GLOBAL GEOLOGY Vol. 32 No. 2 Jun U -Pb :

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1 GLOBAL GEOLOGY Vol. 32 No. 2 Jun U -Pb : 乌兰德勒岩体为一个由两次岩浆侵入形成的大型复式岩体, 主要由黑云母正长花岗岩和黑云母二长花岗岩组成, 两种岩石的形成年龄分别为 140 ± 2 Ma 和 161 ± 1 Ma 黑云母正长花岗岩显示高分异花岗岩的地球化学特征, 该类岩石与成矿关系密切黑云母二长花岗岩表现为低 Sr 高 Yb 的地球化学特征地球化学资料显示黑云母二长花岗岩为 A 型花岗岩, 形成时的构造环境为伸展体制 : 内蒙古 ; 花岗岩 ; 岩浆作用 ; 晚侏罗世 ; 早白垩世 ; 乌兰德勒岩体 : P597. 3; P595 : A doi: /j. issn Zircon U -Pb age geochemical feature and tectonic significance of the granite pluton in northern Hegen Mountain of Inner Mongolia ZHANG Kuo 1 2 SUN Feng-yue 1 ZHAO Xiao-liang 3 GUAN Qin 4 LOU Yun-he 5 LI Cheng-dong 2 ZHAO Li-gang 2 1. College of Earth Sciences Jilin University Changchun China 2. Tianjin Institute of Geology and Mineral Resources Tianjin China 3. CNOOC Energy Development Ltd. Supervision and Technology Branch Tianjin China 4. Shandong Provincial Geo-mineral Engineering Exploration Institution Jinan China 5. Heilongjiang Province Institute of Regional Geology Haerbin China Abstract Wulandele plulon is a large-scale complex massif generated by twice magmatism. The complex massif is made up of biotite-granite and biotite-monzogranite aged in 140 ± 2 Ma and 161 ± 1 Ma respectively. The biotite-granite reflects highly fractionated characteristics geochemically. While the biotite-monzogranite implies low Sr and high Yb in geochemical characteristics. Geochemical data suggest that the biotite-monzogranite are A- type granites which tectonic setting was are mainly dominated by the extensional system. Key words Inner Mongolia granite magmatism Late Jurassic Early Cretaceous Wulandele pluton 400 km sfy@ jlu. edu. cn

2 2 U -Pb / Re -Os ± 3. 3 Ma Fig. 1 1 Geological sketch map of the north of Inner Mongolia 2 36 km 2

3 km 600 ~ 700 km 2 5% ± '46. 6 E 44 44' N km 200 ~ m DEVCON 4 CL 8. 5 mm U -Pb Neptune 2 ~ 5 mm ~ 2 mm LA -MC -ICP -MS U -Pb 35 μm 13 ~ 14J /cm 2 8 ~ 10 Hz He Neptune MC ICP MS 5 GJ - 1 U -Pb GJ -1 6 U Th M127 7 U Th Th /U ICPMSDataCal Pb ~ NM35 mm ~ 2 mm 2 ~ 4. 5 mm Th /U ~ P / 238 U 140 ± 2 Ma MSWD = U -Pb 09NM38 U -Pb - U -Pb CL 09NM35 5% U - ± 15% ~ 20% 45% ~ Pb Th /U ~ % 25% ± 5% ± P / 238 U '18. 8 E 44 47'22. 8 N 161 ± 1 Ma MSWD = NM38 5% ~ 10% 25% ~ 30% 30% ± 20% ~ 25%

4 2 U -Pb 247 Table NM35 09NM38 LA -ICP -MS U -Pb Zircon LA -ICP -MS U -Pb analytical data of sample 09NM35 and 09NM38 from Wulandele granite Pb Th U Th /U /10-6 /10-6 / Pb / 207 Pb 1σ U -Pb 207 Pb / 205 U 1σ 206 Pb / 238 U 1σ /Ma 207 Pb / 206 Pb 1σ 207 Pb / 235 U 1σ 207 Pb / 238 U 1σ 09NM35 1# # # # # # # # # # # # # # NM38 1# # # # # # # # # # Pb #.

248 32 Fig. 2 2 09NM35 CL CL images of zircon crystals from pluton sample 09NM35 73. 04% 72. 56% w Al 2 O 3 4 13. 94% 14. 06% w TiO 2 4. 1 0. 35% 0. 41% 8. 46% 8. 64% 4 5a 09NM35 09NM36 A /CNK 1.

5 Fig NM35 CL CL images of zircon crystals from pluton sample 09NM % % w Al 2 O % % w TiO % 0. 41% 8. 46% 8. 64% 4 5a 09NM35 09NM36 A /CNK A /NK NM38 09NM a 10 4 Ga / Al Zr + Nb + Ce + Y X - XRF 100% LR /HR = ~ ICP -MS REE Eu 4. 2 δeu = ~ w SiO % % w Al 2 O % Ba Sr Eu Ti % w TiO % 0. 20% w K 2 O + Na 2 O 8. 25% ~ 8. 70% 5a A /CNK A /NK ~ b 10 4 Ga /Al > 2. 6 Zr + Nb + Ce + Y a Y Yb Y 6a w SiO 2-13

6 2 U -Pb 249 Table 2 2 Analytical results of major element trace element and REE of pluton 09NM35 09NM36 09NM38 09NM39 09NM35 09NM36 09NM38 09NM39 SiO Ho TiO Er Al 2 O Tm Fe 2 O Yb MnO Lu MgO Y CaO REE Na 2 O LR /HR K 2 O La /Yb P 2 O δeu Los La /Yb N Total Cr Mg # Th A /CNK Rb A /NK Sr La Ba Ce Cs Pr Ta Nd Nb Sm Hf Eu Zr Gd Ga Tb U Dy Ga /Al % SiO 2 -K 2 O 5a NM38 A /CNK A /CNK > b K 2 O -Na 2 O NM36 3 S A A A /CNK Ga /Al > I S

7 Fig. 3 3 U -Pb Zircon U -Pb concordia diagrams of pluton A 15 2A > Zr Nb Ce Y Zr > Zr + Nb + Ce + Y > Sr Yb Sr = Yb = A A Sr Yb Sr 15 A Yb Sr Yb Sr Yb 4 17 Zr ± A Sr Yb Sr Yb Sr Yb 10 4 Ga /Al > A Sr Sr < Zr < Sr NM Yb NM38 09NM39 Sr Zr Zr + Nb + Ce + Y A HREE Yb Yb

2 U -Pb 251 Fig. 4 4 09NM38 CL CL images of zircon crystals from pluton sample 09NM38 Fig.

8 2 U -Pb 251 Fig NM38 CL CL images of zircon crystals from pluton sample 09NM38 Fig. 5 5 K 2 O -Na 2 O a A /NK -A /CNK b Diagrams of K 2 O -Na 2 O a and A /NK -A /CNK b for pluton Sr Yb A 17 Sr -Yb Sr Yb Sr Yb 15 Yb Sr Yb

9 Fig. 6 6 a b Primitive mantle normalized trace element a and Chondrite -normalized REEpatterns b for pluton Fig. 7 7 Na 2 O -K 2 O Diagram of Na 2 O -K 2 O for pluton Yb Sr Yb 1 2 Yb Yb Yb -Nb -Rb Y -Nb 8 Fig. 8 8 Tectonic setting discrimination diagrams of granite 19 A

10 2 U -Pb J ZHAO Li-gang RAN Hao ZHANG Qing-hong et al. 6 Dating and origin of Geri Obo Pluton in Abaga Banner Inner Mongolia and its geological significance J. Global 1 LA -ICP -MS -U -Pb Geology ± 2 Ma 161 ± 1 Ma 5. LA-MC-ICP-MS U-Pb J SHI Xing-jun TONG Ying WANG Tao et al. LA-ICP- MS zircon U-Pb age and geochemistry of the Early Permian Halinudeng granite in northern Alxa area western A In- ner Mongolia J. Geological Bulletin of China 2012 成文过程中得到迟效国教授的帮助, 在此表示衷心感谢 Jackson S E Pearson N J Griffin W L et al. The application of laser ablation-inductively coupled plasma-mass spectrometry to in situ U-Pb zircon geochronology J. Chemical Geology / Nasdala L Hofmeister W Norberg N et al. Zircon R. M257-a homogeneous natural reference material for the The Inner Mongolia Autonomous Region Bureau of Geology and Mineral Resources. People s Republic of China regional geological survey Bayinwula geological sites R Geochronology Center J TAO Ji-xiong ZHONG Ren ZHAO Yue-ming et al. Geological characteristics and ore-prospecting criteria of the Ulandler porphyry molybdenum deposit in Sonid Left Banner. Inner Mongolia J. Acta Gepscoemtoca Sinica Xiao W J Windley B F Hao J et al. Accretion leading to collision and the Permian Solonker suture Inner Mongolia China termination of the central Asian orogenic belt J. Tectonics ion microprode U-Pb analysis of zircon J. Geostandards and Geoanalytical Research Ludwig K R. User s manual for isoplot 3. 0 a geochronological tool kit for Microsoft Excel M. Berkeley 9 Anderson T. Correction of common lead in U-Pb analyses that do not report 204Pb J. Chemical Geology / Zhang J H Gao S Ge W C et al. Geochronology of the Mesozoic volcanic rocks in the Great Xing an Range northeastern China implications for subduction-induced delamination J. Chemical Geology / Wu F Y Lin J Q Wilde S A et al. Nature and significance of the Early Cretaceous giant igneous event in eastern China J. Earth and Planetary Science Let-

11 ters / Meng Q R. What drove late Mesozoic extension of the northern China -Mongolia tract J. Tectonophysics / J ZHANG Qi WANG Yan LI Cheng-dong et al. Granite classification on the basis of Sr and Yb contents and its implications J. Acta Petrologica Sinica Zonenshain L P The evolution of central Asian geosynclines through sea-floor spreading J. Tectonophysics M Sr Y Sr Y J DENG Jin-fu LUO Zhao-hua SU Shang-guo et al. Petrogenesis tectonic setting and mineralization M. Beijing Geological Publishing House LI Cheng-dong ZHANG Qi MIAO Lai-cheng et al. Mesozoic high-sr low-y and low-sr Y types granitoids in the northern Hebei Province geochemistry and J petrogenesis and its relation to mineralization of gold deposits J. Acta Petrologica Sinica WU Fu-yuan LI Xian-hua YANG Jin-hui et al. Discussions on the petrogenesis of granites J. Acta Petrologica Sinica A J / Whalen J B Currie K L Chappell B W et al. A-typegranites geochemical characteristics discrimination LI Xiao-wei MO Xuan-xue ZHAO Zhi-dan et al. A and petrogenesis J. Contributions to Mineralogy and Petrology Sr-Yb discussion on how to discriminate A-type granite J. Geological Bulletin of China /

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km 5 km Pt 2 x 2 1 Au 65 ~ ~ km 5 km 10 km 2 Au Au 38 1 2015 3 JOURNAL OF EAST CHINA INSTITUTE OF TECHNOLOGY Vol. 38 No. 1 Mar. 2015 doi 10. 3969 /j. issn. 1674-3504. 2015. 01. 002 1 2 1 2 3 1. 471000 2. 471000 3. 510640 9 P618. 51 A 1674-3504 2015 01-0012-11.