The cause for the north–south orientation of the crustal dichotomy and the equatorial location of Tharsis on Mars

Roberts, J. H.; Zhong, Shijie

doi:10.1016/j.icarus.2007.03.002

Cited by 24 publications

(3 citation statements)

References 37 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…TPW on Mars has been a controversial topic. Significant TPW (>50°) in the last 4 Gyr was suggested in studies on paleomagnetic poles [ Arkani‐Hamed and Boutin , 2004; Hood et al , 2005] and deformed ancient shorelines [ Perron et al , 2007] while TPW during or prior to Early Noachian (4.08–3.93 Ga) was inferred from the analysis of the moment of inertia from the Martian crustal dichotomy [ Roberts and Zhong , 2007]. However, the lack of global tectonic deformation predicted from TPW calculations [ Melosh , 1980; Grimm and Solomon , 1986] and stabilizing effect of thick elastic shell on the spin axis [ Willemann , 1984] were used as evidence for negligible TPW on Mars, although recent theoretical work by Matsuyama et al [2006] indicated that significant post‐Tharsis TPW is possible, which provided the basis to interpret the paleoshorelines in terms of TPW [ Perron et al , 2007]; recently, Matsuyama and Manga [2010] have reduced somewhat estimates of likely TPW.…”

Section: Discussionmentioning

confidence: 99%

Martian crustal dichotomy and Tharsis formation by partial melting coupled to early plume migration

Šrámek¹,

Zhong²

2012

J. Geophys. Res.

Self Cite

View full text Add to dashboard Cite

[1] A recently proposed model links the formation and early evolution of the Tharsis volcanic province on Mars to the preexisting hemispheric dichotomy (Zhong, 2009). A key aspect of this model is the assumption of a deep lithospheric root below the thicker crust of the southern highlands. We implemented a parameterization of partial melting into the 3-D spherical shell mantle convection code CitcomS in order to investigate whether the required lithospheric thickness variation can be generated self-consistently by partial melting when stiffening of the melt residue due to devolatilization is considered. The rate of melt production strongly depends on the mantle temperature, and additional strong coupling between the flow and partial melting is introduced through the stiffening effect on the melt residue. We find that it is possible to generate a lithospheric keel by partial melting above a single upwelling that excites a relative rotation between the one-plate lithosphere and the mantle below while producing the amount of melt distributed in a broad region constrained to one hemisphere that is necessary to form the crustal dichotomy. This scenario thus offers an internal mechanism for the Martian dichotomy formation and validates the hypothesis of Zhong (2009).Citation: Šrámek, O., and S. Zhong (2012), Martian crustal dichotomy and Tharsis formation by partial melting coupled to early plume migration,

show abstract

Section: Discussionmentioning

confidence: 99%

Martian crustal dichotomy and Tharsis formation by partial melting coupled to early plume migration

Šrámek¹,

Zhong²

2012

J. Geophys. Res.

Self Cite

View full text Add to dashboard Cite

show abstract

“…Of course, this appealing scenario would have to be confirmed, by looking for other correlations between geological structures and magnetic signatures. A possible alternative but possible scenario is one in which the rotation equilibrium of Mars is not altered by the growth of the Tharsis bulge solely, but also by the hemispheric dichotomy, which is older than Tharsis [38]. Definitive answer might come from absolute timing of the surface, or from a better knowledge of the lithospheric structure, possibly using seismometers [27].…”

Section: Polar Wandermentioning

confidence: 99%

New perspectives on Mars’ crustal magnetic field

Langlais¹,

Quesnel²

2008

Comptes Rendus. Géoscience

View full text Add to dashboard Cite

The planet Mars lacks, today, a planetary, dynamic magnetic field, but strong, intense, localized magnetic fields of lithospheric origin, one to two orders of magnitude larger than the terrestrial lithospheric field, are present. This lithospheric magnetic field is the result of magnetization processes in the presence of a magnetic dynamo and of demagnetization processes after the dynamo shutdown, such as impact or volcanoes. This crude scenario can be more accurately specified by interpreting global and local models of the current magnetic field of Mars. Some specific areas are studied, including the intensely magnetized Terra Sirenum, as well as the magnetic anomaly associated with Apollinaris Patera. Magnetic minerals could be of primary and/or secondary origin; this latter would imply an early hydration of a basaltic crust. A scenario, in which Mars experienced a major polar wander due to the Tharsis bulge, prior to the cessation of its dynamo, is proposed and discussed. To cite this article: B.

show abstract

“…Degree-one convection is suspected to be responsible for the Martian crustal dichotomy [Wise et al, 1979;Harder and Christensen, 1996;Roberts and Zhong, 2007;Keller and Tackley, 2009;Šrámek and Zhong, 2012] and may also have been active in the Earth and the early Moon [Stevenson, 1980;Zhong et al, 2000]. Yoshida and Santosh [2011] reviewed the possibility of the degree-one and -two convection regimes in the Earth's mantle.…”

Section: Degree-one Single-plume State and Subcritical Convectionmentioning

confidence: 99%

Self‐consistent generation of single‐plume state for Enceladus using non‐Newtonian rheology

et al. 2014

View full text Add to dashboard Cite

The thermal dichotomy of Enceladus suggests an asymmetrical structure in its global heat transfer. So far, most of the models proposed that obtained such a distribution have prescribed an a priori asymmetry, i.e., some anomaly in or below the south polar ice shell. We present here the first set of numerical models of convection that yield a stable single-plume state for Enceladus without prescribed mechanical asymmetry. Using the convection code StagYY in a 2-D spherical annulus geometry, we show that a non-Newtonian ice rheology is sufficient to create a localized, single hot plume surrounded by a conductive ice mantle. We obtain a self-sustained state in which a region of small angular extent has a sufficiently low viscosity to allow subcritical to weak convection to occur due to the stress-dependent part of the rheological law. We find that the single-plume state is very unlikely to remain stable if the rheology is Newtonian, confirming what has been found by previous studies. In a second set of numerical simulations, we also investigate the first-order effect of tidal heating on the stability of the single-plume state. Tidal heating reinforces the stability of the single-plume state if it is generated in the plume itself. Lastly, we show that the likelihood of a stable single-plume state does not depend on the thickness of the ice shell.

show abstract

The cause for the north–south orientation of the crustal dichotomy and the equatorial location of Tharsis on Mars

Cited by 24 publications

References 37 publications

Martian crustal dichotomy and Tharsis formation by partial melting coupled to early plume migration

Martian crustal dichotomy and Tharsis formation by partial melting coupled to early plume migration

New perspectives on Mars’ crustal magnetic field

Self‐consistent generation of single‐plume state for Enceladus using non‐Newtonian rheology

Contact Info

Product

Resources

About