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Record 10 of 720
Could Giant Basin-Forming Impacts Have Killed Martian Dynamo?
External Online Source: doi:10.1002/2014GL061818
Author and Affiliation:
Kuang, W.(NASA Goddard Space Flight Center, Greenbelt, MD United States)
Jiang, W.(Science Systems and Applications, Inc., Lanham, MD, United States)
Roberts, J.(Johns Hopkins Univ., Laurel, MD, United States)
Frey, H. V.(NASA Goddard Space Flight Center, Greenbelt, MD United States)
Abstract: 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.
Publication Date: Nov 22, 2014
Document ID:
20160005758
(Acquired May 06, 2016)
Subject Category: GEOSCIENCES (GENERAL)
Report/Patent Number: GSFC-E-DAA-TN31859
Document Type: Journal Article
Publication Information: Geophysical Research Letters; p. 8006-8012; (ISSN 0094-8276); Volume 41; Issue 22
Publisher Information: AGU Publications
Contract/Grant/Task Num: NNG12HP06C
Financial Sponsor: NASA Goddard Space Flight Center; Greenbelt, MD United States
Organization Source: NASA Goddard Space Flight Center; Greenbelt, MD United States
Description: 7p; In English
Distribution Limits: Unclassified; Publicly available; Unlimited
Rights: Copyright
NASA Terms: STRUCTURAL BASINS; MARS SURFACE; HETEROGENEITY; POLAR REGIONS; MAGNETIZATION; CORE-MANTLE BOUNDARY; MAGNETIC FIELDS; SIMULATION
Other Descriptors: MARTIAN DYNAMO; MAGNETIC FIELDS; PALEOPOLAR REORIENTATION
Availability Source: Other Sources
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