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对珠江三角洲西江河口附近PRD05孔(113°11′02″E,22°31′24″N)的岩性和介形类的高分辨率分析表明,受海平面变化和河流作用的影响,研究区晚第四纪经历了多次环境变化。26600aBP以前为河流环境,底部为河道沙砾沉积,随后水动力条件减弱,发育河漫滩沉积。26600—13400aBP前期发育泛滥平原相沉积,后期受末次冰期的影响,本区暴露地表遭受风化剥蚀,泛滥平原相沉积的上部风化成杂色黏土。珠江口地区冰后期海侵应开始于约13400aBP。13400—9000aBP为海侵初期,本区形成沼泽相沉积。9000—4850aBP为全新世大海侵时期,本区为持续的河口海湾环境,发育以海相—半咸水型为主的介形类动物群,发生了3次小规模的海平面波动,导致水体条件发生变化,从而影响了介形类动物群的组成和丰度。最大海侵发生于7500—7140aBP之间,PRD05孔主要介形类属种的丰度在这一阶段达到全新世最大值。4850aBP以来为持续海退期,河流作用增强,本区逐渐转变为上三角洲平原环境。
High-resolution analysis of the lithology and the ostracod of PRD05 (113 ° 11’02 “E, 22 ° 31’24” N) near the Xijiang River estuary in the Pearl River Delta shows that, subject to changes in sea level and the effects of rivers, Late Quaternary experienced many environmental changes. 26600aBP was formerly a riverside environment, with the bottom of the riverway gravel deposits, followed by weakened hydrodynamic conditions and the development of floodplain deposits. 26600-13400aBP Early stage of development of floodplain facies deposition, the latter part of the last glacial period affected by exposure to surface weathering and erosion in this area, floodplain facies upper weathered into variegated clay. The late icy sea transgression in the Pearl River Estuary should begin at about 13400 a BP. 13400-9000aBP is the initial stage of transgression, and the swamp facies formed in this area. During the Holocene transgression period, the region 9000-4850aBP developed into a continuous estuarine environment with the development of marine-brackish water-dominated ostracods. Three small-scale sea level fluctuations occurred, causing the water bodies Changes in conditions affect the composition and abundance of the ostracods. The maximum transgression occurred between 7500-7140 aBP. The abundance of major ostracods in PRD05 reached the maximum Holocene at this stage. Since 4850aBP, the sea level has been continuously deepened and the role of the river has been strengthened. The area has gradually transformed into the plains of the upper reaches of the delta.