Sustained fluvial deposition recorded in Mars' Noachian stratigraphic record

Research areas:
Year:
2020
Authors:
  • Francesco Salese
  • William J. McMahon
  • Matthew R. Balme
  • Véronique Ansan
  • Joel M. Davis
  • Maarten G. Kleinhans
Journal:
NATURE COMMUNICATIONS
Volume:
11
Number:
1
Month:
MAY 5
ISSN:
2041-1723
Abstract:
Orbital observation has revealed a rich record of fluvial landforms on
Mars, with much of this record dating 3.6-3.0 Ga. Despite widespread
geomorphic evidence, few analyses of Mars' alluvial
sedimentary-stratigraphic record exist, with detailed studies of
alluvium largely limited to smaller sand-bodies amenable to study
in-situ by rovers. These typically metre-scale outcrop dimensions have
prevented interpretation of larger scale channel-morphology and
long-term basin evolution, vital for understanding the past Martian
climate. Here we give an interpretation of a large sedimentary
succession at Izola mensa within the NW Hellas Basin rim. The succession
comprises channel and barform packages which together demonstrate that
river deposition was already well established >3.7 Ga. The deposits
mirror terrestrial analogues subject to low-peak discharge variation,
implying that river deposition at Izola was subject to sustained,
potentially perennial, fluvial flow. Such conditions would require an
environment capable of maintaining large volumes of water for extensive
time-periods, necessitating a precipitation-driven hydrological cycle.
Using high-resolution orbital imagery of the Martian surface, the
authors Salese et al. here describe the first discovered stratigraphic
product of multiple extensive fluvial-channel belts in an exposed
vertical section at Izola Mensa in the northwestern rim of the Hellas
Basin.