1 / 20

Characterizing the magnetic fields of Mars: What do the tell us about the history of Mars?

Characterizing the magnetic fields of Mars: What do the tell us about the history of Mars?. Michael Purucker, Raytheon ITSS @ Planetary Geodyn. Laboratory, GSFC/NASA Greenbelt. Inst. Planet. Res.,DLR, Berlin: 23 Feb 2005. Outline. What controls the observed magnetic field?

gallia
Télécharger la présentation

Characterizing the magnetic fields of Mars: What do the tell us about the history of Mars?

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Characterizing the magnetic fields of Mars:What do the tell us about the history ofMars? Michael Purucker, Raytheon ITSS @ Planetary Geodyn. Laboratory, GSFC/NASA Greenbelt Inst. Planet. Res.,DLR, Berlin: 23 Feb 2005

  2. Outline • What controls the observed magnetic field? • A new magnetization model for Mars • A magnetic history of Mars

  3. What controls the observed magnetic fields ? • Core field strength, geometry, and duration • Thickness of magnetic crust • Material properties of magnetic crust • Subsequent history such as impacts and tectonics (Radial field at 200 km)

  4. Comparative magnetic properties Purucker, 2002: Memoire Proposal

  5. Power spectra compared Voorhies et al, 2002 and Olsen, 2002

  6. Magnetic fields reflect crustal thickness variations

  7. Magnetic fields can be described by source functions (magnetizations) on a global basis. Magnetization highs also correspond globally to areas of thick cool crust as determined by seismology

  8. Martian crustal thickness Few, if any, magnetic features are predicted by the above crustal thickness model and a dipolar magnetic field, suggesting either that magnetic thickness variations are not an important at Mars, or that we don’t yet have a good handle on the (magnetic) crustal thickness.

  9. Magnetics are also useful for tectonic interpretations

  10. M A new magnetization model Inclination Whaler and Purucker, 2005

  11. Interpretation of a new magnetization model

  12. Old terranes lacking large-scale magnetizations Purucker, 2002

  13. Purucker, 2002

  14. Mars’ most intense magnetic fields Purucker, 2002

  15. Structural control of Valles Marineris Purucker et al., 2001

  16. A new paleomagnetic pole made using the distribution and intensity of large scale magnetic features

  17. External field at Mars In addition to a static external field, there are dynamic fields associated with magnetopause boundary crossing in the northern hemisphere. External fields are currently the limiting factor in describing the crustal magnetic field at Mars.

  18. Conclusions • Much as we create a chronology tied to a planet’s impact history, we can create a chronology of magnetic events. • We still have a poor understanding of the factors responsible for Mars’ intense crustal magnetic field • Paleomagnetic poles can provide information on large-scale geodynamic problems. • Further progress will come through a better understanding of the external field, and new, lower altitude observations.

More Related