A strong temperature effect on U/Ca in planktonic foraminiferal carbonates
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- 作者：Jimin Yu ; Henry Elderfield ; Zhangdong Jin ; Linda Booth
- 刊名：Geochimica et Cosmochimica Acta
- 出版年：2008
- 出版时间：15 October 2008
- 年：2008
- 卷：72
- 期：20
- 页码：4988-5000
- 全文大小：382 K
文摘
Three planktonic foraminiferal species Globigerina bulloides, Neogloboquadrina pachyderma (d), and Globorotalia inflata collected from core-tops spanning 35° to 65°N in the North Atlantic were used for U/Ca and Mg/Ca and foraminiferal shell weight analyses. Except for U/Ca in G. bulloides calcified under warm conditions (>13 °C), U/Ca ratios in all three studied species increase with decreasing latitude and show strong positive correlations with Mg/Ca ratios. A dissolution effect on planktonic U/Ca is suggested by decreased shell weight and U/Ca and Mg/Ca ratios for shells from very deep water depth (>4.4 km) along the latitudinal transect. G. bulloides from down core samples in the North Atlantic show low U/Ca ratios during the last glacial and high ratios during the Holocene, similar to the Mg/Ca evolution trend. In general, our data indicate that the U incorporation into planktonic foraminiferal carbonates is strongly influenced by calcification temperature, although U/Ca in G. bulloides may be affected by seawater carbonate ion concentration under warm conditions and/or other factors.