaver B L.The origin of ocean island basalts endmember compositions:Trace element and isotopic constraints[J].Earth and Planetary Science Letters,1991,104:381-397.
- [25]Zhao Z H,Bao Z W,Zhang B Y.Geochemistry of the Mesozoic basaltic rocks in southern Hunan Province[J].Science China:Series D,1998,41(S):102-112.
- [26]Qi Q,Taylor L A,Zhou X.Petrology and geochemistry of an unusual tridymite-ercynite xenolith in tholeiite from Southeastern China[J].Mineralogy and Petrology,1994,50(4):195-207.
- [27]Pearce J A,Norry M J.Petrogenetic implications of Ti,Zr,Y,and Nb variations in volcanic rocks[J].Contributions to Mineralogy and Petrology,1979,69:33-47.
- [28]Pearce J A.Role of the sub-continental lithosphere in magma genesis at active continental margins[C]∥Hawkesworth C J,Norry M J.Continental basalts and mantle xenoliths.Nantwich:Shiva Publishing,1983:158-185.
- [29]McCulloch M T,Gamble J A.Depleted source for volcanic arc basalts:Constraints from basalts of Kemadec-Taupo volcanic zone based on trace elements,isotopes and subduction chemical geodynamics[C]∥Anon.Continental Magmatism.New Mexico:Bur.Miner,Resour.Bull.,1989:1-180.
- [30]汪云亮,张成江,修淑芝.玄武岩形成的大地构造环境的Th/Hf-Ta/Hf图解判别[J].岩石学报,2001,17(3):413-421.