| Project/Area Number |
17340149
|
|---|
| Research Category |
Grant-in-Aid for Scientific Research (B)
|
| Allocation Type | Single-year Grants |
|---|
| Section | 一般 |
|---|
| Research Field |
Geology
|
|---|
| Research Institution | Shimane University |
|---|
Principal Investigator |
TAKASU Akira Shimane University, Geoscince, Professor (00183848)
|
|---|
| Co-Investigator(Kenkyū-buntansha) |
TAGIRI Michio Ibaraki University, Earth Science, Professor (50007829)
AKASAKA Masahide Shimane University, Geoscience, Professor (20202509)
KAMEI Atsushi Shimane University, Geoscience, Associate Professor (60379691)
OHIRA Hiroto Shimane University, Geoscience, Assistant Professor (60273918)
|
|---|
| Project Period (FY) |
2005 – 2007
|
| Project Status |
Completed (Fiscal Year 2007)
|
| Budget Amount *help |
¥14,580,000 (Direct Cost: ¥14,100,000、Indirect Cost: ¥480,000)
Fiscal Year 2007: ¥2,080,000 (Direct Cost: ¥1,600,000、Indirect Cost: ¥480,000)
Fiscal Year 2006: ¥2,300,000 (Direct Cost: ¥2,300,000)
Fiscal Year 2005: ¥10,200,000 (Direct Cost: ¥10,200,000)
|
|---|
| Keywords | metamorphic geology / Tien-Shan Mountains / geochronology / tectonics / zircon / monazite / Sambagawa metamorphic belt / 三波川変成岩 |
|---|
| Research Abstract |
(1)The clasts of glaucophane eclogites were newly found from a conglomerate bed tectonically overlying on the regional eclogite formation (Choloktor Formation) in the Atbashy area The eclogites in the Choloktor Formation ware crystallized thorn the conditions of the glaucophane schist fides to the eclogite facies (>15kb, 500-560℃). The eclogites from the conglomerate have experienced two events of high pressure type metamorphism, ie. metamorphismform to form. eclogite (>15 kb, 490-590℃) and metamorphism from the glaucophane schist facies to the epidote amphibolite fades. These suggest that there are at least two tectonic and metamorphic events of eclogite formation in the Paleozoic Southern Tien-Shan .
(2) Coesites have been newly described from talc-garnet-chloritoid schists and quartzites in the Makbal area. This suggests that the matrix metamorphic rocks of the eclogite blocks are suffered UHP metamorphism.
(3) The metamorphic conditions of the eclogites form the Neldy Formation and Makbal Formation are >12 kb, 480-570℃ and >15 kb, 540-620℃, respectively. Both eclogites were suffered prograde metamorphism of the epidote amphibolite facies and the glaucophane schist facies, respectively.
(4) Monazite separated from the talc-garnet-chloritoid schists were dated by COME U-Pb method, and the ages of the monazite are 480 Ma The ages of the monazites in garnet porphyroblasts were also measured and the ages are the same as those of separated monazites, 480 Ma is the age of the UHF metamorphism in the Makbal area. The K-Ar ages of biotite schists and amphibolites are 769 Ma and 881 Ma, respectively and they are older than the age of the UHP metamorphism.
(4) Eclogites in the Aktyuz area experienced the amphibolite to granulite facies metamorphism (4-10 kb, 560-660℃) before the eclogite metamorphism (15-25 kb, 600-710℃), suggesting a metamorphism of inception of subduction event.
|
