Reconstruction of Early Paleozoic arc-trench system: a case study in the eastern Gondwana margin

早古生代弧沟系统的重建——以冈瓦纳大陆边缘东部为例

• 批准号: 10041102
• 负责人: WATANABE Teruo
• 金额: $ 7.23万
• 依托单位: HOKKAIDO UNIVERSITY
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (A).
• 财政年份: 1998
• 资助国家: 日本
• 起止时间: 1998 至 1999
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-10041102/
• 关键词: Gondwana; Rodinia; eclogite; Serpentinite melange; Australia; arc-trench system; Gondwana; Rodinia; U-Pb SHRIMP年代; Sm-Nd年代; Ar-Ar法; 古生代前期; 蛇紋岩メランジ帯; 原生代後期-古生代初期; 島弧; ニューイングランド褶曲帯; MORB,SHRIMP年代

The target of our research is to reconstruct the Early Paleozoic arc-trench system along the eastern margin of Gondwanaland. However, the chronological results on Attunga eclogite and host gabbro in the serpentinite melange yield a range from 660Ma to 460Ma zircon U-Pb SHRIMP gaes with 660Ma, thus the time span for rearch has been expanded to Neoproterozoic. Tectonics of Neoproterozoic along the later Gondwana eastern margin include those of breakup process of the Rodinia supercontinient . We obtain the following results1) We propose a model of the Phillipne type for Early Paleozoic Gondwana margin.2) In Latest Neoproterozoic, a subduction zone was produced. Simultneously, a rifting and opening of an ocean in the Kanmantoo Fold Belt occurred in the Eastern Gondwana part.3) Serpentinite melange includes various kinds or igneous and metamorphic rocks. Their ages range from Neoproterozoic to Early Mesozoic.4) During the Rodinia breakup, petrochemical evidence of mantle plume activity is obatained.After the breakup, arc systems were formed firstly in SW Siberia and then Australia.

我们的研究目标是恢复冈瓦纳大陆东缘沿着早古生代的弧沟体系。然而，蛇纹岩混杂岩中的Attunga榴辉岩和寄主辉长岩的年代学结果显示，锆石U-Pb SHRIMP年龄范围为660 Ma至460 Ma，为660 Ma，因此研究的时间跨度扩大到新元古代。冈瓦纳古陆东缘新元古代沿着的构造包括Rodinia超大陆裂解过程的构造。我们得到以下结果：1）提出了早古生代冈瓦纳大陆边缘的Phillipne型模式。2）新元古代晚期，形成了俯冲带。同时，冈瓦纳东部发生了坎曼图褶皱带的一次裂陷和大洋开启。3）蛇纹岩混杂岩包括多种火成岩和变质岩。4）Rodinia裂解过程中，获得了地幔柱活动的岩石化学证据，裂解后首先在西伯利亚西南部形成了岛弧体系，然后在澳大利亚形成了岛弧体系。