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Martian outflow channels: How did their source aquifers form, and why did they drain so rapidly?

Rodriguez JA, Kargel JS, Baker VR, Gulick VC, Berman DC, Fairén AG, Linares R, Zarroca M, Yan J, Miyamoto H, Glines N - Sci Rep (2015)

Bottom Line: Using more recent mission data, we argue that during the Late Noachian fluvial and glacial sediments were deposited into a clastic wedge within a paleo-basin located in the southern circum-Chryse region, which at the time was completely submerged under a primordial northern plains ocean [corrected].Subsequent Late Hesperian outflow channels were sourced from within these geologic materials and formed by gigantic groundwater outbursts driven by an elevated hydraulic head from the Valles Marineris region.Thus, our findings link the formation of the southern circum-Chryse outflow channels to ancient marine, glacial, and fluvial erosion and sedimentation.

View Article: PubMed Central - PubMed

Affiliation: Planetary Science Institute, 1700 East Fort Lowell Road, Suite 106, Tucson, AZ 85719-2395, USA.

ABSTRACT
Catastrophic floods generated ~3.2 Ga by rapid groundwater evacuation scoured the Solar System's most voluminous channels, the southern circum-Chryse outflow channels. Based on Viking Orbiter data analysis, it was hypothesized that these outflows emanated from a global Hesperian cryosphere-confined aquifer that was infused by south polar meltwater infiltration into the planet's upper crust. In this model, the outflow channels formed along zones of superlithostatic pressure generated by pronounced elevation differences around the Highland-Lowland Dichotomy Boundary. However, the restricted geographic location of the channels indicates that these conditions were not uniform. Furthermore, some outflow channel sources are too high to have been fed by south polar basal melting. Using more recent mission data, we argue that during the Late Noachian fluvial and glacial sediments were deposited into a clastic wedge within a paleo-basin located in the southern circum-Chryse region, which at the time was completely submerged under a primordial northern plains ocean [corrected]. Subsequent Late Hesperian outflow channels were sourced from within these geologic materials and formed by gigantic groundwater outbursts driven by an elevated hydraulic head from the Valles Marineris region. Thus, our findings link the formation of the southern circum-Chryse outflow channels to ancient marine, glacial, and fluvial erosion and sedimentation.

No MeSH data available.


Related in: MedlinePlus

(a) Sketches depicting the inferred geologic evolution of a subsided highland plateau in southern circum-Chryse. (1) Submarine troughs become infilled with water-saturated sediments during the Late Noachian. (2) The sedimentary deposits freeze into permafrost upon the ocean’s retreat stage. (3) The troughs’ infilling deposits undergo melting to generate vast systems of interconnected water-filled caverns that extend to eastern Valles Marineris. (4) Groundwater outbursts lead catastrophic flooding. (5) Subsidence occurs over the evacuated caverns and hydrid canyons form close to the paleoshoreline elevation. (5a) View of a hybrid canyon. (b) Sketches depicting the inferred relationship between the eastern Valles Marineris, zones of subsidence and outflow channel formation in southern circum-Chryse. Ice/water-saturated sediments contained within buried troughs (1) undergo extensive melting and interconnect with a highly pressurized aquifer in eastern Valles Marineris (2). Extensive groundwater drainage along the trough interior deposits leads to outflow channel activity in southern circum-Chryse as well as to extensive subsidence over evacuated conduits (3). The pre- and post-subsidence surface elevations were constructed using MOLA elevation profiles and the topographic analyses described in the supplement. We produced the sketches using adobe illustrator.
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f4: (a) Sketches depicting the inferred geologic evolution of a subsided highland plateau in southern circum-Chryse. (1) Submarine troughs become infilled with water-saturated sediments during the Late Noachian. (2) The sedimentary deposits freeze into permafrost upon the ocean’s retreat stage. (3) The troughs’ infilling deposits undergo melting to generate vast systems of interconnected water-filled caverns that extend to eastern Valles Marineris. (4) Groundwater outbursts lead catastrophic flooding. (5) Subsidence occurs over the evacuated caverns and hydrid canyons form close to the paleoshoreline elevation. (5a) View of a hybrid canyon. (b) Sketches depicting the inferred relationship between the eastern Valles Marineris, zones of subsidence and outflow channel formation in southern circum-Chryse. Ice/water-saturated sediments contained within buried troughs (1) undergo extensive melting and interconnect with a highly pressurized aquifer in eastern Valles Marineris (2). Extensive groundwater drainage along the trough interior deposits leads to outflow channel activity in southern circum-Chryse as well as to extensive subsidence over evacuated conduits (3). The pre- and post-subsidence surface elevations were constructed using MOLA elevation profiles and the topographic analyses described in the supplement. We produced the sketches using adobe illustrator.

Mentions: We propose the following regional geologic reconstruction leading to the development of the OFCS aquifers: The vast fluvial, or glacial-glaciofluvial, canyon systems of southern Margaritifer Terra423 discharged enormous volumes of sediments into southern circum-Chryse, where lower portions of these canyons were completely buried and integrated into the regional upper crustal stratigraphy (Fig. 4a). Coeval fluvial activity through the huge Uzboi-Ladon-Morava channel system, which connects the Argyre basin to the northern plains, is thought to have discharged vast volumes of water generated by the melting of a Late Noachian south polar ice sheet32. This enormous fluvial system could have also contributed to regional sedimentation in southern circum-Chryse233. In the proposed geologic scenario the upper extent of regional sedimentation would have been controlled by the elevation of Oceanus Borealis (Fig. 3b, sketches 1 and 2 in Fig. 4a).


Martian outflow channels: How did their source aquifers form, and why did they drain so rapidly?

Rodriguez JA, Kargel JS, Baker VR, Gulick VC, Berman DC, Fairén AG, Linares R, Zarroca M, Yan J, Miyamoto H, Glines N - Sci Rep (2015)

(a) Sketches depicting the inferred geologic evolution of a subsided highland plateau in southern circum-Chryse. (1) Submarine troughs become infilled with water-saturated sediments during the Late Noachian. (2) The sedimentary deposits freeze into permafrost upon the ocean’s retreat stage. (3) The troughs’ infilling deposits undergo melting to generate vast systems of interconnected water-filled caverns that extend to eastern Valles Marineris. (4) Groundwater outbursts lead catastrophic flooding. (5) Subsidence occurs over the evacuated caverns and hydrid canyons form close to the paleoshoreline elevation. (5a) View of a hybrid canyon. (b) Sketches depicting the inferred relationship between the eastern Valles Marineris, zones of subsidence and outflow channel formation in southern circum-Chryse. Ice/water-saturated sediments contained within buried troughs (1) undergo extensive melting and interconnect with a highly pressurized aquifer in eastern Valles Marineris (2). Extensive groundwater drainage along the trough interior deposits leads to outflow channel activity in southern circum-Chryse as well as to extensive subsidence over evacuated conduits (3). The pre- and post-subsidence surface elevations were constructed using MOLA elevation profiles and the topographic analyses described in the supplement. We produced the sketches using adobe illustrator.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
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getmorefigures.php?uid=PMC4562069&req=5

f4: (a) Sketches depicting the inferred geologic evolution of a subsided highland plateau in southern circum-Chryse. (1) Submarine troughs become infilled with water-saturated sediments during the Late Noachian. (2) The sedimentary deposits freeze into permafrost upon the ocean’s retreat stage. (3) The troughs’ infilling deposits undergo melting to generate vast systems of interconnected water-filled caverns that extend to eastern Valles Marineris. (4) Groundwater outbursts lead catastrophic flooding. (5) Subsidence occurs over the evacuated caverns and hydrid canyons form close to the paleoshoreline elevation. (5a) View of a hybrid canyon. (b) Sketches depicting the inferred relationship between the eastern Valles Marineris, zones of subsidence and outflow channel formation in southern circum-Chryse. Ice/water-saturated sediments contained within buried troughs (1) undergo extensive melting and interconnect with a highly pressurized aquifer in eastern Valles Marineris (2). Extensive groundwater drainage along the trough interior deposits leads to outflow channel activity in southern circum-Chryse as well as to extensive subsidence over evacuated conduits (3). The pre- and post-subsidence surface elevations were constructed using MOLA elevation profiles and the topographic analyses described in the supplement. We produced the sketches using adobe illustrator.
Mentions: We propose the following regional geologic reconstruction leading to the development of the OFCS aquifers: The vast fluvial, or glacial-glaciofluvial, canyon systems of southern Margaritifer Terra423 discharged enormous volumes of sediments into southern circum-Chryse, where lower portions of these canyons were completely buried and integrated into the regional upper crustal stratigraphy (Fig. 4a). Coeval fluvial activity through the huge Uzboi-Ladon-Morava channel system, which connects the Argyre basin to the northern plains, is thought to have discharged vast volumes of water generated by the melting of a Late Noachian south polar ice sheet32. This enormous fluvial system could have also contributed to regional sedimentation in southern circum-Chryse233. In the proposed geologic scenario the upper extent of regional sedimentation would have been controlled by the elevation of Oceanus Borealis (Fig. 3b, sketches 1 and 2 in Fig. 4a).

Bottom Line: Using more recent mission data, we argue that during the Late Noachian fluvial and glacial sediments were deposited into a clastic wedge within a paleo-basin located in the southern circum-Chryse region, which at the time was completely submerged under a primordial northern plains ocean [corrected].Subsequent Late Hesperian outflow channels were sourced from within these geologic materials and formed by gigantic groundwater outbursts driven by an elevated hydraulic head from the Valles Marineris region.Thus, our findings link the formation of the southern circum-Chryse outflow channels to ancient marine, glacial, and fluvial erosion and sedimentation.

View Article: PubMed Central - PubMed

Affiliation: Planetary Science Institute, 1700 East Fort Lowell Road, Suite 106, Tucson, AZ 85719-2395, USA.

ABSTRACT
Catastrophic floods generated ~3.2 Ga by rapid groundwater evacuation scoured the Solar System's most voluminous channels, the southern circum-Chryse outflow channels. Based on Viking Orbiter data analysis, it was hypothesized that these outflows emanated from a global Hesperian cryosphere-confined aquifer that was infused by south polar meltwater infiltration into the planet's upper crust. In this model, the outflow channels formed along zones of superlithostatic pressure generated by pronounced elevation differences around the Highland-Lowland Dichotomy Boundary. However, the restricted geographic location of the channels indicates that these conditions were not uniform. Furthermore, some outflow channel sources are too high to have been fed by south polar basal melting. Using more recent mission data, we argue that during the Late Noachian fluvial and glacial sediments were deposited into a clastic wedge within a paleo-basin located in the southern circum-Chryse region, which at the time was completely submerged under a primordial northern plains ocean [corrected]. Subsequent Late Hesperian outflow channels were sourced from within these geologic materials and formed by gigantic groundwater outbursts driven by an elevated hydraulic head from the Valles Marineris region. Thus, our findings link the formation of the southern circum-Chryse outflow channels to ancient marine, glacial, and fluvial erosion and sedimentation.

No MeSH data available.


Related in: MedlinePlus