Keywords:stalagmite, isotope, solar activity
Correlations between atmospheric Δ14C and oxygen isotope (δ18O) record of the stalagmites suggest that the variations of Indian and Asian monsoons are influenced by solar activity during the Holocene (Neff et al., 2001; Wang et al., 2005; Duan et al., 2014). To evaluate the influence of solar activity on a small oceanic island in East Asian monsoon region, we investigate multi-proxy records of a stalagmite from Okinawa, Japan. A stalagmite, HSN1, was collected in Hoshino cave in Minami Daito Island, Okinawa, Japan. The δ18O of the calcite was measured using Gas-bench IRMS (Delta V advantage). The isotope compositions of the fluid-inclusion water were measured using a semi-automated version of our fluid inclusion analysis system described in Uemura et al. (2016). U-Th dates were measured at National Taiwan University. The HSN1 stalagmite grew from ca. 6,000 to 8,000 years before present with a high growth rate (ca. 130μm/yr). The pattern of calcite δ18O variation (e.g., 80-year periodicity) was similar to that of the atmospheric Δ14C.
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Uemura et al., Geochimica et Cosmochimica Acta, 172, 159–176, 2016