High-resolution paleoclimatic information from Chinese eolian sediments based on grayscale intensity profiles

Grayscale intensity profiles from photographic images offer a rapid means o f obtaining paleoclimate proxy records from Chinese loess, dune sand, and p aleosols. Although the data can be obtained using conventional 35-mm film i mages, a digital camera and laptop computer will produce a high-resolution grayscale profile at a field site within minutes. Comparison of grayscale p rofiles with profiles of magnetic susceptibility measured down loess and du nesand sections at sites on the Loess Plateau and Tibetan Plateau in a rang e of altitudes and climatic regimes shows that the two parameters are highl y correlated. Therefore, grayscale intensity is a convenient alternative to magnetic susceptibility for generating paleoclimatic data in the loess and desert-margin regions of China. The resolution of both grayscale and susce ptibility profiles ultimately is limited by bioturbation, which is most pro nounced in paleosols. (C) 2000 University of Washington.