Color reflectance of Chinese loess and its implications for climate gradient changes during the last two glacial-interglacial cycles

Abstract

To examine the relationship between color changes of loess deposits and paleoclimate conditions, a north-south transect consisting of twelve loess sections were studied. Color reflectance was measured on loess-paleosol samples from the loess transect which accumulated over the last two glacial-interglacial cycles. The redness value, a*, shows an overall southward increase for both loess and soil units, coinciding with the pattern of a southerly increase in pedogenic development and the present north-south climatic gradient. The redness of loess deposits is linearly correlated with latitude values, implying that this parameter is an efficient proxy for the weathering intensity of loess deposits. The gradient of weathering intensity is much steeper during interglacials than in glacials, by comparison of color records for different time interval. © 2003 by the American Geophysical Union.