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地质力学学报:2021,27(5):768-782
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东南极Windmill群岛与罗迪尼亚超大陆聚合相关构造热事件的时代:来自Bailey半岛镁铁质片麻岩和淡色片麻岩锆石SHRIMP U-Pb年龄的约束
(1.中国地质科学院地质研究所北京离子探针中心, 北京 100037;2.西北大学地质学系大陆动力学国家实验室, 陕西 西安 710069;3.Research School of Earth Sciences, The Australian National University, Canberra, ACT 0200, Australia)
Zircon U-Pb ages of the mafic gneiss and leucogneiss from the Bailey Peninsula: Constraints on the timing of the tectonothermal events related to the amalgamation of Rodinia in the Windmill Islands, East Antarctica
(1.Beijing SHRIMP Center, Institute of Geology, Chinese Academy of Geological Sciences, Beijing 100037, China;2.State Key Laboratory of Continental Dynamics, Department of Geology, Northwest University, Xi'an 710069, Shaanxi, China;3.Research School of Earth Sciences, The Australian National University, Canberra, ACT 0200, Australia)
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投稿时间:2021-06-28    修订日期:2021-08-23
中文摘要: 东南极Windmill群岛变质杂岩经历的变质和岩浆事件与西澳大利亚Albany-Fraser造山带在时间上相对应,并可能与罗迪尼亚超大陆的拼合有关。Windmill群岛Bailey半岛的镁铁质片麻岩(角闪石-单斜辉石-斜方辉石-黑云母-斜长石-石英-磁铁矿-锆石)被认为具有较早的形成年龄,其中还出露属于正片麻岩的淡色片麻岩(斜长石-钾长石-石英-黑云母-锆石)。对这两种片麻岩中的锆石分别进行了SHRIMP U-Pb年龄测定,首次获得该区镁铁质片麻岩锆石核部207Pb/206Pb加权平均年龄1403±28 Ma,该年龄记录了本区中元古代早期岩浆事件,这是Windmill群岛地区记录的最早一期岩浆事件,可能受到了东部莫森大陆(Mawson Continent)构造岩浆活动的影响。铁镁质片麻岩锆石增生边的年龄为1318±34 Ma,则记录了早期构造热事件。淡色片麻岩中锆石核部年龄为1257±51 Ma,与Bailey半岛的片麻状含石榴子石花岗岩侵位年龄一致,共同记录了该区的一期岩浆活动。淡色片麻岩中锆石增生边的年龄为1197±26 Ma,记录了晚期的变质事件。这些新的年龄数据强烈支持1375~1151 Ma期间东南极Windmill群岛与西澳大利亚Albany-Fraser造山带相连接的构造模型,同时也为罗迪尼亚超大陆拼合过程提供了重要的年代学约束。
Abstract:We report new geochronological data of the mafic gneiss and leucogneiss from the Windmill Islands, East Antarctica, in order to unravel the tectonothermal events related to the amalgamation of Rodinia. SHRIMP zircon U-Pb dating from the mafic gneiss (Hbl-Cpx-Opx-Bt-Pl-Qtz-Mag-Zrn) yielded early Mesoproterozoic magmatic ages of 1403±28 Ma from igneous cores, and middle Mesoproterozoic metamorphic ages of 1318±34 Ma from overgrown rims. The leucogneiss (Pl-Kfs-Qtz-Bt-Zrn) in the Bailey Peninsula has intrusive ages of 1257±51 Ma from magmatic origin zircon cores, and metamorphic ages of 1197±26 Ma from overgrown rims and/or structureless grains. The intrusive age of mafic gneiss indicates the existence of a ca.1.40 Ga igneous activity in the Windmill Islands. This is likely the earliest igneous record of the Windmill Islands, possibly relating to the final period of igneous activity of the Mawson Continent. The age of high-grade metamorphism of the mafic gneiss from the Bailey Peninsula can be constrained by the metamorphic zircon overgrowth at 1318±34 Ma, suggesting that the Windmill Islands was possibly involved in the Albany-Fraser-Windmill (East Antarctic) orogeny during the 1375~1151 Ma period. This study further supports the tectonic model in which the Windmill Islands and the Albany-Fraser Orogeny are parallel convergence during the Mesoproterozoic Rodinia amalgamation.
文章编号:     中图分类号:P597.3    文献标志码:
基金项目:国家自然科学基金项目(40773042,41073014,41373052,41773049);国家海洋局极地考察办公室对外合作项目(IC201707)
引用文本:
王彦斌,王浩,任留东,等,2021.东南极Windmill群岛与罗迪尼亚超大陆聚合相关构造热事件的时代:来自Bailey半岛镁铁质片麻岩和淡色片麻岩锆石SHRIMP U-Pb年龄的约束[J].地质力学学报,27(5):768-782.DOI:10.12090/j.issn.1006-6616.2021.27.05.063
WANG Yanbin,WANG Hao,REN Liudong,et al,2021.Zircon U-Pb ages of the mafic gneiss and leucogneiss from the Bailey Peninsula: Constraints on the timing of the tectonothermal events related to the amalgamation of Rodinia in the Windmill Islands, East Antarctica[J].Journal of Geomechanics,27(5):768-782.DOI:10.12090/j.issn.1006-6616.2021.27.05.063

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