A rapid and precise method of establishing age model for coral skeletal radiocarbon to study surface oceanography using coupled X-ray photos and ICP-AES measurement

A high-precision age model is a critical component of coral skeletology. Here we propose a rapid and precise method, coupling coral growth band counting based on X-ray photo and Sr/Ca measurement using inductively coupled plasma atomic emission spectroscopy (ICP-AES) to establish the high-resolution age model. We measured Sr/Ca ratio of the Kikai coral, southeast of Japan using ICP-AES and compared the results with a previous study using laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS). Sr/Ca values in 1947-2009 obtained by ICP-AES measurement were well correlated with Sr/Ca values obtained by LA-ICP-MS. Therefore, our study once again proved the feasibility of establishing age models by using Sr/Ca of temperate corals, and a smaller sample amount was applied for ICP-AES measurement to obtain higher-resolution data. The age model established by both Sr/Ca ratio and X-ray photo of corals will be contributed to the high-resolution coral skeletology, such as reconstructing high-resolution paleoceanography using coral skeletal radiocarbon.

Automated summary

A new method combining coral growth band counting and Sr/Ca measurement using ICP-AES was proposed to establish a high-resolution age model. The study demonstrated the feasibility of using Sr/Ca for age modeling in coral and the ability of ICP-AES to provide higher-resolution data.