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Volcanogenic fluvial-lacustrine environments in iceland and their utility for identifying past habitability on Mars.

Cousins C - Life (Basel) (2015)

Bottom Line: The availability of liquid water coupled with the potential longevity of such systems renders these localities prime targets for the future exploration of Martian biosignatures.This meltwater can be stored to create subglacial, englacial, and proglacial lakes, or be released as catastrophic floods and proglacial fluvial systems.Sedimentary deposits produced by the resulting fluvial-lacustrine activity are extensive, with lithologies dominated by basaltic minerals, low-temperature alteration assemblages (e.g., smectite clays, calcite), and amorphous, poorly crystalline phases (basaltic glass, palagonite, nanophase iron oxides).

View Article: PubMed Central - PubMed

Affiliation: UK Centre for Astrobiology, School of Physics and Astronomy, University of Edinburgh, Mayfield Road, Edinburgh EH9 3JZ, UK. c.cousins@ed.ac.uk.

ABSTRACT
The search for once-habitable locations on Mars is increasingly focused on environments dominated by fluvial and lacustrine processes, such as those investigated by the Mars Science Laboratory Curiosity rover. The availability of liquid water coupled with the potential longevity of such systems renders these localities prime targets for the future exploration of Martian biosignatures. Fluvial-lacustrine environments associated with basaltic volcanism are highly relevant to Mars, but their terrestrial counterparts have been largely overlooked as a field analogue. Such environments are common in Iceland, where basaltic volcanism interacts with glacial ice and surface snow to produce large volumes of meltwater within an otherwise cold and dry environment. This meltwater can be stored to create subglacial, englacial, and proglacial lakes, or be released as catastrophic floods and proglacial fluvial systems. Sedimentary deposits produced by the resulting fluvial-lacustrine activity are extensive, with lithologies dominated by basaltic minerals, low-temperature alteration assemblages (e.g., smectite clays, calcite), and amorphous, poorly crystalline phases (basaltic glass, palagonite, nanophase iron oxides). This paper reviews examples of these environments, including their sedimentary deposits and microbiology, within the context of utilising these localities for future Mars analogue studies and instrument testing.

No MeSH data available.


Related in: MedlinePlus

Examples of proglacial fluvial environments and sedimentary deposits. (a) Skeiðarársandur, yellow box highlights the location of the fluvial-lacustrine sedimentary succession described in [70], and shown in (d); Image credit: SPOT5/Google Earth; (b) jokulhlaup sediments and channels at Sólheimajökull (adapted from [73]). Image credit: SPOT5/Google Earth; (c) National Land Survey of Iceland (NLSI) infrared satellite image (IS 50V database/SPOT data) of the Kverkjökull sandur described in [59]; (d) Cross section (approx. 240 m long) of fluvial-lacustrine sediments exposed along the Gígjukvísl river [70] at the location marked on (a), image credit Philip Marren.
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life-05-00568-f005: Examples of proglacial fluvial environments and sedimentary deposits. (a) Skeiðarársandur, yellow box highlights the location of the fluvial-lacustrine sedimentary succession described in [70], and shown in (d); Image credit: SPOT5/Google Earth; (b) jokulhlaup sediments and channels at Sólheimajökull (adapted from [73]). Image credit: SPOT5/Google Earth; (c) National Land Survey of Iceland (NLSI) infrared satellite image (IS 50V database/SPOT data) of the Kverkjökull sandur described in [59]; (d) Cross section (approx. 240 m long) of fluvial-lacustrine sediments exposed along the Gígjukvísl river [70] at the location marked on (a), image credit Philip Marren.

Mentions: Further to the south of Vatnajökull, the Skeiðarársandur proglacial sediments form the largest active outwash plain in the world [38], and as such record an extensive history of fluvial-lacustrine sedimentary deposition throughout the Holocene. An assemblage of fluvial and lacustrine sediments [70] is revealed along the Gígjukvísl River (Figure 5a), cut by the jökulhlaup in 1996. The section exposed here is ~240 m long with a maximum height of over 20 m (Figure 5d), and contains seven lithofacies, of which three are identified as fluvial, and four as lacustrine, forming a succession of depositional environments including a shallow ice-marginal braided river, proglacial braided river gravel bed, glaciolacustrine deposits, a high energy subaqueous flow, and finally a jökulhlaup event [70]. This outcrop therefore provides a variety of continuous sedimentary lithofacies for investigating biosignature deposition across a range of environments, and testing of future robotic instrumentation (Table 1). Sedimentary structures within the different fluvial lithofacies range from horizontally stratified or channelized sand layers within the ice marginal shallow braided stream, to well-sorted and cross-bedded gravels in the braided river gravel bed. Glaciolacustrine lithofacies encompass interbedded silts and fine sand and rippled silt layers. Finally, the jökulhlaup deposit encompasses the coarsest sediments with cross-cutting scours cutting into poorly sorted gravels, with well-developed imbrication [70]. Sediments exposed along the Gígjukvísl river have already been used for Mars analogue work investigating the utility of hand-lens imager type datasets (e.g., similar to data produced by the Mars Hand Lens Imager (MAHLI) on NASA’s MSL Curiosity rover) in characterizing sedimentary grain size and morphology, from which fluvial palaeoflows and processes can be interpreted [71]. Fluvial conglomerates comprising of cemented rounded pebbles have since been identified on Mars by the MSL Curiosity rover, providing the first in situ evidence of fluvial sedimentary deposition, most likely as part of a distal alluvial fan deposit [72].


Volcanogenic fluvial-lacustrine environments in iceland and their utility for identifying past habitability on Mars.

Cousins C - Life (Basel) (2015)

Examples of proglacial fluvial environments and sedimentary deposits. (a) Skeiðarársandur, yellow box highlights the location of the fluvial-lacustrine sedimentary succession described in [70], and shown in (d); Image credit: SPOT5/Google Earth; (b) jokulhlaup sediments and channels at Sólheimajökull (adapted from [73]). Image credit: SPOT5/Google Earth; (c) National Land Survey of Iceland (NLSI) infrared satellite image (IS 50V database/SPOT data) of the Kverkjökull sandur described in [59]; (d) Cross section (approx. 240 m long) of fluvial-lacustrine sediments exposed along the Gígjukvísl river [70] at the location marked on (a), image credit Philip Marren.
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Related In: Results  -  Collection

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life-05-00568-f005: Examples of proglacial fluvial environments and sedimentary deposits. (a) Skeiðarársandur, yellow box highlights the location of the fluvial-lacustrine sedimentary succession described in [70], and shown in (d); Image credit: SPOT5/Google Earth; (b) jokulhlaup sediments and channels at Sólheimajökull (adapted from [73]). Image credit: SPOT5/Google Earth; (c) National Land Survey of Iceland (NLSI) infrared satellite image (IS 50V database/SPOT data) of the Kverkjökull sandur described in [59]; (d) Cross section (approx. 240 m long) of fluvial-lacustrine sediments exposed along the Gígjukvísl river [70] at the location marked on (a), image credit Philip Marren.
Mentions: Further to the south of Vatnajökull, the Skeiðarársandur proglacial sediments form the largest active outwash plain in the world [38], and as such record an extensive history of fluvial-lacustrine sedimentary deposition throughout the Holocene. An assemblage of fluvial and lacustrine sediments [70] is revealed along the Gígjukvísl River (Figure 5a), cut by the jökulhlaup in 1996. The section exposed here is ~240 m long with a maximum height of over 20 m (Figure 5d), and contains seven lithofacies, of which three are identified as fluvial, and four as lacustrine, forming a succession of depositional environments including a shallow ice-marginal braided river, proglacial braided river gravel bed, glaciolacustrine deposits, a high energy subaqueous flow, and finally a jökulhlaup event [70]. This outcrop therefore provides a variety of continuous sedimentary lithofacies for investigating biosignature deposition across a range of environments, and testing of future robotic instrumentation (Table 1). Sedimentary structures within the different fluvial lithofacies range from horizontally stratified or channelized sand layers within the ice marginal shallow braided stream, to well-sorted and cross-bedded gravels in the braided river gravel bed. Glaciolacustrine lithofacies encompass interbedded silts and fine sand and rippled silt layers. Finally, the jökulhlaup deposit encompasses the coarsest sediments with cross-cutting scours cutting into poorly sorted gravels, with well-developed imbrication [70]. Sediments exposed along the Gígjukvísl river have already been used for Mars analogue work investigating the utility of hand-lens imager type datasets (e.g., similar to data produced by the Mars Hand Lens Imager (MAHLI) on NASA’s MSL Curiosity rover) in characterizing sedimentary grain size and morphology, from which fluvial palaeoflows and processes can be interpreted [71]. Fluvial conglomerates comprising of cemented rounded pebbles have since been identified on Mars by the MSL Curiosity rover, providing the first in situ evidence of fluvial sedimentary deposition, most likely as part of a distal alluvial fan deposit [72].

Bottom Line: The availability of liquid water coupled with the potential longevity of such systems renders these localities prime targets for the future exploration of Martian biosignatures.This meltwater can be stored to create subglacial, englacial, and proglacial lakes, or be released as catastrophic floods and proglacial fluvial systems.Sedimentary deposits produced by the resulting fluvial-lacustrine activity are extensive, with lithologies dominated by basaltic minerals, low-temperature alteration assemblages (e.g., smectite clays, calcite), and amorphous, poorly crystalline phases (basaltic glass, palagonite, nanophase iron oxides).

View Article: PubMed Central - PubMed

Affiliation: UK Centre for Astrobiology, School of Physics and Astronomy, University of Edinburgh, Mayfield Road, Edinburgh EH9 3JZ, UK. c.cousins@ed.ac.uk.

ABSTRACT
The search for once-habitable locations on Mars is increasingly focused on environments dominated by fluvial and lacustrine processes, such as those investigated by the Mars Science Laboratory Curiosity rover. The availability of liquid water coupled with the potential longevity of such systems renders these localities prime targets for the future exploration of Martian biosignatures. Fluvial-lacustrine environments associated with basaltic volcanism are highly relevant to Mars, but their terrestrial counterparts have been largely overlooked as a field analogue. Such environments are common in Iceland, where basaltic volcanism interacts with glacial ice and surface snow to produce large volumes of meltwater within an otherwise cold and dry environment. This meltwater can be stored to create subglacial, englacial, and proglacial lakes, or be released as catastrophic floods and proglacial fluvial systems. Sedimentary deposits produced by the resulting fluvial-lacustrine activity are extensive, with lithologies dominated by basaltic minerals, low-temperature alteration assemblages (e.g., smectite clays, calcite), and amorphous, poorly crystalline phases (basaltic glass, palagonite, nanophase iron oxides). This paper reviews examples of these environments, including their sedimentary deposits and microbiology, within the context of utilising these localities for future Mars analogue studies and instrument testing.

No MeSH data available.


Related in: MedlinePlus