from Part III - Mineralogy and Remote Sensing of Rocks, Soil, Dust, and Ices
Published online by Cambridge University Press: 10 December 2009
ABSTRACT
The surface and aeolian dust on Mars is rich in iron compounds, and significant quantities of dust have been observed to stick to permanent magnets that are either exposed to the dusty atmosphere, exposed to dust released by grinding into rocks, or inserted into the soil. All successful lander missions to Mars so far have carried permanent magnets of various designs for the purpose of studying dust magnetic properties. The magnetism of the aeolian dust is the result of the presence of magnetite, which apparently derives from mechanical weathering of magnetite-rich surface rocks. A strong correlation between the elements titanium and iron is observed in elemental abundance spectra of dust attracted to permanent-magnet surfaces, suggesting that the magnetite responsible for the magnetization of the dust is actually titanomagnetite. Overall, the dust can be shown to have a saturation magnetization of less than 2 A m2 kg− 1. However, some grains are significantly more magnetic, and by interaction with a permanent magnet it is possible to separate the airborne dust into populations of more and less magnetic grains. Subpopulations attracted to a magnet have been seen to have magnetizations above 7 A m2 kg− 1. The widespread presence of magnetite and other easily oxidized minerals like olivine in rocks and in the global Martian dust imply that the Martian surface has been largely devoid of liquid water for a very long time.
To save this book to your Kindle, first ensure no-reply@cambridge.org is added to your Approved Personal Document E-mail List under your Personal Document Settings on the Manage Your Content and Devices page of your Amazon account. Then enter the ‘name’ part of your Kindle email address below. Find out more about saving to your Kindle.
Note you can select to save to either the @free.kindle.com or @kindle.com variations. ‘@free.kindle.com’ emails are free but can only be saved to your device when it is connected to wi-fi. ‘@kindle.com’ emails can be delivered even when you are not connected to wi-fi, but note that service fees apply.
Find out more about the Kindle Personal Document Service.
To save content items to your account, please confirm that you agree to abide by our usage policies. If this is the first time you use this feature, you will be asked to authorise Cambridge Core to connect with your account. Find out more about saving content to Dropbox.
To save content items to your account, please confirm that you agree to abide by our usage policies. If this is the first time you use this feature, you will be asked to authorise Cambridge Core to connect with your account. Find out more about saving content to Google Drive.