塔康运动与广西运动的地层学依据

Stratigraphic evidences on Taconican and Guangxian Orogeny

塔康运动和广西运动是分别发生在北美洲和华南志留纪之前发生的两次紧密衔接的重要构造运动。本文对塔康运动推覆构造模式作了论述，对广西运动的前缘增生楔推进模式作了新的解释，并将它和广西运动同步的华北抬升与柯坪抬升作了对比，从而把塔康运动和广西运动从地层时代对比上联系为一次全球性的构造事件。

The Taconican Orogeny in North America was one of the most important pre-Silurian tectonic movements which has been well investigated during the past one hundred years. The authors investigated the type areas of this orogeny from Quebec, Canada as well as New York state, USA during 1982 and 1995 respectively. Having compared with the Guangxian Orogeny in South China and the uplifts of the North China and Tarim platforms, the authors concluded that the connection and coincidence between the Taconican and the Guangxian, as well as the uplifts of the North China and Tarim indicate a global tectonic event during Ordovician. The graptolite Climacograptus (Diplacanthograptus)spiniferus Zone was the duration when the most dramatic Taconic thrust happened. In South China, elastic deposits which indicate a elastic wedge of the Guangxian Orogeny occur in the Nanshicong Formation from central Hunan. This formation is designed to be C. (D. ) spiniferus Zone interval since the underlying formation (D.clingani Zone) and the overlain unit (D. complexus Zone). The Guangxian elastic wedge was progressing northwestwards onto the Yangtze platform through Ashgill to early Llandovery accompanying the increasing of the Cathaysian land. Finally, the whole Yangtze platform uplifted by the end of Telychian.The North China platform uplifted during the same time interval of the C. (D. ) spiniferus Zone based on the conodont fauna from the top of the Badou Formation. However, there was a short time break between the Yingan and Kalpintage formations from the Tarim platform. The graptolite fauna of the Yingan Formation indicates also a C. (D. ) spiniferus Zone age.