珠江口北岸SX97孔7 ka B.P.以来的矿物分析

MINERAL ANALYSIS OF CORE SX97 ON THE NORTH BANK OF THE PEARL RIVER MOUTH SINCE 7000 a B.P.

珠江口北岸SX97孔的矿物分析揭示这一地区自中全新世 7kaB P 以来气候环境演化可以分为 5个阶段 ,第 1、第 3和第 5阶段对应高海面、气候湿热时期 ,而第 2和第 4阶段对应低海面气候相对偏干偏凉的时期。这些与海岸沙丘、海滩岩和海相沉积地层的资料能比较好地对应。矿物之间的相关关系揭示珠江口 7kaB P 以来的物质沉积受到气候环境变化 -河口响应系统的控制。第 1、第 3和第 5阶段的高海面湿热时期沉积物较细 ,沉降的各类粘土矿物也较多 ,石英较少 ;而第 2和第 4阶段情况相反。珠江口北岸的沉积物中更多的可能来自东江流域。 7kaB P 以来物源区和沉积区的气候环境以湿热为主 ,但在总体湿热的背景中有一些波动。

According to the mineral analysis of core SX97 on the north bank of the Pearl River mouth,the climate and environment evolution around this area since 7000 a B P can be divided into 5 stages The 1st,the 3rd and the 5th stages were relatively hot and humid with relatively higher sea level,and the 2nd and the 4th stages were relatively cool and arid with relatively lower sea level These coincide with the development of coastal dunes,beach rocks and marine deposits The correlation between minerals,especially that between clay minerals and quartz,reveals that the deposits at the Pearl River mouth since 7000 a B P have been controlled by the river response system to climatic and environmental oscillation The deposits during the 1st,the 3rd and the 5th stages are relatively thin with less quartz and more clay minerals (such as kaolinite and illite),while those during the 2nd and the 4th stages are relatively coarse with more quartz and less clay minerals Much more deposits at the north side of the Pearl River mouth probably came from the Dongjiang River drainage The climate of both the source and the deposit area since 7000 a B P has been mainly hot and humid with some undulations