| タイトル | Could Giant Basin-Forming Impacts Have Killed Martian Dynamo? |
| 著者（英） | Frey, H. V.; Roberts, J.; Kuang, W.; Jiang, W. |
| 著者所属（英） | NASA Goddard Space Flight Center |
| 発行日 | 2014-11-22 |
| 言語 | eng |
| 内容記述 | The observed strong remanent crustal magnetization at the surface of Mars suggests an active dynamo in the past and ceased to exist around early to middle Noachian era, estimated by examining remagnetization strengths in extant and buried impact basins. We investigate whether the Martian dynamo could have been killed by these large basin-forming impacts, via numerical simulation of subcritical dynamos with impact-induced thermal heterogeneity across the core-mantle boundary. We find that subcritical dynamos are prone to the impacts centered on locations within 30 deg of the equator but can easily survive those at higher latitudes. Our results further suggest that magnetic timing places a strong constraint on postimpact polar reorientation, e.g., a minimum 16 deg polar reorientation is needed if Utopia is the dynamo killer. |
| NASA分類 | Geosciences (General) |
| レポートNO | GSFC-E-DAA-TN31859 |
| 権利 | Copyright |
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