福建沿岸晚第四纪地层的混合现象

The mixing phenomena of sediment in the Late Quaternary strata along the Fujian coast

本文根据福建省海岸带和海涂资源以及台湾海峡西部海域等综合调查资料进行研究,报道了福建沿岸晚第四纪地层存在着新老沉积物的混合现象。混合层分布在易受老碳玷污的闵江等河流入海区附近,存在于0.6～1.0m深的沉积物中,发生在10ka以近的时间里。这是由于冰后期气候、构造条件发生大变异,使老地层裸露、风化、剥蚀,其沉积物搬运后,在水动力条件适宜的海区与年轻沉积物发生混合沉积.在使用这些混合层的测年资料时应当加以研究,当沉积物与沉积层具有同时性时,沉积物年代可以代表沉积层年代;如果两者不具同时性,应当通过对比和必要的校正后方能做为地层划分的重要依据。

The paper proposes the existence of the mixing phenomena of the old and young sediments in the Late Quaternary strata along the Fujian coast by use of comprehensive survey data (?)f Fujian coastal zone and western Taiwan Strait. The mixed layer is located around the area easily affected by old carbon where the Minjiang River and other rivers input the sea. It is found in the sediment of 0. 6～1. 0m deep dated since 10~4 a old. This strongly proves the fact that the old strata are exposed, then weathered, eroded, transported and mixed with the young sediment in the sea area under the suitable hydrodynamical condition owing to the great change of the climate and structure conditions in the postglacial period.In order to make use of the dating results of mixed layers, it is necessary to analyze the representation of sediment. The chronology of sediment could represent sediment layer only when both are formed simultaneously, and if both are formed in different times, it is on the contrary and the necessary correction must be used for the strata division.