Abstract: The environmental magnetic properties of sediments from the middle and lower reaches of the Yangtze River were investigated for the study of environmental information of Yangtze River basin. The results show that magnetic properties of the sediments in both the mainstream and tributaries are affected by ferrimagnetic magnetite, with the magnetic domain being pseudo single domain (PSD) - multi-domain (MD). Compared with the sediments of the mainstream, the contents of imperfect anti-ferromagnetic material are higher and ferrimagnetic mineral particles are finer in those of the tributaries. With material from the tributaries into the mainstream, magnetic properties of sediments in the estuary and lower reaches of the Yangtze River change correspondingly.The contribution of the tributary sources may be the main factor controlling the regional differences of sedimentary magnetic properties in the middle and lower reaches of the Yangtze River.

Key words: sediment, the middle and lower reaches of the Yangtze River, environmental magnetism, sediment, the middle and lower reaches of the Yangtze River