Ancient sedimentary deposits on mars: insights from orbital and rover missions
File(s)
Author(s)
Harris, Emma Rosemary Ann
Type
Thesis
Abstract
Exploration of sedimentary deposits guides interpretations of palaeo-environments. Within this thesis, I investigate two rover landing sites, focussing on rocks of the Noachian to early-Hesperian age (~4-3.6 Ga), a time during which Mars may have seen a global climatic shift from warm and wet, to cold and arid.
I first investigate Oxia Planum, the future landing site of the ExoMars Rosalind Franklin rover mission, which will search for preserved biosignatures in a phyllosilicate-bearing unit. Overlying the phyllosilicate-bearing unit is a dark, capping unit; here known as the Low albedo, Thin, Resistant (LTR) unit, which may have protected the phyllosilicate-bearing unit over geological time from solar radiation. I map the LTR unit using orbital remote sensing datasets and assess its morphology, discovering possible volcaniclastic and groundwater influences.
Next, I investigate the sulfate-bearing unit of Gale crater’s Aeolis Mons (“Mount Sharp”). Using remote sensing data from the Mars Science Laboratory (MSL) Curiosity rover, I analyse ~140 vertical metres of sulfate-bearing stratigraphy within a butte named Texoli. I interpret aeolian strata dissected by erosional surfaces that may represent regional aeolian or alluvial processes.
Finally, I assess of the regional extent of the erosional surfaces using long-distance rover imagery. Forty-three erosional surfaces are found to dissect 300 m of the wider sulfate-bearing unit at Gale crater. I suggest that the erosional surfaces represent regional aeolian deflation and multiple episodes of non-deposition that are likely unique to the sulfate-bearing unit within Mount Sharp.
The regions investigated show palaeo-environments dominated by aeolian activity alongside influences of aqueous activity. The sedimentary deposits explored represent aridification sequences suggesting that the drying of Mars was not confined to the transition from the Noachian to the Hesperian. Evidence for non-linear aridification with respect to surface environments indicates limits to habitability, both spatially and temporally, that were observed into the mid-Hesperian.
I first investigate Oxia Planum, the future landing site of the ExoMars Rosalind Franklin rover mission, which will search for preserved biosignatures in a phyllosilicate-bearing unit. Overlying the phyllosilicate-bearing unit is a dark, capping unit; here known as the Low albedo, Thin, Resistant (LTR) unit, which may have protected the phyllosilicate-bearing unit over geological time from solar radiation. I map the LTR unit using orbital remote sensing datasets and assess its morphology, discovering possible volcaniclastic and groundwater influences.
Next, I investigate the sulfate-bearing unit of Gale crater’s Aeolis Mons (“Mount Sharp”). Using remote sensing data from the Mars Science Laboratory (MSL) Curiosity rover, I analyse ~140 vertical metres of sulfate-bearing stratigraphy within a butte named Texoli. I interpret aeolian strata dissected by erosional surfaces that may represent regional aeolian or alluvial processes.
Finally, I assess of the regional extent of the erosional surfaces using long-distance rover imagery. Forty-three erosional surfaces are found to dissect 300 m of the wider sulfate-bearing unit at Gale crater. I suggest that the erosional surfaces represent regional aeolian deflation and multiple episodes of non-deposition that are likely unique to the sulfate-bearing unit within Mount Sharp.
The regions investigated show palaeo-environments dominated by aeolian activity alongside influences of aqueous activity. The sedimentary deposits explored represent aridification sequences suggesting that the drying of Mars was not confined to the transition from the Noachian to the Hesperian. Evidence for non-linear aridification with respect to surface environments indicates limits to habitability, both spatially and temporally, that were observed into the mid-Hesperian.
Version
Open Access
Date Issued
2025-03-28
Date Awarded
2025-11-01
Copyright Statement
Attribution-NonCommercial 4.0 International Licence (CC BY-NC)
License URL
Advisor
Davis, Joel
Gupta, Sanjeev
Grindrod, Peter
Publisher Department
Department of Earth Science & Engineering
Publisher Institution
Imperial College London
Qualification Level
Doctoral
Qualification Name
Doctor of Philosophy (PhD)