Magnetic Properties of Late Pleistocene Sediments in Core DSH-1C from Northern South China Sea and Their Environment Significance

Abstract

Abstract:

A study of magnetic properties of sediments at the piston core DSH-1C from deep sea area of Dongsha, the South China Sea was carried out. The 626 cm-core was subdivided into three lithologic units as follows: Holocene clayey silt (Unit I, MIS1) at the top interval of the core, Late Pleistocene turbidity sequences characterized by 3 to 4 major sand layers in the middle interval (Unit II, MIS2), and the lowest sequences composed by clayey silt interbedded with thin silty sand or silt layers (Unit III, MIS3). The average value of the χ of the sediments is 1.72×10-7m3/kg, and all samples show high values of IRM, over 80% of SIRM, while the minimum of S300 for all samples is 0.605. According to magnetic properties obtained, it was inferred that sediments from the core contained very rare magnetic minerals. Lowest values of magnetic properties (χ, NRM and SIRM) were observed in the intervals of Unit II, where turbidity layers containing abundant calcareous foraminifera shells occurred, indicating the dilution of carbonate in these sediment layers. On the other hand, higher values of those parameters were seen in the interglacial period (MIS1 and MIS3), probably owing to terrigenous of debris input during warm periods in this area.

Key words: magnetic property, grain size analysis, Late Pleistocene, Dongsha, South China Sea

CLC Number:

P736.2

LUO Yi, SU Xin, CHEN Fang, HUANG Yong-Yang. Magnetic Properties of Late Pleistocene Sediments in Core DSH-1C from Northern South China Sea and Their Environment Significance[J]. Geoscience, 2010, 24(3): 521-527.

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