Abstract
Chronology is a necessary component of paleoclimatology. Radiocarbon dating plays a central role in determining the ages of geological samples younger than ca. 50 ka BP. However, there are many limitations for its application, including radiocarbon reservoir effects, which may cause incorrect chronology in many lakes. Here we demonstrate temporal changes in the radiocarbon reservoir age of Lake Xingyun, Southwestern China, where radiocarbon ages based on bulk organic matter have been reported in previous studies. Our new radiocarbon ages, determined from terrestrial plant macrofossils suggest that the radiocarbon reservoir age changed from 960 to 2200 years during the last 8500 cal a BP years. These changes to the reservoir effect were associated with inputs from either pre-aged organic carbon or 14C-depleted hard water in Lake Xingyun caused by hydrological change in the lake system. The radiocarbon reservoir age may in return be a good indicator for the carbon source in lake ecosystems and depositional environment.
Highlights
The Indian Summer Monsoon domain is a key region to understand past climatic changes [1]
Because the radiocarbon ages from the two cores were not from the same depths, we used the mixed-effect regression model based on the work of Heegaard et al [43] by fitting a cubic spline function of smoothing through the 68% age ranges and assigning a 95% confidence level to the interpolated ages at 2 cm intervals
The equation for the uncertainty in the reservoir offset (RRO) was derived from the proppaffiffigffiffiaffiffitffiffiiffioffiffiffinffiffiffioffiffiffifffiffieffiffirffirors, assuming independence between radiocarbon ages of the bulk organic (RBO) and RPM was calculated as: sRRO 1⁄4 s2RBO þ s2RPM where σRBO and σRPM were the uncertainty in RBO and RPM, respectively
Summary
The Indian Summer Monsoon domain is a key region to understand past climatic changes [1]. This region has continuous and well-preserved lake sediment, which provides excellent archives for paleoclimatic reconstructions of the terrestrial environment [1,2,3]. Many dating methods have been applied in lacustrine sediments, including 210Pb and 137Cs dating, optically stimulated luminescence (OSL) dating, and radiocarbon (14C) dating. Among these methods, radiocarbon dating has been used most extensively for providing a chronological framework for the past 50 kyr [4, 5]. Due to the lack of plant macrofossils or an insufficient concentration
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
