Abstract
Paleoclimatic researches have revealed that the East Asian summer monsoon (EASM) strengthened and precipitation increased in north China during the early to middle Holocene. The lacustrine landform and sediment recorded approximately simultaneous Holocene high lake levels. However, relatively few studies have been reported involving the quantitative reconstruction of precipitation and lake areas in the Mu Us Desert (MUD), northwest edge area of the modern EASM. Based on the lacustrine landform, and by using the lake hydrologic model, this study quantitatively reconstructed precipitation and lake areas during the early to middle Holocene in the MUD. The results revealed the following: 1) A total of 127 paleolakes existed in the closed drainage area during the early to middle Holocene. The area of paleolakes was 896.1 km2, which is 2.96 times that of modern lakes. The relative height between the highstand and the modern lake surface is ∼5–9 m. 2) Precipitation during the early to middle Holocene decreased from 550 mm in the southeast to 350 mm in the northwest. The 400 mm isohyet moved 130–170 km to the northwest, roughly coincident with the modern 250 mm isohyet. 3) The relative increase in precipitation was ∼32–60%, and the increase in the west was significantly higher than in the east. The precipitation gradient in much of the MUD was lower than the present. The results show that the monsoon edge area and monsoon rain belt migrated to the northwest during the early to middle Holocene. The MUD was stably dominated by the EASM. Data also showed that the spatio-temporal pattern of the climate during the early to middle Holocene was relatively humid with a decreased precipitation gradient for millennia.
Highlights
There were variations in monsoon precipitation in the geological data recorded in China during the Holocene (An et al, 2000)
The reconstruction results showed that the increase percentage in precipitation during the early to middle Holocene ranged from ~30% to 100% compare with the present in north China, with significant differences near the northwestern limit of the East Asian summer monsoon (EASM) domain
The results show that the precipitation during the early to middle Holocene in the Mu Us Desert (MUD) decreased from about 550 mm in the southeast to about 350 mm in the northwest, which is consistent with present levels
Summary
There were variations in monsoon precipitation in the geological data recorded in China during the Holocene (An et al, 2000). Precipitation reconstruction from the Gonghai Lake in the north loess plateau revealed gradually increasing rainfall since the last deglaciation, reaching a maximum of 30% higher than the present during the middle Holocene (Chen et al, 2015). In eastern Inner Mongolia Plateau, pollen records of Chagan Nuur showed that the East Asian monsoon precipitation began to increase in the early Holocene and reached a maximum in the middle Holocene, which was 30–50% higher than modern rainfall (Li et al, 2020). The reconstruction results showed that the increase percentage in precipitation during the early to middle Holocene ranged from ~30% to 100% compare with the present in north China, with significant differences near the northwestern limit of the EASM domain
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