North polar region of Mars: Advances in stratigraphy, structure, and erosional modification

Mars Advanced Radar for Subsurface and Ionospheric Sounding (MARSIS) after nine years of operation: A summary

“…The higher quality of the data allowed the mapping of the BU over the entire extent of Planum Boreum. Weak echoes within the BU outlined a two-layer structure, perhaps corresponding to the Rupes Tenuis unit and the Planum Boreum Cavi unit identified by Tanaka et al (2008) within the BU . The echo time delay between the surface return and the lower contact of the BU was used to derive a real relative dielectric constant of approximately 4 for its material, significantly higher than that of pure water ice, or of the NPLD alone observed at Gemina Lingula .…”

Geochemistry of Carbonates on Mars: Implications for Climate History and Nature of Aqueous Environments

“…They could have been derived from the Vastitas Borealis and Scandia deposition events, deposited as carbonate-bearing dust, and/or formed by pedogenic processes. The Phoenix landing site is situated on the ejecta from the Heimdall Crater (Heet et al 2009) that might contain material from both the mid to late Hesperian Vastitas Borealis Formation (VBF) and the early Amazonian Scandia material which are both penetrated by Heimdall Crater (Salvatore et al 2010;Tanaka et al 2008). The VBF has been speculated to have formed from sediments generated by outflow channels during the Hesperian ) and therefore might contain carbonate minerals eroded during those events or formed during the evaporation or freezing of the outflow channel effluents.…”

The construction of Chasma Boreale on Mars

“…1a). Beneath approximately 60% of the NPLD 11 , sandy deposits overlie older ice-rich layers [12][13][14] and together comprise what has been termed the ''basal unit'' 12 . It has been postulated 12,15 that Chasma Boreale is located along the basal unit's edge in that area, although a causal relationship was not established.…”

“…It has been postulated 12,15 that Chasma Boreale is located along the basal unit's edge in that area, although a causal relationship was not established. Further work has indicated that the floor of Chasma Boreale is probably a residual shelf of lower basal unit 13,16,17 .…”

“…This has led some researchers to conclude that Chasma Boreale was formed as a result of aeolian processes, rather than a basal melt event 8,9,13 . Until recently, however, neither comprehensive NPLD stratigraphy nor large-scale basal topography has been available to construct a full history of Chasma Boreale development or more fully test formation hypotheses.…”