Jiuxian Cave, China 19KYr Stalagmite Oxygen Isotope Data Cai, Y.; Tan, L.; Cheng, H.; An, Z.; Edwards, R.L.; Kelly, M.J.; Kong, X.; Wang, X. Cai, Y. Tan, L. Cheng, H. An, Z. Edwards, R.L. Kelly, M.J. Kong, X. Wang, X. Monsoon earth science/paleoclimate/speleothems (age,null,null,calendar year before present,null,speleothems,null,null,N,null) earth science/paleoclimate/speleothems (delta 18O,calcium carbonate,null,per mil VPDB,null,speleothems,raw,isotope ratio mass spectrometry,N,null) earth science/paleoclimate/speleothems (Jiuxian Cave>LATITUDE 33.5667>LONGITUDE 109.1) Two stalagmites (C996-1 and C996-2) collected from the Jiuxian Cave in the Shaanxi Province in central China have been studied with U-series dating and stable isotope analysis. Thirty-eight 230Th dating results showed that the stalagmite C996-1 was continuously deposited through the last 8.5 ka BP (thousand years before present, present=1950 AD), and C996-2 was deposited through the last 19 ka BP excluding two growth hiatuses between 8.3 and 5.7 ka BP, and 15.4 and 11.9 ka BP. With a relatively stable boundary condition, we interpret the d18O of speleothem calcite as most indicative of the amount of summer monsoon precipitation, although temperature and other factors might have some minor impact. The d18O records show notable changes within the last glacial maximum (LGM), resembling other East Asian monsoon records such as those from the Hulu and Sanbao Caves, suggesting that significant monsoonal climate changes occurred in eastern Asia as far north as the Qinling Mountains during the LGM interval. A comparison of our records to precisely dated contemporaneous speleothem records from other caves shows that the increasing trend of d18O during the Holocene commenced as early as ~7.5 ka BP in the low-latitude monsoonal area, i.e. the Hoti Cave, while at higher latitudes this shift occurred later, such as ~7.0 ka BP in the Dongge Cave, ~5.3 ka BP in the Heshang Cave, ~4.7 ka BP in the Sanbao Cave and ~4.5 ka BP in the Jiuxian Cave. These results imply an asynchronous change of the summer monsoon precipitation occurred in East Asia during the Holocene. The asynchrony may be related to the responses of a coupled tropical and subtropical monsoon system to changes of the insolation and the differences in thermal forcing, which result from the complex geographical configuration. The variation of sea surface temperature (SST) in the western tropical Pacific may also have important impacts on the summer monsoon precipitation changes in central and northern China because it affects the Northwestern Pacific Subtropical High, a monsoon-front regulator. More robust tests are needed to confirm this phenomenon and to evaluate the contribution of different factors in detail. STUDY NOTES: Oxygen isotope data and U-Th dates from two stalagmites collected in 1999 near the end of Jiuxian Cave, Shaanxi Province, central China. Stalagmite C996-1 is ~32 cm in height and 8-13 cm in diameter, and stalagmite C996-2 is ~21 cm in height and 6-9 cm in diameter. Twenty-three and fifteen 230Th dates were acquired from C996-1 and C996-2, respectively. The chronologies show that C996-1 was continuously deposited through the past 8.5 ka BP, and C996-2 grew through the past 19.0 ka BP, excluding two hiatuses between 8.3 and 5.7 ka BP, and 15.4 and 11.9 ka BP. Temporal resolutions for the d18O measurements vary from 4 to 77 years for C996-1, and from 36 to 112 years for C996-2. Data: 230Th dating results of two stalagmites from Jiuxian cave by ICP-MS. The error is 2sigma error. Lambda230=9.1577×10-6 year-1, Lambda234=2.8263×10-6 year-1 (Cheng et al., 2000), Lambda238=1.55125×10-10 year-1 (Jaffey et al., 1971). Corrected 230Th ages assume the initial 230Th/232Th atomic ratio of 4.4±2.2×10-6. Those are the values for a material at secular equilibrium, with the bulk earth 232Th/238U value of 3.8. The errors are arbitrarily assumed to be 50%. *a d234U=([234U/238U]activity-1)×1000. *b d234Uinitial was calculated based on 230Th age (T), i.e., d234Uinitial=d234Umeasured×eLambda234×T. *c BP stands for “Before Present” where the “Present” is defined as the year 1950 AD. NCDC-Paleoclimatology https://www.ncdc.noaa.gov/data-access/paleoclimatology-data - Bauer Bruce Investigator : Cai, Y. Investigator : Tan, L. Investigator : Cheng, H. Investigator : An, Z. Investigator : Edwards, R.L. Investigator : Kelly, M.J. Investigator : Kong, X. Investigator : Wang, X. 2010-10-07 ONLINE Files online, ASCII https://www.ncdc.noaa.gov/paleo/study/9742 https://www1.ncdc.noaa.gov/pub/data/paleo/speleothem/asia/china/jiuxian2010.xls https://www1.ncdc.noaa.gov/pub/data/paleo/syntrace/speleothem/cave-jiuxian-c996-2.txt https://www1.ncdc.noaa.gov/pub/data/paleo/speleothem/asia/china/jiuxian2010.txt https://www1.ncdc.noaa.gov/pub/data/paleo/syntrace/speleothem/cave-jiuxian-c996-1.txt https://www1.ncdc.noaa.gov/pub/data/paleo/speleothem/asia/china/jiuxian2010.xls https://www1.ncdc.noaa.gov/pub/data/paleo/syntrace/speleothem/cave-jiuxian-c996-2.txt https://www1.ncdc.noaa.gov/pub/data/paleo/speleothem/asia/china/jiuxian2010.txt https://www1.ncdc.noaa.gov/pub/data/paleo/syntrace/speleothem/cave-jiuxian-c996-1.txt English https://www.ncdc.noaa.gov/paleo/study/9742 https://www1.ncdc.noaa.gov/pub/data/paleo/speleothem/asia/china/jiuxian2010.xls https://www1.ncdc.noaa.gov/pub/data/paleo/syntrace/speleothem/cave-jiuxian-c996-2.txt https://www1.ncdc.noaa.gov/pub/data/paleo/speleothem/asia/china/jiuxian2010.txt https://www1.ncdc.noaa.gov/pub/data/paleo/syntrace/speleothem/cave-jiuxian-c996-1.txt Cai, Y., L. Tan, H. Cheng, Z. An, R.L. Edwards, M.J. Kelly, X. Kong, and X. Wang. 2010. The variation of summer monsoon precipitation in central China since the last deglaciation. Earth and Planetary Science Letters, Vol. 291, pp.21-31. doi:10.1016/j.epsl.2009.12.039 START YEAR: 18958 cal yr BP * END YEAR: -48 cal yr BP 109.1 33.5667 109.1 33.5667