Venera 13 and Venera 14: Sedimentary Rocks on Venus?

Abstract

Venera 13 and Venera 14 transmitted almost complete panoramic views of their landing sites. Analyses of the photographs show the presence of rock formations undergoing geomorphic degradation. The formations display ripple marks, thin layering, differential erosion, and curvilinear fracturings. Some of them are interpreted as lithified clastic sediments. The lithification could have taken place at depth or at the surface, resulting in a type of duricrust. The origin of the sediments is unknown but could be aeolian, volcanic, or related to impacts or to turbidity currents.

Solid Planet–Atmosphere Interactions

“…Porous layered deposits have been observed at the landing sites on Venus (e.g., Basilevsky et al, 1985;Florensky et al, 1977Florensky et al, , 1983aGarvin et al, 1984), at Meridiani Planum on Mars (Squyres et al, 2006), and at the Columbia Hills in Gusev crater (Figures 1 and 2). Planetary surfaces are partially covered by wind-blown material, rock fragments, and fine-grained soil.…”

VenSAR on EnVision: Taking earth observation radar to Venus

“…Dunes and other aeolian features are rarely large enough to be visible in Magellan images so new data to understand its modern sedimentary processes is key to distinguishing whether ancient deposits formed under similar Although chemically similar to basalts, the layering is more similar to sedimentary or pyroclastic bedding (Florensky et al 1983a), formed by cycles of air fall or ground flow. Based on load carrying capacities derived from the penetrometer and dynamic loads during lander impact (Marov and Grinspoon 1998;Surkov et al 1984), the strength of the surface at the Venera 13 site is similar to that of a dense sand or weak rock.…”

EnVision: taking the pulse of our twin planet

“…Although Venus is apparently largely devoid of sediments, landers have shown that the surface is strongly weathered and may consist of sedimentary rocks (Florensky et al, 1983); dunes, wind-streaks and landslides have all been detected in Magellan data. Particularly enigmatic are the canali (Figure 1): moderately sinuous, parallel-sided channels crossing the plains, with widths of a few km and lengths of hundreds to thousands of km (Baker et al, 1992, Komatsu andBaker, 1994) that may represent exotic lava flow channels (Komatsu et al, 2001), ancient river beds (Jones and Pickering, 2003) or the result of turbidity currents (Waltham et al, 2008) in the dense atmosphere.…”