Generation Mechanism of Carboniferous Arc Magma and Cumulate Column in Middle Arc Crust, Hadanxun of Northeast Junggar
-
摘要:
为了阐明东北准噶尔弧岩浆形成机制和破译中地壳P波高速块体，对哈旦逊石炭纪侵入杂岩进行了锆石U-Pb年龄(324.8~323.1 Ma)和δ18O及εHf(t)、矿物化学、主微量元素和Nd-Sr同位素分析. 其稀土元素分布模式上凹，从闪长岩(夹带角闪石岩堆晶)到二长花岗岩的主微量元素变异可以用两阶段分离结晶模拟. 结果显示侵入杂岩高Sr/Y、低Y，锆石δ18O加权平均值为6.42‰，来源于俯冲洋壳板片. 运用角闪石全铝压力计计算得到角闪石岩堆晶种群1、种群2的结晶深度分别为26~22 km、20~18 km，表明堆晶构成了中地壳P波高速块体. 侵入杂岩具有高的正的锆石εHf(t) (加权平均值为12.99)、εNd(t) (6.22~6.55)和(87Sr/86Sr)i (0.703 7~0.704 0)，源岩不含洋壳残片和阿尔泰陆壳物质. 东北准噶尔是一个洋内弧，大洋板块的俯冲持续到石炭纪.
Abstract:Secondary-ion mass spectrometric U-Pb age (324.8-323.1 Ma) and δ18O and laser-ablation multi-collector ICP-MS εHf(t) of zircons, mineral chemistry and whole-rock geochemistry and Nd-Sr isotopes of the Carboniferous intrusive complex of Hadanxun were analyzed in this study in order to expound the mechanism of arc magma generation and decipher high P-wave velocity body in the middle crust of Northeast Junggar. Their rare earth element distribution patterns are concave-up. The major and trace element variations from diorite (with entrained hornblendite cumulate) to monzogranite, with decreasing Dy/Yb and primitive-mantle normalized NbN/TaN, can be reproduced with quantitative modeling of fractional crystallization of hornblendite (Stage 1) and feldspar-dominated minerals (Stage 2). They exhibit high Sr/Y, low Y and mean zircon δ18O of 6.42‰, suggesting derivation from subducting oceanic-slab. Al-in-hornblende barometer reveals that the hornblendite cumulate (population 1: 26-22 km depth; population 2: 20-18 km) constitutes high P-wave velocity body in the middle crust of Northeast Junggar. The Carboniferous intrusive complex of Hadanxun exhibits high positive zircon εHf(t) (weighted mean=12.99) and depleted εNd(t) (6.22-6.55) and (87Sr/86Sr)i (0.703 7-0.704 0), precluding oceanic crust and continental-crustal materials from Chinese Altay as source component. Thus, the Northeast Junggar was an intra-oceanic arc and the oceanic-plate subduction continued until the Carboniferous.
-
图 1 东北准噶尔(a)和哈旦逊侵入杂岩(b)地质简图
Fig. 1. Geological sketch maps of the Northeast Junggar (a) and the Hadanxun intrusive complexes (b)
图 2 哈旦逊侵入杂岩南岩体的野外关系
a. 岩性从山丘顶部的灰色二长闪长岩渐变到山脚的肉红色石英二长岩；b. 灰色闪长岩变化到较浅色的二长闪长岩，闪长岩夹带着直径约3 m的深色角闪石岩堆晶的碎块
Fig. 2. Photos showing field relation of the southern pluton
图 3 哈旦逊石炭纪侵入杂岩的显微照片所展示的岩相特征
南岩体：闪长岩(图a)、闪长岩夹带的角闪石岩堆晶HDX79(图b和图c)、二长闪长岩(图d)、石英二长岩(图e)；哈旦逊北岩体北西侧的二长花岗岩(图f). 在图c左边，种群2(population 2)角闪石与种群1(population 1)角闪石呈压痕状边界，并且轻微交代后者. 笔圈标记电子探针分析靶点. 矿物代号：Plg.斜长石；Kf.钾长石；Hb.角闪石；Bt.黑云母；Qz.石英；Ch.微斜‒条纹长石；Mt.磁铁矿；Ilm.钛铁矿；Oxd.金属氧化物
Fig. 3. Photomicrographs showing petrography of the Carboniferous intrusive complex of Hadanxun
图 4 哈旦逊石炭纪侵入杂岩的锆石U-Pb谐和图
Fig. 4. U-Pb concordia diagrams of zircons from the Carboniferous intrusive complex of Hadanxun
图 5 哈旦逊石炭纪侵入杂岩的锆石的阴极发光图像所揭示的岩相学特征
每个阴极发光图像包含以下信息：初次流喷溅区域(长方形)和分析锆石的编号及其测定206Pb/238U年龄或δ18O测定值(括弧中数值)；激光剥蚀区域(红色圆圈)和分析锆石的编号及其εHf(t)测定值(括弧中红色数值)
Fig. 5. Cathodoluminescence images showing petrographic characteristics of zircon from the Carboniferous intrusive complex of Hadanxun
图 6 哈旦逊石炭纪侵入杂岩的锆石的εHf(t)±2σ (a)和δ18O±2σ (b)相对概率密度分布图
Fig. 6. Relative probability density plots of zircon εHf(t)±2σ (a) and δ18O±2σ (b) from the Carboniferous intrusive complex of Hadanxun
图 7 哈旦逊石炭纪侵入杂岩的长石的An (钙长石): Ab (钠长石): Or (正长石)三角图(a)和每个黑云母分子的Mg vs. (Fe2++ Fe3++Mn)离子协变图(b)
Fig. 7. The triangular diagram of An (anorthite): Ab (albite): Or (orthoclase) in feldspar (a) and Mg vs. (Fe2++ Fe3++Mn) ions per formular of biotite (b) from the Carboniferous intrusive complex of Hadanxun
图 8 哈旦逊石炭纪侵入杂岩的角闪石的每矿物分子的Si vs. Mg/(Mg + Fe2+)(a)、Si/Altotal vs. (Na + K)A(b)及Mg/(Mg + Fe2+) vs. Al2O3 (c)图解
Fig. 8. Classification diagrams of Si vs. Mg/(Mg + Fe2+) (a), Si/Altotal vs. (Na + K)A (b) and Mg/(Mg + Fe2+) vs. Al2O3 (c) of hornblendes from the Carboniferous intrusive complex of Hadanxun
图 9 哈旦逊石炭纪侵入杂岩的Al2O3 (a)、MgO (b)、TFe2O3 (c)、TiO2 (d)和CaO (e)与SiO2的协变图
Fig. 9. Diagrams of Al2O3 (a), MgO (b), TFe2O3 (c), TiO2 (d) and CaO (e) vs. SiO2 from the Carboniferous intrusive complex of Hadanxun
图 10 哈旦逊石炭纪侵入杂岩的Sr (a)、Cr (b)、Ni (c)和V (d)与SiO2的协变图
Fig. 10. Diagrams of Sr (a), Cr (b), Ni (c) and V (d) vs. SiO2 from the Carboniferous intrusive complex of Hadanxun
图 11 哈旦逊石炭纪侵入杂岩的球粒陨石标准化稀土元素分布模式(a)和Dy/Yb vs. SiO2协变图(b)
图a据Boynton，1984；第一阶段和第二阶段分离结晶的残余熔体的微量元素含量模拟值($ {C}_{\mathrm{l}}^{1} $、$ {C}_{\mathrm{l}}^{2} $)也展示于图a
Fig. 11. Chondrite-normalized rare earth element distribution pattern (a) and Dy/Yb vs. SiO2 covariation diagram (b) of the Carboniferous intrusive complex of Hadanxun
图 12 哈旦逊石炭纪侵入杂岩的多元素原始地幔标准化微量元素蛛网图
图a据Sun and McDonough，1989；第一阶段和第二阶段分离结晶的残余熔体的微量元素含量模拟值($ {C}_{\mathrm{l}}^{1} $、$ {C}_{\mathrm{l}}^{2} $)分别展示于图b和图c
Fig. 12. Multi-element primitive mantle-normalized trace element spider diagrams of the Carboniferous intrusive complex of Hadanxun
图 13 哈旦逊石炭纪侵入杂岩的Sr/Y-Y协变图
埃达克岩和岛弧火山岩的投影区域据Defant and Drummond (1990)
Fig. 13. Sr/Y vs. Y diagram of the Carboniferous intrusive complex of Hadanxun
图 14 哈旦逊石炭纪侵入杂岩的εNd(t) vs. (87Sr/86Sr)i图及其与其他岩石的投影范围对比
a. 东北准噶尔的浅部地壳岩石；b. 阿尔曼太蛇绿岩(数据来自黄萱等，1997)、阿尔泰陆壳物质(Wang et al.，2009)及阿尔泰南缘的玛因鄂博强过铝质花岗岩基(t = 283 Ma)(周刚，2007). 图a的对比岩石包括沿着F3断裂处于哈旦逊北北西~25 km的老山口中泥盆统北塔山组火成岩(Liang et al.，2016)、东北准噶尔索尔库都克的托让格库都克组埃达克岩和富Nb玄武岩(Niu et al.，2006)、东准噶尔西北部的石炭纪花岗岩类(Liu et al.，2019). MORB和OIB的区域(Zindler and Hart，1986)也显示于图a、图b. 所有火成岩的εNd(t)和(87Sr/86Sr)i值都校正到其结晶年龄，除了托让格库都克组的埃达克岩和富Nb玄武岩及阿尔曼太蛇绿岩，后两者的εNd(t)和(87Sr/86Sr)i值校正到290 Ma
Fig. 14. εNd(t) vs. (87Sr/86Sr)i diagram of the Carboniferous intrusive complex of Hadanxun in comparison to representative rocks
-
Allègre, C. J., Minster, J. F., 1978. Quantitative Models of Trace Element Behavior in Magmatic Processes. Earth and Planetary Science Letters, 38(1): 1-25. https://doi.org/10.1016/0012-821x(78)90123-1 Boynton, W. V., 1984. Cosmochemistry of the Rare Earth Elements: Meteorite Studies. In: Henderson, P., ed., Rare Earth Element Geochemistry, Developments in Geochemistry 2. Elsevier, Amsterdam. Cavosie, A. J., Kita, N. T., Valley, J. W., 2009. Primitive Oxygen-Isotope Ratio Recorded in Magmatic Zircon from the Mid-Atlantic Ridge. American Mineralogist, 94(7): 926-934. https://doi.org/10.2138/am.2009.2982 Chen, B., Jahn, B. M., 2004. Genesis of Post-Collisional Granitoids and Basement Nature of the Junggar Terrane, NW China: Nd-Sr Isotope and Trace Element Evidence. Journal of Asian Earth Sciences, 23(5): 691-703. https://doi.org/10.1016/s1367-9120(03)00118-4 Davidson, J., Turner, S., Handley, H., et al., 2007. Amphibole "Sponge" in Arc Crust? Geology, 35(9): 787-790. https://doi.org/10.1130/g23637a.1 Defant, M. J., Drummond, M. S., 1990. Derivation of Some Modern Arc Magmas by Melting of Young Subducted Lithosphere. Nature, 347(6294): 662-665. https://doi.org/10.1038/347662a0 Dhuime, B., Hawkesworth, C., Cawood, P., 2011. When Continents Formed. Science, 331(6014): 154-155. https://doi.org/10.1126/science.1201245 Geng, H. Y., Sun, M., Yuan, C., et al., 2009. Geochemical, Sr-Nd and Zircon U-Pb-Hf Isotopic Studies of Late Carboniferous Magmatism in the West Junggar, Xinjiang: Implications for Ridge Subduction? Chemical Geology, 266(3-4): 364-389. https://doi.org/10.1016/j.chemgeo.2009.07.001 Hammarstrom, J.M., Zen, E.A., 1986. Aluminum in Hornblende: An Empirical Igneous Geobarometer. American Mineralogist, 71(11-12): 1297-1313. https://doi.org/10.1180/minmag.1986.050.358.28 Hollister, L. S., Grissom, G. C., Peters, E. K., et al., 1987. Confirmation of the Empirical Correlation of Al in Hornblende with Pressure of Solidification of Calc-Alkaline Plutons. American Mineralogist, 72(3): 231-239 http://www.minsocam.org/ammin/am72/am72_231.pdf Huang, X., Jin, C.W., Sun, B.S., et al., 1997. Study on the Age of Armantai Ophiolite, Xinjiang by Nd-Sr Isotope Geology. Acta Petrologica Sinica, 13(1): 85-91 (in Chinese with English abstract). Leake, B. E., Woolley, A. R., Arps, C. E. S., et al., 1997. Nomenclature of Amphiboles Report of the Subcommittee on Amphiboles of the International Mineralogical Association Commission on New Minerals and Mineral Names. The Canadian Mineralogist, 35: 219-246. doi: 10.1180/minmag.1997.061.405.13 Lee, C. T. A., Morton, D. M., Kistler, R. W., et al., 2007. Petrology and Tectonics of Phanerozoic Continent Formation: From Island Arcs to Accretion and Continental Arc Magmatism. Earth and Planetary Science Letters, 263(3-4): 370-387. https://doi.org/10.1016/j.epsl.2007.09.025 Li, Q., Cheng, X.Q., Chen, W., et al., 2021. Discovery of Early-Middle Triassic Andesite in Erguna Massif and Its Indication of Southward Subduction of Mongol-Okhotsk Ocean Plate. Earth Science, 46(8): 2768-2785 (in Chinese with English abstract). Liang, P., Chen, H. Y., Hollings, P., et al., 2016. Geochronology and Geochemistry of Igneous Rocks from the Laoshankou District, North Xinjiang: Implications for the Late Paleozoic Tectonic Evolution and Metallogenesis of East Junggar. Lithos, 266-267: 115-132. https://doi.org/10.1016/j.lithos.2016.08.021 Liu, B.S., Cheng, Z.X., Qian, C., et al., 2021. The Geochronology and Geodynamic Background Study of the Late Triassic Bimodal Pattern Intrusive Rock in Da Hinggan Mountains Duobaoshan Area. Earth Science, 46(7): 2311-2328 (in Chinese with English abstract). Liu, W., Liu, X. J., Liu, L. J., 2013. Underplating Generated A- and I-Type Granitoids of the East Junggar from the Lower and the Upper Oceanic Crust with Mixing of Mafic Magma: Insights from Integrated Zircon U-Pb Ages, Petrography, Geochemistry and Nd-Sr-Hf Isotopes. Lithos, 179: 293-319. https://doi.org/10.1016/j.lithos.2013.08.009 Liu, X. J., Liu, W., Si, C. Q., 2019. Petrogenesis and Source Rocks of the High-K Calc-Alkaline and Shoshonitic I-Type Granitoids in the Northwestern Part of East Junggar, NW China. Lithos, 326-327: 298-312. https://doi.org/10.1016/j.lithos.2018.12.033 Long, X.P., Sun, M., Yuan, C., et al., 2006. Genesis of Carboniferous Volcanic Rocks in the Eastern Junggar: Constraints on the Closure of the Junggar Ocean. Acta Petrologica Sinica, 22(1): 31-40 (in Chinese with English abstract). http://en.cnki.com.cn/Article_en/CJFDTOTAL-YSXB200601003.htm Niu, H. C., Sato, H., Zhang, H. X., et al., 2006. Juxtaposition of Adakite, Boninite, High-TiO2 and Low-TiO2 Basalts in the Devonian Southern Altay, Xinjiang, NW China. Journal of Asian Earth Sciences, 28(4-6): 439-456. https://doi.org/10.1016/j.jseaes.2005.11.010 Page, F. Z., Fu, B., Kita, N. T., et al., 2007. Zircons from Kimberlite: New Insights from Oxygen Isotopes, Trace Elements, and Ti in Zircon Thermometry. Geochimica et Cosmochimica Acta, 71(15): 3887-3903. https://doi.org/10.1016/j.gca.2007.04.031 Putirka, K., 2016. Amphibole Thermometers and Barometers for Igneous Systems and Some Implications for Eruption Mechanisms of Felsic Magmas at Arc Volcanoes. American Mineralogist, 101(4): 841-858. https://doi.org/10.2138/am-2016-5506 Schmidt, M. W., 1992. Amphibole Composition in Tonalite as a Function of Pressure: An Experimental Calibration of the Al-in-Hornblende Barometer. Contributions to Mineralogy and Petrology, 110(2/3): 304-310. https://doi.org/10.1007/bf00310745 Sun, S. S., McDonough, W. F., 1989. Chemical and Isotopic Systematics of Oceanic Basalts: Implications for Mantle Composition and Processes. Geological Society, London, Special Publications, 42(1): 313-345. https://doi.org/10.1144/gsl.sp.1989.042.01.19 Tang, G. J., Wang, Q., Wyman, D. A., et al., 2020. Petrogenesis of the Ulungur Intrusive Complex, NW China, and Implications for Crustal Generation and Reworking in Accretionary Orogens. Journal of Petrology, 61(2): egaa018. https://doi.org/10.1093/petrology/egaa018 Tiepolo, M., Vannucci, R., Oberti, R., et al., 2000. Nb and Ta Incorporation and Fractionation in Titanian Pargasite and Kaersutite: Crystal-Chemical Constraints and Implications for Natural Systems. Earth and Planetary Science Letters, 176(2): 185-201. https://doi.org/10.1016/s0012-821x(00)00004-2 Velázquez Santana, L. C., McLeod, C. L., Blakemore, D., et al., 2020. Bolivian Hornblendite Cumulates: Insights into the Depths of Central Andean Arc Magmatic Systems. Lithos, 370-371: 105618. https://doi.org/10.1016/j.lithos.2020.105618 Wang, T., Jahn, B. M., Kovach, V. P., et al., 2009. Nd-Sr Isotopic Mapping of the Chinese Altai and Implications for Continental Growth in the Central Asian Orogenic Belt. Lithos, 110(1-4): 359-372. https://doi.org/10.1016/j.lithos.2009.02.001 Xiao, W. J., Windley, B. F., Huang, B. C., et al., 2009. End-Permian to Mid-Triassic Termination of the Accretionary Processes of the Southern Altaids: Implications for the Geodynamic Evolution, Phanerozoic Continental Growth, and Metallogeny of Central Asia. International Journal of Earth Sciences, 98(6): 1189-1217. https://doi.org/10.1007/s00531-008-0407-z Xu, X.Z., Wang, Y.X., Jiang, Y.M., et al., 1992. Crustal Velocity Structure and Geotectonic Unit Division in Xinjiang-Gansu Section Based on Deep Seismic Sounding. Xinjiang Geology, 10(2): 147-154 (in Chinese with English abstract). Zhou, G., 2007. Geochronology, Petrology and Geochemistry of the Post-Collisional Granites along the Mayinebo Fault Zone, Altay, Xinjiang (Dissertation). Chinese Academy of Geological Sciences, Beijing (in Chinese with English abstract). Zhou, G., Zhang, Z.C., Luo, S.B., et al., 2007. Confirmation of High Temperature Strongly Peraluminous Mayin'ebo Granites in the South Margin of Altay, Xinjiang: Age, Geochemistry and Tectonic Implications. Acta Petrologica Sinica, 23(8): 1909-1920 (in Chinese with English abstract). Zindler, A., Hart, S., 1986. Chemical Geodynamics. Annual Review of Earth and Planetary Sciences, 14: 493-571. https://doi.org/10.1146/annurev.ea.14.050186.002425 黄萱, 金成伟, 孙宝山, 等, 1997. 新疆阿尔曼太蛇绿岩时代的Nd-Sr同位素地质研究. 岩石学报, 13(1): 85-91. https://www.cnki.com.cn/Article/CJFDTOTAL-YSXB701.006.htm 李强, 程学芹, 陈伟, 等, 2021. 额尔古纳地块早-中三叠世安山岩的发现及其对蒙古-鄂霍茨克洋南向俯冲的指示. 地球科学, 46(8): 2768-2785. doi: 10.3799/dqkx.2020.319 刘宝山, 程招勋, 钱程, 等, 2021. 大兴安岭多宝山晚三叠世双峰式侵入岩年代学及地球动力学背景. 地球科学, 46(7): 2311-2328. doi: 10.3799/dqkx.2020.214 龙晓平, 孙敏, 袁超, 等, 2006. 东准噶尔石炭系火山岩的形成机制及其对准噶尔洋盆闭合时限的制约. 岩石学报, 22(1): 31-40. https://www.cnki.com.cn/Article/CJFDTOTAL-YSXB200601003.htm 徐新忠, 王有学, 蒋亚明, 等, 1992. 新-甘地震测深剖面的地壳速度结构及大地构造单元划分. 新疆地质, 10(2): 147-154. https://www.cnki.com.cn/Article/CJFDTOTAL-XJDI199202006.htm 周刚, 2007. 新疆阿尔泰玛因鄂博断裂带两侧后碰撞花岗岩类的年代学、岩石学和地球化学研究(博士学位论文). 北京: 中国地质科学院. 周刚, 张招崇, 罗世宾, 等, 2007. 新疆阿尔泰山南缘玛因鄂博高温型强过铝花岗岩: 年龄、地球化学特征及其地质意义. 岩石学报, 23(8): 1909-1920. https://www.cnki.com.cn/Article/CJFDTOTAL-YSXB200708011.htm -
下载:
点击查看大图
计量
- 文章访问数: 866
- HTML全文浏览量: 445
- PDF下载量: 49
- 被引次数: 0
