Holocene aeolian activity in the Ganzihe sandy land, Qinghai Lake basin

Abstract Although there are still some conflicts, previous studies based on lacustrine or aeolian deposits provide an overall understanding of the Holocene environment in the Qinghai Lake Basin. Compared to lacustrine deposits, aeolian sediments have received less attention, and the loess on the south coast and the Hudong Sandy Land on the east coast has received the most attention. The Ganzihe Sandy Land, the second largest sandy land in the Qinghai Lake Basin, is far from lakeshore areas and shows an obvious degradation trend. Very few reports have been published on the Ganzihe Sandy Land, especially regarding the Holocene environment. Here, we report a new and well-reserved aeolian sand-paleosol profile found in the Ganzihe Sandy Land. We used 7 optically stimulated luminescence (OSL) and accelerator mass spectrometry (AMS) 14C dating to establish the chronological framework and measured the magnetic susceptibility (MS), grain size, color parameters and total organic carbon (TOC) in the profile. Combined with lithologic changes and chronological data from published aeolian profiles, the results indicate that the aeolian activity in the Ganzihe Sandy Land during the Holocene was mainly affected by climate change in marginal monsoon areas by at least ~10 ka; the climate then improved, and vegetation began to develop from ~10 ka-~8 ka; from ~8 ka-~4 ka, the climate was warm/wet and stable, dunes were fixed and the sandy land entered the “Holocene climatic optimum”; since ~4 ka, the regional climate has gradually become drier and cooler, and aeolian sand has again accumulated on a large scale, particularly in the past thousand years. To prevent further environmental deterioration in the Ganzihe Sandy Land, we believe that straw-breaks should be established and increasing efforts should be made to artificially enclose the mobile dune region inside the sandy land, control the amount of animal husbandry and emphasize water conservation in the marginal areas. Further, sand control stations should be set up to carry out land monitoring and forecasting, and local residents should be educated about scientific and legal issues.