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Thi Thu Hien Nguyen, Weiguo Zhang1, Zhen Li, Jie Li, Can Ge, Jinyan Liu, XuexinBai, Huan Feng, and Lizhong Yu (2016).

Magnetic properties of sediments of the Red River, VietnamEffect of sorting on the source-to-sink pathway and its implications for environmental reconstructionGeochemistry, Geophysic. Geosystems, 17(2), pp. 1-12 doi:10.1002/ 2015GC006089.


Abstracts
We conducted a mineral magnetic study of river bank and subaqueous delta sediments from
the Red River, in order to examine the role of sedimentary sorting on the variation of sedimentary magneticproperties from source to sink. The magnetic mineralogy mainly consists of magnetite and hematite. Bulksediment particle-size variations have a strong influence on magnetic properties, with the frequently usedmagnetic parameters χfd%, χARM, χARM/v, and χARM/SIRM exhibiting positive correlations with the <4 µmfraction, while S-ratios are negatively correlated with this fraction. Compared with river bank sediments andshallow shoreface (<5 m water depth) sediments, sediments from the deeper (>5 m water depth) part ofthe subaqueous delta have lower v and SIRM values, a finer ferrimagnetic grain-size and higher proportionsof hematite, consistent with selective loss of coarse ferrimagnetic grains on the source-to-sink pathway. Wesuggest that variations in magnetic properties in response to particle-size compositions and therefore depo-sitional environment changes should be carefully addressed when magnetic proxies such as χARM/SIRM areused in the study of coastal and marine environmental changes (e.g., sea-level change). In such cases, thecombined use of magneticproperties and geochemical indicators, such as Al/Ti ratio, may provide better results for paleoenvironmental reconstruction.
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