Determination on ^87Sr/^86Sr ratio and stratigraphic dating of single-grain foraminifera

• Published in: Chinese science bulletin Vol. 51; no. 17; pp. 2141 - 2145
• Main Authors: Tong, Jinggui, Li, Shengrong, Li, Xianghui, Li, Qiuli, Fang, Nianqiao, Chu, Fengyou, Chen, Fukun
• Format: Journal Article
• Language: English
• Published: Key Laboratory of Lithosphere Tectonics and Lithoprobing Techology of Ministry of Education, China University of Geosciences, Beijing 100083, China%Laboratory for Radiogenic Isotope Geochemistry, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100029, China%Key Laboratory of Submarine Geosciences, State Oceanic Administration, Hangzhou 310012, China 01.09.2006; State Key Laboratory of Geological Processes and Mineral Resources, China University of Geosciences, Beijing 100083, China
• Subjects: 地层学; 有孔虫; 锶同位素定年; foraminifer; dating; ferromanganese crust; 87Sr/ 86Sr ratios; single-grain
• ISSN: 1001-6538; 1861-9541
• DOI: 10.1007/s11434-006-2069-1

The Sr isotopic has been used in studies of composition of foraminifera chronstratigraphy and sedimentary geochemistry. However, it is difficult to sample foraminifera without overprinting of later diagenesis, which contains enough amount of Sr for isotopic measurement. Analysis of single-grain foraminifera was successively conducted by a combination of low Sr procedural blank and high precision determination of ^87Sr/^86Sr ratio. This combination of single-grain foraminifera can be significant for the study and application of Sr isotopic composition of foraminifera. Measured foraminifera of this study, having a size between 250μm and 400μm, were sampled from the carbonate basement of a ferromanganese crust in western Pacific. Mean value of 87Sr/86Sr ratios of the analyzed single-grain foraminifera is 0.709150 ±0.000013 with internal precision between 4ppm and 8 ppm for each measurement run. Average value of total procedural blank of Sr is 14 pg. It is significant but difficult to date foraminifera in carbonate basements of ferromanganese crusts. Based on the obtained value of ^87Sr/^86Sr ratio, the analyzed foraminifera can be dated at 0.91 ±0.33/-0.39 Ma.