The Mass Spectrometry society of Japan - The 68th Annual Conference on Mass Spectrometry, Japan
Japanese

Abstract

Table of contents

Timetable

Plenary Lectures

Award Lecture

Oral Sessions (Day1, Day2, Day3)

Poster Presentations (Day1, Day2, Day3)

Panel Discussion

Luncheon Seminars (Day1, Day2, Day3)

Corporate Program

Oral Sessions

Day 2, June 23（Thu.）　10:20-10:40　Room C (411 and 412)

2C-O1-1020　　PDF

Development of an Analytical Technique for U-series Disequilibrium Dating Methods for Holocene Samples utilising Laser Ablation-ICP-Triple Quadrupole-Mass Spectrometry

(1Univ. Tokyo, 2Kyoto Fission-Track)
oSota Niki1, Shuhei Kosugi1, Hideki Iwano1,2, Tohru Danhara2, Takafumi Hirata1

U-series disequilibrium dating methods are conducted for Quaternary samples, especially volcanic rocks and minerals to derive chronological information of magmatic processes including volcanic eruptions, restorage/mixing of magma, and melt generation. To understand the multiplicated magmatic processes, statistical treatments of chronological data are effective, and rapid and in situ analytical techniques for U-series disequilibrium dating are highly desired.
Faced with this problem, we have developed an in situ 238U-230Th dating method using an ICP-triple quadrupole-mass spectrometer coupled with a multiple-spot femtosecond laser ablation sampling technique (msfsLA-ICP-QQQ-MS). With a kinetic energy discrimination (KED) technique applied by the QQQ system, the polyatomic interferences can be effectively eliminated while the loss of the ion transmission through the KED was only 30%. Moreover, owing to the msfs LA system with the repetition rate of 60 kHz, laser sampling from 1×1 mm2 area can be carried out with short time durations (e.g., < 1 s), resulting in the better signal-to-noise ratios (SNRs) of the analytes and the higher analysis throughput. For age determinations on Holocene samples, the 230Th-226Ra disequilibria are also important, and the present msfsLA-ICP-QQQ-MS technique was applied for the in situ measurements of 226Ra from standard zircon and standard rock materials. Analytical capability of the present system for the 238U-230Th-226Ra dating method onto Holocene volcanic samples will be discussed in this talk.