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| Titel |
Mercurian megaregolith layer and surface heat flows constraints |
| VerfasserIn |
Isabel Egea-González, Javier Ruiz |
| Konferenz |
EGU General Assembly 2013
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 15 (2013) |
| Datensatznummer |
250073194
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| Zusammenfassung |
| Mercury is covered by a thermally insulating megaregolith layer. Despite the fact that it is
known that this poor conducting layer has important influences on surface heat flows, most
thermal modeling studies have overlooked it. Mercurian megaregolith is not very well known,
but data provided by MESSENGER suggest that mercurian megaregolith is less insulating
than its lunar counterpart. This information together with brittle-ductile transition
(BDT) depths, estimated from the analysis of fault geometries associated with lobate
scarps, allow us to constrain the surface heat flow on Mercury at the time of scarps
formation.
In this work, we have solved the heat conduction equation in order to constrain surface
heat flows. Firstly, we obtain an upper limit in surface heat flows by using published values of
the BDT depth and by neglecting the megaregolith layer. Then, we calculate a lower limit by
including in the heat equation a top layer with thermal properties representative of the lunar
megaregolith. In our calculations we have taken into account volumetric heat production
rates obtained from the surface abundances of radioactive elements provided by
MESSENGER. Heat equation solutions constrain surface heat flows to a range
of 6 – 29 mWm-2. These results suggest the possibility that surface heat flows
could be lower than those calculated in previous works, which is in agreement
with the small amount of radial contraction detected on Mercury. Furthermore,
the procedure followed in this article can be easily applied to other planets and
satellites, which will improve our knowledge about the thermal evolution of these
bodies. |
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