“燕山运动”的分期及几个关键问题

The Phasing of Yanshan Movement and Its Several Important Questions

翁文灏最初定义的"燕山运动"主要根据《北京西山地质志》所提供的信息,当时并未对"燕山运动"分期。在赴辽西北票地区考察后,翁文灏将"燕山运动"分为A、B两期,A期为绪动,B期为主要期。详细的文献研读发现,翁文灏对"燕山运动"在北京西山和辽西的原始定义有出入。经对比分析,本文认为在北京西山一带代表"燕山运动"的主不整合面应在上窑坡组煤系地层与龙门组砾岩之间,在辽西一带应为北票组煤系地层与海房沟组砾岩之间。另外,本文认为"燕山运动"的A期(绪动)可能与中国东部北东向区域性大断裂发生同时。最为重要的是,本文认为A期"燕山运动"形成于极短的时间,如同时间坐标上的一个点,这个点构成了B期的边界点。

The Yanshan Movement was originally defined by Weng Wenhao. This was based on the book of “Geology of Western Hills of Peking”. In fact, there was no phasing for the Yanshan movement in that time. After the field geological investigation of Western Liaoning province, Weng Wenhao divided the Yanshan Movement into two phases, named Phase A and B. While, Phase A is the period of triggering, Phase B is the main stage. However, after the detailed literature studies, we found the inconsistency of the original definition of the Yanshan movement between Western hills of Beijing and West Liaoning province. Using comparative analysis, this paper considers that the unconformity of the Yanshan movement should be between the Yaopo coal bearing strata and the Longmen conglomerate in western hills. As well as, in the western Liaoning province, it should be between the Beipiao coal bearing strata and the Haifanggou conglomerate. In addition, this paper considers that the period A may be related to the regional major faults showing the NE extension in Chinese continent. It is most important that this paper considers the Phase A of Yanshan Movement is a very short period. Maybe, it is a starting point which constitutes the boundary point of the Phase B.