4.1 Major Element Analyses
In addition to detrital zircon U-Pb dating, bulk sediment samples were analyzed for their major element contents by Inductively Coupled Plasma Emission Spectrometry (ICP-ES) at Boston University (BU), USA. Sediment samples were decarbonated with acetic acid, washed with distilled and deionized water with a purity of 9–12 megaohms, and hand powdered at Louisiana State University (LSU) before total fusion preparation at BU. Glass beads for each sample were made in a muffle furnace under 1050˚C by fusing 100 ± 0.5 mg of sample mixed with 400 ± 0.5 mg lithium metaborate (LiBO2). The melted mixture was then dissolved in 5% HNO3, sonicated, manually shaken until no visible grains were observed, and further diluted for analysis [Dunlea et al. , 2015]. Precision for all elements was better than 1% of the measured value, and accuracy was confirmed by repeated analyses of International Standard Reference Materials (Basalt, Hawaiian Volcano Observatory, BHVO-2)[Wilson , 1997]. Results of the geochemical measurements are shown in Table 1.