Project Examples

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MULTICHRON: A chronological study consists of a series of procedures before dissolving a rock and applying high-precision isotope-analysis-technique. Project in 2009 was named multichron and Sanbagawa metamorphic rocks were the target. The rock experienced multiple processes during subduction and exhumation. On petrography, the interns tried to pick texture and mineral phases that is resulted from different processes. Next before the chronology, elemental abundances of concern in mineral phases were determined by in-situ ion probe technique. Finally multiple chronologies was applied using by TIMS and ICPMS. Nether-less to say, zircons are dated by high-resolution SIMS at the same time.

• Multichronology of the highest-grade quartz-rich eclogite from the Sambagawa metamorphic belt, SW Japan (2009)
• Time decoding for the subduction and exhumation processes in an ancient convergent plate margin: Multichronology of the Paleozoic eclogites in Japan (2008)
• MULTIPLUTON: Orogen-perpendicular geochemical and geochronological exploration of multiple plutons (2010)
• Isochron dating of mid-crustal (Barrovian-type) metamorphism in an active convergent margin (2011)

METEORITES: PML is interested in not only rock in earth but from the space. Three extra-terrestrial rock (meteorites named carbonaceous chondrites) were picked and elemental transportation between chondrules and rock was discussed. The rocks are though to from asteroid that stopped geological evolution for unknown reason. Since we cannot tell where the meteorites (they correspond to rolling stones in the earth) we try to observe behavior of multi elements to extract process on the asteroid. Trace elements are especially important because its behavior is free from phase control and only by geochemical behavior. The intern students analyzed bulk elemental composition (30 elements) and phase-to-phase trace elemental analyzed to discuss elemental transportation.

• An application of comprehensive geochemical analysis onto carbonaceous-chondrite constituents (2008)
• The preliminary survey for the Chelyabinsk Meteorite (2013)
• Age determination of the Begga and the Olivanza chondrites using step-wise leaching technique (2014)
• Major- and trace-element distribution and transportation on enstatite-chondrite parent-body -- Comprehensive evaluation of phases using in-situ and whole-rock techniques (2015)
• Major and trace element distribution on Howardites: homogeneity and heterogeneity of 4 Vesta (2016)
• Basalt from Vesta: major and trace element heterogeneity preserved on the surface of molten asteroid (2017)
• Geochemical probing: comprehensive analyses of carbonaceous chondrites (2018)

SYNTHESIS: One of important procedure for in-situ work in geochemistry is to prepare reference material. Even you are only interested in processes on earth, you cannot avoid to spend time on preparation on analysis sometimes. Projects in 2006 and 2007 were design to have this experience. Isotopically doped glass with various major element composition were synthesized using gas mixing furnace, cold-seal hydrothermal apparatus, and piston-cylinder apparatus. Its lithium and oxygen isotope-composition was determined using ICP-MS and oxygen stable-mass-spectrometry and reference materials for ion probe was generated.

• Synthesis of glass-reference materials for secondary ion mass spectrometry (2007)
• Glass standard preparation of SA-86 and JA-1 for lithium and boron isotope analysis (2006)