In recent decades, environmental magnetism has become an important method for studying past global climatic and environmental changes. For an environmental magnetic study, it is important to understand the magnetic properties of various magnetic minerals in lacustrine sediments and the processes involved in the formation, transport, and preservation of these magnetic minerals. The magnetic response of lacustrine sediments to climatic change may vary widely from lake to lake. To reconstruct the processes contributing to paleoclimatic and paleoenvironmental change, it is, therefore, necessary to derive a complete understanding of the potential origin of the magnetic signal observed.
HU Shouyun, DENG Chenglong, E. Appel & K. L. VerosubNanjing Institute of Geography and Limnology, Nanjing 210008, China
Detailed rock magnetic investigations and mineralogical analysis were conducted on lacustrine sediments recovered from Zoigê Basin, eastern Tibetan Plateau. Greigite, with fine and homogenous grain size, is found as a main magnetic carrier, which is suspected to be of biochemical origin. In contrast to some reports, greigite within the sediments is not oxidized even after exposure to air for a few years, which could be due to the fact that greigite is sealed by silicate.
