Holocene Aeolian Activity Recorded by Mountain Paleosols, Gonghe Basin, Northeast Qinghai-Tibet Plateau

Chunxia Xu,Jing Zhang,Zhaokang Zhang,Yongxin Zeng,Yunkun Shi,Manping Sun,Chongyi E

doi:10.3389/feart.2022.832993

Chunxia Xu, Jing Zhang + Show 5 more

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https://doi.org/10.3389/feart.2022.832993

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Abstract

The Gonghe Basin (GHB) on the northeastern Qinghai-Tibet Plateau (NE-QTP) is sensitive to climatic change due to the interplay of the Asian summer monsoon and the westerlies. Extensive aeolian sediments in the basin represent important archives of regional environmental evolution. However, the paleosol development timing is still not clear because of limited number of optically stimulated luminescence (OSL) sampling and dating, which restricts our understanding of past aeolian activities during the Holocene in GHB. In this study, a loess-paleosol section, Najiao (NJ), from the southeastern margin of GHB was investigated. Eighteen OSL samples were obtained from the 400-cm section in order to construct a high-resolution chronological framework. Paleoenvironmental proxies including grain size distribution (GS), magnetic susceptibility (MS), total organic carbon (TOC), and geochemical elements were measured to reconstruct the Holocene aeolian activity. Results show a successive accumulation from Early to Middle Holocene at NJ section, but a c. 3 ka sedimentary hiatus is found between c. 5 and 1.5 ka. Paleosol ages are constrained by high-resolution OSL ages which are from c. 7–5 ka. Consistent with previous studies, strong aeolian activities occurred in GHB during the Early Holocene (c. 13–9 ka), indicating dry climate conditions. Initiation of pedogenesis was at c. 9 ka, and the intensified soil development and lowest aeolian activity were between c. 7 and 5 ka. The increased sand content after c. 1.5 ka indicates enhanced human activities in the interior of GHB in the Late Holocene.

Highlights

The arid/semi-arid northeastern Qinghai-Tibet Plateau (NE-QTP) is sensitive to climatic change as it is under the interplay between the Asian summer monsoon and the westerlies (An et al, 2012; Chen et al, 2016)
Trend similar to total organic carbon (TOC) and magnetic susceptibility (MS) is observed in the rubidium/strontium ratio (Rb/Sr) ratio, which shows the highest value in paleosol and the lowest in loess (Figure 6)
The duration of mountain soil development in Gonghe Basin (GHB) was effectively constrained by high-resolution optically stimulated luminescence (OSL) ages from c. 7–5 ka

Summary

Introduction

The arid/semi-arid northeastern Qinghai-Tibet Plateau (NE-QTP) is sensitive to climatic change as it is under the interplay between the Asian summer monsoon and the westerlies (An et al, 2012; Chen et al, 2016). Tree rings, and ice cores are important archives of regional environmental and climatic change on the NE-QTP (An et al, 2012; Chen et al, 2016). Aeolian deposits are widespread on the arid NE-QTP, and taken as an important proxy for reconstructing paleoclimatic change, which is well-studied since the 1980s (Xu, 1987; Liu et al, 2012; Qiang et al, 2013; Sun et al, 2014; Hu et al, 2015; Qiang et al, 2016; Liu et al, 2017; Qin et al, 2017; Li et al, 2020). Intensifying human disturbance in dust source regions of northern China (Chen et al, 2021). Aeolian activity is related to climate change, and to human activity, on different timescales

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