| Project/Area Number |
22340167
|
|---|
| Research Category |
Grant-in-Aid for Scientific Research (B)
|
| Allocation Type | Single-year Grants |
|---|
| Section | 一般 |
|---|
| Research Field |
Geochemistry/Astrochemistry
|
|---|
| Research Institution | National Institute of Polar Research |
|---|
Principal Investigator |
MISAWA Keiji 国立極地研究所, 研究教育系, 准教授 (70212230)
|
|---|
| Co-Investigator(Kenkyū-buntansha) |
KAIDEN Hiroshi 国立極地研究所, 研究教育系, 助教 (10302811)
|
|---|
| Research Collaborator |
NIIHARA Takafumi Lunar and Planetary Institute, 博士研究員
LARRY E. Nyquist アメリカ航空宇宙局, ジョンソン宇宙センター, 研究員
CHI-YU Shih ヤコブステクノロジー, 研究員
PARK Jisun Lunar and Planetary Institute, 研究員
|
|---|
| Project Period (FY) |
2010 – 2012
|
| Project Status |
Completed (Fiscal Year 2012)
|
| Budget Amount *help |
¥14,170,000 (Direct Cost: ¥10,900,000、Indirect Cost: ¥3,270,000)
Fiscal Year 2012: ¥3,380,000 (Direct Cost: ¥2,600,000、Indirect Cost: ¥780,000)
Fiscal Year 2011: ¥5,070,000 (Direct Cost: ¥3,900,000、Indirect Cost: ¥1,170,000)
Fiscal Year 2010: ¥5,720,000 (Direct Cost: ¥4,400,000、Indirect Cost: ¥1,320,000)
|
|---|
| Keywords | 同位体 / 放射年代 / 火星 / 火成活動 / 結晶分化 |
|---|
| Research Abstract |
Shock-recovery and annealing experiments on basalt-baddeleyite mixtures were undertaken to evaluate shock effects on U-Pb systematics of baddeleyite. Complete radiogenic lead loss due to shock metamorphism and subsequent annealing was not observed in the baddeleyites studied here. In order to address the timescale over which Mars was geologically active, we have undertaken U-Pb studies on baddeleyite in the Roberts Massif 04261 shergottite. In situ U-Th-Pb isotopic analyses of baddeleyite yield a young 238U-206Pb age of ~200 Ma. The present results imply that Martian magma was still forming only 200 Ma ago, and that Mars had been geologically active until the recent past. The present results confirm the previous Rb-Sr, Sm-Nd and Lu-Hf systematics but conflict with the Pb-Pb ages of 4.1 Ga for shergottites by the Lyon group, possibly due to Martian crustal component(s) which might have been incorporated into constituent phases of shergottites during shock metamorphism.
|
