Aeolian landform processes since the last deglaciation revealed by OSL chronology and stratigraphy in the Hulunbuir dune field in NE China |
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Affiliation: | 1. Institute of Marine Sciences, Guangdong Provincial Key Laboratory of Marine Disaster Prediction and Prevention, Shantou University, Shantou, 515063, China;2. Nanning Tiantao Experimental School Education Group (Cuizhu Campus), Nanning, 530022, China;3. National Research Center for Geoanalysis, Beijing, 100037, China;4. Key Laboratory of Eco-geochemistry, Ministry of Natural Resources, Beijing, 100037, China;5. Key Laboratory of Comprehensive and Highly Efficient Utilization of Salt Lake Resources, Qinghai Institute of Salt Lakes, Chinese Academy of Sciences, Xining, 810008, China;6. Shantou University Affiliated Middle School, Shantou, 515063, China;7. Shandong Provincial Key Laboratory of Water and Soil Conservation and Environmental Protection, School of Resources and Environment, Linyi University, Linyi, 276000, China;8. Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Zhuhai, 519082, China |
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Abstract: | The Hulunbuir dune field (HLB) is situated near the northern limit of the East Asian summer monsoon (EASM), and vulnerable to climate change. The aeolian sand–paleosol sequences of this region are crucial for understanding the past landform processes in response to climate change, but not yet understood well due to chronological controversies. Here, we presented 20 optically stimulated luminescence (OSL) ages from five aeolian sand–paleosol profiles in the HLB, and reconstructed the aeolian landform processes since 18 ka. The findings of this study suggested that the HLB was probably dominated by mobile dunes before 18 ka, as 10 out of 11 aeolian samples were dated to 18–12 ka. Two strong sandy paleosol layers were found and dated to ∼9 ka and 5–0.5 ka, indicating that strong in situ pedogenic process on the accumulative sand could occur during the Holocene. The OSL ages of samples near the top of three profiles were >9.5 ka, indicating two possible surface processes. First, the land surface was stable since 9.5 ka after stabilization, with no accumulation or erosion. Alternatively, the surface could have been erosive with the eroded sediments feeding downwind active dunes. The latter explanation is consistent with the current local landforms, which has widespread blowout pits, indicators of strong wind erosion. We emphasized that the OSL age of a sand layer sample in fossil dunes implied the onset of mobile dune stabilization, not the age of dune activity, as previously stated. |
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Keywords: | Hulunbuir dune field Sand–paleosol sequence OSL dating Land surface processes Global climate changes |
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