Primary Characteristics of Sediments from Zhongshan Warship and Its Dating Function

Key words: 
• Zhongshan warship /
• magnetic suscep tibility /
• ferromagnetic mineral /
• recent sediments

Abstract: It is suggested that the remarkable changes ofmagnetic suscep tibility in sediments can be used as the distinguishing indicator of the relative ages of sediments and the spherical magnetic metallic waste, which is related to modem industry in sediments, may be used as the marker of determining ages by analyzing the relations of veins, magnetic suscep tibility and ferromagnetic minerals in sediments from Zhongshan warship and Yangtze water level and ferro- magnetic minerals carried by atmospheric pollution, as well as historical documents, in this paper. The evident increasing magnetic suscep tibility in sediments is considered as the increase of ferromagnetic minerals being caused by environmental changes. It is in 1959 that the spherical magnetic metallic waste is first found in sediments, which is corresponding to that Wuhan Company of Iron and Steel put into the river. It was among 1938 and 1958 when the magnetic suscep tibility in sediments are relatively low and after 1959 when the magnetic suscep tibility in sediments was evidently increased. It is concise in principle, convenient in practice and inexpensive in cost to use the dating method of combining magnetic characteristics of sedimentswith historical documents. The method can be used in investigations of great scale sedimentary environment in the crowded population regions in inland and will not be affected by the changes of sedimentary environment