Geochemical Journal, Vol. 52, 2018
JUN-ICHI KIMURA1*, QING CHANG1 and AKIRA FURUSAWA2
1Department of Solid Earth Geochemistry, Japan Agency for Marine-Earth Science and Technology (JAMSTEC), 2-15 Natsushima-Cho, Yokosuka, 237-0061, Japan
2Furusawa Geological Survey Co. Ltd., 93-7 Yashiki, Tosaki-Cho, Okazaki, 444-0840, Japan
(Received August 2, 2017; Accepted October 17, 2017)
In this paper, we report the analytical results of a new synthetic rhyolitic glass block fabricated from purified glass shards of Aso-4 tephra by using both solution and laser ablation (LA) inductively coupled plasma mass spectrometry (ICP-MS). The Aso-4 b-W glass block is extremely homogeneous in 10 major and 32 trace elements with 1-standard deviation error (1SD), which is better than ∼10% by LA-ICP-MS (n = 200). The Aso-4 b-W rhyolite glass was utilized to evaluate the matrix effect in LA-ICP-MS by using SRM 610 synthetic, GSE-1G basaltic andesite, and BHVO-2G basalt glasses as standards. The GSE-1G glass showed heterogeneity. Thus, the analytical results of Aso-4 b-W were normalized using BHVO-2G as the secondary standard. The major and trace element compositions were in good agreement within ∼10% relative deviation (% RD) compared with those from electron probe micro analyzer and solution ICP-MS, respectively. However, the use of the SRM 610 standard showed a matrix bias of −24% RD in heavy rare earth elements, but these concentrations were in good agreement when renormalized to BHVO-2G. A matrix-matched glass standard is strongly recommended for precise analysis of rhyolitic glass. The Aso-4 b-W and the ATHO-G rhyolite glasses were analyzed using GSE-1G as the standard with BHVO-2G normalization. The results for both standard glasses were in good agreement with the reference values, thereby showing the importance of the matrix-matched standard. Moreover, this indicates that the new Aso-4 b-W glass block is suitable as a check standard in analyses of unknown rhyolitic glasses.
Key words: Rhyolite glass, major element, trace element, LA-ICP-MS