Tectonic implications of Mars crustal magnetism

doi:10.1073/pnas.0507469102

Tectonic implications of Mars crustal magnetism

^*National Aeronautics and Space Administration Goddard Space Flight Center, Greenbelt, MD 20771; ^‡University of Delaware, Newark, DE 19716; ^¶University of California, Berkeley, CA 94720; ^§Catholic University of America, Washington, DC 20064; and ^∥Centre d'Etude Spatiale des Rayonnements, 31028 Toulouse Cedex 4, France

Contributed by N. F. Ness, August 29, 2005

Abstract

Mars currently has no global magnetic field of internal origin but must have had one in the past, when the crust acquired intense magnetization, presumably by cooling in the presence of an Earth-like magnetic field (thermoremanent magnetization). A new map of the magnetic field of Mars, compiled by using measurements acquired at an ≈400-km mapping altitude by the Mars Global Surveyor spacecraft, is presented here. The increased spatial resolution and sensitivity of this map provide new insight into the origin and evolution of the Mars crust. Variations in the crustal magnetic field appear in association with major faults, some previously identified in imagery and topography (Cerberus Rupes and Valles Marineris). Two parallel great faults are identified in Terra Meridiani by offset magnetic field contours. They appear similar to transform faults that occur in oceanic crust on Earth, and support the notion that the Mars crust formed during an early era of plate tectonics.

Footnotes

↵ † To whom correspondence may be addressed. E-mail: jack.connerney{at}nasa.gov or nfnudel{at}yahoo.com.
Author contributions: J.E.P.C., M.H.A., N.F.N., R.P.L., and H.R. designed research; J.E.P.C., M.H.A., N.F.N., G.K., D.L.M., R.P.L., and H.R. performed research; J.E.P.C. contributed new reagents/analytic tools; J.E.P.C., G.K., and D.L.M. analyzed data; and J.E.P.C. wrote the paper.
Abbreviation: MGS, Mars Global Surveyor.
Freely available online through the PNAS open access option.