We have recently investigated variations in marine reservoir ages for the South China Sea (SCS) during the Holocene. Porites corals from Leizhou Peninsula (20º14'N, 109º55'E), Sanya (southern coast of Hainan Island, 18º12'N, 109º29'E) and Nansha Islands (9º32'-9º42'N, 112º52'-113º04'E), ranging from 0.8 to 7.5 kyrs BP were used for this study. Twenty unaltered coral samples (based on XRD analysis, d234U and initial 230Th/232Th ratios) were analysed for 230Th/U and 14C. 230Th dates, which reflect the absolute ages of the coral samples, were determined by TIMS U-series methods using the ACQUIRE facility at the University of Queensland, with a precision better than 0.5%. Aliquots of these dated corals were then taken for radiocarbon assay. The samples were carefully pretreated, converted to graphite and measured by AMS using the STAR facility at ANSTO. A typical precision for 14C analysis is 0.3-0.4%. The radiocarbon ages together with the IntCal04 calibration curve were used for the determination of marine reservoir ages for the SCS, using the method of [1]. The results of this investigation will be compared with those of previous studies for the central and southern SCS during the late Holocene [2], Sanya in the northern SCS for the period 4.8-6.8 kyrs BP [3], and Leizhou Peninsula in the northern SCS for the period 7.0-7.5 kyrs BP [4]. Variations in marine reservoir ages for the SCS for the mid- to late Holocene, and their possible mechanisms will be then discussed.
[1] P.J. Reimer, R.W. Reimer, Radiocarbon 43 (2001) 461. [2] J. Southon, M. Kashgarian, et al., Radiocarbon 44 (2002) 167. [3] Z.B. Ma, J.L. Xiao, et al., J. Coastal Res. 19 (2003) 296. [4] K.F. Yu, J.X. Zhao, et al., Earth Planet. Sci. Lett. 224 (2004) 143-155.
This work was supported by AINSE (grant 04/178), CcASH Project (ANSTO 0203v) and NSF (China – grant 40231009).
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