Reconstruction of paleoglacial equilibrium-line altitudes during the Last Glacial Maximum in the Diancang Massif, Northwest Yunnan Province, China

Abstract

Abstract Equilibrium-line altitudes (ELAs) are an important proxy of the fluctuations and mass–balance characteristics of glaciers and have been widely used to reconstruct regional paleoclimatic conditions. The Diancang Massif, which has experienced the well-known "Tali Glacial Stage" was uplifted during MIS 3b (marine isotope stages). With its unique characteristics, the Diancang Massif has become an irreplaceable area for the study of inland paleoclimatic and paleo-environmental changes in China. Nevertheless, despite the considerable amount of glaciological studies on this area, a detailed and systematic estimation of paleoglacial ELAs during the Last Glacial Maximum remains to be performed. In this study, several approaches are employed to estimate the ELAs on the basis of previous studies. The results are compared and analyzed, and the final results are determined using a weighted arithmetic average method. Finally, the weighted root mean square error is applied to evaluate the accuracy of the results. Moreover, two critical parameters, differences between positive and negative effects and the distance ratio between the accumulation area and ablation area, are discussed in detail. In the comprehensive results, the final estimated paleoglacial ELAs of the north slope of “Yuju Peak” and the south slope of “Longquan Peak” are 3,773 and 3,883 m, and their median errors are 18.73 and 45.00 m, respectively. Overall, paleoglacial ELAs in the Diancang Massif could be systematically and scientifically estimated for the first time, which is expected to provide fundamental data for accurate modeling of paleoclimatic changes in this area.