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| Titel |
Depth of thrust faulting and ancient heat flows in the Kuiper region of Mercury from lobate scarp topography |
| VerfasserIn |
Isabel Egea-González, Javier Ruiz, Carlos Fernández, Jean-Pierre Williams, Álvaro Márquez, Luisa M. Lara |
| Konferenz |
EGU General Assembly 2011
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 13 (2011) |
| Datensatznummer |
250051395
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| Zusammenfassung |
| Mercury’s most characteristic tectonic features are lobate scarps, which are interpreted to be
the surface expression of thrust faults and provide important clues on the geological and
thermal history of this planet. In fact, the large depth of faulting deduced from modeling
lobate scarps topography suggests that it represents the crustal brittle-ductile transition, which
in turn permits us to put limits on the thermal and mechanical properties of the lithosphere at
the time when faulting occurred.
In this work we use a forward modeling procedure in order to analyze the fault geometries
and depths associated with a group of prominent lobate scarps located in the Kuiper region of
Mercury for which Earth-base radar topographic profiles are available. A back
thrust, the first one reported for a Mercurian lobate scarp, has been included in this
study. Best fits to the topographies are obtained for thrust fault depths of 30-39
km. This result is consistent with the depths of faulting previously calculated by
different authors for other lobate scarps on Mercury. This could be indicative of a
relatively homogeneous brittle-ductile transition depth at the time when the lobate
scarps were formed. However, the heterogeneous insolation pattern on the surface
of Mercury should imply a slightly shallower brittle-ductile transition depth for
the Kuiper region, although our results do not have sufficient resolution to clearly
reveal this difference. Furthermore, the formation of the scarps analyzed in different
regions might not have been contemporaneous, and for that reason the depths of
faulting obtained might not be indicative of a homogeneous brittle-ductile transition
depth.
Calculations of surface heat flow have been performed from the brittle-ductile transition
depth beneath these lobate scarps by taking into account crustal heat sources and a
heterogeneous surface temperature due to the variable insolation pattern. Deduced surface
heat flows are between 16 and 28 mW m-2. These values are compatible with the
predictions of thermal history models for the range of time relevant for scarp formation. |
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