Hellas quadrangle - Revision history

Suitupshowup: /* Crater Lakes */

2026-04-06T13:03:27Z

Crater Lakes

Suitupshowup: /* Crater Lakes */ added omage pf crater lake

2026-04-06T12:56:48Z

Crater Lakes: added omage pf crater lake

Suitupshowup: /* Additional Images in Hellas quadrangle */

2026-04-04T23:53:59Z

Additional Images in Hellas quadrangle

Suitupshowup: /* Additional Images in Hellas quadrangle */ created new section on crater lakes

2026-04-04T23:53:13Z

Additional Images in Hellas quadrangle: created new section on crater lakes

Suitupshowup: /* Additional Images in Hellas quadrangle */

2026-04-02T16:34:29Z

Additional Images in Hellas quadrangle

Suitupshowup: /* Additional Images in Hellas quadrangle */

2026-04-02T16:33:01Z

Additional Images in Hellas quadrangle

Suitupshowup: /* Additional Images in Hellas quadrangle */ added image of crater lake

2026-04-02T16:29:19Z

Additional Images in Hellas quadrangle: added image of crater lake

Suitupshowup: /* Upper Plains Unit */ added ref

2026-03-25T01:11:31Z

Upper Plains Unit: added ref

Suitupshowup: added image

2026-02-28T16:08:54Z

added image

Suitupshowup: /* Honeycomb terrain */ added image

2026-02-28T15:42:42Z

Honeycomb terrain: added image

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 Many craters on Mars probably became lakes. <ref> Fassett C. I. and Head J. W. 2008. Icarus. 195 61</ref>  <ref> Goudge T. A., Aureli K. L., Head J. W., Fassett C. I. and Mustard J. F. 2015 Icarus. 260 346</ref>  There could have been several sources for the water.  Like:
-Runoff and River Inlets: Many craters show evidence of channels eroded into their rims, indicating that water flowed across the landscape and broke through the crater walls.  Dense, branching valley networks across the southern highlands suggest that ancient rain or snowmelt carved channels that eventually breached crater rims. <ref>Bamber, E. R., Goudge, T. A., Fassett, C. I., Osinski, G. R., & Stucky de Quay, G. (2022). Paleolake inlet valley formation: Factors controlling which craters breached on early Mars. Geophysical Research Letters, 49, e2022GL101097. https://doi.org/10.1029/2022GL101097</ref>
+(1)  Runoff and River Inlets: Many craters show evidence of channels eroded into their rims, indicating that water flowed across the landscape and broke through the crater walls.  Dense, branching valley networks across the southern highlands suggest that ancient rain or snowmelt carved channels that eventually breached crater rims. <ref>Bamber, E. R., Goudge, T. A., Fassett, C. I., Osinski, G. R., & Stucky de Quay, G. (2022). Paleolake inlet valley formation: Factors controlling which craters breached on early Mars. Geophysical Research Letters, 49, e2022GL101097. https://doi.org/10.1029/2022GL101097</ref>
-Glacial Melting: Researchers have found evidence that some lakes were fed by runoff from glaciers. In this scenario, glaciers occupying the area, or sitting on the crater walls, melted and transported water to the center of the crater.
+(2)  Glacial Melting: Researchers have found evidence that some lakes were fed by runoff from glaciers. In this scenario, glaciers occupying the area, or sitting on the crater walls, melted and transported water to the center of the crater.
-Groundwater Sapping: In some cases, water may have broken through the ground surface, known as groundwater sapping, feeding the lake from below or through the crater walls.<ref>  Goudge T. A., Aureli K. L., Head J. W., Fassett C. I. and Mustard J. F. 2015 Icarus. 260 346
+(3)  Groundwater Sapping: In some cases, water may have broken through the ground surface, known as groundwater sapping, feeding the lake from below or through the crater walls.<ref>  Goudge T. A., Aureli K. L., Head J. W., Fassett C. I. and Mustard J. F. 2015 Icarus. 260 346
 </ref> <ref>Salese F., Pondrelli M., Neeseman A., Schmidt G. and Ori G. G. 2019. JGRE. Vol. 124. P. 374</ref>    Some craters, like McLaughlin Crater, lack large surface inflow channels. Instead, they feature layered rocks containing carbonate and clay minerals, suggesting that groundwater from underground aquifers came up  through fractures in the crater floor.<ref>https://www.jpl.nasa.gov/news/martian-crater-may-once-have-held-groundwater-fed-lake/</ref>
 Once water accumulated in a crater, it behaved in ways similar to terrestrial lakes.
 Delta Formation: As water entered the crater via an inlet channel, it slowed down and dropped its sediment load, creating fan-shaped structures known as deltas. The Perseverance Rover has documented these, along with sloping layers known as foreset beds, which are characteristic of deltas building into a lake.  At times, water input was so significant that the lakes filled to the brim and overflowed the crater rim, creating outlet canyons and changing the surrounding landscape.

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 <gallery class="center" widths="380px" heights="360px">
+File:ESP 078227 2195lake.jpg|Channels that filled crater to make a crater lake, as seen by HiRISE under HiWish program.
 File:91766 1455 open crater lake.jpg|Open crater lake--it has both an inlet and and outflow channel.
 </gallery>
   Martian crater lakes may have  lasted from a million years down to just a century.<ref>https://www.nhm.ac.uk/discover/news/2022/september/ancient-crater-lakes-mars-could-have-hosted-life.html</ref>
 ==Additional Images in Hellas quadrangle==

← Older revision		Revision as of 23:53, 4 April 2026
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	<gallery class="center" widths="380px" heights="360px">		<gallery class="center" widths="380px" heights="360px">
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−	~~File:91766 1455 open crater lake.jpg\|Open crater lake--it has both an inlet and and outflow channel.~~

	File:55421 1395ribbed.jpg\|Hollows on floor of Reull Vallis, as seen by HiRISE under HiWish program		File:55421 1395ribbed.jpg\|Hollows on floor of Reull Vallis, as seen by HiRISE under HiWish program

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 ESP 049304 1215scallops.jpg|Scalloped terrain, as seen by HiRISE under HIWish program Dust devil tracks are also visible.
 </gallery>
 ==Additional Images in Hellas quadrangle==

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 Possible dike and troughs  The arrows point to the possible dike along the left edge of picture.  Straight features are rare in nature; they are often due to dikes and joints.
 <gallery class="center" widths="380px" heights="360px">
 File:55421 1395ribbed.jpg|Hollows on floor of Reull Vallis, as seen by HiRISE under HiWish program

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 Some regions of the upper plains unit display large fractures and troughs with raised rims; such regions are called ribbed upper plains.  Fractures are believed to have started with small cracks from stresses.  Stress is suggested to initiate the fracture process since ribbed upper plains are common when debris aprons come together or near the edge of debris aprons—such sites would generate compressional stresses.  Cracks expose more surfaces, and consequently more ice in the material sublimates into the planet's thin atmosphere.  Eventually, small cracks become large canyons or troughs.<ref>Morgenstern, A., et al.  2007</ref> <ref name="Baker, D. 2015">Baker, D., J. Head.  2015.  Extensive Middle Amazonian mantling of debris aprons and plains in Deuteronilus Mensae, Mars:  Implication for the record of mid-latitude glaciation.  Icarus: 260, 269-288.</ref>
-The upper plains unit is probably just a very thick pile of mantle that has dropped from the sky.  It drapes various surfaces and as is the case for other mantle deposits, it  has layers, is fine-grained, and is ice-rich. It is widespread; it does not seem to have a point source.  The surface appearance of some regions of Mars is due to how this unit has degraded. This unit also degrades into a feature named brain terrain; it looks like the human brain.   Brain terrain is a region of maze-like ridges 3–5 meters high.  Some ridges may consist of an ice core, so they may be sources of water for future colonists.
+The upper plains unit is probably just a very thick pile of mantle that has dropped from the sky.  It drapes various surfaces and as is the case for other mantle deposits, it  has layers, is fine-grained, and is ice-rich. It is widespread; it does not seem to have a point source.  The surface appearance of some regions of Mars is due to how this unit has degraded. This unit also degrades into a feature named brain terrain; it looks like the human brain.   Brain terrain is a region of maze-like ridges 3–5 meters high. <ref> https://www.hou.usra.edu/meetings/lpsc2026/pdf/1626.pdf</ref>  <ref>Dundas, C., et al.  2026.  STRATIGRAPHIC OBSERVATIONS OF MARTIAN “BRAIN TERRAIN” AND IMPLICATIONS FOR
 ==Origin of Dao Vallis==

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 In the Northwest portion of Hellas Planitia is a strange type of surface called complex banded terrain or taffy-pull terrain. Its process of formation is still largely unknown, although it appears to be due to erosion of hard and soft sediment along with ductile deformation. Ductile deformation results from layers undergoing strain.<ref>http://hirise.lpl.arizonai.edu/P/sP_008559_1405</ref>
+<gallery class="center" widths="380px" heights="360px">
 ==Giant Lake==

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 ESP 049330 1425honeycomb.jpg|Honeycomb terrain
+File:68704 1455honeycomb terrain.jpg|Honeycomb terrain, as seen by HiRISE under HiWish program
 File:ESP 057110 1365ridges.jpg|Ridges