Replicated stalagmite-inferred centennial- to decadal-scale monsoon precipitation variability in southwest China since the mid Holocene

A lack of agreement between stalagmite records of the centennial- to decadal-scale Asian summer monsoon (ASM) variability since the mid Holocene limited our understanding of forcings and the possible impacts on culture evolution. Here we present replicated high-resolution stalagmite delta O-18 profiles from Dark Cave in Guizhou province, southwest China, established with 512 oxygen isotope data and 28 Th-230 ages, providing a continuous history of the ASM precipitation from 6100 to 300 years before present (yr BP, before AD 1950). Consistency of stalagmite delta O-18-inferred long-term decreasing ASM trends since the mid Holocene between caves at this site and others in the Indian and East Asian monsoon realms on orbital timescales supports the effect of primary orbital solar forcings on monsoonal precipitation. The Dark Cave records display significant centennial- to decadal-scale variations, more evident than previous stalagmite records. Spectral analysis of the Dark Cave delta O-18 time series yields periodicities of 731-723, 281, 91-83, 67, and 55-54 yr, implying ASM intensity for the last 6 kyr could be associated with solar activity and variability of El Nino-Southern Oscillation.