Large-scale deformational systems in the South Polar Layered Deposits (Promethei Lingula, Mars): “Soft-sediment” and Deep-Seated Gravitational Slope Deformations Mechanisms

Physical modelling of large-scale deformational systems in the South Polar Layered Deposits (Promethei Lingula, Mars): new geological constraints and climatic implications

“…Large-scale motion of Promethei Lingula is negligible at present (e.g. Pathare & Paige 2005;Fishbaugh & Hvidberg 2006;Guallini et al 2012). Moreover, the estimated current viscosity/rheology of the ice would not result in the development of the observed regional deformation.…”

“…In an earlier study, Guallini et al (2012) presented a semi-quantitative structural and kinematic analysis of the large-scale deformation systems observed in the SPLDs along the margins of the Promethei Lingula ice sheet (Fig. 1a, c).…”

“…By systematically collecting structural data of the surveyed deformation features (particularly normal and transtensional faults), and by characterizing the cross-cutting relationships of the structures, these authors proposed a deformation history consisting of two superimposed, well-defined tectonic stages, and argued for soft-sediment and deepseated gravitational slope deformation (DSGSD) mechanisms within the SPLD. Here, we focus on the representative 'S 2 ' deformation system analysed by Guallini et al (2012) (Fig. 1a, b).…”

“…This means that at a certain point in time, the forces within the Promethei Lingula ice sheet locally exceeded the strength of the SPLD layers, leading to their deformation. On the basis of a structural analysis, Guallini et al (2012) suggested that the combined action of four main factors predisposed and/or triggered deformation of the SPLD: † Gravity (i.e. lithostatic stress).…”

“…The deformational behaviour of the S 2 system could be a useful tool with which to investigate the internal properties of its constituent layers and the physical conditions present during deformation. The purpose of this study is therefore to investigate the validity of the above-mentioned four sets of observations suggested by the structural analysis of Guallini et al (2012). In particular, this study aims to: (1) physically characterize the surveyed deformation; (2) understand the rheology of the Promethei Lingula ice sheet; (3) better identify the global-scale triggering mechanisms of the observed types of deformation; and (4) determine what effect (if any) past climate changes had on the South Pole of Mars and on the compositional variations within the SPLD.…”