Abstract
A deformation path of amygdules in basic schists that underwent contact metamorphism in Itoshima area, northern Kyushu, Japan, has been revealed using shape and internal microstructure of the amygdules. The amygdules are filled mainly with plagioclase that was recrystallized during the contact metamorphism. Crystal size of the plagioclase decreases with increasing aspect ratio of the amygdules. Some amygdules with low-aspect ratio contain plagioclase showing flat twin boundaries. This suggests that such amygdules were undeformed after peak of the contact metamorphism and preserved the strain accumulated until then, which probably includes prograde stage of the contact metamorphism and former regional Renge metamorphism. In contrast, the amygdules with high-aspect ratio underwent superimposition of deformation taking place after peak of the contact metamorphism. The strain analysis shows the constriction types for the former amygdules while the plane-strain types for the latter. This reveals a deformation path of the amygdules such that the constrictional strain before the peak of contact metamorphism was partially overprinted by later flattening strain, showing the apparent plane-strain types.
| Original language | English |
|---|---|
| Article number | e12246 |
| Journal | Island Arc |
| Volume | 27 |
| Issue number | 4 |
| DOIs | |
| Publication status | Published - Jul 1 2018 |
Fingerprint
All Science Journal Classification (ASJC) codes
- Geology
Cite this
Deformation path of amygdules in basic schists in Itoshima area, northern Kyushu, Japan. / Yamasaki, Yukiko; Ikeda, Takeshi.
In: Island Arc, Vol. 27, No. 4, e12246, 01.07.2018.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Deformation path of amygdules in basic schists in Itoshima area, northern Kyushu, Japan
AU - Yamasaki, Yukiko
AU - Ikeda, Takeshi
PY - 2018/7/1
Y1 - 2018/7/1
N2 - A deformation path of amygdules in basic schists that underwent contact metamorphism in Itoshima area, northern Kyushu, Japan, has been revealed using shape and internal microstructure of the amygdules. The amygdules are filled mainly with plagioclase that was recrystallized during the contact metamorphism. Crystal size of the plagioclase decreases with increasing aspect ratio of the amygdules. Some amygdules with low-aspect ratio contain plagioclase showing flat twin boundaries. This suggests that such amygdules were undeformed after peak of the contact metamorphism and preserved the strain accumulated until then, which probably includes prograde stage of the contact metamorphism and former regional Renge metamorphism. In contrast, the amygdules with high-aspect ratio underwent superimposition of deformation taking place after peak of the contact metamorphism. The strain analysis shows the constriction types for the former amygdules while the plane-strain types for the latter. This reveals a deformation path of the amygdules such that the constrictional strain before the peak of contact metamorphism was partially overprinted by later flattening strain, showing the apparent plane-strain types.
AB - A deformation path of amygdules in basic schists that underwent contact metamorphism in Itoshima area, northern Kyushu, Japan, has been revealed using shape and internal microstructure of the amygdules. The amygdules are filled mainly with plagioclase that was recrystallized during the contact metamorphism. Crystal size of the plagioclase decreases with increasing aspect ratio of the amygdules. Some amygdules with low-aspect ratio contain plagioclase showing flat twin boundaries. This suggests that such amygdules were undeformed after peak of the contact metamorphism and preserved the strain accumulated until then, which probably includes prograde stage of the contact metamorphism and former regional Renge metamorphism. In contrast, the amygdules with high-aspect ratio underwent superimposition of deformation taking place after peak of the contact metamorphism. The strain analysis shows the constriction types for the former amygdules while the plane-strain types for the latter. This reveals a deformation path of the amygdules such that the constrictional strain before the peak of contact metamorphism was partially overprinted by later flattening strain, showing the apparent plane-strain types.
UR - http://www.scopus.com/inward/record.url?scp=85044633812&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=85044633812&partnerID=8YFLogxK
U2 - 10.1111/iar.12246
DO - 10.1111/iar.12246
M3 - Article
VL - 27
JO - Island Arc
JF - Island Arc
SN - 1038-4871
IS - 4
M1 - e12246
ER -