Sedimentary facies and environment of the Pearl River Delta (Zhujiang-River, South China Sea)
Final Report Abstract
The interrelation of the depositional environment and the sedimentary facies of the Pearl River Estuary (PRE), South China Sea, has been investigated. The current system is described by numerical model data for the wet and the dry season. Measured data from samples have been used for the parameterisation of the facies of the uppermost sediments. These data were obtained by a sampling campaign carried out in the frame of this project as well as from local data basis. The following main results have been achieved. • The basic granulometrlcal and physical sediment parameters (e.g. grain size median and sorting, water content) as well as geochemical parameters (e.g. Hg, Cd, As, SiO2, TIC, Corg) of the samples have been determined and their spatial distributions have been mapped using geostatistical methods. • Multivariate geostatistics applied to geochemical and sedimentary data have been used for sediment facies classification. • Three main sub-areas within the PRE have been discriminated based on Regionalised Classification. Here, marine influenced regions can be clearly separated from those determined by the geological catchment area and the ones depending on river discharge. • The anthropogenic impact has been evaluated by maps of selected standardised geochemical parameters. Locations close to HuMen reflect the highest anthropogenic influence. • Based on a comparison of the critical shear velocity derived from sedimentary parameters and shear velocity obtained by the modelled data, erosion frequency, erosion direction, and erosion risk have been determined for selected current scenarios. • Numerical experiments with different grain sizes have lead to maps of erosion risks as a function of granulometry. These maps can be used by decision makers to select dumping sites for dredged sediments. • Through a combination of new measurements with published data the accumulation rates of sediments within the PRE have been mapped. • From concentration maps of geochemical parameters together with sediment accumulation rates annual rates of deposition for selected chemical elements have been derived. • Taking into account future scenarios of coast line change based on land claim planning the depositional capacity of the PRE will be reduced anthropogenically by 3.8x10^6 t/year.
Publications
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2004. A method to correlate granulometrical sediment parameters and hydrographical data. Die Küste: 68: 165-186
Heise, B., Bobertz, B., Harff, J., Ren, J. and Liang, K.
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2010. Classification of the Pearl River Estuary via Principal Component Analysis and Regionalisation. Journal of Coastal Research, 26(4): 769-779
Heise, B., Bobertz, B. and Harff, J.
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2010. Patterns of potential sediment erosion in the Pearl River Estuary. Journal of Marine Systems, 82(Supplement 1):S62-S82
Heise, B., Harff, J., Ren, J. and Liang, K.
