西藏中冈底斯扎布耶茶卡北部晚侏罗世则弄群火山岩的锆石U-Pb年代学及其成因意义
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摘要
冈底斯带晚中生代构造演化模式一直存在争议。此次研究了中冈底斯带扎布耶茶卡北部区域则弄群火山岩的野外特征和锆石U-Pb年龄。锆石U-Pb定年结果表明,扎布耶茶卡北部则弄群火山岩主要喷发于154.2~142.1 Ma。研究首次获得晚侏罗世的则弄群火山岩年龄为154 Ma,比前人提出的则弄群火山岩浆活动起始时间(130 Ma)提前了24 Ma,据此将则弄群的时代定为晚侏罗世至早白垩世。根据研究获得的最新年代学数据,结合冈底斯带火山岩的前人研究资料,显示冈底斯带中生代弧火山岩具有从南向北逐渐年轻的趋势。因此,最早期南冈底斯弧中生代火山岩可能与新特提斯洋板片北向俯冲有关,晚侏罗世至早白垩世的中冈底斯带弧火山岩受到了新特提斯洋板片北向俯冲和班公湖-怒江洋板片南向俯冲的双重影响,早白垩世中期的北冈底斯带弧火山岩则与班公湖-怒江洋板片的南向俯冲密切相关。研究成果为冈底斯带晚中生代构造演化模式提供了火山岩方面的新证据。
The Late Mesozoic tectonic evolution models of the Gangdese belt in Tibet remain controversial. We present here the fieldobservations and zircon U-Pb ages of the volcanic rocks from the Zabuyechaka in the Mid-Gangdese belt. Zircon U-Pb dating resultssuggest that the volcanic rocks of the Zenong Group were formed during 154.2-142.1 Ma. This study first obtain the Late Jurassic agesof the Zenong Group(154 Ma), which is approximately 24 m.y. older than previously published data. The data from this study, andcombined with previously published data on Mesozoic volcanic rocks in the whole Gangdese belt show obviously northward youngertrends. It suggests that the Early Jurassic arc volcanic rocks in the south Gangdese belt were associated with the subduction of theNeo-Tethys oceanic plate, and the Middle-Early Cretaceous arc volcanic rocks in the north Gangdese belt were related to thesubduction of the Bangonghu-Nujiang oceanic plate, and the Late Jurassic to Early Cretaceous arc volcanic rocks in the middleGangdese belt were jointly affected by the northward subduction of the Neo-Tethys and the southward subduction of theBangonghu-Nujiang oceanic plates. This study provides new evidence for the Late Mesozoic tectonic evolution of the Gangdese belt.
The Late Mesozoic tectonic evolution models of the Gangdese belt in Tibet remain controversial. We present here the fieldobservations and zircon U-Pb ages of the volcanic rocks from the Zabuyechaka in the Mid-Gangdese belt. Zircon U-Pb dating resultssuggest that the volcanic rocks of the Zenong Group were formed during 154.2-142.1 Ma. This study first obtain the Late Jurassic agesof the Zenong Group(154 Ma), which is approximately 24 m.y. older than previously published data. The data from this study, andcombined with previously published data on Mesozoic volcanic rocks in the whole Gangdese belt show obviously northward youngertrends. It suggests that the Early Jurassic arc volcanic rocks in the south Gangdese belt were associated with the subduction of theNeo-Tethys oceanic plate, and the Middle-Early Cretaceous arc volcanic rocks in the north Gangdese belt were related to thesubduction of the Bangonghu-Nujiang oceanic plate, and the Late Jurassic to Early Cretaceous arc volcanic rocks in the middleGangdese belt were jointly affected by the northward subduction of the Neo-Tethys and the southward subduction of theBangonghu-Nujiang oceanic plates. This study provides new evidence for the Late Mesozoic tectonic evolution of the Gangdese belt.
引文
莫宣学,董国臣,赵志丹,等.2005.西藏冈底斯带花岗岩的时空分布特征及地壳生长演化信息[J].高校地质学报,11(3):281-290.
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刘伟,李奋其,袁四化,等.2010.西藏措勤地区则弄群火山岩源区-地球化学及Sr-Nd同位素制约[J].岩石矿物学杂志,(4):367-376.
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康志强,许继峰,董彦辉,等.2008.拉萨地块中北部白垩纪则弄群火山岩:Slainajap洋南向俯冲的产物[J].岩石学报,(2):303-314.
黄丰,许继峰,陈建林,等.2015.早侏罗世叶巴组与桑日群火山岩:特提斯洋俯冲过程中的陆缘弧与洋内弧[J].岩石学报,31(7)2089-2100.
张志平,董瀚,吴勇,等.2016.西藏改则县错果错地区则弄群火山岩岩石地球化学特征及其构造意义[J].甘肃地质,(4):22-29.
周华,邱检生,喻思斌,等.2016.西藏措勤地区火山岩的年代学与地球化学及其对岩石成因的制约[J].地质学报,90(11):3173-3191.
朱弟成,潘桂棠,王立全,等.2008a.西藏冈底斯带侏罗纪岩浆作用的时空分布及构造环境[J].地质通报,27(4):458-468.
朱弟成,莫宣学,赵志丹,等.2008b.西藏冈底斯带措勤地区则弄群火山岩锆石U-Pb年代学格架及构造意义[J].岩石学报,(3):401-412.
朱弟成,潘桂棠,莫宣学,等.2006.冈底斯中北部晚侏罗世-早白垩世地球动力学环境:火山岩约束[J].岩石学报,22(3):16-28.
Black L P and Gulson B L.1978.The age of the Mud Tank carbonatite,Stran gways Range,Northern Territory[J].BMR Journal of Australian Geology and Geophysics,3:227-232.
Coulon C,Maluski H,Bollinger C,et al.1986.Mesozoic and Cenozoic volcanic rocks from central and southern Tibet:39Ar-40Ar dating petrological characteristics and geodynamical significance[J].Earth and Planetary Science Letters,79(3):281-302.
Guo L,Liu Y,Liu S,et al.2013.Petrogenesis of early to middle Jurassic granitoid rocks from the Gangdese belt,southern Tibet:Implications for early history of the Neo-Tethys[J].Lithos,179(5):320-333.
Griffin W L,Belousova E A,Shee S R,et al.2004.Archean crustal evolution in the northern Yilgarn Craton:U-Pb and Hf-isotope evidence from detr ital zircons[J].Precambrian Res.,131,231-282.
Hoskin P W O and Black L P.2000.Metamorphic zircon formation by solid-state recrystallization of protolith igneous zircon[J].Journal of Metamorphic Geology,18(4):423-439.
Jackson S E,Pearson N J,Griffin W L,et al.2004.The application of laser ablation-inductively coupled plasma-mass spectrometry to in situ U-Pb zircon geochronology[J].Chemical Geology,211(1):47-69.
Kang Z Q,Xu J F,Wilde S A,et al.2014.Geochronology and geochemistry of the Sangri Group volcanic rocks,Southern Lhasa Terrane:Implications for the early subduction history of the Neo-Tethys and Gangdese magmatic arc[J].Lithos,200-201:157-168.
Kapp P,Murphy M A,Yin A,et al.2003.Mesozoic and Cenozoic tectonic evolution of the Shiquanhe area of western Tibet[J].Tectonics,22(4):253-253.
Ludwig K R.2003.Isoplot/Ex Version 3.00:A Geochronological Toolkit for Microsoft Excel[M].Berkeley:Berkeley Geochronology Center Special Publications:1-73.
Murphy M A,Yin A,Harrison T M,et al.1997.Did the Indo-Asian collision alone create the Tibetan Plateau[J].Geology,25(8):719-722.
Zhang K J,Zhang Y X,Tang X C,et al.2012.Late Mesozoic tectonic evolution and growth of the tibetan plateau prior to the indo-asian collision[J].Earth-Science Reviews,114(3-4),236-249.
Zhu D C,Zhao Z D,Niu Y L,et al.2011.The Lhasa terrane:record of a microcontinent and its histories of drift and growth[J].Earth and Planetary Science Letters,301(1-2):241-255.
Zhu D C,Li S M,Cawood P A,et al.2016.Assembly of the Lhasa and qiangtang terranes in central tibet by divergent double subduction[J].Lithos,245:7-17.
(1)谢国刚,邹爱建,袁建芽,等.2003.邦多区幅区域地质调查报告(1:25万).
刘珂辛,张勇强,雷波.2014.西藏则弄群火山岩特征及其俯冲极性判断[J].矿床地质,(S1):111-112.
刘伟,李奋其,袁四化,等.2010.西藏措勤地区则弄群火山岩源区-地球化学及Sr-Nd同位素制约[J].岩石矿物学杂志,(4):367-376.
潘桂棠,莫宣学,侯增谦,等.2006.冈底斯造山带的时空结构及演化[J].岩石学报,22(3):521-533.
彭智敏,耿全如,张璋,等.2011.西藏那曲地区流纹岩LA-ICP-MS锆石U-Pb年龄和地球化学特征[J].地质通报,30(7):1050-1059.
康志强,许继峰,王保弟,等.2009.拉萨地块北部白垩纪多尼组火山岩的地球化学:形成的构造环境[J].地球科学-中国地质大学学报,34(1):93-108.
康志强,许继峰,董彦辉,等.2008.拉萨地块中北部白垩纪则弄群火山岩:Slainajap洋南向俯冲的产物[J].岩石学报,(2):303-314.
黄丰,许继峰,陈建林,等.2015.早侏罗世叶巴组与桑日群火山岩:特提斯洋俯冲过程中的陆缘弧与洋内弧[J].岩石学报,31(7)2089-2100.
张志平,董瀚,吴勇,等.2016.西藏改则县错果错地区则弄群火山岩岩石地球化学特征及其构造意义[J].甘肃地质,(4):22-29.
周华,邱检生,喻思斌,等.2016.西藏措勤地区火山岩的年代学与地球化学及其对岩石成因的制约[J].地质学报,90(11):3173-3191.
朱弟成,潘桂棠,王立全,等.2008a.西藏冈底斯带侏罗纪岩浆作用的时空分布及构造环境[J].地质通报,27(4):458-468.
朱弟成,莫宣学,赵志丹,等.2008b.西藏冈底斯带措勤地区则弄群火山岩锆石U-Pb年代学格架及构造意义[J].岩石学报,(3):401-412.
朱弟成,潘桂棠,莫宣学,等.2006.冈底斯中北部晚侏罗世-早白垩世地球动力学环境:火山岩约束[J].岩石学报,22(3):16-28.
Black L P and Gulson B L.1978.The age of the Mud Tank carbonatite,Stran gways Range,Northern Territory[J].BMR Journal of Australian Geology and Geophysics,3:227-232.
Coulon C,Maluski H,Bollinger C,et al.1986.Mesozoic and Cenozoic volcanic rocks from central and southern Tibet:39Ar-40Ar dating petrological characteristics and geodynamical significance[J].Earth and Planetary Science Letters,79(3):281-302.
Guo L,Liu Y,Liu S,et al.2013.Petrogenesis of early to middle Jurassic granitoid rocks from the Gangdese belt,southern Tibet:Implications for early history of the Neo-Tethys[J].Lithos,179(5):320-333.
Griffin W L,Belousova E A,Shee S R,et al.2004.Archean crustal evolution in the northern Yilgarn Craton:U-Pb and Hf-isotope evidence from detr ital zircons[J].Precambrian Res.,131,231-282.
Hoskin P W O and Black L P.2000.Metamorphic zircon formation by solid-state recrystallization of protolith igneous zircon[J].Journal of Metamorphic Geology,18(4):423-439.
Jackson S E,Pearson N J,Griffin W L,et al.2004.The application of laser ablation-inductively coupled plasma-mass spectrometry to in situ U-Pb zircon geochronology[J].Chemical Geology,211(1):47-69.
Kang Z Q,Xu J F,Wilde S A,et al.2014.Geochronology and geochemistry of the Sangri Group volcanic rocks,Southern Lhasa Terrane:Implications for the early subduction history of the Neo-Tethys and Gangdese magmatic arc[J].Lithos,200-201:157-168.
Kapp P,Murphy M A,Yin A,et al.2003.Mesozoic and Cenozoic tectonic evolution of the Shiquanhe area of western Tibet[J].Tectonics,22(4):253-253.
Ludwig K R.2003.Isoplot/Ex Version 3.00:A Geochronological Toolkit for Microsoft Excel[M].Berkeley:Berkeley Geochronology Center Special Publications:1-73.
Murphy M A,Yin A,Harrison T M,et al.1997.Did the Indo-Asian collision alone create the Tibetan Plateau[J].Geology,25(8):719-722.
Zhang K J,Zhang Y X,Tang X C,et al.2012.Late Mesozoic tectonic evolution and growth of the tibetan plateau prior to the indo-asian collision[J].Earth-Science Reviews,114(3-4),236-249.
Zhu D C,Zhao Z D,Niu Y L,et al.2011.The Lhasa terrane:record of a microcontinent and its histories of drift and growth[J].Earth and Planetary Science Letters,301(1-2):241-255.
Zhu D C,Li S M,Cawood P A,et al.2016.Assembly of the Lhasa and qiangtang terranes in central tibet by divergent double subduction[J].Lithos,245:7-17.
(1)谢国刚,邹爱建,袁建芽,等.2003.邦多区幅区域地质调查报告(1:25万).