Temperature and seawater isotopic controls on two stalagmite records since 83 ka from maritime Japan

摘要

Millennialscale interstadial Dansgaard-Oeschger (D-O) cycles and Heinrich (H) stadial events are pronounced paleoclimatic features during the last glacial period, which were first demonstrated in the North Atlantic region. These stadial and interstadial events are expressed in marine and terrestrial high resolution records elsewhere in the world, but the magnitude and mode of the regional climate changes are still poorly quantified. Here we present new replicated stalagmite delta O-18 profiles from two caves in central Japan, which extend back to 83.4 ka. The records clearly display the H7 to H3 events, but not D-O cycles. An important feature of the two Japanese stalagmites is the small difference (similar to 2.9 parts per thousand) in delta O-18 values between the mid-Holocene and the Last Glacial Maximum (LGM). Long-term trends of the stalagmite delta O-18 values at the more maritime site generally follow that of the delta O-18 record of seawater, which is responsible for similar to 1.1 parts per thousand of the similar to 2.9 parts per thousand difference between mid-Holocene and LGM. The remaining 1.8 parts per thousand in the difference can be accounted for by +9 degrees C of warming between the LGM and mid-Holocene and -3 degrees C cooling at H events, which are comparable with the previous estimates of land paleotemperature in the Japanese Islands. The attenuated isotopic signal associated with D-O interstadials indicates that the warming in the Atlantic did not significantly transfer to the maritime Japan. These unique features of the isotopic records of the Japanese stalagmites are due to the geographic position at the vicinity of the moisture source, Kuroshio warm current. (C) 2018 Elsevier Ltd. All rights reserved.