现代珠江三角洲地区QZK4孔第四纪沉积年代

摘要

With a changeable geological environment, there exist several viewpoints on the chronology of Quaternary sediments in the modern Pearl River Delta region. Based on AMS 14C and optically stimulated luminescence (OSL) dating in conjunction with sea level records from the South China Sea, the authors have found that the age of the oldest Quaternary sediments at the bottom of drill hole QZK4 is about 43.71ka BP, which is located at the center of the Pearl River Delta region. The Quaternary environment record-ed is responding well to the sea level changes reconstructed from the South China Sea in the drill core: the fluvial deposits and the weathered layers were formed during a low stand of the sea level from the last glacial period to the early Holocene, and the estuarine-coastal sediments were deposited following the high stand of sea level since the early to middle Holocene. It is inferred that the bot-tom of Quaternary sediments in the modern Pearl River Delta region is probably older than the record from this drill hole according to the environmental analysis.%在地质环境变迁迅速的现代珠江三角洲地区，对于第四纪沉积的年代存在多种认识。结合南中国海的海平面变化记录，通过AMS 14C和光释光测年发现，珠江三角洲腹地QZK4孔第四纪岩心底部最老年龄约为43.71ka BP。岩心记录的第四纪环境对南中国海海平面变化有着良好的响应：岩心下部陆相河流沉积和暴露风化层发育于末次冰期至早全新世的低海平面时期，上部滨海-河口湾沉积发育于早中全新世以来的高海平面时期。根据钻孔岩心的环境分析，推测现代珠江三角洲地区第四纪的底界可能较本钻孔记录的更老。