Environmental implications of the magnetic record in Pleistocene lacustrine sediments of the Qaidam Basin, NE Tibetan Plateau

摘要

The application of magnetic proxies in paleoclimate studies has the advantage of fast and nondestructive measurement procedures, which is an important precondition for obtaining high-resolution datasets within a manageable time frame. Here we demonstrate the advantage of using magnetic proxies for a ~940-m-long drill core comprising lacustrine sediments from the Qaidam Basin (NE Tibetan Plateau), which was previously dated by magnetostratigraphy and optical stimulated luminescence (OSL) dating. Comparison of three independent mass-specific magnetic susceptibility (%) datasets confirms the horizontal homogeneity of the drill core at scales of several cm3. The potential linkage of x to astronomical forcing is suggested by spectral analysis. Magnetic grain size- and mineralogy-dependent parameters were used to evaluate possible scenarios explaining the % variation. Moreover, using additional palynological results we demonstrate the correlation of x with climatic constraints, thereby showing the climate sensitivity of x- Higher and lower x values are related to dry and more humid conditions, respectively. Our results lead us to conclude that x variations are caused by the interference of two driving mechanisms: low-temperature oxidation in the catchment area and a changing catchment area. In summary, this study confirms the informative value of magnetic proxies for detecting paleoenvironmental change in high resolution.