TERRAPUB Geochemical Journal

Geochemical Journal, Vol. 48 (No. 2), pp. 145-152, 2014

Precise determination of Sr/Ca by laser ablation ICP-MS compared to ICP-AES and application to multi-century temperate corals

Yuta Kawakubo,1,2 Yusuke Yokoyama,1,2,3 Atsushi Suzuki,4 Takashi Okai,4 Chantal Alibert,5 Leslie Kinsley5 and Stephen Eggins5

1Atmosphere and Ocean Research Institute, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8564, Japan
2Department of Earth and Planetary Science, Graduate School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
3Institute of Biogeosciences, Japan Agency for Marine-Earth Science and Technology, 2-15 Natsushima, Yokosuka, Kanagawa 237-0061, Japan
4Geological Survey of Japan, National Institute of Advanced Industrial Science and Technology (AIST), 1-1-1 Higashi, Tsukuba, Ibaraki 305-8567, Japan
5Research School of Earth Sciences, Australian National University, Australia

(Received August 31, 2013; Accepted November 18, 2013)

Abstract: Coral skeletal Sr/Ca compositions are valuable tools for the reconstruction of past tropical climate. While solution-based ICP-AES has become the preferred method to obtain monthly-resolved Sr/Ca records as proxy for sea-surface temperature (SST), laser ablation ICP-MS (LA-ICP-MS) allows a more rapid and still precise analysis of multiple elemental ratios at higher spatial resolution and, measurements can easily be replicated. However, the methodology still needs to be refined for long corals. It is applied here to a 435 year old Porites coral from the temperate region of southern Japan. Sr/Ca ratios measured by LA-ICP-MS and ICP-AES for three 10-15 yr periods are shown to be highly consistent. Resolution, data processing and Sr/Ca-SST calibration issues are discussed, and a replicate strategy is proposed to ensure high-precision Sr/Ca records from multi-century corals using LA-ICP-MS.
Key words: Sr/Ca, laser ablation ICP-MS, ICP-AES

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