インターンプログラム

PMLグループのインターンへの取り組み


我々は地球の進化に不可欠なプロセスを理解したいと考えています.そのために (1) 石を記載,(2) プロセスの識別,(3) 年代測定, そして (4) ダイナミクスの演繹,というステップを踏むことにしています.

地球や太陽系の進化を記録しているのはなんといっても石です。すべての石の原子配置の記述、これが最高到達点といえなくもありません。しかし、それでも現在の配置はいくつものプロセスによる原子再配置の蓄積であり、ただ現在の配置を記述すればいいというわけではありません。我々は本質的なプロセスを理解するために、多次元連立方程式を解く、というスタンスで研究にあたっています。その連立方程式は3つの視点で記述されます。それは多元素、年代学、そしてマルチスケールという視点です。こういった分析を可能とするシステムが CASTEM です。

  • elemental (アラユルニウム): We determine of 57 (major and trace) elemental abundances.  Each element is unique; however, sometimes they behave similarly on a geological process.  The shared chemical property responds to the dominant process.  See elemental patterns - this rhapsody is one dimension to identify the process.
  • chronological: We believe rate of radiogenic decay to be constant.  By analyzing parent-daughter elemental ratio and isotope ratio of the daughter we date a process.  However as noted in elemental section, each chronometry responds differently to different geologic process.  Clocks are soft.  Different chronometry should be applied to date process of interest.  The Persistence of Memory are Pb-Pb, Rb-Sr, U-Pb, Sm-Nd, Lu-Hf, Mn-Cr chronometers.
  • scales: The largest scale is covered by meteorites from asteroidal belt (2 AU).  Earth-size scale is covered by field trip.  Down to 1 cm is by picking appropriate area.  After the selection of area, rocks are powered, homogenized, and elemental and isotope abundances are determined. To the 1 micron scale is evaluated by in-situ technique like electron and ion probe.  This year (2010) we step into the new scale by installing Transmission Electron Microscopy (TEM) and Field-Emission SEM (FE-SEM).  Our scale goes down to nano.

Through the intern program, we want to offer students opportunity to have an experience of this multi dimensional approach.  Clue cannot be noticed only by two eyes.

 

  

PROJECT EXAMPLES


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 eclogites 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)

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)

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)

WHAT IS THE PROJECT ON 2010?: As noted above, we have installed nano eye, Transmission Electron Microscopy (TEM) together with nano hand, Focus Ion Beam (FIB) to manipulate nano-scale sample.  We are thinking about intern project on 2010 to be one not only elemental and chronological but nano-scale related.  No matter what the project is, it will be design to access our facility CASTEM thoroughly.

DAILY, WEEKLY, then the LAST


Since many machines and tutors are involved during the intern period, we will have coffee time from 9:45am to 10:00am everyday to exchange daily info.  Cookies made in Japan will be supplied.

At the conclusion of the program, an intern symposium is held to orally present research results.  Our experience tells weekly summary helps very much to make the presentation good.  A typical rhythm in PML intern program is lab works from Monday to Thursday than summarize what you learned on Friday (, then enjoy weekend in Japan).

 

 

TECHNIQUES YOU CAN LEARN


Techniques that you might access during the internship program is listed. Note that if you really want to learn all techniques, you have to visit Misasa again as graduate student.

  • wet chemistry in clean lab:  column chemistry and operation of mass spectrometry (ICPMS and TIMS)
  • dry chemistry: XRF
  • micro beam: EPMA for major and SIMS for trace element determination
  • petrography: FE-SEM and conventional microscope (still useful)
  • stable isotope: high-precision oxygen isotope determination
  • nano: FIB and TEM

 

 

JAPANESE CLASS


The ISEI runs Japanese class for postdoc and non-Japanese students.  Since most of intern students are interested in the class, we arrange the project to let you have the class.  A little phrase helps when you communicate with local Japanese.

 

SOCIAL ACTIVITIES


We think social activities are important as well as science is.  Misasa is located in country side surrounded by mountains.  We usually take students to little mountain called Mt. Mitoku (that has a national treasure) and serious mountain called Mt. Daisen.  In the early August, our town Misasa has a Marie Currie dancing festival.  The intern students join the activity usually. 

We also run running and soccer club.

 

 

 

WANT TO KNOW MORE?


Look for our web page. Then contact us somehow.  We hope to see you.

 

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