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滇西云县地区中二叠世火山岩的发现及其对昌宁-孟连古特提斯洋俯冲作用的约束

  • 刘军平1,2,3

    机 构：

    1. 云南省地质调查院,云南昆明, 650216

    2. 中国地质大学地球科学与资源学院,北京, 100083

    3. 自然资源部三江成矿作用及资源勘查利用重点实验室,云南昆明, 650051

    ×
  • ，宛胜4

    机 构：

    4. 江西省地质调查院,江西南昌, 330000

    ×
  • ，田素梅1

    机 构：

    1. 云南省地质调查院,云南昆明, 650216

    ×
  • ，王伟1

    机 构：

    1. 云南省地质调查院,云南昆明, 650216

    ×
  • ，包佳凤1

    机 构：

    1. 云南省地质调查院,云南昆明, 650216

    ×

1. 云南省地质调查院,云南昆明, 650216；
2. 中国地质大学地球科学与资源学院,北京, 100083；
3. 自然资源部三江成矿作用及资源勘查利用重点实验室,云南昆明, 650051；
4. 江西省地质调查院,江西南昌, 330000；

Discovery of the Middle Permian volcanic rocks in the Yunxian area, western Yunnan and constraints on subduction of the Changning-Menglian Paleo-Tethys Ocean

  • LIU Junping1,2,3

    Affiliation：

    1. Yunnan Institute of Geological Survey, Kunming, Yunnan 650216 , China

    2. School of Earth Science and Resources, China University of Geosciences, Beijing 100083 , China

    3. Key Laboratory of Sanjiang Metallogeny and Resources Exploration and Utilization, MNR, Kunming,Yunnan 650051 , China

    ×
  • ，WAN Sheng4

    Affiliation：

    4. Geological Survey of Jiangxi Province, Nanchang, Jiangxi 330000 , China

    ×
  • ，TIAN Sumei1

    Affiliation：

    1. Yunnan Institute of Geological Survey, Kunming, Yunnan 650216 , China

    ×
  • ，WANG Wei1

    Affiliation：

    1. Yunnan Institute of Geological Survey, Kunming, Yunnan 650216 , China

    ×
  • ，BAO Jiafeng1

    Affiliation：

    1. Yunnan Institute of Geological Survey, Kunming, Yunnan 650216 , China

    ×

1. Yunnan Institute of Geological Survey, Kunming, Yunnan 650216 , China；
2. School of Earth Science and Resources, China University of Geosciences, Beijing 100083 , China；
3. Key Laboratory of Sanjiang Metallogeny and Resources Exploration and Utilization, MNR, Kunming,Yunnan 650051 , China；
4. Geological Survey of Jiangxi Province, Nanchang, Jiangxi 330000 , China；

作者简介:

刘军平,男,1983年生。高级工程师,从事区域地质与构造地质调查研究。E-mail:271090834@qq.com。

通讯作者:

宛胜,男,1985年生。工程师,从事区域地质与矿产地质调查研究。E-mail:214879248@qq.com。

DOI:10.19762/j.cnki.dizhixuebao.2022257

参考文献
Atherton M P, Sanderson L M. 1985. The chemical variation and evolution of the super-units of thesegmented Coastal Batholith. In: Pitcher W S, Atherton M P, Cobbing E J, Beckinsale R D, eds. Magmatism at a Plate Edge: The Peruvian Andes. Glasgow: Blackie Halsted Press, 208~227.
查找原文
参考文献
Atherton M P, Petford N. 1993. Generation of sodium-rich magmas from newly underplated basaltic crust. Nature, 36(2): 144~146.
查找原文
参考文献
Carkey T L, Miller C F, Wooden J L, Padilla A J, Schmitt A K, Economos R C, Bindeman I L, Jorfaan B T. 2014. Iceland is not a magmatic analog for the Hadean: evidence from the zircon record. Earth and Planetary Science Letters, 405: 85~97.
查找原文
参考文献
Drummond M S, Defant M J. 1990. A model for trondhjemite-tonalitedacite genesis and crustal growth via slab melting: Archean to modern comparisons. Journal of Geophysical Research, 95 (B13): 21503~21521.
查找原文
参考文献
Fan Weiming, Peng Touping, Wang Yuejun. 2009. Triassic magmatism in the southern Lancangjiang zone, southwestern China and its constraints on the tectonic evolution of Paleo-Tethys. Earth Science Frontiers, 16(6): 291~302 (in Chinese with English abstract).
查找原文
参考文献
Han Wenwen, Peng Zhimin, Zhang Ji, Guan Junlei, Hu Jingfeng, Liu Yunhe. 2020. U-Pb dating of zircon, Hf isotope composition and tectonic significance of the albite-leptite of the Lancang Group in the Shuangjiang area of western Yunnan, China. Acta Geologica Sinica, 94(4): 1282~1294 (in Chinese with English abstract).
查找原文
参考文献
Kong Huilei, Dong Guochen, Mo Xuanxue, Zhao Zhidan, Zhu Dicheng, Wang Shuo, Li Rong, Wang Qiaolin. 2012. Petrogenesis of Lincang granites in Sanjiang area of western Yunnan Province: constraints from geochemistry, zircon U-Pb geochronology and Hf isotope. Acta Petrologica Sinica, 28(5): 1438~1452 (in Chinese with English abstract).
查找原文
参考文献
Li Shuguang. 1993. Ba-Nb-Th-La Diagrams used to identify tectonic environments of ophiolite. Acta Petrologica Sinica, 9(2): 146~157 (in Chinese with English abstract).
查找原文
参考文献
Liu Junping, Tian Sumei, Cong Feng, Sun Baidong, Huang Xiaoming, Xu Yunfei. 2017. The Shale granites from the southern part of the Lancang River, western Yunnan: zircon U-Pb age, geochemistry and geological implications. Sedimentary Geology and Tethyan Geology, 37(4): 59~70 (in Chinese with English abstract).
查找原文
参考文献
Liu Junping, Hu Shaobin, Li Jing, Sun Baidong, Sun Zaibo, Wang Wei, Guan Xueqing, Xu Guixiang. 2018. U-Pb age of zircon from metamorphic rocks of the Tuanliangzi Formation in western Yunnan Province and its tectonic significance. Geological Bulletin of China, 37(11): 2079~2086 (in Chinese with English abstract).
查找原文
参考文献
Liu Junping, Hu Shaobin, Tian Sumei, Lu Xiaoping, Sun Baidong, Yu Saiying, Zhu Xunzao, Sun Peng, Wang Xiaofeng. 2019. U-Pb ages of zircon from metamorphic dolomite of the Wuliangshan Rock Group in Nanjian area, western Yunnan, and its tectonic significance. Geological Bulletin of China, 38(8): 1327~1334 (in Chinese with English abstract).
查找原文
参考文献
Liu Junping, Yang Aiping, Wang Xiaohu, Luo Guangming, Tian Sumei, Zhu Xunzao, Yin Wei, Zhang Kun. 2020. Zircon U-Pb age, geochemistry characteristics and arc-continent subduction to collision of the Xiaowan granite in Fengqing area, western Yunnan Province. Geology in China, http: //kns. cnki. net/kcms/detail/11. 1167. p. 20200601. 1613. 012. html.
查找原文
参考文献
Liu Benpei, Feng Qinglai, Fang Nianqiao, Jia Jinhua, He Yanxiang. 1993. Tectonic evolution of Paleo-Tethys poly-island-ocean in Changning-Menglian and Lancangjiang belts, Southwestern Yunnan. China. Earth Science, 18(5): 529~538 (in Chinese with English abstract).
查找原文
参考文献
Liu Benpei, Feng Qinglai, Chonglakmani C, Helmcke D. 2002. Frame work of Paleotethyan Archipelago Ocean of western Yunnan and its elongation towards North and South. Earth Science Frontiers, 9(3): 161~171 (in Chinese with English abstract).
查找原文
参考文献
Ludwig K R. 2003. ISOPLOT 3. 00: A Geochronological toolkit for Microsoft excel. Berkeley Geochronology Center Special Publicantion,
查找原文
参考文献
Lü Liuyan, LI Jing, Zeng Wentao, Yu Saiying, Sun Zaibo, Wang Xiaofeng. 2019. The discovery of Early Jurassic volcanic rocks along the Southern Lancangjiang tectonic magmatic belt in southwest Yunnan, with a discussion on the upper limit of Indosinian tectonic cycles in Yunnan Province. Geology in China, 46(6): 1270~1283 (in Chinese with English abstract).
查找原文
参考文献
Luo Liang, Wang Dongbing, Chu Daoliang, Wang Yu, Luo Bo. 2018. The definition of the age of Manghuai Formation based on the study of palaontology and zircon U-Pb chronology in western Yunnan Province. Geology in China, 45(6): 1312~1313 (in Chinese with English abstract).
查找原文
参考文献
Mao Xiaochang, Wang Liquan, Li Bing, Wang Baodi, Wang Dongbing, Yin Fuguang, Sun Zhiming. 2012. Discovery of the Late Silurianvolcanic rocks in the Dazhonghe area Yunxian-Jinghong volcanic arc belt, western Yunnan, China and its geological significance. Acta Petrologica Sinica, 28(5): 1517~1528 (in Chinese with English abstract).
查找原文
参考文献
Middlemost E A K. 1994. Naming materials in the magma/igneous rock system. Earth-Science Reviews, 37: 215~224.
查找原文
参考文献
Mo Xuanxue, Lu Fengxiang, Shen Shangyue, Zhu Qinwen, Hou Zengqian, Yang Kaihui, Deng Jinfu, Liu Xiangpin, He Changxiang. 1993. Tethys Volcanism and Mineralization in the Sanjiang Area. Beijing: Geological Publishing House, 1~77 (in Chinese).
查找原文
参考文献
Nie Xiaomei, Feng Qinglai, Metcalfe Ian, Baxter Alan T, Liu Guichun. 2016. Discovery of a Late Devonianmagmatic arc in the southern Lancangjiang zone, western Yunnan: geochemical and zircon U-Pb geochronological constraintson the evolution of Tethyan ocean basins in SW China. Journal of Asian Earth Sciences, 118: 32~50.
查找原文
参考文献
Pan Guitang, Xu Qiang, Hou Zengqian, Wang Liquan, Du Dexun, Mo Xuanxue, Li Dingmou, Wang Mingjie, Li Xingzhen, Jiang Xinsheng, Hu Yunzhong. 2003. Arckipelagic Orogenesis Metallogenic Systems and Assessment of the Mineral Resources along the Sanjiang Area in Southwestern China. Beijing: Geological Publishing House, 1~420 (in Chinese).
查找原文
参考文献
Peccerillo A, Taylor S R. 1976. Geochemistry of Eocene calc-alkaline volcanic rocks from the Kastamonu area, northern Turkey. Contributions to Mineralogy and Petrology, 58(1): 63~81.
查找原文
参考文献
Peng Touping, Wang Yuejun, Zhao Guochun, Fan Weiming, Peng Bingxia. 2008. Arc-like volcanic rocks from the southern Lancangjiang zone, SW China: geochronological and geochemical constraints on their petrogenesis and tectonic implications. Lithos, 102(1~2): 358~373.
查找原文
参考文献
Peng Zhimin, Fu Yuzhen, Wang Guozhi, Guan Junlei, Geng Quanru, Hu Jinfeng, Liu Yunhe, Zhang Zhang. 2020. The results of geochronological, geochemical and Sr-Nd-Hf isotopic investigations on amphibolites in the Qingpingregion, Changning-Menglian suture zone. Acta Geologica Sinica, 94(2): 511~526 (in Chinese with English abstract).
查找原文
参考文献
Sun S S, McDonough W F. 1989. Chemical and isotopic systematics of oceanic basalts: implications for mantle composition and processes. Geological Society Special Publication, 42: 313~345.
查找原文
参考文献
Sun Zaibo, Lü Xiaoping, Yu Saiying, Liu Junping, Tian Sumei, Li Xugui. 2015. Zircon U-Pb ages and petro-geochemical characteristics of Manxiu diorite pluton, Jinghong City, Yunnan Province, China. Acta Mineralogica Sinica, 35(4): 473~480 (in Chinese with English abstract).
查找原文
参考文献
Sun Zaibo, Hu Shaobin, Zhou Kun, Zhao Feng, Li Xiaojun, Bao Jiafeng, Zhang Xiaofan, She Zhongming. 2020. Petrogenesis and tectonic implications of Manbing granitoids, southern Lancangjiang zone: constraints by geochemistry, zircon U-Pb chronology and Hf isotope. Acta Petrologica Sinica, 36(5): 1389~1408 (in Chinese with English abstract).
查找原文
参考文献
Wang Baodi, Wang Liquan, Wang Dongbing, Yin Fuguang, He Juan, Peng Zhimin, Yan Guochuan. 2018. Tectonic evolution of the Changning-Menglian Proto-Paleo Tethys Ocean in the Sanjiang area, southwestern China. Earth Science, 43(8): 2527~2550 (in Chinese with English abstract).
查找原文
参考文献
Wang Dongbing, Yin Fuguang, Luo Liang, Tang Yuan, Liao Shiyong, Sun Jie, Ren Fei. 2015. U-Pb dating of detrital zircons from the Damenglong group in the Niujinshan area ofChangning-Menglian tectonic belt and itd geological significance. J. Mineral. Petrol. , 35(3): 72~80 (in Chinese with English abstract).
查找原文
参考文献
Wang Dongbing, Luo Liang, Tang Yuan, Yin Fuguang, Wang Baodi, Wang Liquan. 2016. Zircon U-Pbdating and petrogenesis of Early Paleozoic adakites from the Niujingshan ophiolitic mélange in the Changning-Menglian suture zone and its geological implications. Acta Petrologica Sinica, 32(8): 2317~2329 (in Chinese with English abstract).
查找原文
参考文献
Wang Fang, Liu Fulai, Ji Lei, Liu Lishuang. 2017. LA-ICP-MS U-Pb dating of detrital zircon from low-grade metamorphic rocks of the Lancang Group in the Lancangjiang complex and its tectonic implications. Acta Petrologica Sinica, 33(9): 2975~2985 (in Chinese with English abstract).
查找原文
参考文献
Wang Yuejun, Zhang Aimei, Fan Weiming, Peng Touping, Zhang Feifei, Zhang Yanhua, Bi Xiawu. 2010. Petrogenesis of late Triassic post-collisional basaltic rocks of the Lancangjiang tectonic zone, southwest China, and tectonic implications for the evolution of the eastern Paleotethys: geochronological and geochemical constraints. Lithos, 120: 529~46.
查找原文
参考文献
Wei Junqi, Wang Xiaodi, Zhuang Xiao, Liu Yunhua. 2008. Zircon SHRIMP U-Pb dating of diorite among Jicha serpentine and Eza grabbro from Lancangjiang belt, Yunnan Province and its geological significance. Acta Petrologica Sinica, 24(6): 1297~1301 (in Chinese with English abstract).
查找原文
参考文献
Wu Yuanbao, Zheng Yongfei. 2004. Study on the mineralogy of zircon and its constraints on the interpretation of U-Pb age. Chinese Science Bulletin, 49(16): 1589~1604 (in Chinese).
查找原文
参考文献
Yu Saiying, Li Kunqiong, Shi Yuping, Zhang Huihua. 2003. Astudy on the granodiorite in the middle part of Lincang granite batholith. Yunnan Geology, 22(4): 426~442 (in Chinese with English abstract).
查找原文
参考文献
范蔚茗, 彭头平, 王岳军. 2009. 滇西古特提斯俯冲-碰撞过程的岩浆作用记录. 地学前缘, 16(6) : 291~302.
查找原文
参考文献
韩文文, 彭智敏, 张辑, 关俊雷, 胡金锋, 刘云鹤. 2020. 滇西澜沧岩群钠长浅粒岩锆石U-Pb测年、Hf同位素组成及构造意义. 地质学报, 94(4): 1282~1294.
查找原文
参考文献
孔会磊, 董国臣, 莫宣学, 赵志丹, 朱弟成, 王硕, 李荣, 王乔林. 2012. 滇西三江地区临沧花岗岩的岩石成因: 地球化学、锆石U-Pb年代学及Hf同位素约束. 岩石学报, 28(5): 1438~1452.
查找原文
参考文献
李曙光. 1993. 蛇绿岩生成构造环境的Ba-Th-Nb-La 判别图. 岩石学报, 9(2): 146~157.
查找原文
参考文献
刘军平, 田素梅, 丛峰, 孙柏东, 黄晓明, 徐云飞. 2017. 滇西澜沧江南段沙乐花岗岩的锆石U-Pb年龄、地球化学特征及其地质意义. 沉积与特提斯地质, 37(4): 59~70.
查找原文
参考文献
刘军平, 胡绍斌, 李静, 孙柏东, 孙载波, 王伟, 关学卿, 徐桂香. 2018. 滇西云县地区团梁子岩组变质岩锆石U-Pb定年及其构造意义. 地质通报, 37(11): 2079~2086.
查找原文
参考文献
刘军平, 胡绍斌, 田素梅, 卢晓萍, 孙柏东, 俞赛赢, 朱勋早, 孙鹏, 王晓峰. 2019. 滇西南涧地区无量山岩群变质英安岩锆石U-Pb年龄及其构造意义. 地质通报, 38(8): 1327~1334.
查找原文
参考文献
刘军平, 杨爱平, 王小虎, 罗光明, 田素梅, 朱勋早, 殷伟, 张坤. 2020. 滇西凤庆地区小湾花岗岩年代学、地球化学特征及其弧-陆俯冲向碰撞汇聚作用. 中国地质, https: //kns. cnki. net/kcms/detail/11. 1167. p. 20200825. 1426. 002. html.
查找原文
参考文献
刘本培, 冯庆来, Chonglakmani C, Helmcke D. 2002. 滇西古特提斯多岛洋的结构及其南北延伸. 地学前缘, 9(3): 161~171.
查找原文
参考文献
刘本培, 冯庆来, 方念乔, 贾进华, 何馥香. 1993. 滇西南昌宁—孟连带和澜沧江带古特提斯多岛洋构造演化. 地球科学, 18(5): 529~538.
查找原文
参考文献
吕留彦, 李静, 曾文涛, 俞赛赢, 孙载波, 王晓峰. 2019. 滇西南南澜沧江构造岩浆岩带早侏罗世火山岩的发现——兼论云南省境内印支构造旋回的上限. 中国地质, 46(6): 1270~1283.
查找原文
参考文献
罗亮, 王冬兵, 楚道亮, 王宇, 罗波. 2018. 滇西南忙怀组时代的限定: 基于叶肢介化石和锆石U-Pb年龄. 中国地质, 45(6): 1312~1313.
查找原文
参考文献
毛晓长, 王立全, 李冰, 王保弟, 王冬兵, 尹福光, 孙志明. 2012. 云县-景谷火山弧带大中河晚志留世火山岩的发现及其地质意义. 岩石学报, 28(5): 1517~1528.
查找原文
参考文献
莫宣学, 路凤香, 沈上越, 朱勤文, 侯增谦, 杨开辉, 邓晋福, 刘祥品, 何昌祥. 1993. 三江特提斯火山作用与成矿. 北京: 地质出版社, 1~77.
查找原文
参考文献
潘桂棠, 徐强, 候增谦, 王立全, 杜德勋, 莫宣学, 李定谋, 汪名杰, 李兴振, 江新胜, 胡云中. 2003. 西南“三江”多岛弧造山过程成矿系统与资源评价. 北京: 地质出版社, 1~420.
查找原文
参考文献
彭智敏, 付于真, 王国芝, 关俊雷, 耿全如, 胡金锋, 刘云鹤, 张璋. 2020. 昌宁-孟连结合带清平地区斜长角闪岩锆石年代学及Sr-Nd-Hf同位素研究. 地质学报, 94(2): 511~526.
查找原文
参考文献
孙载波, 卢晓萍, 俞赛赢, 刘军平, 田素梅, 李序贵. 2015. 云南景洪曼秀闪长岩体锆石U-Pb 年龄与岩石地球化学特征. 矿物岩石, 35(4): 473~480.
查找原文
参考文献
孙载波, 胡绍斌, 周坤, 赵枫, 李小军, 包佳凤, 张小凡, 佘中明. 2020. 南澜沧江带曼兵岛弧花岗岩成因与构造启示: 元素地球化学、锆石U-Pb 年代学及Hf 同位素约束. 岩石学报, 36(5): 1389~1408.
查找原文
参考文献
王保弟, 王立全, 王冬兵, 尹福光, 贺娟, 彭智敏, 闫国川. 2018. 三江昌宁-孟连带原-古特提斯构造演化. 地球科学, 43(8): 2527~2550.
查找原文
参考文献
王冬兵, 尹福光, 罗亮, 唐渊, 廖世勇, 孙洁, 任飞. 2015. 昌宁-孟连构造带牛井山地区大勐龙岩群碎屑锆石U-Pb定年及其地质意义. 矿物岩石, 35(3): 72~80.
查找原文
参考文献
王冬兵, 罗亮, 唐渊, 尹福光, 王保弟, 王立全. 2016. 昌宁-孟连结合带牛井山早古生代埃达克岩锆石U-Pb年龄、岩石成因及其地质意义. 岩石学报, 32(8): 2317~2329.
查找原文
参考文献
王舫, 刘福来, 冀磊, 刘利双. 2017. 澜沧江杂岩带澜沧群浅变质岩系碎屑锆石LA-ICP-MS U-Pb年代学及其构造意义. 岩石学报, 33(9): 2975~2985.
查找原文
参考文献
魏君奇, 王晓地, 庄晓, 刘云华. 2008. 澜沧江缝合带吉岔蛇纹岩中闪长岩和俄咱辉长岩中锆石 SHRIMP U-Pb 定年及其地质意义. 岩石学报, 24(06): 1297~1301.
查找原文
参考文献
吴元保, 郑永飞. 2004. 锆石成因矿物学研究及其对U-Pb年龄解释的制约. 科学通报, 49(16): 1589~1604.
查找原文
参考文献
俞赛赢, 李昆琼, 施玉萍, 张惠华. 2003. 临沧花岗岩基中段花岗闪长岩类研究. 云南地质, 22(4): 426~442.
查找原文
目录contents

    摘要

    多年来,对滇西云县-南涧一带广泛出露的中晚三叠世火山岩的形成时代及大地构造属性一直存在争议。出露于云县漫湾地区的原划中三叠统忙怀组中新发现有厚数米的英安岩、英安质凝灰岩夹流纹岩、凝灰岩组合。本次研究采集英安岩D0001进行锆石U-Pb LA-ICP-MS定年,获得262.5±3.1Ma的岩浆结晶年龄和447.4±9.1Ma的继承性年龄,时代厘定为中二叠世晚期,而非前人认为的中三叠世。对岩石组合、同位素测年及地球化学的详细研究表明,这套火山岩属石炭-二叠系龙洞河组,为一套中酸性火山岩组合;SiO2含量68.14%~74.62%,Eu负异常,在TAS图解中全部落入英安岩-流纹岩区;微量元素蛛网图明显富集Rb、Th、Ce等大离子亲石元素,亏损Nb、Ta、Ti等高场强元素,具典型火山岛弧特征,是目前临沧岩浆弧发现的最为年轻的岛弧型酸性火山岩记录,其岩浆源区为受壳源物质混染的下地壳镁铁质岩石部分熔融;应为早中二叠世昌宁-孟连洋向东俯冲的产物。本次的发现,为西南三江地区昌宁-孟连洋向东俯冲提供有利的岩石学记录及时代约束,也为石炭-二叠系龙洞河组北延提供有利支撑,澜沧江断裂以西区域前人划分的忙怀组的分布范围和规模需要重估。

    Abstract

    For many years, there have been controversies over the formation time and tectonic attributes of the volcanic rocks of the late Triassic that are widely exposed from Yunxian to Nanjian, western Yunnan. A few meters of thick dacite, dacite tuff intercalated with rhyolite and tuff were newly discovered in the original Middle Triassic Manghuai Formation in the Manwan area of Yunxian County. In this study, the zircon U-Pb LA-ICP-MS dating was carried out on D0001 andesite, and the magmatic crystallization age of 262.5±3.1 Ma and the inherited age of 447.4±9.1 Ma were obtained. The age was determined to be late Middle Permian, not the Middle Triassic as considered by predecessors. The detailed study of rock assemblage isotopic dating and geochemistry shows that the volcanic rocks belong to the Carboniferous-Permian Longdonghe Formation and are a set of intermediate-acid volcanic rock assemblages. The content of SiO2 (68.14%~74.62%) has weak deficit in varying degrees and falls into the dacite-rhyolite area in the TAS diagram. The trace element cobwebs are obviously enriched in Rb, Th, Ce and other large ion lithophile elements and depleted in high field strength elements such as Nb, Ta, Ti, which are characterized by volcanic island arc.It is the youngest island-arc acid volcanic record within the Lincang magmatic arc. The magma source area is the partial melting of mafic rocks in the lower crust mixed with crust source materials. It should be the product of the eastward subduction of the early and middle Permian Changning-Menglian Ocean. This discovery provides favorable petrological records and chronological constraints for the eastward subduction of the Changning-Menglian Ocean in the Sanjiang area in the southwest, and also provides favorable support for the north extension of the Carboniferous-Permian Longdonghe Formation. The distribution and scale of the Manghuai Formation needs to be reassessed.

  • 滇西地处欧亚板块与印度板块的结合部位，是原/古特提斯构造域的重要组成部分，是研究特提斯构造演化的重要场所。自20世纪80年代以来，国内外学者在该区针对原/古特提斯的演化进行了大量的研究，相继报道了远洋沉积、洋岛/海山组合、蛇绿混杂岩、洋岛玄武岩、高压蓝闪石片岩、俯冲增生杂岩、榴辉岩、洋内弧火山岩、岛弧花岗岩等，均证实原/古特提斯洋在该区的存在及其主洋盆为昌宁-孟连洋盆（Mo Xuanxue et al.，1993; Liu Benpei et al.，1993，2002; Pan Guitang et al.，2003; Kong Huilei et al.，2012; Mao Xiaochang et al.，2012; Liu Junping et al.，2017，2020; Wang Baodi et al.，2018; Lü Liuyan et al.，2019; Han Wenwen et al.，2020）。而且，最新资料表明昌宁-孟连结合带所代表的特提斯洋在早古生代至晚古生代可能是一个连续演化的大洋; 铜厂街蛇绿混杂岩及湾河蛇绿混杂岩是昌宁-孟连特提斯洋消亡的残迹（Wang Baodi et al.，2018）。昌宁-孟连带以三叠纪碰撞型花岗岩和同时期的火山岩研究程度较高，而西南三江南段经历了碰撞后的伸展剥蚀作用及新生代印度-欧亚大陆碰撞作用，导致与古特提斯洋俯冲型相关的岩浆活动及沉积记录难以保存，目前仅昌宁-孟连洋南段大勐龙地区曼兵一带有二叠纪俯冲型花岗岩报道（Peng Zhimin et al.，2020; Sun Zaibo et al.，2020）。而昌宁-孟连洋中段云县-南涧一带向东俯冲典型的二叠纪弧火山岩目前均无报道，仅有三叠纪碰撞型花岗岩及无量山岩群志留纪弧火山岩报道（Liu Junping et al.，2019）; 由此在昌宁-孟连洋中段寻找二叠纪弧火山岩成为目前研究的方向，对古特提洋俯冲南北岩浆活动贯穿及重塑其构造演化极为重要。

  • 本次在野外调查和岩石学观察基础上，选取原划中三叠统忙怀组新发现的英安岩为研究对象，利用LA-ICP-MS对岩石中的锆石进行精确U-Pb定年，结合英安岩锆石形态特征、地球化学特征和构造演化等，为该套火山岩的时代、地层归属提供新的年代学依据，也为昌宁-孟连洋中段云县-南涧一带向东俯冲提供有利的岩石学记录及时代约束。

  • 1 区域地质背景

  • 研究区位于滇西云县公郎镇哨街乡，构造上位于羌塘-三江造山系和班公湖-双湖-怒江-昌宁-孟连对接带，地层属于华南地层大区、羌北-昌都-思茅地层区、兰坪-思茅地层分区的澜沧地层小区及漾濞地层小区❶（图1）。区域出露地层以古元古界、中元古界、中生界为主，发育大量二叠纪、三叠纪花岗岩体，少量新生代地层（图1），1∶25万凤庆幅根据岩石组合把澜沧江断裂以西云县漫湾地区施家村—大村一带的火山岩夹火山碎屑岩对比为中三叠统忙怀组（T2m），并无同位素年龄约束，其呈北西向展布，与三叠纪花岗岩呈侵入接触; 区内古元古界崇山岩群为一套角闪岩相深变质岩; 中元古界团梁子岩组为一套绿片岩相浅变质岩; 三叠纪地层为一套海陆交互相碎屑岩、碳酸盐岩沉积，侏罗系漾江组为一套碎屑岩陆相沉积; 新近系三营组为一套成熟度低的碎屑岩河湖相沉积。

  • 本次研究的样品采自澜沧江断裂带以西，层位属原划中三叠统忙怀组（T2m），地点在云县漫湾镇施家村（图1）。在漫湾施家村一带，原中三叠统忙怀组（T2m）总体呈北西向展布，东、西两侧均被三叠纪粗粒黑云二长花岗岩侵入，出露厚度120 m左右，出露面积约15 km2; 大村一带与中元古界团梁子岩组浅变质岩呈断层接触，岩性为灰绿色英安岩、英安质凝灰岩夹流纹岩、凝灰岩及凝灰质粉砂岩（图2），岩石轻微变质，露头新鲜，本次采集同位素及地球化学样品为灰绿色英安岩。