EGU2020-6486
https://doi.org/10.5194/egusphere-egu2020-6486
EGU General Assembly 2020
© Author(s) 2020. This work is distributed under
the Creative Commons Attribution 4.0 License.

Early and late Holocene paleoenvironmental reconstruction of the Pearl River estuary, South China Sea

Huixian Chen1,2, Jianhua Wang1, Nicole S. Khan3, Jiaxue Wu4, and Benjamin P. Horton2,3
Huixian Chen et al.
  • 1Nanyang Technological University, Earth Observatory of Singapore, Singapore (huixian.chen@ntu.edu.sg)
  • 2Earth Observatory of Singapore, Nanyang Technological University, Singapore.
  • 3Asian School of the Environment, Nanyang Technological University, Singapore.
  • 4School of Marine Science, Sun Yat-Sen University, Guangzhou, China.

Proxy reconstructions of estuarine evolution provide perspectives on regional to global environmental changes, including relative sea-level changes, climatic changes, and agricultural developments. Although there are studies of the Holocene sedimentary processes in the Pearl River estuary, the understanding of early Holocene sedimentation in unknown due to limited preservation.

Here, we present a new record of lithological, benthic foraminiferal, and geochemical (δ13C and C/N) change from a sediment core in the west shoal of the modern Lingding Bay along a paleo-valley. The lithologic and foraminiferal record reveal the transgressive evolution from fluvial, inner estuary to middle estuary in the early Holocene between 11300 and 8100 cal a BP in response to rapid sea-level rise. δ13C and C/N data indicate high freshwater discharge from 10500 to 8100 cal a BP driven by a strong Asian monsoon. The middle Holocene (8100 - 3300 cal a BP) sediment is absent in this core and others in the northward of the Lingding Bay. Seismic profiles reveal a tidal ravinement surface across Lingding Bay, which contributed to subaqueous erosion on the mid-Holocene sedimentation hiatus, might be resulted from unique geomorphology of the Pearl River Delta. In the late Holocene (3300 cal a BP to the present), the lithology and foraminiferal assemblages suggest further regressive evolution from outer estuary, middle estuary channel, to middle estuary shoal due to deltaic progradation under stable relative sea levels. In the last 2000 years, δ13C and C/N values reveal the intensive development of agriculture coupled with the reduction of freshwater input derived from a weakening Asian monsoon. Our study illustrates the interaction of Asian monsoon and sea-level changes within the Pearl River estuary landform and their impact on Holocene sedimentary processes.

How to cite: Chen, H., Wang, J., Khan, N. S., Wu, J., and Horton, B. P.: Early and late Holocene paleoenvironmental reconstruction of the Pearl River estuary, South China Sea, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-6486, https://doi.org/10.5194/egusphere-egu2020-6486, 2020

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