Comparison in geochemical characteristics and genesis models of different boninites between Qilian Orogen and Izu-Bonin arc system
-
摘要:
玻安岩为一类具有特殊地球化学性质的岩石，具有高SiO2（＞52%）、高MgO（＞8%）和低TiO2（＜0.5%）等特征。前人认为其形成主要是在俯冲起始阶段大洋板块所释放的流体导致亏损程度较高的难熔地幔楔发生熔融，因此其成因的研究对深入理解板块俯冲起始等地球动力学问题具有重要意义。虽然普遍认为俯冲物质对玻安岩岩浆源区具有重要贡献，但玻安岩中元素的不同富集程度反映了复杂的俯冲板片流体物理化学性质和对玻安岩形成的不同影响。通过对比分析伊豆–小笠原（Izu-Bonin）和北祁连造山带大岔大坂地区玻安岩样品，发现二者具有明显的地球化学差异：与伊豆–小笠原玻安岩相比，大岔大坂玻安岩中没有呈现“U”型稀土配分模式，不富集轻稀土元素或Zr、Hf等元素；而二者流体活动性/不相容元素比值（如Ba/La）变化较大，并具有较高的(87Sr/86Sr)i。这些特征反映了俯冲板片释放的流体和熔体分别对大岔大坂和伊豆–小笠原玻安岩岩浆地幔源区的贡献，从而表明大岔大坂玻安岩形成过程与伊豆–小笠原玻安岩所代表的俯冲初始形成模型不同，更可能形成于存在弧后扩张作用的成熟岛弧阶段。结合区域地质背景和前人研究，本文针对大岔大坂玻安岩成因提出了两种与俯冲初始阶段无关的可能形成机制：① 玻安岩产出于弧后扩张中心，弧后岩石圈的拉张环境和较热的地幔上隆区为玻安质岩浆的形成提供了温压条件，充分交代的水化地幔楔和蛇纹岩化地幔也参与了玻安质岩浆的形成；② 虽与弧后扩张中心相关，但玻安岩的产出位于前弧或弧。由于弧后地幔对弧下深度地幔楔进行侧向加热，导致地幔楔内部对流重新启动，弧后地区已经熔融出弧后玄武岩的残余橄榄岩进入前弧–弧下地幔楔，地幔楔底部和俯冲板片表面被重新加热而发生变质脱水，富水流体交代上部地幔楔使其部分熔融形成玻安质岩浆。
Abstract:Boninites are characterized by high-Si (＞52 wt.%), high-Mg (＞8 wt.%), and low-Ti (＜0.5 wt.%). Boninite is thought to be originated from the partial melting of the refractory mantle induced by fluids released from the subducting seafloor during the subduction initiation. Therefore, study on petrogenesis of boninite is of great significance to further understand the geodynamic mechanism of subduction initiation. Although contribution of subducted materials for the boninitic magma source is significant as people commonly believed, the varying enriched extents of incompatible elements among different boninites reflect the complex physicochemical properties of subducting slab-derived fluids for the formation of boninites. In this study, we compared boninite from the Izu-Bonin-Mariana (IBM) arc system and the North Qilian orogenic belt, and found many geochemical differences between them. Compared to Izu-Bonin boninites, boninite from the North Qilian orogeny does not show U-shaped rare earth element (REE) pattern or enriched light REEs and Zr-Hf, while both of them have highly varied ratios of fluid-soluble element to incompatible element (e.g. Ba/La) and high (87Sr/86Sr)i values. These characteristics reflect the contribution of slab-derived fluids / melts to the magma source for Qilian/Izu-Bonin boninite, respectively. Different from the Izu-Bonin boninite, the Qilian boninite is likely to be produced in a mature subduction system with back-arc spreading centers. Combined with previous studies, we proposed two potential ways for the formation of the Qilian boninite unrelated to the seafloor subduction initiation: (1) the back-arc lithosphere extension and the hot mantle upwelling provided a suitable temperature and pressure for the formation of boninite magmas, with the contribution of the hydrated/serpentinized mantle; (2) the corner flow carried the residual peridotite of the back-arc mantle into the sub-arc/fore-arc mantle, which can be melted and possibly induce dehydration of the subducting slab again to produce boninite magmas.
-
Key words:
- boninites /
- subducting slab /
- fluids /
- geochemistry /
- hydrous melts /
- subduction-zone magmatism
-
-
图 5 大岔大坂玻安岩与伊豆–小笠原玻安岩、伊豆–小笠原前弧玄武岩、IBM岛弧玄武岩/安山岩的N-MORB标准化微量元素(a)及CI碳质球粒陨石标准化稀土元素配分模式图(b)[33]
Figure 5.
-
[1] Parkinson I J, Hawkesworth C J, Cohen A S. Ancient mantle in a modern arc: Osmium isotopes in Izu-Bonin-Mariana forearc peridotites [J]. Science, 1998, 281(5385): 2011-2013. doi: 10.1126/science.281.5385.2011
[2] Stern R J. Subduction zones [J]. Reviews of Geophysics, 2002, 40(4): 1012.
[3] Reagan M K, Ishizuka O, Stern R J, et al. Fore-arc basalts and subduction initiation in the Izu-Bonin-Mariana system [J]. Geochemistry, Geophysics, Geosystems, 2010, 11(3): Q03X12.
[4] Ishizuka O, Hickey-Vargas R, Arculus R J, et al. Age of Izu-Bonin-Mariana arc basement [J]. Earth and Planetary Science Letters, 2018, 481: 80-90. doi: 10.1016/j.jpgl.2017.10.023
[5] Li H Y, Zhao R P, Li J, et al. Molybdenum isotopes unmask slab dehydration and melting beneath the Mariana arc [J]. Nature Communications, 2021, 12(1): 6015. doi: 10.1038/s41467-021-26322-8
[6] Shervais J W, Reagan M K, Godard M, et al. Magmatic response to subduction initiation, Part II: boninites and related rocks of the Izu-Bonin arc from IODP expedition 352 [J]. Geochemistry, Geophysics, Geosystems, 2021, 22(1): e2020GC009093.
[7] Crawford A J, Falloon T J, Green D H. Classification, petrogenesis and tectonic setting of boninites[M]//Crawford A J. Boninites and Related Rocks, Unwin and Hyman. London: Australian Research Council, 1989: 1-49.
[8] Falloon T J, Danyushevsky L V. Melting of refractory mantle at 1 · 5, 2 and 2 · 5 GPa under, anhydrous and H2O-undersaturated conditions: Implications for the petrogenesis of high-Ca boninites and the influence of subduction components on mantle melting [J]. Journal of Petrology, 2000, 41(2): 257-283. doi: 10.1093/petrology/41.2.257
[9] Ishizuka O, Kimura J, Li Y, et al. Early stages in the evolution of Izu–Bonin arc volcanism: New age, chemical, and isotopic constraints [J]. Earth and Planetary Science Letters, 2006, 250(1-2): 385-401. doi: 10.1016/j.jpgl.2006.08.007
[10] Dilek Y, Thy P. Island arc tholeiite to boninitic melt evolution of the Cretaceous Kizildag (Turkey) ophiolite: model for multi-stage early arc-forearc magmatism in Tethyan subduction factories [J]. Lithos, 2009, 113(1-2): 68-87. doi: 10.1016/j.lithos.2009.05.044
[11] Reagan M K, Pearce J A, Petronotis K, et al. Subduction initiation and ophiolite crust: new insights from IODP drilling [J]. International Geology Review, 2017, 59(11): 1439-1450. doi: 10.1080/00206814.2016.1276482
[12] Stern R J. Subduction initiation: spontaneous and induced [J]. Earth and Planetary Science Letters, 2004, 226(3-4): 275-292. doi: 10.1016/S0012-821X(04)00498-4
[13] Pearce J A. Role of the sub-continental lithosphere in magma genesis at active continental margins[M]//Hawkesworth C J, Norry M J. Continental Basalts and Mantle Xenoliths. Nantwich, Cheshire: Shiva Publications, 1983: 230-249.
[14] König S, Münker C, Schuth S, et al. Boninites as windows into trace element mobility in subduction zones [J]. Geochimica et Cosmochimica Acta, 2010, 74(2): 684-704. doi: 10.1016/j.gca.2009.10.011
[15] 宋述光, 吴珍珠, 杨立明, 等. 祁连山蛇绿岩带和原特提斯洋演化[J]. 岩石学报, 2019, 35(10):2948-2970 doi: 10.18654/1000-0569/2019.10.02
SONG Shuguang, WU Zhenzhu, YANG Liming, et al. Ophiolite belts and evolution of the proto-tethys ocean in the qilian orogen [J]. Acta Petrologica Sinica, 2019, 35(10): 2948-2970. doi: 10.18654/1000-0569/2019.10.02
[16] 赵国军. 中祁连西段早古生代洋内弧后盆地岩浆作用的厘定及地质意义的研究[D]. 西北大学硕士学位论文, 2019.
ZHAO Guojun. Determination and geological significance of magmatism in the Early Paleozoic intra-ocean back-arc basins in The Western Central Qilian belt[D]. Master Dissertation of Northwest University, 2019.
[17] 孟繁聪, 张建新, 郭春满, 等. 大岔大坂MOR型和SSZ型蛇绿岩对北祁连洋演化的制约[J]. 岩石矿物学杂志, 2010, 29(5):453-466 doi: 10.3969/j.issn.1000-6524.2010.05.001
MENG Fancong, ZHANG Jianxin, KER C M, et al. Constraints on the evolution of the North Qilian ocean basin: MOR-type and SSZ-type ophiolites from Dachadaban [J]. Acta Petrologica et Mineralogica, 2010, 29(5): 453-466. doi: 10.3969/j.issn.1000-6524.2010.05.001
[18] Xia X H, Song S G, Niu Y L. Tholeiite–Boninite terrane in the North Qilian suture zone: Implications for subduction initiation and back-arc basin development [J]. Chemical Geology, 2012, 328: 259-277. doi: 10.1016/j.chemgeo.2011.12.001
[19] 冯益民, 何世平. 北祁连蛇绿岩的地质地球化学研究[J]. 岩石学报, 1995, 11(S1):125-146
FENG Yimin, HE Shiping. Research for geology and geochemistry of several ophiolites in the north Qilian Mountains, China [J]. Acta Petrologica Sinica, 1995, 11(S1): 125-146.
[20] 张旗, 钱青, 陈雨. 蛇绿岩、蛇绿岩上覆岩系及其与洋壳的对比[J]. 地学前缘, 1998, 5(4):193-200 doi: 10.3321/j.issn:1005-2321.1998.04.002
ZHANG Qi, QIAN Qing, CHEN Yu. Ophiolite, overlying rock series of ophiolite and their comparison to the oceanic crust [J]. Earth Science Frontiers, 1998, 5(4): 193-200. doi: 10.3321/j.issn:1005-2321.1998.04.002
[21] 韩松, 贾秀琴, 钱青, 等. 北祁连大岔大坂两类辉长岩的地质地球化学特征及其构造环境[J]. 岩石矿物学杂志., 2000, 19(2):106-112
HAN Song, JIA Xiuqin, QIAN Qing, et al. Geological and geochemical characteristics of two types of gabbro in Dachadaban, North Qilian and its tectonic environment [J]. Acta Petrologica et Mineralogica, 2000, 19(2): 106-112.
[22] Li H, Arculus R J, Ishizuka O, et al. Basalt derived from highly refractory mantle sources during early Izu-Bonin-Mariana arc development [J]. Nature Communications, 2021, 12(1): 1723. doi: 10.1038/s41467-021-21980-0
[23] Song S G, Niu Y L, Su L, et al. Tectonics of the North Qilian orogen, NW China [J]. Gondwana Research, 2013, 23(4): 1378-1401. doi: 10.1016/j.gr.2012.02.004
[24] Ishizuka O, Taylor R N, Umino S, et al. Geochemical evolution of arc and slab following subduction initiation: a record from the Bonin Islands, Japan [J]. Journal of Petrology, 2020, 61(5): egaa050. doi: 10.1093/petrology/egaa050
[25] Chen S, Wang X H, Niu Y L, et al. Simple and cost-effective methods for precise analysis of trace element abundances in geological materials with ICP-MS [J]. Science Bulletin, 2017, 62(4): 277-289. doi: 10.1016/j.scib.2017.01.004
[26] Sun P, Niu Y L, Guo P Y, et al. Elemental and Sr-Nd-Pb isotope geochemistry of the Cenozoic basalts in Southeast China: Insights into their mantle sources and melting processes [J]. Lithos, 2017, 272-273: 16-30. doi: 10.1016/j.lithos.2016.12.005
[27] Pearce J A, Reagan M K. Identification, classification, and interpretation of boninites from Anthropocene to Eoarchean using Si-Mg-Ti systematics [J]. Geosphere, 2019, 15(4): 1008-1037. doi: 10.1130/GES01661.1
[28] Perez A, Umino S, Yumul G P Jr, et al. Boninite and boninite-series volcanics in northern Zambales ophiolite: doubly vergent subduction initiation along Philippine Sea plate margins [J]. Solid Earth, 2018, 9(3): 713-733. doi: 10.5194/se-9-713-2018
[29] Le Bas M J. IUGS reclassification of the High-Mg and picritic volcanic rocks [J]. Journal of Petrology, 2000, 41(10): 1467-1470. doi: 10.1093/petrology/41.10.1467
[30] Ohnenstetter D, Brown W L. Compositional variation and primary water contents of differentiated interstitial and included glasses in boninites [J]. Contributions to Mineralogy and Petrology, 1996, 123(2): 117-137. doi: 10.1007/s004100050146
[31] Miyashiro A. Volcanic rock series in island arcs and active continental margins [J]. American Journal of Science, 1974, 274(4): 321-355. doi: 10.2475/ajs.274.4.321
[32] Mcdonough W F, Sun S S. The composition of the earth [J]. Chemical Geology, 1995, 120(3-4): 223-253. doi: 10.1016/0009-2541(94)00140-4
[33] Sun S S, McDonough W F. Chemical and isotopic systematics of oceanic basalts: implications for mantle composition and processes [J]. Geological Society, London, Special Publications, 1989, 42(1): 313-345. doi: 10.1144/GSL.SP.1989.042.01.19
[34] Taylor B, Fujioka K. Rifting and the volcanic-tectonic evolution of the Izu-Bonin-Mariana arc[C]. Proceedings of the Ocean Drilling Program, Scientific Results, 1992, 126: 627-651.
[35] Kanayama K, Umino S, Ishizuka O. Eocene volcanism during the incipient stage of Izu-Ogasawara Arc: geology and petrology of the Mukojima Island Group, the Ogasawara islands [J]. Island Arc, 2012, 21(4): 288-316. doi: 10.1111/iar.12000
[36] Patriat M, Falloon T, Danyushevsky L, et al. Subduction initiation terranes exposed at the front of a 2 Ma volcanically-active subduction zone [J]. Earth And Planetary Science Letters, 2019, 508: 30-40. doi: 10.1016/j.jpgl.2018.12.011
[37] Singh M R, Manikyamba C, Ganguly S, et al. Paleoproterozoic arc basalt-boninite-high magnesian andesite-Nb enriched basalt association from the Malangtoli volcanic suite, Singhbhum Craton, eastern India: Geochemical record for subduction initiation to arc maturation continuum [J]. Journal of Asian Earth Sciences, 2017, 134: 191-206. doi: 10.1016/j.jseaes.2016.09.015
[38] Whattam S A, Stern R J. Late Cretaceous plume-induced subduction initiation along the southern margin of the Caribbean and NW South America: The first documented example with implications for the onset of plate tectonics [J]. Gondwana Research, 2015, 27(1): 38-63. doi: 10.1016/j.gr.2014.07.011
[39] Umino S, Kanayama K, Kitamura K, et al. Did boninite originate from the heterogeneous mantle with recycled ancient slab? [J]. Island Arc, 2018, 27(1): e12221. doi: 10.1111/iar.12221
[40] Jenner F E, O'neill H S C. Analysis of 60 elements in 616 ocean floor basaltic glasses [J]. Geochemistry, Geophysics, Geosystems, 2012, 13(2): Q02005.
[41] Murton B J. Tectonic controls on boninite genesis [J]. Geological Society, London, Special Publications, 1989, 42(1): 347-377. doi: 10.1144/GSL.SP.1989.042.01.20
[42] Meffre S, Falloon T J, Crawford T J, et al. Basalts erupted along the Tongan fore arc during subduction initiation: Evidence from geochronology of dredged rocks from the Tonga fore arc and trench [J]. Geochemistry, Geophysics, Geosystems, 2012, 13(12): Q12003.
[43] 熊小林, 刘星成, 李立, 等. 俯冲带微量元素分配行为研究: 进展和展望[J]. 中国科学:地球科学, 2020, 63(12):1938-1951 doi: 10.1007/s11430-019-9631-6
XIONG Xiaolin, LIU Xingcheng, LI Li, et al. The partitioning behavior of trace elements in subduction zones: Advances and prospects [J]. Science China Earth Sciences, 2020, 63(12): 1938-1951. doi: 10.1007/s11430-019-9631-6
[44] Plank T, Langmuir C H. The chemical composition of subducting sediment and its consequences for the crust and mantle [J]. Chemical Geology, 1998, 145(3-4): 325-394. doi: 10.1016/S0009-2541(97)00150-2
[45] Manikyamba C, Naqvi S M, Subba Rao D V, et al. Boninites from the Neoarchaean gadwal greenstone belt, Eastern Dharwar Craton, India: implications for Archaean subduction processes [J]. Earth and Planetary Science Letters, 2005, 230(1-2): 65-83. doi: 10.1016/j.jpgl.2004.06.023
[46] Falloon T J, Crawford A J. The petrogenesis of high-calcium boninite lavas dredged from the northern Tonga Ridge [J]. Earth and Planetary Science Letters, 1991, 102(3-4): 375-394. doi: 10.1016/0012-821X(91)90030-L
[47] Plank T. Constraints from thorium/lanthanum on sediment recycling at subduction zones and the evolution of the continents [J]. Journal of Petrology, 2005, 46(5): 921-944. doi: 10.1093/petrology/egi005
[48] Veizer J. Strontium isotopes in seawater through time [J]. Annual Review of Earth and Planetary Sciences, 1989, 17: 141-167. doi: 10.1146/annurev.ea.17.050189.001041
[49] Elliott T, Plank T, Zindler A, et al. Element transport from slab to volcanic front at the Mariana arc [J]. Journal of Geophysical Research: Solid Earth, 1997, 102(B7): 14991-15019. doi: 10.1029/97JB00788
[50] Van Der Straaten F, Halama R, John T, et al. Tracing the effects of high-pressure metasomatic fluids and seawater alteration in blueschist-facies overprinted eclogites: Implications for subduction channel processes [J]. Chemical Geology, 2012, 292-293: 69-87. doi: 10.1016/j.chemgeo.2011.11.008
[51] Plank T. The chemical composition of subducting sediments[M]//Keeling P F. Treatise on Geochemistry. 2nd ed. Amsterdam: Elsevier, 2014: 607-629.
[52] Savov I P, Ryan J G, D'Antonio M, et al. Shallow slab fluid release across and along the Mariana arc-basin system: Insights from geochemistry of serpentinized peridotites from the Mariana fore arc [J]. Journal of Geophysical Research:Solid Earth, 2007, 112(B9): B09205.
[53] Zheng Y F. Subduction zone geochemistry [J]. Geoscience Frontiers, 2019, 10(4): 1223-1254. doi: 10.1016/j.gsf.2019.02.003
-
下载:
图(8)
计量
- 文章访问数: 2469
- PDF下载数: 76
- 施引文献: 0