Martian gullies - Revision history

Suitupshowup: /* Dry ice makes gullies today */ added image

2026-02-23T16:21:35Z

Dry ice makes gullies today: added image

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2026-01-31T17:28:22Z

Dry ice makes gullies today: added ref

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Dry ice makes gullies today: added ref

Suitupshowup at 21:35, 21 June 2025

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Suitupshowup at 14:15, 4 June 2025

2025-06-04T14:15:56Z

Suitupshowup: added ref about gullies and water

2025-05-10T19:26:30Z

added ref about gullies and water

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added image

Suitupshowup at 20:03, 7 October 2024

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← Older revision		Revision as of 16:21, 23 February 2026
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	As more pictures are examined and analyzed opinions on whether water was involved are shifting. A large team of researchers published a paper in Science that showed that water would have existed where the gullies formed when the tilt of Mars went to 35 degrees. It has done that many times; the last time just 630,000 years ago. When the tilt increases to 35 degrees, both the pressure and temperature are such that ice in the ground will melt. Places that are too high in altitude, and thus have too low a pressure, do not display gullies. Gullies are found on many places with steep slopes. However, the Thaumasia Highlands have many steep slopes, but very, very few gullies. The rather high elevation of the Thaumasia area keeps the pressure low--too low for liquid water to form.<ref>Dickson, J., et al. 2023. Gullies on Mars could have formed by melting of water ice during periods of high obliquity. Science. Vol 380, Issue 6652. pp. 1363-1367. DOI: 10.1126/science.abk246</ref> <ref>https://www.science.org/doi/10.1126/science.abk2464</ref>		As more pictures are examined and analyzed opinions on whether water was involved are shifting. A large team of researchers published a paper in Science that showed that water would have existed where the gullies formed when the tilt of Mars went to 35 degrees. It has done that many times; the last time just 630,000 years ago. When the tilt increases to 35 degrees, both the pressure and temperature are such that ice in the ground will melt. Places that are too high in altitude, and thus have too low a pressure, do not display gullies. Gullies are found on many places with steep slopes. However, the Thaumasia Highlands have many steep slopes, but very, very few gullies. The rather high elevation of the Thaumasia area keeps the pressure low--too low for liquid water to form.<ref>Dickson, J., et al. 2023. Gullies on Mars could have formed by melting of water ice during periods of high obliquity. Science. Vol 380, Issue 6652. pp. 1363-1367. DOI: 10.1126/science.abk246</ref> <ref>https://www.science.org/doi/10.1126/science.abk2464</ref>
		+
		+	<gallery class="center" widths="380px" heights="360px">
		+	File:ESP 090786 1420gullies.jpg\|Gullies in crater
		+
		+	File:90786 1420largealcoveslabeled.jpg\|Close view of gullies in a crater. Note how alcoves are much larger than the aprons. This may be because much ice has disappeared.
		+	</gallery>

	In support of water being involved is the fact that many gully alcoves have a greater volume than the aprons. The material that was in the alcove may have contained much water ice that disappeared into the atmosphere.<ref>Gulick, V. and N. Glines. 2021. STUDIES OF MARTIAN GULLY SYSTEMS AND THEIR POTENTIAL PALEOENVIRONMENTAL		In support of water being involved is the fact that many gully alcoves have a greater volume than the aprons. The material that was in the alcove may have contained much water ice that disappeared into the atmosphere.<ref>Gulick, V. and N. Glines. 2021. STUDIES OF MARTIAN GULLY SYSTEMS AND THEIR POTENTIAL PALEOENVIRONMENTAL

← Older revision		Revision as of 17:28, 31 January 2026
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	J Geophys Res Planets, 126. 10.1029/2020JE006539</ref>		J Geophys Res Planets, 126. 10.1029/2020JE006539</ref>

−	In summary of our present understanding of gullies it can be said: A number of studies have demonstrated that gullies are being modified on present day Mars. <ref>C.M. Dundas, A.S. McEwen, S. Diniega, C.J. Hansen, S. Byrne, J.N. McElwaine. The formation of gullies on Mars today. Geol. Soc. London Spec. Publ., 467 (2019), pp. 67-94, 10.1144/SP467.5</ref> <ref>C.M. Dundas, S. Diniega, C.J. Hansen, S. Byrne, A.S. McEwen. Seasonal activity and morphological changes in Martian gullies. Icarus, 220 (2012), pp. 124-143, 10.1016/j.icarus.2012.04.005 </ref> <ref>.M. Dundas, S. Diniega, A.S. McEwen. Long-term monitoring of Martian gully formation and evolution with MRO/HiRISE. Icarus, 251 (2015), pp. 244-263, 10.1016/j.icarus.2014.05.013</ref> <ref>J. Raack, S.J. Conway, T. Heyer, V.T. Bickel, M. Philippe, H. Hiesinger, A. Johnsson, M. Massé. Present-day gully activity in Sisyphi Cavi, Mars - flow-like features and block movements. Icarus, 350 (2020), 10.1016/j.icarus.2020.113899. article #113899</Ref> Today, liquid water cannot exist on the Red planet because the both the pressure and the temperature is too low. Further evidence that water is not involved is that minerals are not changed by gully formation.<ref>J.I. Núñez, O.S. Barnouin, S.L. Murchie, F.P. Seelos, J.A. McGovern, K.D. Seelos, D.L. Buczkowski. New insights into gully formation on Mars: constraints from composition as seen by MRO/CRISM. Geophys. Res. Lett., 43 (2016), pp. 8893-8902, 10.1002/2016GL068956</ref> For many years, many believed that gullies had to be made with liquid water. However, with more and more observations researchers have proposed other mechanisms that could account for gully formation without liquid water.<ref>S.J. Conway, T. de Haas, T.N. Harrison. Martian gullies: a comprehensive review of observations, mechanisms and insights from Earth analogues. Geol. Soc. London Spec. Publ., 467 (2019), pp. 7-66, 10.1144/SP467.14</ref> Most involve dry ice (solid carbon dioxide) accumulating during cold seasons and then changing to a gas in the spring. The gas coming off could start material moving down slopes. The gas mixed with sand and other debris could act like water to erode channels. Also, pieces of dry ice could easily side down due to the lubricating effect of gas coming off the dry ice.	+	In summary of our present understanding of gullies it can be said: A number of studies have demonstrated that gullies are being modified on present day Mars. <ref> https://www.uahirise.org/ESP_032011_1425</ref> <ref>C.M. Dundas, A.S. McEwen, S. Diniega, C.J. Hansen, S. Byrne, J.N. McElwaine. The formation of gullies on Mars today. Geol. Soc. London Spec. Publ., 467 (2019), pp. 67-94, 10.1144/SP467.5</ref> <ref>C.M. Dundas, S. Diniega, C.J. Hansen, S. Byrne, A.S. McEwen. Seasonal activity and morphological changes in Martian gullies. Icarus, 220 (2012), pp. 124-143, 10.1016/j.icarus.2012.04.005 </ref> <ref>.M. Dundas, S. Diniega, A.S. McEwen. Long-term monitoring of Martian gully formation and evolution with MRO/HiRISE. Icarus, 251 (2015), pp. 244-263, 10.1016/j.icarus.2014.05.013</ref> <ref>J. Raack, S.J. Conway, T. Heyer, V.T. Bickel, M. Philippe, H. Hiesinger, A. Johnsson, M. Massé. Present-day gully activity in Sisyphi Cavi, Mars - flow-like features and block movements. Icarus, 350 (2020), 10.1016/j.icarus.2020.113899. article #113899</Ref> Today, liquid water cannot exist on the Red planet because the both the pressure and the temperature is too low. Further evidence that water is not involved is that minerals are not changed by gully formation.<ref>J.I. Núñez, O.S. Barnouin, S.L. Murchie, F.P. Seelos, J.A. McGovern, K.D. Seelos, D.L. Buczkowski. New insights into gully formation on Mars: constraints from composition as seen by MRO/CRISM. Geophys. Res. Lett., 43 (2016), pp. 8893-8902, 10.1002/2016GL068956</ref> For many years, many believed that gullies had to be made with liquid water. However, with more and more observations researchers have proposed other mechanisms that could account for gully formation without liquid water.<ref>S.J. Conway, T. de Haas, T.N. Harrison. Martian gullies: a comprehensive review of observations, mechanisms and insights from Earth analogues. Geol. Soc. London Spec. Publ., 467 (2019), pp. 7-66, 10.1144/SP467.14</ref> Most involve dry ice (solid carbon dioxide) accumulating during cold seasons and then changing to a gas in the spring. The gas coming off could start material moving down slopes. The gas mixed with sand and other debris could act like water to erode channels. Also, pieces of dry ice could easily side down due to the lubricating effect of gas coming off the dry ice.

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 </gallery>
-Some gullies on sand dunes have been observed to change noticeably in just one year.  The changes occur when dry ice has accumulated and has started to disappear.  It is thought that dry ice could be causing a flow in the sand as it sublimates; the carbon dioxide gas released would speed up the flow.<ref>C.M. Dundas, S. Diniega, A.S. McEwen.  2014.  Long-term monitoring of martian gully formation and evolution with MRO/HiRISE.  Icarus, 251.  pp. 244-263, 10.1016/j.icarus.2014.05.013</ref> <ref>C.M. Dundas, A.S. McEwen, S. Diniega, C.J. Hansen, S. Byrne, J.N. McElwaine.  2017.  The formation of gullies on Mars today.  Geol. Soc. Lond. Spec. Publ., 46710.1144/SP467.5</ref>  A team of researchers examined changes in a sand dune gully in Matara Crater (49.5°S; 34.9°E - Noachis quadrangle)  for 5 years.  Each year there were changes. The changes were in the length of the gully, the curviness of the gully, and changes in the volume both the alcove and the apron.  The alcove lost material, while the apron gained.  In just one Martian year, the apron went from a length of 800 meters to a length of nearly 940 meters.  Moreover, the changes happened just as the dry ice began to sublimate.<ref>https://www-sciencedirect-com.wikipedialibrary.idm.oclc.org/science/article/pii/S0019103518304627</ref> <ref>Pasquon, K., et al.  2019.  Present-day development of gully-channel sinuosity by carbon dioxide gas supported flows on Mars.
+Some gullies on sand dunes have been observed to change noticeably in just one year.  The changes occur when dry ice has accumulated and has started to disappear.  It is thought that dry ice could be causing a flow in the sand as it sublimates; the carbon dioxide gas released would speed up the flow.<ref>  https://www.uahirise.org/hipod/ESP_039701_1095</ref> <ref>C.M. Dundas, S. Diniega, A.S. McEwen.  2014.  Long-term monitoring of martian gully formation and evolution with MRO/HiRISE.  Icarus, 251.  pp. 244-263, 10.1016/j.icarus.2014.05.013</ref> <ref>C.M. Dundas, A.S. McEwen, S. Diniega, C.J. Hansen, S. Byrne, J.N. McElwaine.  2017.  The formation of gullies on Mars today.  Geol. Soc. Lond. Spec. Publ., 46710.1144/SP467.5</ref>  A team of researchers examined changes in a sand dune gully in Matara Crater (49.5°S; 34.9°E - Noachis quadrangle)  for 5 years.  Each year there were changes. The changes were in the length of the gully, the curviness of the gully, and changes in the volume both the alcove and the apron.  The alcove lost material, while the apron gained.  In just one Martian year, the apron went from a length of 800 meters to a length of nearly 940 meters.  Moreover, the changes happened just as the dry ice began to sublimate.<ref>https://www-sciencedirect-com.wikipedialibrary.idm.oclc.org/science/article/pii/S0019103518304627</ref> <ref>Pasquon, K., et al.  2019.  Present-day development of gully-channel sinuosity by carbon dioxide gas supported flows on Mars.
 Icarus.  Volume 329.  Pages 296-313</ref>

← Older revision		Revision as of 21:35, 21 June 2025
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	J Geophys Res Planets, 126. 10.1029/2020JE006539</ref>		J Geophys Res Planets, 126. 10.1029/2020JE006539</ref>

−	In summary of our present understanding of gullies it can be said: A number of studies have demonstrated that gullies are being modified on present day Mars. <ref>C.M. Dundas, A.S. McEwen, S. Diniega, C.J. Hansen, S. Byrne, J.N. McElwaine. The formation of gullies on Mars today. Geol. Soc. London Spec. Publ., 467 (2019), pp. 67-94, 10.1144/SP467.5</ref> <ref>C.M. Dundas, S. Diniega, C.J. Hansen, S. Byrne, A.S. McEwen. Seasonal activity and morphological changes in Martian gullies. Icarus, 220 (2012), pp. 124-143, 10.1016/j.icarus.2012.04.005 </ref> <ref>.M. Dundas, S. Diniega, A.S. McEwen. Long-term monitoring of Martian gully formation and evolution with MRO/HiRISE. Icarus, 251 (2015), pp. 244-263, 10.1016/j.icarus.2014.05.013</ref> <ref>J. Raack, S.J. Conway, T. Heyer, V.T. Bickel, M. Philippe, H. Hiesinger, A. Johnsson, M. Massé. Present-day gully activity in Sisyphi Cavi, Mars - flow-like features and block movements. Icarus, 350 (2020), 10.1016/j.icarus.2020.113899. article #113899</Ref> Today, liquid water cannot exist on the Red planet because the both the pressure and the temperature is too low. Further evidence that water is not involved is that minerals are not changed by gully formation.<ref>J.I. Núñez, O.S. Barnouin, S.L. Murchie, F.P. Seelos, J.A. McGovern, K.D. Seelos, D.L. Buczkowski. New insights into gully formation on Mars: constraints from composition as seen by MRO/CRISM. Geophys. Res. Lett., 43 (2016), pp. 8893-8902, 10.1002/2016GL068956</ref> For many years, many believed that gullies had to be made with liquid water. So, researchers have proposed other mechanisms that could account for gully formation without liquid water.<ref>S.J. Conway, T. de Haas, T.N. Harrison. Martian gullies: a comprehensive review of observations, mechanisms and insights from Earth analogues. Geol. Soc. London Spec. Publ., 467 (2019), pp. 7-66, 10.1144/SP467.14</ref> Most involve dry ice (solid carbon dioxide) accumulating during cold seasons and then changing to a gas in the spring. The gas coming off could start material moving down slopes. The gas mixed with sand and other debris could act like water to erode channels. Also, pieces of dry ice could easily side down due to the lubricating effect of gas coming off the dry ice.	+	In summary of our present understanding of gullies it can be said: A number of studies have demonstrated that gullies are being modified on present day Mars. <ref>C.M. Dundas, A.S. McEwen, S. Diniega, C.J. Hansen, S. Byrne, J.N. McElwaine. The formation of gullies on Mars today. Geol. Soc. London Spec. Publ., 467 (2019), pp. 67-94, 10.1144/SP467.5</ref> <ref>C.M. Dundas, S. Diniega, C.J. Hansen, S. Byrne, A.S. McEwen. Seasonal activity and morphological changes in Martian gullies. Icarus, 220 (2012), pp. 124-143, 10.1016/j.icarus.2012.04.005 </ref> <ref>.M. Dundas, S. Diniega, A.S. McEwen. Long-term monitoring of Martian gully formation and evolution with MRO/HiRISE. Icarus, 251 (2015), pp. 244-263, 10.1016/j.icarus.2014.05.013</ref> <ref>J. Raack, S.J. Conway, T. Heyer, V.T. Bickel, M. Philippe, H. Hiesinger, A. Johnsson, M. Massé. Present-day gully activity in Sisyphi Cavi, Mars - flow-like features and block movements. Icarus, 350 (2020), 10.1016/j.icarus.2020.113899. article #113899</Ref> Today, liquid water cannot exist on the Red planet because the both the pressure and the temperature is too low. Further evidence that water is not involved is that minerals are not changed by gully formation.<ref>J.I. Núñez, O.S. Barnouin, S.L. Murchie, F.P. Seelos, J.A. McGovern, K.D. Seelos, D.L. Buczkowski. New insights into gully formation on Mars: constraints from composition as seen by MRO/CRISM. Geophys. Res. Lett., 43 (2016), pp. 8893-8902, 10.1002/2016GL068956</ref> For many years, many believed that gullies had to be made with liquid water. However, with more and more observations researchers have proposed other mechanisms that could account for gully formation without liquid water.<ref>S.J. Conway, T. de Haas, T.N. Harrison. Martian gullies: a comprehensive review of observations, mechanisms and insights from Earth analogues. Geol. Soc. London Spec. Publ., 467 (2019), pp. 7-66, 10.1144/SP467.14</ref> Most involve dry ice (solid carbon dioxide) accumulating during cold seasons and then changing to a gas in the spring. The gas coming off could start material moving down slopes. The gas mixed with sand and other debris could act like water to erode channels. Also, pieces of dry ice could easily side down due to the lubricating effect of gas coming off the dry ice.

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 SETTINGS. 52nd Lunar and Planetary Science Conference 2021 (LPI Contrib. No. 2548).  2773.pdf.</ref> <ref>Gulick et al. 2017 LPSC #1970</ref> <ref>Huang, H, and V. Gulick.  2023.  MORPHOLOGIC ANALYSIS OF MARTIAN GULLIES IN FOUR HIGH-NORTHERN LATITUDE
 CRATERS.  54th Lunar and Planetary Science Conference 2023 (LPI Contrib. No. 2806).  1863.pdf</ref>  Addition evidence that water is involved is that some gullies occur on slopes that are not steep enough for a dry flow, but would be steep enough if water was involved.<ref> https://www-sciencedirect-com.wikipedialibrary.idm.oclc.org/science/article/pii/S0019103525001599</ref> <ref> Huang, R. and V. Gulick.
-.  Examining the role of water in Martian lowland gully formation.  Icarus.  https://www-sciencedirect-com.wikipedialibrary.idm.oclc.org/journal/icarus/vol/437/suppl/C<ref> Huang, R., et al.  2021.  SLOPE ANALYSIS OF MARTIAN GULLIES IN THREE HIGH-NORTHERN LATITUDE CRATERS.  52nd Lunar and Planetary Science Conference 2021 (LPI Contrib. No. 2548).  2625.pdf.</ref> Also, some gullies erode over 40 meters into bedrock, which so a long period of erosion is required--maybe more than dry ice could do.<ref> Huang, R., and V. Gulick.   2023.  MORPHOLOGIC ANALYSIS OF MARTIAN GULLIES IN FOUR HIGH-NORTHERN LATITUDECRATERS.  54th Lunar and Planetary Science Conference 2023 (LPI Contrib. No. 2806).  1863.pdf.</ref>
+.  Examining the role of water in Martian lowland gully formation.  Icarus.  https://www-sciencedirect-com.wikipedialibrary.idm.oclc.org/journal/icarus/vol/437/suppl/C</ref> <ref>Huang, R., et al.  2021.  SLOPE ANALYSIS OF MARTIAN GULLIES IN THREE HIGH-NORTHERN LATITUDE CRATERS.  52nd Lunar and Planetary Science Conference 2021 (LPI Contrib. No. 2548).  2625.pdf.</ref> Also, some gullies erode over 40 meters into bedrock, which so a long period of erosion is required--maybe more than dry ice could do.<ref> Huang, R., and V. Gulick.   2023.  MORPHOLOGIC ANALYSIS OF MARTIAN GULLIES IN FOUR HIGH-NORTHERN LATITUDECRATERS.  54th Lunar and Planetary Science Conference 2023 (LPI Contrib. No. 2806).  1863.pdf.</ref>
 Some small patches of light-toned material have been observed in gullies.  These have gotten smaller over time.

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 File:ESP 084896 1355 small gullies 03.jpg|Small gully  This gully may be in its initial state of formation.
 File:ESP 084896 1355 small gullies 04.jpg|Gully, as seen by HiRISE
 </gallery>

← Older revision		Revision as of 20:03, 7 October 2024
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	[[File:50858 1435gullies.jpg\|600pxr\|Image of gullies with main parts labeled. The main parts of a Martian gully are alcove, channel, and apron. Since there are no craters on this gully, it is thought to be rather young. Picture was taken by HiRISE under HiWish program.]]		[[File:50858 1435gullies.jpg\|600pxr\|Image of gullies with main parts labeled. The main parts of a Martian gully are alcove, channel, and apron. Since there are no craters on this gully, it is thought to be rather young. Picture was taken by HiRISE under HiWish program.]]
−
−	[[ File:Gullies from around Mars 16.jpg\|600pxr\|gullies on Mars. Gullies from on steep slopes. Today, they seem to be produced with the action of dry ice; in the past liquid water may have been involved. The colored ones are from a colored strip in the center of each HiRISE image. ]]

	<gallery class="center" widths="380px" heights="360px">		<gallery class="center" widths="380px" heights="360px">

← Older revision		Revision as of 20:02, 7 October 2024
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	[[File:50858 1435gullies.jpg\|600pxr\|Image of gullies with main parts labeled. The main parts of a Martian gully are alcove, channel, and apron. Since there are no craters on this gully, it is thought to be rather young. Picture was taken by HiRISE under HiWish program.]]		[[File:50858 1435gullies.jpg\|600pxr\|Image of gullies with main parts labeled. The main parts of a Martian gully are alcove, channel, and apron. Since there are no craters on this gully, it is thought to be rather young. Picture was taken by HiRISE under HiWish program.]]
		+
		+	[[ File:Gullies from around Mars 16.jpg\|600pxr\|gullies on Mars. Gullies from on steep slopes. Today, they seem to be produced with the action of dry ice; in the past liquid water may have been involved. The colored ones are from a colored strip in the center of each HiRISE image. ]]

	<gallery class="center" widths="380px" heights="360px">		<gallery class="center" widths="380px" heights="360px">

← Older revision		Revision as of 20:01, 7 October 2024
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	[[File:50858 1435gullies.jpg\|600pxr\|Image of gullies with main parts labeled. The main parts of a Martian gully are alcove, channel, and apron. Since there are no craters on this gully, it is thought to be rather young. Picture was taken by HiRISE under HiWish program.]]		[[File:50858 1435gullies.jpg\|600pxr\|Image of gullies with main parts labeled. The main parts of a Martian gully are alcove, channel, and apron. Since there are no craters on this gully, it is thought to be rather young. Picture was taken by HiRISE under HiWish program.]]
−
−	Gullies on Mars. Gullies from on steep slopes. Today, they seem to be produced with the action of dry ice;<ref>Pasquon, K., et al. 2019. Present-day development of gully-channel sinuosity by carbon dioxide gas supported flows on Mars. Icarus. Volume 329. Pages 296-313</ref> in the past liquid water may have been involved.<ref> Dundas, C., et al. 2012. Seasonal activity and morphological changes in martian gullies. Icarus: 220, 124-143.</ref> <ref>Dickson, J., et al. 2023. Gullies on Mars could have formed by melting of water ice during periods of high obliquity. Science. Vol 380, Issue 6652. pp. 1363-1367. </ref> <ref>Dundas, et al. 2023. Martian gully activity and the gully sediment transport system. Icarus. Volume 386, 1 November 2022, 115133</ref> <ref>C.M. Dundas, A.S. McEwen, S. Diniega, C.J. Hansen, S. Byrne, J.N. McElwaine. 2017. The formation of gullies on Mars today. Geol. Soc. Lond. Spec. Publ., 46710.1144/SP467.5</ref> The colored ones are from a colored strip in the center of each HiRISE image.
−

	<gallery class="center" widths="380px" heights="360px">		<gallery class="center" widths="380px" heights="360px">