N. A. Chuikova, L. P. Nasonova, T. G. Maximova
This study determined the contribution of Martian topography and the density
jump at the Mohorovicic discontinuity (M) to the gravity in a quadratic
approximation. It also resolved the problem of determining the possible depths
of compensation for topography harmonics of various degrees and orders. It
shows that all the topography compensation is within the depth range from 0 to
1400 km. Different topographic irregularities are most likely to be compensated
at depths that correspond to the upper crust (d =(4.5 +- 3.7)km), crust-mantle
transition layer (d = (78 +- 24)km), lithospheric boundary (d = (200 +- 34)km),
upper-middle mantle transition layer (d = (400 +- 70)km), or middle-lower
mantle transition layer (d =(1120 +- 180)km). This paper presents the lateral
distributions of compensation masses for these depths and the respective maps.
According to calculations, stresses in the Martian crust and mantle may be as
high as 10^8 Pa. This paper shows that the topographic anomalies of the Tharsis
volcanic plateau and the symmetric formation in the eastern hemisphere could
have originated and be dynamically maintained by two plumes of melted mantle
substance enriched with fluids; these plumes may have their origin at the
boundary of the lower mantle.
View original:
http://arxiv.org/abs/1202.2246
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