TROPICAL GEOGRAPHY ›› 2016, Vol. 36 ›› Issue (3): 364-373.doi: 10.13284/j.cnki.rddl.002849

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Holocene Paleoenvironment Reconstruction Based on Pollen Data in the Sanshui Basin, Northern Pearl River Delta

HUANG Kangyou1,HE Jiahui1a,ZONG Yongqiang2,ZHENG Zhuo1a,ZHANG Guifang1a,CAO Linglong3   

  1. (1. a. School of Earth Science and Geological Engineering;b. Guangdong Provincial Key Laboratory of Mineral Resources & Geological Processes, Sun Yet-san University,Guangzhou 510275,China;2. Department of Earth Sciences,The University of Hong Kong,Hong Kong,China; 3. South China Sea Marine Engineering and Environment Institute,SOA,Guangzhou 510300,China)
  • Online:2016-05-05 Published:2016-05-05

Abstract: Sanshui basin is located on the convergence of Xijiang and Beijiang Rivers of the northern Pearl River delta, where the sediment recorded the sea level changes during Holocene. Based on 12 AMS 14C dating results, pollen and diatom analyses were used to reconstruct paleoenvironment and seal level change during early Holocene. The results showed that because of the rapid sea-level rise Sanshui basin was inundated and the onset of rapid deltaic accumulation was at ~9 000 cal. a B.P. and 3 000 cal. a B.P. respectively. The environment varied as an evolution process of fluvial - river bay - estuarine - tidal-flat - estuarine- alluvial flat facieses. The sediment rate was at 1.6 cm/a in early Holocene, the sediment was mainly composed of fine silt. The marine transgression occurred at ~8 700 cal. a B.P., and reached the highest sea level stand at ~7 600 cal. a B.P. The mangrove forest was distributed around the seacoast, but the regional vegetations were characterized by subtropical evergreen forest which was dominated by Castanopsis and Quercus-evergreen type. The sediment consisted of silty peat at mid- and late Holocene (6 500-2 200 cal. a B.P.), with the sediment rate of 0.2-0.5 cm/a. The mangrove forest disappeared and the swamp developed, which was composed of Cyperaceae, Poaceae and spores. Since the age of ~2 200 cal. a B.P., the sediment rate has reached the highest value (1.7 cm/a) and the delta plain expended rapidly. Pollen evidence showed that the natural forest was likely disturbed by agricultural development during the late Holocene.

Key words: Holocene, the Pearl River Delta, pollen assemblage, Paleoenvironment change