| Flowstones are formed by water flowing in the cave, which are deposited along the wall or the ground. Compared with other natural materials, flowstones have much superiority, such as wide-ranging distribution, long-time span, and sensitive to outside environment, suitable for U-series dating full-scale information. They offered us a kind of distinctive data source as continental paleoclimate archives.The studied flowstones are sample from Hulu Cave, 28 km east of Nanjing (32°30’N, 119°10’E).The Hulu Cave is situated in the East Asian Summer Monsoon frontal belt. And East Asian is located between Pacific and Eurasia, which has the greatest temperature gradient and air pressure gradient. This is the typical monsoon area.The author reconstructs the climate record during MIS7、MIS6 and MIS4 respectively, based on 3 dating ages (232.4 (+5.8/-5.5) ka BP、152.17 (+2.43/-2.40) ka BP、69.7 (+1.9/-1.9) ka BP) and 158 data of stable isotope to investigate the paleoclimate signal in the oxygen isotope and a general relationship between the oxygen isotope and high frequency variability of East Asian monsoon.The oxygen record in the flowstones reveals the general high-frequency oscillations climate changes, which corresponds to the cold/warm climate events. In addition, the oxygen curve of the climatic changes from MIS7、MIS6 and MIS4 exhibit different amplitude and frequency characteristics, such as the precipitation and cold/warm and dry/wet events.The last glacial had a low-temperate and cold background, there still existed the growing flowstones, which indicates that it was not extremely cold during the last glacial in Nanjing area. The reason is that the flowstone can grow in the relative warm and wet condition.The carbon record in the flowstones displays a larger amplitude and high frequency, which indicate that the carbon isotope have more complex relationship with the cave environment. |
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