Inverted Channel Belts and Floodplain Clays to the East of Tempe Terra, Mars: Implications for Persistent Fluvial Activity on Early Mars

TL;DR

This study analyzes sinuous ridges east of Tempe Terra on Mars, suggesting they record persistent fluvial activity and floodplain deposits, implying a long-lasting warming event during early Mars' Noachian period.

Contribution

It provides evidence for sustained fluvial activity and floodplain formation on early Mars, indicating a prolonged warm period during the Noachian.

Findings

Sinuous ridges may be exhumed channel belts from meander rivers.

Layered smectite-bearing minerals are associated with floodplain deposits.

Persistent warming event lasted over 1500 years during the Noachian.

Abstract

The climate on early Mars is one of the major unsolved problems. It is unclear whether early Mars was warm and wet or cold and icy. Morphological features on Mars such as sinuous ridges could provide critical constraints to address this issue. Here we investigate several sinuous ridges to the east of Tempe Terra, Mars and find they may have recorded persistent fluvial activity on early Mars. Our analysis indicates that these ridges may represent exhumation of the channel belts and overbank deposits formed from meander rivers over significant geologic time. Layered smectite-bearing minerals, distributed along the ridge flanks, could be detrital or authigenic floodplain clays. Our interpretation of the stratigraphic relationships indicates that the layered smectite-bearing materials lie between channel belt deposits, supporting the floodplain interpretation. Our results suggest that a persistent warming event has persisted for a geologically significant interval (>1500 yr) during the Noachian period of Mars.