Magnetic properties of surficial sediments and distribution of authengenic iron sulfide in modern tidal flat at Yangtze estuary
Gao Xiaoqin1 Wang Zhanghua2 Li Lin1 Wu Xuxu1
1 Department of Geography，East China Normal University，Shanghai 200062 2 State Key Laboratory for Estuarine and Coastal Research，East China Normal University，Shanghai 200062
Abstract：The present paper measured grain size and magnetic parameters to examine magnetic properties and the distributions of magnetic minerals，especially the authengenic greigite(Fe3S4)along the tidal flat sections from the northern coast of Chongming island，Yangtze estuary.The results revealed that ferromagnetic minerals and superparamagnetic(SP)minerals are predominant in the surficial sediments.Single-domain(SD)and superparamagnetic(SP)grains prevail in the sediments of high to middle tidal flat from progradational coast.By contrast，the major magnetic feature of middle and lower tidal flat sediments from the regradational coast is dominated by pseudo-single domain/multi-domain(PSD/MD)grains，reflecting the hydrodynamic sorting and dissolution of fine-grained magnetite during the early diagenesis.Moreover，authengenic greigite occurs generally in the reed zone of supra and high tidal flat of Beisiyaogang section which is located easternmost，while it also exists locally in the high tidal flat of Beipugang and Xinwei sections，reflecting that organic matter and fine-grained sedments can generate greigite with the limited inundation time of sea water in the study area．
Gao Xiaoqin,Wang Zhanghua,Li Lin et al. Magnetic properties of surficial sediments and distribution of authengenic iron sulfide in modern tidal flat at Yangtze estuary[J]. JOPC, 2012, 14(5): 673-684.
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