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.