Abstract
DCB (Dithionite-Citrate-Carbonate) and AOD (Ammonium Oxalate in the Dark) extractions as well as magnetic measurements were conducted on intertidal sediments of the Yangtze estuary, China. The results are used to explore the relationship between iron oxides and magnetic properties, estimate different iron oxide pools semi-quantitatively, and investigate the impact of DCB extraction on the variations of magnetic properties. It is revealed that magnetic susceptibility and SIRM (Saturation Isothermal Remanent Magnetization) show significant correlations with DCB- and AOD-extractable iron oxides. A semi-quantitative estimation reveals a dominance by amorphous iron oxides, with magnetite occupies only 12 percent of the total iron oxides. The efficiency of DCB extraction relies on the grain size as well as the content of magnetic minerals. DCB extraction removes a large fraction of fine-grained (< 2μm) iron oxides. Coarse magnetite can also be dissolved by DCB extraction. The differences between pre- and post-DCB values of S-100 and HIRM (Hard Isothermal Remanent Magnetization) suggest that anti-ferromagnetic iron oxides are more abundant than magnetite in the clay fraction (< 2μm).
| Original language | English |
|---|---|
| Pages (from-to) | 79-85 |
| Number of pages | 7 |
| Journal | Acta Geophysica Sinica |
| Volume | 46 |
| Issue number | 1 |
| State | Published - Jan 2003 |
Keywords
- DCB extraction
- Intertidal zone
- Iron oxides
- Magnetic properties
- The Yangtze estuary