Holocene climate change in the Maoyaba Basin, western Sichuan Plateau

Abstract

Objective The Holocene climate of the Tibetan Plateau (TP) is mainly controlled by midlatitude westerlies, the East Asian monsoon, and the Indian monsoon. Previous studies have identified different patterns of Holocene climate change in different regions of the TP. Holocene climate reconstructions for the entire TP help us comprehensively understand the internal linkages of different factors influencing the climate change in the TP. Methods In this paper, we study the Holocene climate in the eastern TP based on 14C dating, lithology and various proxies from the glaciolacustrine strata in the Maoyaba Basin in Litang County, western Sichuan Plateau. Results The Early-Middle Holocene glaciolacustrine sediments covered the last glacial moraines, and then the alluvial-proluvial fans were common during the Late Holocene in the Maoyaba Basin. The grain size of all samples mainly shows a bimodal size distribution after sieving out >2 mm particles. The content of the grain size below medium silt (< 32 μm) is more than 80%, which may be produced by glacial abrasion. The magnetic susceptibility increases obviously in the paleosol, and the appearance of < 1 μm particle size components may indicate that the strong magnetic minerals were generated by pedogenesis. However, the magnetic susceptibility decreased significantly in the glaciolacustrine sediments, which may be related to the dissolution of magnetic minerals in the reducing environment. Conclusion Comprehensive analysis of the sedimentary environment, grain size, magnetic susceptibility, total organic carbon (TOC) and color parameters indicates that the Maoyaba Basin was temperate and dry in the Early Holocene, warm and wet in the Middle Holocene, and temperate and dry in the Late Holocene. This pattern is consistent with the general trend of the Holocene climate in the eastern TP. The paleosol dated to~2 700 cal.yr. B.P. in the Maoyaba Basin indicates a relatively wet period against the background of cooling and a dry climate in the Late Holocene.

Keywords

• tibetan plateau
• western sichuan plateau
• maoyaba basin
• holocene
• climate change