Resurfacing event observed in Morpheos basin (Eridania Planitia) and the implications to the formation and timing of Waikato and Reull Valles, Mars

• Published in: Planetary and space science 2017-06, Vol.140, p.35-48
• Main Authors: Kostama, V.-P., Kukkonen, S., Raitala, J.
• Format: Article
• Language: English
• ISSN: 0032-0633; 1873-5088
• DOI: 10.1016/j.pss.2017.04.001

The large scale outflow channels of the Hellas impact basin are characteristic to its eastern rim region. Although the majority of the valles are located in the large-scale topographic trough connecting Hesperia Planum and Hellas basin, the most far-reaching of them, Reull Vallis is situated to the south-southeast of this trough cutting through Promethei Terra. Reull Vallis and the general geology of the region has been studied in the past, but new higher resolution image data enables us to look into the details of the features implicating the fluvial history of the region. Photogeological mapping using the available data and extensive crater counting utilizing CTX, HiRISE and HRSC provided new insights to the timing of the regional events and episodes. The study resulted in more detailed age constraints compared to the previous results from Viking images. These calculations and the geological study of the upper WMR system (Waikato Vallis – Morpheos basin – Reull Vallis) region and southern Hesperia Planum enabled us to estimate the time-frame of the (fluid) infilling of this reservoir to a model time period of 3.67–3.52Ga which is thus also the time of the visible activity of the upper Reull Vallis and Waikato Vallis outflow channels. The results also more explicitly defined the size of previously identified Morpheos basin (confined to the 500–550m contour lines). We also present a geological analysis of the upper parts of the WMR system, and using the observations and calculations, present an updated view of the evolution of the system and associated region. •Studied outflows were formed in time period between 3.67 and 3.52Ga.•Several activity pulses from the outflow channels were identified.•Geological map of the southern Hesperia Planum was produced.•Morpheos basin was filled to the limit defined by the 500–550 contour lines.