Zircon U-Pb isotopic geochronology of Tongao schist in Taiwan and its geological significance
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摘要:
台湾东澳片岩位于台湾东部，属太鲁阁带的北东部分，由绿泥绿帘片岩、绿泥钠长片岩、云母石英片岩、石英片岩夹含石墨云母片岩组成。在野外地质调查的基础上，结合岩石学、岩石主微量元素分析研究结果表明，原岩为玄武岩、副长岩或碱性玄武岩及陆源碎屑岩，岩石主要为碱性系列，具低Ba、Sr和高Pb，稀土总量普遍较低，具有轻稀土富集、铕无亏损的稀土分布模式，与陆源裂陷的火山(岩浆)-沉积作用特征类似；锆石可分为自形晶或尖棱角状、次棱角状及圆状三类；LA-ICP-MS锆石U-Pb年龄具多个峰值，其中206Pb/238U有4个，最小值为(95±3)Ma，为自形晶或尖棱角状锆石，代表了晚白垩世火山作用的时代；其余3个分别为(118±2)Ma(早白垩世)、(160±5)Ma(晚侏罗世)、(250±3)Ma(早三叠世)，为次棱角状和少量自形晶锆石，代表了相应时代源岩的岩浆年龄；207Pb/206Pb表面年龄峰值2个，分别为(1838±41)Ma和(2404±27)Ma(古元古代)，为磨圆状的变质锆石或岩浆锆石，代表了古元古代变质基底的年龄。东澳片岩形成时代为晚白垩世，属欧亚陆块边缘构造环境下火山-沉积作用的产物。
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关键词:
- 台湾东澳片岩 /
- 火山岩 /
- LA-ICP MS锆石定年 /
- 晚白垩世 /
- 大陆边缘裂陷
Abstract:Located in the eastern part of Taiwan, the Tongao schist belongs to the northeast part of Tailuko belt and is composed of chlorite epidote schist, chlorite albite schist, mica quartz schist, quartz schist, and mica schist intercalated with graphite mica schist layer. Based on geological survey in combination with petrologic as well as major and trace element analysis, the authors hold that the original rocks were basalt, foidite or alkaline basalts and terrigenous clastic rocks. The rocks are mainly of alkaline series characterized by low Ba, high Sr and Pb, generally low total rare earth, and REE distribution patterns with features of LREE enrichment and no loss of europium. These features are similar to features of terrigenous rifting (magmatic) volcano-sedimentary rock combination. Zircons can be divided into three types, i.e., euhedral or sharply angular, subangular, and rounded ones. LAICP-MS U-Pb zircon ages have multiple peaks, in which there are four 206Pb/238U ratios; the minimum value is (95 ±3)Ma, representing euhedral zircons or sharply angular zircons and indicating late Cretaceous volcanic activity; the remaining three values are 118±2 Ma (Early Cretaceous), 160±5 Ma (Late Jurassic), and (250±3) Ma, Early Triassic), representing subangular and small euhedral zircons and indicating the magma age of corresponding source rock; there are two 207Pb/206Pb surface peak ages, i.e., 1838±41Ma and 2404±27Ma (Paleoproterozoic), representing rounded metamorphic zircons or magmatic zircon and indicating the age of Paleoproterozoic metamorphic basement. The Tongao schist was formed during the late Cretaceous in the Eurasian continental margin tectonic environment, being a product of volcanic-sedimentary activity.
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图 2 东澳片岩的TAS图解(据Le Maitre等, 1989；邓晋福等, 2015)
Figure 2.
表 1 东澳片岩全岩主量元素(%)、微量和稀土元素(10-6)分析数据
Table 1. Analytical whole-rock data for Tongao schist and major parameters (major elements: wt%, trace elements: 10-6)
下载: 导出CSV
表 2 锆石U-Th-Pb同位素分析数据和计算的年龄值
Table 2. Analytical data of zircon U-Th-Pb isotopes and calculated age values
下载: 导出CSV
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Bureau of geologicaland exploration of Fujian Province. 2015.Regional Geology of Tawan Province[M]. Beijing:Geological Publishing House (in Chinese with English abstract).
Chai B H T. 1972. Structure and tectonic ovolution of Taiwab. Tour[J]. Sciences, 272:389-422.
Chen Zaoxia. 1998. Metamorphic rocks of Taiwan[M]. Central Geological Survey, Moea (in Chinese with English abstract).
Huang Chiyue, Wu Weiyu, Chang Chungpai, Tsao S, Yuan Peter B, Lin Chingweei, Kuan Yuanxia. 1997. Tectonic evolution of accretionary prism in the arc-continent collision terrane of Taiwan[J]. Tectonophysics, 281:31-51. doi: 10.1016/S0040-1951(97)00157-1
Huang Changhuang. 2015. Fujian Dongshan late Mesozoic granite LA-ICP-MS zircon isotope dating and its geological significance[J]. Geology of Fujian, 34(4):261-271(in Chinese with English abstract). http://en.cnki.com.cn/Article_en/CJFDTotal-FJDZ201504001.htm
Huang Changhuang. 2016a. Zircon U-Pb isotopic geochronology of metamorphic rock in thr shen' ao area, Longhai, Fujian Province and its geologic significance[J]. East China Geology, 37(1):28-35(in Chinese with English abstract). https://www.sciencedirect.com/science/article/pii/S0301926816303825
Huang Changhuang. 2016b. Isotopic age of zircon of the Dongshan metamorphic rocks in Fujian Province and its geologic significance[J]. Geology in China, 43(3):738-750(in Chinese with English abstract).
Huang C Y, Jien C W, Chang C P, Peter B. 2008. The Lichi Melange:A tectonic collision complex originated form sheared forearc in Coastal Range, eastern Taiwan[J]. Bulletin of the Geological Society of America, 436:127-154.
Liu Y S, Gao S, Hu Z C, Gao C G, Zong K Q, Wang D B. 2010.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 from mantle xenoliths[J]. Journal of Petrology, 51:537-571. doi: 10.1093/petrology/egp082
Mao Jianren, Li Zilong, Ye Min. 2014. Mesozonic tectonic-magmatic activities in South China:Retrospect and prospect[J]. Science China:Earth Sciences, 57:2853-2877(in Chinese with English abstract). doi: 10.1007/s11430-014-5006-1
Shu L S, Zhou X M, Deng P. Wang B, Jiang S, Yu J H, Zhao X X. 2009. Mesozoic tectonic evolution of the southeast china block; New insights from basin analysis[J]. Journal of Asian Earth Sciences, 34:376-391. doi: 10.1016/j.jseaes.2008.06.004
Shu Liangshu, Zhou Xinmin, Deng Ping, Yu Xinqi Wang Bin, Zhu Puping. 2004. Geological features and tectonic evolution of MesoCenozoic basins in southeastern China[J]. Geological Bulletin of China, 23(9/10):876-884 (in Chinese with English abstract). http://en.cnki.com.cn/article_en/cjfdtotal-zqyd2004z2007.htm
Xu Xianbing, Zhang Yueqiaom, Jia Dong, Shu Liangshu, Wang Ruirui. 2009. Early Mesozoic geotectonic processes in South China[J]. Geology in China, 36(3):573-593 (in Chinese with English abstract). http://en.cnki.com.cn/article_en/cjfdtotal-dizi200903009.htm
Yui T F, Maki K, Lan C Y, Hirata T, Chu H T, Kon Y, Yokoyama T D, Jahn B M, Ernst W G. 2012. Detrital zircons from the Tananao metamorphic complex of Taiwan:Implications for sediment provenance and Mesozoic tectonics[J]. Tectonophysics, 541-543:31-42. doi: 10.1016/j.tecto.2012.03.013
陈肇夏. 1998. 台湾的变质岩[M]. 经济部中央地质调查所.
邓晋福, 刘翠, 冯艳芳, 肖庆辉等. 2015.关于火成岩常用图解的正确使用:讨论与建议[J]..地质论评, 61 (4):717-734. http://www.cqvip.com/QK/91067X/201504/665535688.html
冯艳芳, 邓晋福, 肖庆辉, 邢光福. 2013.长乐-南澳构造带花岗岩类年代学岩石组合与构造演化[M].北京:地质出版社.
福建省地质矿产局. 1992. 台湾省区域地质志[M]. 地质出版社.
福建省地质调查研究院. 2015. 台湾省区域地质志[M]. 地质出版社.
黄长煌. 2015.福建东山晚中生代花岗岩的LA-ICP-MS锆石同位素定年及其地质意义[J].福建地质, 34(4):261-271. http://www.cnki.com.cn/Article/CJFDTOTAL-DQKX201302010.htm
黄长煌. 2016a.福建东山变质岩LA-ICP-MS同位素年龄及其地质意义[J].中国地质, 43(3):738-750. http://geochina.cgs.gov.cn/ch/reader/view_abstract.aspx?file_no=20160304&flag=1
黄长煌. 2016b.福建龙海深澳变质岩锆石U-Pb同位素年代学及地质意义[J].华东地质, 37(1):28-35. http://www.cnki.com.cn/Article/CJFDTotal-DQSK201401001.htm
侯可军, 李延河, 田有荣.2009. LA-MC-ICP-MS锆石微区原位UPb定年技术[J].矿床地质, 28(4):481-492. http://mall.cnki.net/magazine/Article/KCDZ200904009.htm
李松茂, 曾维军. 1987.台湾地质与板块构造模式[J].海洋地质与第四纪地质, 7(4):29-37.
林启文, 高铭建. 2009. 1: 5万台湾地质图说明书. 苏澳幅, 第二版[M]. 经济部中央地质调查所.
毛建仁, 厉子龙, 叶敏. 2014.华南中生代构造-岩浆活动研究:现状与前景[J].中国科学:地球科学, , 44(12):2593-2617. http://www.cnki.com.cn/Article/CJFDTOTAL-JDXK201412001.htm
舒良树, 周新民, 邓平, 余心起, 王彬, 祖辅平. 2004.中国东南部中、新生代盆地特征与构造演化[J].地质通报, 23 (9-10):876-884. http://d.old.wanfangdata.com.cn/Periodical/zgqydz200409008
徐先兵, 张岳桥, 贾东, 舒良树, 王瑞瑞. 2009.华南早中生代大地构造过程[J].中国地质, 36(3):573-593. http://geochina.cgs.gov.cn/ch/reader/view_abstract.aspx?file_no=20090307&flag=1
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