利用富钴结壳碳酸盐基岩有孔虫矿物标型重建古海洋温度

重建古海洋海表温度(SST),是研究地质历史时期气候变化控制过程的关键。组成有孔虫化石的矿物Mg/Ca值是海水温度的可靠代用指标,是重建古海洋SST的一个非常好的手段。麦哲伦海山区的富钴结壳和基岩中普遍存在有孔虫化石,这对重建该区的SST有重要意义。利用LA-ICP-MS测得西太平洋麦哲伦海山区富钴结壳碳酸盐基岩中8颗浮游有孔虫化石Globigerinoides sacculifer的Mg/Ca值为3.84±0.36(mmol/mol),通过线性公式:T(℃)=2.898Mg/Ca(mmol/mol)+13.76及已有的定年数据,得到0.91Ma±西太平洋麦哲伦海山区海表温度为24.9+1.1/-1.0℃,未能检索到前人关于该区0.91Ma±前海表温度数据。

Reconstruction of sea surface temperature of paleaoocean using biomineral of fossil foraminifer in the carbonate basement of the ferromanganese crust

Reconstruction of past sea surface temperatures(SST)is essential for understanding processes that control climate change throughout the Earth's history.The Mg/Ca ratio of the foraminifer is a reliable sea water temperature proxy and is a good tool to reconstruct the SST of palaeoocean.The foraminifer samples were collected from the carbonate basement of a ferromanganese crust from a Magellan seamount in the West Pacific and their age was 0.91 Ma±.Eight of them were examined by LA-ICP-MS for their Mg/Ca ratios.The average of their Mg/Ca ratio was 3.84±0.36(mmol/mol).Based on the linear fitting(T(℃)=2.898 Mg/Ca(mmol/mol)+13.76),the SST of the area around the Magellan Seamounts around 0.91 Ma ago was given at 24.9+1.1/-1.0 ℃.