[A-HW35] [EJ] Isotope Hydrology 2017

[AHW35-07] Isotope analysis of past drip water preserved as fluid-inclusions in stalagmites

★Invited papers

*Ryu Uemura¹, Masashi Nakamoto¹, Satoru Mishima¹, Masakazu Gibo¹, Ryuji Asami¹, Chen Jin-Ping², Chung-Che Wu², Yu-Wei Chang², Chuan-Chou Shen² (1.University of the Ryukyus, 2.National Taiwan University)

Keywords:stable isotope, speleothem, fluid inclusioon

The oxygen isotope composition (δ¹⁸O) of speleothem is widely used as paleoclimate proxy. Interpretation of the δ¹⁸O value is not straightforward because it is controlled by two factors; δ¹⁸O of dripwater and temperature at calcite formation. The δ¹⁸O of speleothem fluid-inclusions, paleo-dripwaters in cave (i.e., paleo ground water), will provide an important constraint for the unknown quantity. Its paleoclimatic applications, however, have been hampered by technical difficulties for isotope measurements of fluid inclusions, recent developments of a new laser-based isotope ratio mass spectrometer have opened a new door of fluid inclusions analysis (e.g., Affolter et al., 2014; Arienzo et al., 2013). We also have developed a precise isotopic technique based on cavity ring-down spectroscopy with a low sample-amount requirement of 20-300 nL of inclusion water from stalagmites (Uemura et al., 2016). I will show detailed comparison with modern observation and recent results.