| 南极普里兹造山带性质及构造变形过程 |
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| 关键词:east Antarctica Prydz tectonic belt Pan-Africa tectonic event Grove mountains |
| 基金项目:南极普里兹带1∶50万地质图编制(编号:1212010511505); 南极埃默里冰架—格罗夫山综合地质调查与研究项目(编号:1212010711509); 国家科技基础条件平台建设项目(编号:2005DKA21406) |
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| Advances in the Study of the Orogeny and Structural Deformation of Prydz Tectonic Belt in East Antarctica |
| Antarctica is one of the oldest continents in Earth and is an important part of the Gondwana super-continent.Since the first Chinese Research Expedition team set foot on the Antarctica,geologists from the Chinese Academy of Geological Sciences(CAGS) have kept working on this continent.Up till now,there have been 33 CAGS geologists landed to Antarctica,and two of them have studied the Grove mountain area and made tremendous achievements.Traditionally,east Antarctica has been regarded as an Archean core complex surrounded with the Proterozoic mobile belts,which were formed during the Late Proterozoic Grenville events.At the beginning of the 1990's,some geologists discovered the late Neoproterozoic?early Paleozoic Pan-Africa events(about 500 Ma) in different areas of the Grenville belt within east Antarctica.Of these Pan-Africa events,the one discovered in Prydz Bay has been proved by some Chinese geologists to extend to the Grove mountain area of inner Antarctica.Therefore,whether there exists a Pan-Africa tectonic belt dividing the east Antarctic continent into two parts in east Antarctica is a challenge to the traditional east Antarctica continental model.There have long existed serious controversies concerning the nature of the Prydz belt.Recently,the discussion has been focused on whether the Prydz belt is an intra-continent deformation belt or a continent collision belt.The character of the Prydz belt is the key to understand the reformation of east Antarctica and the Gondwana continent.The research conducted by the authors has confirmed the continental collision character of the Prydz belt.In the course of implementing the projects of "1:500000 Geological Mapping of the Prydz Belt in Antarctica" and "Comprehensive Investigation and Research of Emery Ice Shelf-Grove Mountains,Antarctica" in 2007,remarkably progresses were achieved in the study of the Prydz belt.The new progresses are as follows: ①The first middle scale mapping(1:500000)in Prydz,Antarctica,was completed.The map serves as a foundational base for the research on the Prydz belt and the reformation of the Gondwana continent.②High pressure metamorphic granulite rocks were first found in the Grove area.Based on the striped components of garnets and the composition of clinopyroxene,the peak metamorphic condition should be P=12.9～15.8 kb and T=810～910°C,whereas the degrading metamorphic condition is P=7.6～10.3 kb and T=700～760°C.The metamorphism has the feature of a clockwise P-T path.The SHRIMP zircon age for the high pressure granulites is 545～542 Ma.These data serve as the important continental collision evidence for the Prydz belt.③The ITD+IBC path determined by the Pan-Africa metamorphism and granitoids in the Prydz belt is another petrological indicator of continental collision.④The tectonic framework,deformation sequences,and tectonic evolutional process were constructed based on the research on structural analysis.⑤There is a large low angle ductile zone in the Grove Mountains,whose age is around 530 to 480 Ma.⑥The NE-NEE trending valley-ridge topography of the Grove Mountains is a product of the Lambert rift during late Mesozoic and Cenozoic. |
| HU Jian-min,LIU Xiao-chun,ZHAO Yue,XU Gang,LIU Ren-dong.2008.Advances in the Study of the Orogeny and Structural Deformation of Prydz Tectonic Belt in East Antarctica[J].Acta Geoscientica Sinica,29(3):343-354. |
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