| 印支运动及其在中国大地构造演化中的意义 |
| |
| 关键词: |
| 基金项目: |
|
| 摘要点击次数: 4713 |
| 全文下载次数: 3014 |
| 摘要: |
| THE INDOSINIAN OROGENY AND ITS SIGNIFICANCE IN THE TECTONIC EVOLUTION OF CHINA |
| The Indosinian cycle refers to a tectonic stage ranging in age from the Late Permian to the beginning of Jurassic. The In dosinianorogeny took place during the late Middle Triassic to the early Early Jurassic, and it indicates the first intense compression-shear process occurring between the Pacific or and Tethyan Ocean and the Asian continent.Within the Marginal-Pacific Tectonic Domain, the Indosinian orogeny not only folded the Indosinian geosyncline along the eastern margin of the Asian mainland, but also reactivized the continental crust of Eastern China, resulting in folding and overthrusting of basements and covers accompanied by magmatism and mineralization. The Indosinian orogeny closed the North Tethys-Qinling-Songpan-Garze-Sanjiang and its southern extension (Indochina Geosynclines), giving rise to the greatest Indosinian fold system in the world. In the western section of the Central Asian-Mongolian geosyncline, only simple shearing appeared, resulting in nearly horizontal overthrusting, while in the eastern section, strong folding and thrusting, and large-scale magmatism came into being. This was the result of the overprinting of the Marginal Pacific Tectonic Domain upon the Pal-Asian Tectonic Domain.The Indosinian orogeny is of great significance in tectonic development of China and the adjacent countries. It made a final conjunction of the three different continental segments (Yangtze,Sino-Korean and Siberian) in East Asia. It is noted that between the Siberian and Sino-Korean platforms (Central Asian-Mongolian fold system), and between the Sino-Korean and Yang tze paraplatforms (Qinling fold system) occurred strong folding and over-thrusting, and as a result, the earth's crust was further imbricated and shortened. Within the Marginal-Pacific Tectonic Domain, the Indosinian tec-tonism represents the beginning of intense activity of the Bennioff zone in the west Pacific Ocean. Since then, the greater part of eastern China has become reactivized belts of continental margins of the Circum-Pacific. Within the Tethys-Himalayan Tectonic Domain, this orogeny gave rise to a gradual closing of the geosynclinal belt situated in North Tethys, while its south belt,i. e. the Bangong Lake-Nujiang belt and Tethys proper, known as the Yarlung Zangdo River, was further spread and stretched towards the west. And at last Pangea splitted up step by step. In the beginning of Jurassic, Gondwanaland was entirely separated from Laurasia by the Tethyan Ocean.From the point of view of global tectonics, the Indosinian orogeny is also of great importance. It was during the Indosinian cycle that Pangea and Pacifica began to disintegrate; E. suess' Tethys took its original shape; the Pacific tectonic belt showed intense activity. And it was the very Indosinian tectonism that determined the fundamental framework of global tectonics since Meso-Cenozoic times. Therefore, the Indosinian orogeny should be considered as a great turning point in the history of the tectonic development of the earth's crust. |
| REN Ji-shun.1984.THE INDOSINIAN OROGENY AND ITS SIGNIFICANCE IN THE TECTONIC EVOLUTION OF CHINA[J].Acta Geoscientica Sinica,6(2):31-44. |
| 查看全文 查看/发表评论 下载PDF阅读器 |
|
|
|
|
|