Multi‐decadal to centennial‐scale 10Be variations in Holocene sediments of Huguangyan Maar Lake, South China

We report a new high-resolution Holocene Be-10 record from Huguangyan Maar Lake in subtropical-tropical South China, aimed to detect the atmospheric Be-10 production signal in low-latitude regions. After minimizing climatic effects by regression analyses between Be-10 concentration and climatic proxies from the same archive, we successfully distinguished variations in geomagnetic field intensity and solar activity using 2,000-year low-and high-pass filtering, respectively, of the residual Be-10 record (a proxy of the atmospheric Be-10 production rate). The resulting Be-10-derived record of geomagnetic field intensity is generally comparable with geomagnetic models, and the solar-modulated Be-10 signal shows significant correlations with solar activity proxies. The preservation of Be-10 production signal in the sediments of this low-latitude maar lake highlights the largely unexplored potential as well as limitations of Be-10 as a tool to reconstruct variations in solar activity and geomagnetic field intensity. Plain Language Summary The atmospheric production rate of cosmogenic Be-10 depends on the cosmic ray flux penetrating the atmosphere, a process that is mainly controlled by the geomagnetic field strength and solar activity. The geomagnetic imprint on Be-10 has been well established in previous studies of ice cores and marine sediments. The relationship between solar activity and Be-10 has also been studied in ice cores and high-latitude lakes. Here we for the first time present a high-resolution Be-10 record from Huguangyan Maar Lake in subtropical-tropical South China over the Holocene. We successfully separated the atmospheric Be-10 production signal from climatic effects that contribute to up to similar to 52% of the variance in Be-10 concentration. After eliminating the climatic effects, variations in both geomagnetic field intensity and solar activity signals were reconstructed from the residual Be-10 record, using 2,000-year low pass, and high-pass filtering, respectively. The geomagnetic-and solar-modulated Be-10 production signals are evaluated by comparisons with independent records. This result unambiguously indicates that the Be-10-derived solar activity signal at a low-latitude subtropical site can be obtained, even when the Be-10 signal is dominated by regional climate, in our case, accounting for up to similar to 65% of the variance in the record during the early-middle Holocene.