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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) Map showing the distribution of hybrid canyons in terrains located along the boundary between upland fluvial canyons and subsided valleys (context and location in Fig. 1b). (b) Topographic view of an upland fluvial canyon, which shows margins densely marked by small valleys/channels (black arrows). (c,d) Topographic views of a subsided valley (white arrow) that extends eastward to join a hybrid canyon that exhibits a margin dissected by small valleys/channels adjoined by subsidence related fractures (black arrow). We produced the map in this figure using Esri’s ArcGIS geographic information system.
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f2: (a) Map showing the distribution of hybrid canyons in terrains located along the boundary between upland fluvial canyons and subsided valleys (context and location in Fig. 1b). (b) Topographic view of an upland fluvial canyon, which shows margins densely marked by small valleys/channels (black arrows). (c,d) Topographic views of a subsided valley (white arrow) that extends eastward to join a hybrid canyon that exhibits a margin dissected by small valleys/channels adjoined by subsidence related fractures (black arrow). We produced the map in this figure using Esri’s ArcGIS geographic information system.

Mentions: The southern Margaritifer Terra highlands are extensively dissected by vast canyon systems (Fig. 1b and 2a), which exhibit flanks densely marked by channels (e.g., Fig. 2b)4. The formation of these canyons is thought to have been dominated by Middle and Late Noachian fluvial erosion4. Late Noachian equatorial glaciers may have also contributed to their development23. Within the study region, these canyons converge northwestward into the highlands containing the subsided terrains (Fig. 1a,b). Although the contact between these two terrain types is disrupted by the Margaritifer and Iani chaotic terrains, we have identified a relatively narrow stretch of plateau materials that includes a subset of canyons that exhibit transitional morphologies (Fig. 2a). These hybrid canyons include scarp margins marked by dense channel systems and extensional fractures generated by subsidence (Fig. 2c,d), thus offering a rare insight into the regional upper stratigraphy of the outflow channel source region, consistent with the existence of buried canyons underlying the subsided valleys. Similar hybrid morphologies are observable along the flanks of Ladon basin (Fig. 1a), which constitutes large impact basin that partly captured drainage from the upland fluvial canyons (Fig. 1b).


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) Map showing the distribution of hybrid canyons in terrains located along the boundary between upland fluvial canyons and subsided valleys (context and location in Fig. 1b). (b) Topographic view of an upland fluvial canyon, which shows margins densely marked by small valleys/channels (black arrows). (c,d) Topographic views of a subsided valley (white arrow) that extends eastward to join a hybrid canyon that exhibits a margin dissected by small valleys/channels adjoined by subsidence related fractures (black arrow). We produced the map in this figure using Esri’s ArcGIS geographic information system.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4562069&req=5

f2: (a) Map showing the distribution of hybrid canyons in terrains located along the boundary between upland fluvial canyons and subsided valleys (context and location in Fig. 1b). (b) Topographic view of an upland fluvial canyon, which shows margins densely marked by small valleys/channels (black arrows). (c,d) Topographic views of a subsided valley (white arrow) that extends eastward to join a hybrid canyon that exhibits a margin dissected by small valleys/channels adjoined by subsidence related fractures (black arrow). We produced the map in this figure using Esri’s ArcGIS geographic information system.
Mentions: The southern Margaritifer Terra highlands are extensively dissected by vast canyon systems (Fig. 1b and 2a), which exhibit flanks densely marked by channels (e.g., Fig. 2b)4. The formation of these canyons is thought to have been dominated by Middle and Late Noachian fluvial erosion4. Late Noachian equatorial glaciers may have also contributed to their development23. Within the study region, these canyons converge northwestward into the highlands containing the subsided terrains (Fig. 1a,b). Although the contact between these two terrain types is disrupted by the Margaritifer and Iani chaotic terrains, we have identified a relatively narrow stretch of plateau materials that includes a subset of canyons that exhibit transitional morphologies (Fig. 2a). These hybrid canyons include scarp margins marked by dense channel systems and extensional fractures generated by subsidence (Fig. 2c,d), thus offering a rare insight into the regional upper stratigraphy of the outflow channel source region, consistent with the existence of buried canyons underlying the subsided valleys. Similar hybrid morphologies are observable along the flanks of Ladon basin (Fig. 1a), which constitutes large impact basin that partly captured drainage from the upland fluvial canyons (Fig. 1b).

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