Magnetic properties of core sediments from an alpine lake in Southwest China: implications for glacier melting

• Published in: Journal of paleolimnology 2022-04, Vol.67 (4), p.345-357
• Main Authors: Zhang, Lirong, Ouyang, Tingping, Zhang, Yongdong, Li, Mingkun
• Format: Article
• Language: English
• Subjects: Air temperature; Climate Change; Coercivity; Earth and Environmental Science; Earth Sciences; Freshwater & Marine Ecology; Freshwater lakes; Geology; Glaciers; Lake basins; Lakes; Magnetic properties; Magnetism; Magnetite; Meltwater; Mineralogy; Minerals; Mountain lakes; Mountains; Original Paper; Paleontology; Parameters; Physical Geography; Sediment; Sedimentology; Sediments; Temperature dependence; Variation
• ISSN: 0921-2728; 1573-0417
• DOI: 10.1007/s10933-022-00236-x

Variations in the extent of glaciated areas are among the most distinct natural responses to climate change. To explore the response mechanism of sediment magnetic properties to glacial-area variation, detailed environmental magnetism investigations were performed on a sediment core from Lake Heihai, an alpine lake located on Haba Snow Mountain in Yunnan Province. We discuss the changes in sediment magnetic properties in the past century and their response mechanism to variations in glacial area caused by climate change, especially air-temperature change, based on the published chronological data. Results of magnetic mineralogy showed that single- and multi-domain magnetite and a small amount of high coercivity magnetic minerals dominated the sediment magnetic properties throughout the core. Magnetic particles within the sediments of Lake Heihai mainly originated from the terrigenous input of the lake basin discharged by glacial meltwater. Significant positive correlations were found among the annual average air temperature in the study area and concentration-dependent magnetic parameters (χ lf ) while negative correlations occurred among the annual average air temperature and particle size-dependent magnetic parameters (χ ARM /SIRM), indicating that the sediment magnetic properties of alpine lakes were sensitive to glacial-area variations caused by air-temperature change. Increased input of coarse magnetic particles was a result of glacial-area shrink, while decreased coarse-grain input and occurrence of finer magnetic particles corresponded to glacial-area expand. In addition, we identified three glacial-area shrink and expand cycles based on the variations in sediment magnetic properties in the study area. We propose that the sediment magnetic properties of alpine lakes can be used for monitoring variations in glacial area caused by climate change.