Environmental magnetic characteristics and influencing factors on the west coast of Fildes Peninsula, Antarctica

The unique environmental system of the Antarctic ice-free region has been widely studied in recent decades, and environmental magnetism is doubtlessly the method most commonly used in the study. In the year of 2015, a 26 cm long core was collected by the authors from the west coast of the Antarctic peninsula for environmental magnetism, granularity, ²¹⁰Pb and stable carbon isotope testing and analysis. The bedrock of the coast is dominated by andesitic basalt, so the sediments of the core samples are high in magnetic minerals in general, that resulted in high magnetism. The average susceptibility (χ_lf) is about 1597×10⁻⁸ m³·kg⁻¹, almost 3～4 times higher than the beach magnetic susceptibility. The magnetic minerals mainly consist of ferromagnetic particles (magnetite) with small amount of antiferromagnetic particles (hematite). The vertical changes in ²¹⁰Pb and granularity data suggest that the sediment particle size is too fine for water movement, and therefore, the movement of pore water is weak. Under such a circumstance, the fine magnetic mineral grains are easily to be preserved. With the increase in depth, the sediments gradually become coarser, and the movement of water is thus enhanced. Plus the influence of biological organic dissolution, magnetism parameters of the lower part of the core is decreased accordingly.