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根据福建九龙江河口ZK1孔及ZK7孔沉积物AMS(Accelerator Mass Spectrometry,加速器质谱测年技术)14C测年、古地磁和剖面特征分析,进行该地区的第四纪地层划分,依据粒度特征,结合磁化率、微体古生物和Sr/Ba等环境代用指标进行沉积相分析,重建了该区晚第四纪的古环境演变历史。结果表明:(1)九龙江河口第四纪沉积时代为晚更新世中期至全新世晚期。(2)上更新统沉积可划分为下部龙海组洪冲积相和上部东山组河漫滩相沉积,中间有10 ka的沉积间断,末次冰期又再遭受风化剥蚀作用,推测有5~6 ka的风化剥蚀期。(3)全新统最早沉积年代约为14 ka BP,依次出现河口湾相、河口砂坝—分汊河道相、潮滩相沉积。(4)根据年代学数据和沉积相变化,重塑了该区晚第四纪沉积环境变化过程,为该区的第四纪研究和工程地质工作提供了参考依据。
The Quaternary stratigraphic division of the area was carried out based on the 14C dating, paleomagnetic and profile features of AMS (Accelerator Mass Spectrometry) dating from ZK1 hole in Jiulong River Estuary and ZK7 hole in Fujian Province. According to the characteristics of grain size, Based on the analysis of sedimentary facies, such as susceptibility, microfacs paleontology and Sr / Ba, the paleoenvironmental evolution of the Late Quaternary was reconstructed. The results show that: (1) the Quaternary sedimentary age of the Jiulongjiang estuary is from the mid-late Pleistocene to the late Holocene. (2) The Upper Pleistocene sediments can be divided into the Lower Permian flood alluvial facies and the upper Dongshan Cretaceous floodplain facies, with a sedimentary interval of 10 ka in the middle and the weathering and denudation in the last glaciation again, suggesting a weathering of 5-6 ka Denudation period. (3) The earliest sedimentary age of the Holocene was about 14 ka BP, followed by the estuarine facies, the estuarine sand dam-sub-fluvial facies, and the tidal flat facies deposition. (4) Based on the chronological data and sedimentary facies changes, the process of sedimentary environment change in the late Quaternary was reshaped, which provided reference for Quaternary research and engineering geological work in this area.