Identification of the Late Triassic oceanic island rock assemblages in the Ganzi-Litang ophiolite mélange belt and its constraints on the tectonic evolution of the Ganzi-Litang oceanic basin
-
摘要:
甘孜-理塘蛇绿混杂岩带位于特提斯构造域东段，为西南“三江”多岛弧盆系的重要组成部分，具有完整的沟-弧-盆体系。以理塘地区拉扎嘎山一带下坝岩组洋岛型“玄武岩+碳酸盐岩”岩石组合为研究对象，开展岩石学、地球化学和锆石U-Pb测年分析，为甘孜-理塘洋晚三叠世洋陆格局的恢复重建提供新的证据。岩石地球化学分析结果表明，样品SiO2含量为42.16%~48.32%，TiO2为2.81%~3.75%，稀土元素总量为164.51×10-6~414.40×10-6，轻稀土元素较重稀土元素富集，(La/Yb)N值为9.35~34.31，明显富集Rb、Ba、Th、U、K等大离子亲石元素，以及Nb、Ta、Zr、Ti等高场强元素，玄武岩的稀土元素配分曲线和微量元素蛛网图与典型洋岛型玄武岩(OIB)相似。锆石U-Pb测年表明，洋岛型玄武岩形成于211 Ma。这些资料进一步表明，晚三叠世甘孜-理塘洋盆存在洋岛环境，同时，也为甘孜-理塘洋盆晚三叠世处于俯冲消减阶段的认识提供了新的证据。
Abstract:The Ganzi-Litang ophiolite mélange belt is located in the eastern Tethys domain. It is an important part of the Sanjiang (Nujiang River, Lancangjiang River and Jinshajiang River) archipelagic arc-basin system in Southwest China, with a complete trench-arc-basin system. The petrological, geochemical and zircon U-Pb dating analyses of the oceanic island-type "basalt + carbonate" rock assemblage in the Xiaba Formation from the Lazaga Mountain in the Litang area are carried out to provide new evidence for the reconstruction of the Late Triassic ocean-continent configuration of the Ganzi-Litang Ocean. Geochemical analyses show that the SiO2 content of the basalts is 42.16%~48.32%, and the TiO2 content is 2.81%~3.75%. The total rare earth elemnt (ΣREE) ranges from 164.51×10-6 to 414.40×10-6, and the light rare earth elements are more enriched than the heavy rare earth elements [(La/Yb)N=9.35~34.31], and are obviously enriched in lithophile elements such as Rb, Ba, Th, U, K, and high field strength elements such as Nb, Ta, Zr, Ti, etc. The REE distribution curve and trace element spider patterns of the basalts are similar to typical oceanic island basalt (OIB). The zircon U-Pb dating indicates that oceanic-island basalts were formed at 211 Ma. These data further indicate that an oceanic island environment existed in the Ganzi-Litang Ocean during the Late Triassic, and also provide new evidence for understanding that the Ganzi-Litang Ocean was in the subduction stage during the Late Triassic.
-
-
![]()
图 1 研究区大地构造位置(a, 据Yang et al., 2015修改)和四川理塘地区地质简图(b)
Figure 1. Tectonic location map of the study area(a) and geological sketch map of the Litang area, Sichuan(b)
![]()
图版Ⅰ
a.气孔状玄武岩野外露头; b.玄武岩与灰岩整合接触关系; c.玄武岩与大理岩化灰岩整合接触关系; d.玄武岩与大理岩整合接触关系; e.玄武岩中灰岩砾石; f.灰岩中玄武岩砾石
图版Ⅰ.
![]()
图 2 洋岛型岩石组合显微镜下照片
a—斑状玄武岩正交偏光镜下照片; b—灰岩正交偏光镜下照片。Pl—斜长石; Px—辉石; Cal—方解石
Figure 2. The microphotographs of the ocean island rock association
![]()
图 3 下坝岩组玄武岩锆石阴极发光(CL)图像(a)和U-Pb谐和图(b)
Figure 3. The CL images(a) and U-Pb concordia plots(b) of zircons for basalt from the Xiaba Formation
![]()
图 4 下坝岩组玄武岩Nb/Y-Zr/TiO2图解
Figure 4. The Nb/Y-Zr/TiO2 diagram of basalts from the Xiaba Formation
![]()
图 5 下坝岩组玄武岩球粒陨石标准化稀土元素配分曲线(a)和原始地幔标准化微量元素蛛网图(b)
(OIB、球粒陨石及原始地幔标准化值均据Sun et al., 1989)
Figure 5. Chondrite-normalized REE patterns(a) and primitive mantle-normalized trace element spider diagrams(b) of basalts from the Xiaba Formation
![]()
图 6 下坝岩组玄武岩Nb/Yb-Ta/Yb图解(a，据Pearce, 2008)和Nb/Yb-Th/Yb图解(b，据朱永峰等，2007)
Figure 6. Plots of Nb/Yb-Ta/Yb(a) and Nb/Yb-Th/Yb(b) for basalts from the Xiaba Formation
![]()
图 7 下坝岩组玄武岩构造环境判别图解
a—TiO2/10-MnO-10×P2Os 图解(据Mullen, 1983); b—Hf/3-Th-Ta图解(据Wood，1980)
Figure 7. Tectonic discrimination diagrams of basalts from the Xiaba Formation
![]()
图 8 下坝岩组岩屑石英砂岩交错层理及镜下照片
a—下坝岩组灰岩与砂岩接触界线远景; b—下坝岩组灰岩与砂岩接触界线近景; c—下坝岩组交错层理; d—岩屑石英砂岩镜下照(正交偏光)。Qtz—石英; Pl—斜长石; Lv—火山岩岩屑; Ls—沉积岩岩屑; Lc—硅质岩岩屑
Figure 8. The cross bedding and microtexture of the lithic quartz sandstone from the Xiaba Formation
![]()
图 9 索罗门Malait海山(a，Phinney et al., 2004)、克拉玛依洋岛(b，杨高学等，2015)和下坝岩组洋岛(c)综合柱状图
Figure 9. Synthesis column maps of the Solomom Malait seamount(a), Karamay oceanic island(b) and the Xiaba Formation oceanic island(c)
表 1 下坝岩组玄武岩(PM011-23DN1)LA-ICP-MS锆石U-Th-Pb同位素测试结果
Table 1 LA-ICP-MS zircon U-Th-Pb isotope data of basalts(PM011-23DN1) from the Xiaba Formation
分析点 含量/10-6 Th/U 同位素比值 年龄/Ma Pb Th U 207Pb/206Pb 1σ 207Pb/235U 1σ 206Pb/238U 1σ 207Pb/206Pb 1σ 207Pb/235U 1σ 206Pb/238U 1σ 23DN1-1 161 125 265 0.47 0.1819 0.0023 12.4776 0.1772 0.4977 0.0046 2670 21 2641 13 2604 20 23DN1-2 79 53 142 0.37 0.1830 0.0025 11.7986 0.1831 0.4678 0.0047 2680 23 2589 15 2474 21 23DN1-4 24 230 652 0.35 0.0488 0.0022 0.2238 0.0096 0.0334 0.0004 200 106 205 8 212 2 23DN1-5 7 65 205 0.32 0.0509 0.0021 0.2327 0.0092 0.0334 0.0004 239 93 212 8 212 3 23DN1-6 13 112 368 0.30 0.0553 0.0020 0.2537 0.0095 0.0332 0.0003 433 81 230 8 211 2 23DN1-7 4 100 88 1.13 0.0553 0.0045 0.2549 0.0197 0.0338 0.0007 433 181 231 16 214 5 23DN1-8 6 301 208 1.45 0.0530 0.0029 0.1507 0.0078 0.0210 0.0003 328 129 142 7 134 2 23DN1-9 422 224 530 0.42 0.1217 0.0011 5.6422 0.0601 0.3360 0.0023 1981 17 1923 9 1867 11 23DN1-10 28 482 536 0.90 0.0558 0.0014 0.3110 0.0077 0.0405 0.0003 443 57 275 6 256 2 23DN1-12 67 80 127 0.63 0.1653 0.0020 9.5846 0.1715 0.4197 0.0054 2510 16 2396 16 2259 24 23DN1-13 20 188 545 0.34 0.0515 0.0014 0.2372 0.0062 0.0335 0.0003 265 56 216 5 212 2 23DN1-14 29 323 782 0.41 0.0514 0.0013 0.2354 0.0059 0.0332 0.0003 261 53 215 5 211 2 23DN1-15 33 392 546 0.72 0.0568 0.0016 0.3797 0.0104 0.0486 0.0005 483 61 327 8 306 3 23DN1-16 360 514 720 0.71 0.1488 0.0014 7.9673 0.1133 0.3875 0.0041 2332 15 2227 13 2111 19 23DN1-17 31 83 243 0.34 0.0650 0.0014 1.0065 0.0241 0.1121 0.0013 776 43 707 12 685 7 23DN1-18 147 352 471 0.75 0.0943 0.0011 3.2896 0.0470 0.2526 0.0025 1515 24 1479 11 1452 13 23DN1-19 35 568 841 0.67 0.0564 0.0026 0.2633 0.0119 0.0339 0.0005 478 100 237 10 215 3 
下载: 导出CSV
表 2 下坝岩组玄武岩主量、微量和稀土元素分析结果
Table 2 Major, trace and rare earth elements contents of basalts from the Xiaba Formation
元素 PM011-19FX1 PM011-23FX1 PM011-37FX1 PM011-25FX1 PM011-27FX1 元素 PM011-19FX1 PM011-23FX1 PM011-37FX1 PM011-25FX1 PM011-27FX1 玄武岩 斑状玄武岩 玄武岩 斑状玄武岩 SiO2 42.7 43.7 42.2 48.0 48.3 Tm 0.27 0.34 0.37 0.52 0.57 Na2O 0.51 0.42 0.98 4.31 4.02 Yb 1.54 1.87 2.36 2.86 3.06 CaO 7.49 6.28 5.91 5.83 5.60 Lu 0.17 0.19 0.33 0.36 0.35 FeO 9.06 4.58 11.1 4.40 4.17 Y 28.8 35.1 27.9 42.1 43.5 Fe2O3 5.15 10.3 2.39 7.56 7.86 Li 22.4 31.7 29.5 68.9 64.9 Al2O3 8.60 9.24 11.6 13.2 12.9 Sc 23.5 31.4 43.4 31.5 32.8 MgO 18.6 17.1 18.2 8.10 8.13 V 264 305 295 254 249 K2O 0.50 0.24 3.05 3.10 2.94 Cr 799 992 1136 216 242 P2O5 0.46 0.59 0.28 0.48 0.48 Co 82.2 88.0 67.5 45.4 44.0 MnO2 0.23 0.27 0.14 0.22 0.19 Ni 584 591 394 115 119 TiO2 3.13 2.81 3.18 3.75 3.56 Cu 271 148 54.6 3.51 3.45 烧失量 3.40 4.19 1.57 1.41 1.17 Zn 123 127 89.4 103 98.4 总量 96.3 95.5 98.9 99.0 98.2 Ga 17.6 21.4 15.8 22.9 23.6 La 73.8 88.0 30.7 44.0 46.2 Rb 9.55 5.29 58.9 48.8 44.2 Ce 138 174 63.6 92.5 92.8 Sr 102 80.5 86.8 128 116 Pr 16.3 20.5 7.72 11.3 12.3 Zr 38.8 49.6 52.4 156 74.2 Nd 68.2 85.0 34.0 49.2 48.7 Nb 8.92 13.2 12.9 38.6 27.8 Sm 10.4 14.1 6.85 9.97 10.6 Ba 219 53.3 192 213 119 Eu 3.27 4.03 2.12 3.13 3.29 Hf 1.82 1.89 3.24 4.19 3.41 Gd 9.25 11.5 6.04 9.22 9.27 Ta 0.94 1.37 1.04 2.71 2.23 Tb 1.32 1.68 0.93 1.61 1.64 Pb 3.50 3.68 4.22 5.68 3.65 Dy 6.75 8.51 5.57 8.94 9.10 Th 4.46 5.38 2.47 3.21 2.93 Ho 1.23 1.50 1.11 1.78 1.88 U 0.36 0.39 0.46 0.47 0.46 Er 2.81 3.15 2.81 4.01 4.12 注：主量元素含量单位为%，微量和稀土元素含量单位为10-6
下载: 导出CSV
-
Claesson S, Vetrin V, Bayanova T. U-Pb zircon ages from a Devonian carbonatite dyke, Kola peninsula, Russia: A record of geological evolution from the Archaean to the Palaeozoic[J]. Lithos, 2000, 51(1/2): 95-108.
Dilek Y, Furnes H. Ophiolite genesis and global tectonics: Geochemical and tectonic fingerprinting of ancient oceanic lithosphere[J]. Geological Society of America Bulletin, 2011, 123(3/4): 387-411.
Fernando C, John M H, Paul W H O, et al. Atlas of zircon textures[J]. Reviews in Mineralogy and Geochemistry, 2003, 53(1): 469-500. doi: 10.2113/0530469
Hilst R D V D, Widiyantoro S, Engdahl E R. Evidence for deep mantle circulation from global tomography[J]. Nature, 1997, 386(6625): 578-584. doi: 10.1038/386578a0
Jackson W T, Robinson D M, Weislogel A L, et al. Cenozoic reactivation along the Late Triassic Ganzi-Litang suture, eastern Tibetan Plateau[J]. Geoscience Frontiers, 2020, 11(3): 1069-1080. doi: 10.1016/j.gsf.2019.11.001
Kita I, Yamamoto M, Asakawa Y, et al. Contemporaneous ascent of within-plate type and island-arc type magmas in the Beppu-Shimabara graben system, Kyushu Island, Japan[J]. Journal of Volcanology and Geothermal Research, 2001, 111(1/4): 99-109.
Kusky T M, Windley B F, Safonova I, et al. Recognition of ocean plate stratigraphy in accretionary orogens through earth history: A record of 3.8 billion years of seafloor spreading, subduction, and accretion[J]. Gondwana Research, 2013, 24(2): 501-547. doi: 10.1016/j.gr.2013.01.004
Mullen E D. MnO/TiO2/P2O5: a minor element discriminant for basaltic rocks of oceanic environments and its implications for petrogenesis[J]. Earth & Planetary Science Letters, 1983, 62(1): 53-62.
Montelli R, Nolet G, Dahlen F A, et al. Finite-Frequency Tomography Reveals a Variety of Plumes in the Mantle[J]. Science, 2004, 303(5656): 338-343. doi: 10.1126/science.1092485
Phinney E J, Mann P, Coffin M F, et al. Sequence stratigraphy, structural style, and age of deformation of the Malaita accretionary prism (Solomon arc-Ontong Java Plateau convergent zone) [J]. Tectonophysics, 2004, 389(3/4): 221-246.
Pearce J A. Geochemical fingerprinting of oceanic basalts with applications to ophiolite classification and the search for Archean oceanic crust[J]. Lithos, 2008, 100(1/4): 14-48.
Rollison H R. Petrological Geochemistry[C]//Yang X M, Yang X Y, Chen S X (Trans.). Hefei: University of Science and Technology of China Press, 2000: 1-275.
Rudnick R L, Gao S. Composition of the Continental Crust//Rudnick R L. The Crust Treaties on Geochemistry 3[M]. Oxford: Elsevier Pergamon, 2003: 1-64.
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
Wood D A. The application of a Th, Hf, Ta diagram to problems oftectonomagmatic classification and to establishing the nature of crustal contamination of basaltic lavas of the British Tertiary Volcanic Province[J]. Earth & Planetary Science Letters, 1980, 50(1): 11-30.
Wilson B M. Igneous Petrogenesis[M]. London: Unwin Hyman, 1989: 1-25.
Wang B, Wang W, Chen W, et al. Constraints of detrital zircon U-Pb ages and Hf isotopes on the provenance of the Triassic Yidun Group and tectonic evolution of the Yidun Terrane, Eastern Tibet[J]. Sedimentary Geology, 2013, 289: 74-98. doi: 10.1016/j.sedgeo.2013.02.005
Wang C, Liu H, Feng H, et al. Geochemistry and U-Pb ages of the diabases from the Luoji area, western Yunnan, China: Implications for the timing of initial rifting of the Ganzi-Litang Ocean[J]. Geologia Croatica, 2019, 72(Special issue): 19-32. doi: 10.4154/gc.2019.25
Yang L Q, Deng J, Yildirim D, et al. Structure, geochronology, and petrogenesis of the Late Triassic Puziba granitoid dikes in the Mianlue suture zone, Qinling orogen, China[J]. Geological Society of America Bulletin, 2015, 127(11/12): 1831-1854.
Yuan W, Shi Z, Zhu X. New zircon fission track analysis constraints on tectonic-mineralization epochs in theGanzi-Litang gold belt, eastern Qinghai-Tibet plateau[J]. Ore Geology Reviews, 2020, 119(2): 103383.
蔡雄飞, 蔡海磊, 刘德民. 造山带洋岛混杂岩系地层序列和研究意义[J]. 海洋地质前沿, 2006, 22(4): 9-11. https://www.cnki.com.cn/Article/CJFDTOTAL-HYDT200604002.htm 陈刚, 朱志新, 董连慧, 等. 新疆南天山塔什库尔干泥盆—早石炭世洋岛型火山岩的确定及地质意义[J]. 新疆地质, 2010, 28(3): 236-241. https://www.cnki.com.cn/Article/CJFDTOTAL-XJDI201003003.htm 晨辰, 张志诚, 郭召杰, 等. 内蒙古达茂旗满都拉地区早二叠世基性岩的年代学、地球化学及其地质意义[J]. 中国科学: 地球科学, 2012, (3): 343-358. https://www.cnki.com.cn/Article/CJFDTOTAL-JDXK201203005.htm 陈志. 西藏改则地区仲岗洋岛火山-沉积序列与地球化学特征[D]. 成都理工大学硕士学位论文, 2016. 范建军, 李才, 彭虎, 等. 藏北龙木错-双湖-澜沧江板块缝合带发现晚石炭世—早二叠世洋岛型岩石组合[J]. 地质通报, 2014, 33(11): 1690-1695. https://www.cnki.com.cn/Article/CJFDTOTAL-ZQYD201411005.htm 冯庆来, 张世涛, 葛孟春, 等. 滇西北中甸地区哈工组放射虫及其构造古地理意义[J]. 地质科学, 2002, 37(1): 70-78. https://www.cnki.com.cn/Article/CJFDTOTAL-DZKX200201008.htm 侯增谦, 侯立纬, 叶庆同, 等. 三江地区义敦岛弧构造-岩浆演化与火山成因块状硫化物矿床[M]. 北京: 地质出版社, 1995: 1-120. 侯增谦, 卢记仁, 李红阳, 等. 中国西南特提斯构造演化-幔柱构造控制[J]. 地球学报, 1996, 17(4): 439-453. https://www.cnki.com.cn/Article/CJFDTOTAL-DQXB604.008.htm 侯增谦, 杨岳清, 王海平. 三江义敦岛弧碰撞造山过程与成矿系统[M]. 北京: 地质出版社, 2003: 1-235. 侯可军, 李延河, 田有荣. LA-MC-ICP-MS锆石微区原位U-Pb定年技术[J]. 矿床地质, 2009, 28(4): 481-492. https://www.cnki.com.cn/Article/CJFDTOTAL-KCDZ200904009.htm 李文昌. 西南"三江"多岛弧盆-碰撞造山成矿理论与勘查技术[M]. 北京: 地质出版社, 2010: 1-491. 李永森, 陈炳蔚, 周伟勤. 中国西南三江特提斯洋的演化及成矿作用[C]// 三江专著编辑委员会编. 青藏高原地质文集. 北京: 地质出版社, 1983, 15: 173-188. 刘宝田, 江耀明, 曲景川. 四川理塘—甘孜一带古洋壳的发现及其对板块构造的意义[C]//青藏高原地质文集(12). 北京: 地质出版社, 1983: 119-128. 梁信之, 谭庆鹄, 师常庆, 等. 1 : 20万新龙幅、禾尼乡幅、康定幅区域调查报告[R]. 四川省地质矿产局区域地质调查队四分队, 1984: 1-168. 罗建宁, 张正贵. 三江特提斯沉积地质与矿产[M]. 北京: 地质出版社, 1992: 1-186. 莫宣学, 路凤香, 沈上越. 三江特提斯火山作用与成矿[M]. 北京: 地质出版社, 1993: 1-267. 潘桂棠, 陈智梁, 李兴振, 等. 东特提斯地质构造形成演化[M]. 北京: 地质出版社, 1997: 1-218. 任飞, 尹福光, 孙洁, 等. 甘孜-理塘俯冲增生杂岩带中二叠世构造演化——来自龙蟠蛇绿岩年龄、地球化学的证据[J]. 地质通报, 2021, 40(6): 942-954. http://dzhtb.cgs.cn/gbc/ch/reader/view_abstract.aspx?file_no=20210610&flag=1 魏永峰, 罗森林. 甘孜-理塘结合带中部花岗岩的地质特征[J]. 四川地质学报, 2003, 23(1): 5-9. https://www.cnki.com.cn/Article/CJFDTOTAL-SCDB200301001.htm 严松涛, 秦蒙, 谭昌海, 等. 甘孜-理塘蛇绿混杂岩带中段晚古生代硅质岩的识别及其地质意义[J]. 地质学报, 2019a, 93(9): 2197-2208. https://www.cnki.com.cn/Article/CJFDTOTAL-DZXE201909007.htm 严松涛, 秦蒙, 段阳海, 等. 四川理塘地区二叠纪洋岛型岩石组合的识别及其构造意义: 来自岩石学、地球化学和年代学证据[J]. 地质学报, 2019b, 93(2): 381-393. https://www.cnki.com.cn/Article/CJFDTOTAL-DZXE201902007.htm 严松涛, 段阳海, 谭昌海, 等. 甘孜-理塘蛇绿混杂岩带中三叠世洋岛型岩石组合的识别及其构造意义——来自岩石学、地球化学和年代学证据[J]. 地球学报, 2019c, 40(6): 816-826. https://www.cnki.com.cn/Article/CJFDTOTAL-DQXB201906005.htm 严松涛, 吴青松, 李虎, 等. 甘孜-理塘蛇绿混杂岩带中段理塘地区混杂岩物质组成及其洋盆演化史[J]. 中国地质, 2021, 48(6): 1875-1895. https://www.cnki.com.cn/Article/CJFDTOTAL-DIZI202106015.htm 杨文强, 冯庆来, 刘桂春. 滇西北甘孜-理塘构造带放射虫地层、硅质岩地球化学及其构造古地理意义[J]. 地质学报, 2010, 84(1): 78-89. https://www.cnki.com.cn/Article/CJFDTOTAL-DZXE201001004.htm 杨高学, 李永军, 佟丽莉, 等. 准噶尔盆地周缘蛇绿混杂岩中洋岛玄武岩的识别: 地幔柱的产物?[J]. 地质论评, 2015, 61(5): 1021-1031. https://www.cnki.com.cn/Article/CJFDTOTAL-DZLP201505006.htm 张能德, 曹亚文, 廖远安, 等. 四川甘孜-理塘裂谷带地质与成矿[M]. 北京: 地质出版社, 1998: 1-119. 张世涛, 冯庆来, 王义昭. 甘孜-理塘构造带泥盆系的深水沉积[J]. 地质科技情报, 2000a, 19(3): 17-20. https://www.cnki.com.cn/Article/CJFDTOTAL-DZKQ200003003.htm 张世涛, 冯庆来. 中甸地区三叠系的沉积混杂作用[J]. 云南地质, 2000b, 19(1): 1-7. https://www.cnki.com.cn/Article/CJFDTOTAL-YNZD200001000.htm 周斌, 闫全人, 邓莉, 等. 四川木里混杂带海山玄武岩辉石斑晶中的熔体包裹体: 甘孜-理塘古特提斯洋内热点与洋中脊相互作用的记录[J]. 岩石学报, 2020, 36(3): 925-947. https://www.cnki.com.cn/Article/CJFDTOTAL-YSXB202003017.htm 朱永峰, 徐新, 魏少妮, 等. 西准時尔克拉玛依OIB型枕状玄武岩地球化学及其地质意义研究[J]. 岩石学报, 2007, 23(7): 1739-1748. 朱弟成, 莫宣学, 王立全, 等. 新特提斯演化的热点与洋脊相互作用: 西藏南部晚侏罗世-早白垩世岩浆作用推论[J]. 岩石学报, 2008, 24(2): 225-237. https://www.cnki.com.cn/Article/CJFDTOTAL-YSXB200802006.htm
计量
- 文章访问数: 675
- HTML全文浏览量: 355
- PDF下载量: 185
