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首页 > 中国极地考察知识库 > 成果信息库 > 已审查 罗迪尼亚-冈瓦纳古陆演化中的东南极陆块

罗迪尼亚-冈瓦纳古陆演化中的东南极陆块

【标题】罗迪尼亚-冈瓦纳古陆演化中的东南极陆块

【Title】The East Antarctic Block in the Tectonic Evolution of the Rodinia -Gondwana Super Continents

【作者】 刘小汉; 赵越; 仝来喜; 任留东; 刘晓春; 俞良军

【Author】 Liu Xiaohan ; Zhao Yue ; Tong Laixi ; Ren Liudong ; Liu Xiaochun ; Yu Liangjun

【期刊】世界科技研究与发展

【Journal】World Sci-tech R & D

【期刊年份】2002

【卷】24

【期】4

【关键词】 东南极地盾; 格罗夫山; 泛非期构造事件; 冈瓦纳古陆; 拼合

【Keywords】 East Antarctic Shield ,Grove Mountains , Pan -African orogen ,Gondwana Land , assemblage

【摘要】冈瓦纳古陆的研究已经有百年历史, 而东南极又成为冈瓦纳研究的热点地区之一。在东南极拉斯曼丘陵地质考察与构造热年代学研究的基础上, 中国科学家成为国际上最早一批阐明冈瓦纳古陆, 特别是东冈瓦纳陆块形成于5 亿年前的“泛非” 期构造运动的科学家。通过南极内陆格罗夫山地质调查, 查明格罗夫山主要出露高角闪岩相—麻粒岩相深变质岩, 岩石化学特征显示紫苏花岗岩、花岗质片麻岩和花岗岩属铝质A 型深成岩系列, 而长英质和镁铁质麻粒岩则来自岛弧、洋岛和洋中脊环境的表壳岩系列。测区以低角度面理构造为主, 局部出现强剪切变形带。韧性变形可分为3 个阶段:D1 与前泛非期的构造事件有关,D2 相应于区域性麻粒岩相变质作,D3 则可能反映泛非期造山作用后期的伸展作用。变质反应结构多显示为简单的区域性麻粒岩相变质作用, 但镁铁质麻粒岩可鉴别出3 个阶段:M1 的温压条件为800 ℃, 9 .3 ×105Pa ;M2 为800 -810 ℃, 6 .4 ×105Pa ;M3 仅650 ℃。代表性花岗质片麻岩的锆石U Pb 的离子探针分析显示峰期变质年龄集中于529 ±14Ma , 花岗岩侵位年龄534 ±5Ma , 细晶岩脉年龄501 ±7Ma , 属于“泛非”期构造热事件。这些地质新证据显示在东南极内陆存在着一条从普里兹湾、格罗夫山到南查尔斯王子山的巨大“泛非”期造山带, 将传统认为10 亿年来始终稳定的东南极地盾一分为二。这条造山带可能向北与羌塘陆块相连, 应当是冈瓦纳拼合过程中的又一条重要缝合带。

【Abstract】It is more than a century that the research on the Gondwana Super Continent remains , in which the East Antarctica Shield is one of the “ hot point ” regions .Based on the field investigation and thermal -tectonic 极地研究   24 卷 4期 3 5   chronological analyses ,Chinese scientists have proposed , as first range in the world that the Gondwana Land , especially the East Gondwana Continent has been formed in the Pan -African aged orogen(~ 500 my).After the geological survery in the Grove Mountains , it is clear that the Grove Mts .consist mainly of a series of high - grade(upper amphibolite to granulite facies)metamorphic rocks .Geochemical analysis demonstrates that the charnockite , granitic gneiss and granite were belong to aluminous A type plutonic rocks , thus the felsic and mafic granulite were from supracrustal as island arc , oceanic island and middle oceanic ridge basalt .A few high - strained shear zones disperse in regional stable sub -horizontal foliated metamorphic rocks .Three generations of ductile deformation were identified , in which the D1 is related to the event before Pan -African age , D2 corresponds to the regional granulite peak metamorphism , whereas D3 reflects ductile extension in late Pan -African orogenic period .The metamorphic reactions from granitic gneiss indicate a single granutite facies event , but 3 steps were disinterred from mafic granulite , with P -T condition of M1 800 ℃, 9.3 ×105Pa ;M2800 ±810 ℃, 6.4 ×105 Pa ;and M3 650 ℃.The U -Pb age data from representative granitic gneiss indicate(529 ±14)Ma of peak metamorphism , and (534 ±5)Ma of granite emplacement , and (510 ±7)of post -tectonic granodioritic veins .All these evidences suggest a huge Pan -African aged mobile belt inside of East Antarctica Shield extending from Prydz Bay via Grove Mountains to the southern Prince Charles Mountains , bisecting the East Antarctic Craton which was thought stable since 1000 Ma .This orogenic belt could link with the Tibet Block(Qiang Tang Plateau)in north , being another major suture during the Gondwana Land assemblage .

【基金/项目】 1998、1999 年度专项野外考察项目

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