High-resolution stalagmite δ 13C record of soil processes from southwestern China during the early MIS 3

Knowledge of the evolution of pedogenic processes in the carbonate area is important to understand the dynamics of rock desertification. A precisely-dated stalagmite δ ¹³C record between 61.3 and 50.5 ka BP from southwestern China, potentially related to soil biogenic CO₂ production, shifts within a narrow range between ?9‰ and ?7‰, and exhibits a prominent cycle of 350–470 a, independent of the Asian monsoon changes. This indicates that a threshold effect might control the amplitude of calcite δ ¹³C variability, likely associated with the vertical soil loss in the carbonate area. The periodic δ ¹³C changes reflect that the loss/recovery of soil cover can operate on centennial scale. Thus, the rock desertification in southwestern China might at least initiate 60 ka ago and should be of natural origin.