Relaxation of the Martian dichotomy boundary: Faulting in the Ismenius Region and constraints on the early evolution of Mars

Details Relaxation of the Martian dichotomy boundary: Faulting in the Ismenius Region and constraints on the early evolution of Mars Relaxation of the Martian dichotomy boundary: Faulting in the Ismenius Region and constraints on the early evolution of Mars

Dec 2005

adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2005jgre..11012s25g&link_type=abstract

Journal of Geophysical Research, Volume 110, Issue E12, CiteID E12S25

Physics

5

Planetary Sciences: Solar System Objects: Mars, Planetary Sciences: Solid Surface Planets: Tectonics (8149), Planetary Sciences: Solid Surface Planets: Interiors (8147), Planetary Sciences: Solid Surface Planets: Origin And Evolution, Tectonophysics: Dynamics Of Lithosphere And Mantle: General (1213)

Scientific paper

The Martian dichotomy is a global feature separating the cratered southern highlands and smooth northern lowlands. Parts of the boundary are defined by steep slopes with elevation differences of 2-6 km. Here we use constraints from the well-preserved section of the dichotomy in the Ismenius Region. We study the relaxation of the boundary using both finite element and semianalytical techniques to better constrain the thermomechanical conditions in early Mars. We argue that the steep slopes are the product of faulting resulting from relaxation of the edge of the boundary by lower crustal flow. This relaxation requires that the lower crust must be at least 10 km thick and have a viscosity of ~1021 Pa s during the first 100-300 Myr of relaxation. We show that a wet crustal rheology and a thermal gradient of ~15-20 K/km at 4 Ga allows for both the partial relaxation of the Martian dichotomy and preservation of long wavelength topography as observed on Mars. This result is generally consistent with a stagnant-lid model of cooling of Martian interior. The thermal gradient at 4 Ga is also consistent with the estimated elastic thickness on early Mars. Our modeling constrains the original slope of the boundary to approximately 2°. We cannot constrain the crustal thickness more tightly than the current estimates of 50-100 km. On the basis of our semianalytical modeling, the relaxation of the boundary can contribute to the general north-south slope observed on Mars.

Affiliated with

Also associated with

No associations

Rating

Relaxation of the Martian dichotomy boundary: Faulting in the Ismenius Region and constraints on the early evolution of Mars does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.

If you have personal experience with Relaxation of the Martian dichotomy boundary: Faulting in the Ismenius Region and constraints on the early evolution of Mars, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Relaxation of the Martian dichotomy boundary: Faulting in the Ismenius Region and constraints on the early evolution of Mars will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-1611523