珠江三角洲GZ-2孔全新统孢粉特征及古环境意义

The Holocene sporopollen characteristics and their paleoenvironmental significance of Core GZ-2 in Pearl River Delta

根据珠江三角洲GZ-2孔测年结果、岩相特征和孢粉地层信息推断,该地区全新统约在6.0kaBP开始沉积,全新统孢粉组合特征与更新统相比有明显的区别,表明全新世与更新世的气候相比有明显变化。孢粉与沉积信息揭示,全新世本区气候基本以暖湿为主,气候波动不大,在5.0～2.4kaBP表现最为热湿,在2.4～1.9kaBP相对偏凉干,随后恢复暖湿。在这些相对较明显的波动中还包含有次一级的微弱波动。除了反映气候变化,孢粉信息也指示了一定的沉积环境变迁以及人类活动信息。该区在中全新世经历了一次明显的海侵过程,进入晚全新世后人类活动对三角洲植被和环境的影响加剧,期间水深逐渐变浅,沉积环境由河口湾、浅海、滨海潮滩逐渐演变为三角洲平原,区域气候的变化与海平面变化趋势基本一致。

Abstract Based on the age data, the sediment characteristics and the sporopollen stratigraphic infor- mation of the core GZ-2, Pearl River Delta, the Holocene in the region is suggested to begin from 6.0 ka BP. The characteristics of the Holocene sporopollen groups show the obvious difference from those of the Pleistocene, indicating an obvious change of climate. The sporopollen and the sediment information dem- onstrate that the paleoclimate of the Holocene is basically warm and wet, with a moderate fluctuation. The hottest and wettest period appeared around 5.0-2.4 ka BP, then the climate became re｜atively cool and arid around 2.4-1.9 ka BP, warm and wet after 1.9 ka BP, with some weaker fluctuations within these relatively long and remarkable variations. In addition to reflecting the climate change, the sporopollen in- formation indicates also certain deposition environmental changes as well as human activity. An obvious transgression process appeared in the Middle Holocene in this region, and the influence of human activity to the botanic and sedimentary environment intensified gradually after the beginning of the Late Holocene During this period, the water in Pearl River Delta area became shallower gradually, environment changed from estuary-shallow sea to seashore shoal, finally to delta plain tions in the region are essentially consistent with the sea level changes. and the sedimentary The climatic varia-