2013 Fiscal Year Final Research Report
Development of a new method to measure volatile content in small volcanic glasses
| Project/Area Number |
23654182
|
|---|
| Research Category |
Grant-in-Aid for Challenging Exploratory Research
|
| Allocation Type | Multi-year Fund |
|---|
| Research Field |
Petrology/Mineralogy/Science of ore deposit
|
|---|
| Research Institution | The University of Tokyo |
|---|
Principal Investigator |
|
|---|
| Project Period (FY) |
2011 – 2013
|
| Keywords | マグマ / FTIR / 含水量 / 顕微分析 / メルト包有物 |
|---|
| Research Abstract |
A method to quantify water content in small volcanic glasses has been developed. The technique uses Fourier transform infrared (FT-IR) micro reflectance spectroscopy, and thus does not require a doubly polished sample. For standards, we synthesized 32 glasses with different water concentrations ranging from basaltic to rhyolitic composition. An empirical relationship was established between total water contents and the negative peak heights of reflectance spectra. To apply the technique to natural samples of various shapes, we developed a method to correct the spectrum of melt inclusion contaminated with host minerals. As a result, the water content now can be quantified with reasonable accuracy (< 0.3 wt%) for melt inclusions having diameter as small as 20 micron with a typical measuring time of 22 min.
|
