Anomalies of Density, Stresses, and the Gravitational Field in the Interior of Mars

TL;DR

This study analyzes Mars's interior by determining compensation depths, stress distributions, and gravitational anomalies, suggesting mantle plumes influenced by gravitational field variations contribute to surface relief features.

Contribution

It provides the first detailed mapping of compensation depths, stress estimates, and the role of mantle plumes in shaping Martian surface anomalies.

Findings

Relief is fully compensated within 0-1400 km depth.

Estimated nonisostatic stresses are 64 MPa in compression and 20 MPa in tension.

Mantle plumes linked to gravitational anomalies explain surface features.

Abstract

We determined the possible compensation depths for relief harmonics of different degrees and orders. The relief is shown to be completely compensated within the depth range of 0 to 1400 km. The lateral distributions of compensation masses are determined at these depths and the maps are constructed. The possible nonisostatic vertical stresses in the crust and mantle of Mars are estimated to be 64 MPa in compression and 20 MPa in tension. The relief anomalies of the Tharsis volcanic plateau and symmetric feature in the eastern hemisphere could have arisen and been maintained dynamically due to two plumes in the mantle substance that are enriched with fluids. The plumes that originate at the core of Mars can arise and be maintained by the anomalies of the inner gravitational field achieving +800 mGal in the region of plume formation, - 1200 mGal above the lower mantle-core transition layer, and -1400 mGal at the crust.