Testing coral paleothermometers(B/Ca, Mg/Ca, Sr/Ca, U/Ca and δ^(18)O) under impacts of large riverine runoff  

作　　者：CHEN Tianran YU Kefu ZHAO Jianxin YAN Hongqiang SONG Yinxian FENG Yuexing CHEN Tegu 

机构地区：[1]Key Laboratory of Marginal Sea Geology, South China Sea Institute of Oceanology, Chinese Academy of Sciences [2]Radiogenic Isotope Laboratory, School of Earth Sciences, The University of Queensland

出　　处：《Acta Oceanologica Sinica》2015年第8期20-26,共7页海洋学报（英文版）

基　　金：The National Basic Research Program(973 program) of China under contract No.2013CB956104;the National Natural Science Foundation of China under contract Nos 41106054,41306109 and 41476038

摘　　要：Sea surface temperature （SST） proxies including B/Ca, Mg/Ca, St/Ca, U/Ca and δ180 were analyzed in the skeleton of a Porites coral collected from the Zhujiang River （Pearl River） Estuary （ZRE）. These geochemical proxies are influenced by river runoff and this area of the northern South China Sea is strongly affected by seasonal freshwater floods. We assessed the robustness of each SST proxy through comparison with the local instrumental SST. Coral St/Ca shows the highest correlation with SST variations （r2=0.59）, suggesting St/Ca is the most robust SST proxy. In contrast, coral δ180 （r2=0.46）, B/Ca （r2=0.43） and U/Ca （r2=0.41） ratios were only moderately correlated with SST variations, suggesting that they are disturbed by some other factors in addition to SST. The poor correlation （r2=0.27） between SST and Mg/Ca indicates that Mg/Ca in coral skeletons is not a simple function of SST variations. This may ultimately limit the use of Mg/Ca as a coral paleothermometer.Sea surface temperature （SST） proxies including B/Ca, Mg/Ca, St/Ca, U/Ca and δ180 were analyzed in the skeleton of a Porites coral collected from the Zhujiang River （Pearl River） Estuary （ZRE）. These geochemical proxies are influenced by river runoff and this area of the northern South China Sea is strongly affected by seasonal freshwater floods. We assessed the robustness of each SST proxy through comparison with the local instrumental SST. Coral St/Ca shows the highest correlation with SST variations （r2=0.59）, suggesting St/Ca is the most robust SST proxy. In contrast, coral δ180 （r2=0.46）, B/Ca （r2=0.43） and U/Ca （r2=0.41） ratios were only moderately correlated with SST variations, suggesting that they are disturbed by some other factors in addition to SST. The poor correlation （r2=0.27） between SST and Mg/Ca indicates that Mg/Ca in coral skeletons is not a simple function of SST variations. This may ultimately limit the use of Mg/Ca as a coral paleothermometer.

关 键 词：Porites coral SST proxies coral paleothermometers riverine runoff Zhujiang River （Pearl River） Estuary northern South China Sea 

分 类 号：P736.2[天文地球—海洋地质]