Acta Scientiarum Naturalium Universitatis Pekinensis

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Significance of Paleostructure and Paleogeography of Ordovician-Silurian Rock Associations in Northern Xinjiang, China

HE Guoqi, LI Maosong   

  1. Department of Geology, Peking University, Beijing, 100871
  • Received:2000-06-14 Online:2001-01-20 Published:2001-01-20



  1. 北京大学地质学系,北京,100871

Abstract: Traditional tectonic ideas are that the orogenic belts in the northern Xinjiang were formed mainly in the late Paleozoic. However, new data show that there is almost continuous early Paleozoic orogenic belt surrounding the Junggar Basin. The facts will change the traditional idea which only emphasizes the late Paleozoic orogenesis. According to the new data, authors reconstructed the early Paleozoic geologic evolution of the Northern Xinjiang. The Junggar and adjacent old lands began to breakup in the Sinian period. The ancient ocean between those old lands came up to the biggest size at early Ordovician. The inferential Junggar old land often situated below sea level in the period of cracking and spreading of the old land. The ancient ocean of the Northern Xinjiang began to shrink and the old continental margin became active margin in the late Ordovician. Then, convergence, collision and orogenesis were took place among the Junggar, Yili and Siberia old lands. The late Ordovician and early middle Silurian forearc or back arc foreland basins might develop on the side of earn Junggar old land of the early Paleozoic orogenic belts.

Key words: northern Xinjiang, Ordovician-Silurian system, rock association, paleostructure, paleogeography

摘要: 近年的研究结果表明,在准噶尔盆地周边地区存在有几乎连续分布的早古生代造山带,这个事实有可能改变历来只强调北疆晚古生代造山作用的传统认识。震旦纪是准噶尔及其相邻古陆裂解的开始阶段,经寒武纪至早奥陶世,古洋已发展到最大规模。在区域性古陆裂解和伸展的背景下,推测准噶尔古陆经常位于海平面以下。晚奥陶世北疆的古洋开始收缩,古陆缘区转化成活动陆缘,准噶尔古陆先后与伊犁古陆和西伯利亚古陆汇聚和碰撞造山,在这两条早古生代造山带的近准噶尔古陆一侧,可能发育晚奥陶世至早、中志留世的弧前或弧后盆地和前陆拗陷。

关键词: 新疆北部, 奥陶-志留系, 岩石组合, 古构造, 古地理

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