1. Iron species in plagioclase:
20 / Aug. / ‘19
Iron species in plagioclase:
Towards the understanding on magnetite exsolution in plagioclase
200 μm
R. Nakada1), M. Sato2,3), M. Ushioda3), Y. Tamura4), S. Yamamoto4)
1 JAMSTEC, 2 Univ. of Tokyo, 3 AIST, 4 Yokohama National Univ.

2. It is very important to understand the exsolution mechanism
Introduction
200 μm
What is the magnetite exsolution?
・ observed in silicate minerals in plutonic rocks
・ grain size < several μm
・ protected from weathering by matrix mineral
・ possible source of magnetic anomaly
It is very important to understand the exsolution mechanism

3. examine the Fe species in plagioclase
Purpose
Microscopic observation
Speciation analysis
examine the Fe species in plagioclase
understand the crystallization mechanisms of magnetite exsolution
Magnetic measurements
Composition analysis

4. Conclusions ・
Valence state of Fe in plagioclase varies among crystals separated from the same plutonic rock ・
Two different sites are confirmed as a host of Fe in plagioclase from the same rock ・
The valence state of Fe and its distribution in plagioclase may be an important factor in the exsolution mechanism