Medusae Fossae - Revision history

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2025-10-28T12:10:19Z

Evidence of water

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Evidence of water

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Evidence of water: added info and ref

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2025-10-27T22:33:06Z

Evidence of water

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2025-10-27T22:32:35Z

Evidence of water: added info and ref

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2025-10-27T22:01:07Z

Evidence of water: added info and ref

Suitupshowup: added new section with ref and info about water

2025-10-27T14:30:33Z

added new section with ref and info about water

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Suitupshowup: /* Origin and age */ added new info and ref

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Origin and age: added new info and ref

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 The Medusae Fossae Formation is surrounded by possible volcanic sources, including Olympus Mons and the Tharsis Montes to the east, the Elysium volcanoes and Cerberus Fissures to the north, and Apollinaris Mons, an isolated volcano situated in the center of the deposit.
 These eruptions may have caused meteorological events that influenced the surface of Mars. Terrestrial explosive volcanic eruptions are often likened to “dirty thunderstorms” due to their electrical activity, convective updrafts, and elevated water contents (from magmatic volatiles, interactions with water).<ref>Brown, R. J., Bonadonna, C. & Durant, A. J. A review of volcanic ash aggregation. Phys. Chem. Earth, Parts A/B/C. 45, 65–78 (2012).</ref>   This water can encase volcanic ash, leading to phenomena like volcanic hail, graupel, snow, and rain.<ref>Van Eaton, A. R. et al. Hail formation triggers rapid ash aggregation in volcanic plumes. Nat. Commun. 6, 1–7 (2015).</ref>
-Examples include the volcanic hail in the 2009 eruption of Redoubt Volcano in Alaska,<ref>Van Eaton, A. R. et al. Hail formation triggers rapid ash aggregation in volcanic plumes. Nat. Commun. 6, 1–7 (2015).</ref>  and volcanically induced thunderstorms and rain showers following the 1991 Mount Pinatubo, Philippines eruption,<ref> .Oswalt, J. S., Nichols, W. & O’Hara, J. F. Meteorological observations of the 1991 Mount Pinatubo eruption. In Fire and Mud: Eruptions of Pinatubo, Philippines (eds Newhall, C. G. & Punongbayan, S.) 545–570 (University of Washington Press, Seattle, 1996).</ref>
+Examples include the volcanic hail in the 2009 eruption of Redoubt Volcano in Alaska,<ref>Van Eaton, A. R. et al. Hail formation triggers rapid ash aggregation in volcanic plumes. Nat. Commun. 6, 1–7 (2015).</ref>  and volcanically induced thunderstorms and rain showers following the 1991 Mount Pinatubo, Philippines eruption.<ref> .Oswalt, J. S., Nichols, W. & O’Hara, J. F. Meteorological observations of the 1991 Mount Pinatubo eruption. In Fire and Mud: Eruptions of Pinatubo, Philippines (eds Newhall, C. G. & Punongbayan, S.) 545–570 (University of Washington Press, Seattle, 1996).</ref>
 Since most ash particles are effective ice-forming nuclei, volcanic clouds and subsequent precipitation could have played a key role in shaping Mars’ surface by delivering ash-ice mixtures or ice layers covered in ash. This ash can insulate and preserve underlying ice.<ref>Durant, A. J., Shaw, R. A., Rose, W. I., Mi, Y. & Ernst, G. G. J. Ice nucleation and overseeding of ice in volcanic clouds. J. Geophys. Res. Atmospheres 113, 1–13 (2008).</ref>

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 ==Evidence of water==
-Evidence of water in the Medusae Fossae Formation (MFF) has been found by researchers.  It is a vast, ancient deposit of layered water ice buried beneath a thick layer of dry dust. The water may have been deposited during periods of higher axial tilt, when the Martian equator was colder. Scientists have identified this ice using radar, and if melted, it would contain enough water to cover the entire planet in 1.5 to 2.7 meters of water.  The ice was discovered with the  Mars Advanced Radar for Subsurface and Ionospheric Sounding (MARSIS) instrument detected subsurface layers of ice.   These  ice-rich deposits are estimated to be up to 3.7 kilometers thick in some areas.   Calculations suggest a  total volume of water nearly as great as our  Red Sea.  That would be enough to cover Mars with a layer of water 1.5 to 2.7 meters deep. <ref>Thomas Watters et al, Evidence of Ice-Rich Layered Deposits in the Medusae Fossae Formation of Mars, Geophysical Research Letters (2024).</ref>
+Evidence of water in the Medusae Fossae Formation (MFF) has been found by researchers.  It is a vast, ancient deposit of layered water ice buried beneath a thick layer of dry dust. The water may have been deposited during periods of higher axial tilt, when the Martian equator was colder. Scientists have identified this ice using radar, and if melted, it would contain enough water to cover the entire planet in 1.5 to 2.7 meters of water.  The ice was discovered with the  Mars Advanced Radar for Subsurface and Ionospheric Sounding (MARSIS) instrument detected subsurface layers of ice.   These  ice-rich deposits are estimated to be up to 3.7 kilometers thick in some areas.   Calculations suggest a  total volume of water nearly as great as our  Red Sea.<ref>Thomas Watters et al, Evidence of Ice-Rich Layered Deposits in the Medusae Fossae Formation of Mars, Geophysical Research Letters (2024).</ref>
 Scientists are excited about a possible “oasis” of bulk ice in the equatorial region.  Having a source of ice near the equator could make it easier for future human exploration.  Landings near the equator are more efficient at the equator.  We know that Mars has much frozen ground, but at some distance from the equator.
 Explosive volcanic eruptions can propel large pulses of water vapor from the volcano to higher levels of the atmosphere.  These eruptions could  deposit  an ash-ice mixture, or a layer of ice covered in ash.  Under certain conditions the ice may be preserved for long periods.<ref>Ayris, P. M. & Delmelle, P. The immediate environmental effects of tephra emission. Bull. Volcanol. 74, 1905–1936 (2012).</ref>
-However, instruments on Mars orbiters have  detected excess hydrogen in the upper meter of the surface in equatorial regions (That’s between ±30°).   The hydrogen is assumed to come from water molecules.  Water contains the elements hydrogen and oxygen.  These measurements came from the Mars Odyssey Neutron Spectrometer (MONS), <ref>Feldman, W. C. et al. Global distribution of near-surface hydrogen on Mars. J. Geophys. Res.: Planets 109, E09006 (2004).</ref> <ref>Wilson, J. T. et al. Equatorial locations of water on Mars: improved resolution maps based on Mars Odyssey Neutron Spectrometer data. Icarus 299, 148–160 (2018).</ref> <ref>Evans, L. G., Reedy, R. C., Starr, R. D., Kerry, K. E. & Boynton, W. V. Analysis of gamma ray spectra measured by Mars Odyssey. J. Geophys. Res. 111, E03S04 (2006).</ref>
+Instruments on Mars orbiters have  detected excess hydrogen in the upper meter of the surface in equatorial regions (That’s between ±30°).   The hydrogen is assumed to come from water molecules.  Water contains the elements hydrogen and oxygen.  These measurements came from the Mars Odyssey Neutron Spectrometer (MONS),<ref>Feldman, W. C. et al. Global distribution of near-surface hydrogen on Mars. J. Geophys. Res.: Planets 109, E09006 (2004).</ref> <ref>Wilson, J. T. et al. Equatorial locations of water on Mars: improved resolution maps based on Mars Odyssey Neutron Spectrometer data. Icarus 299, 148–160 (2018).</ref> <ref>Evans, L. G., Reedy, R. C., Starr, R. D., Kerry, K. E. & Boynton, W. V. Analysis of gamma ray spectra measured by Mars Odyssey. J. Geophys. Res. 111, E03S04 (2006).</ref>
- the Mars Odyssey High Energy Neutron Detector (HEND),<ref>Mitrofanov, I. G. et al. Soil water content on Mars as estimated from neutron measurements by the HEND instrument onboard the 2001 Mars Odyssey spacecraft. Sol. Syst. Res. 38, 253–257 (2004).</ref>
+the Mars Odyssey High Energy Neutron Detector (HEND),<ref>Mitrofanov, I. G. et al. Soil water content on Mars as estimated from neutron measurements by the HEND instrument onboard the 2001 Mars Odyssey spacecraft. Sol. Syst. Res. 38, 253–257 (2004).</ref>
 and the  ExoMars Trace Gas Orbiter’s Fine Resolution Epithermal Neutron Detector (FREND).<ref>Rossbacher, L. A. & Judson, S. Ground ice on Mars: inventory, distribution, and resulting landforms. Icarus 45, 39–59 (1981).</ref>
 The Medusae Fossae Formation is surrounded by possible volcanic sources, including Olympus Mons and the Tharsis Montes to the east, the Elysium volcanoes and Cerberus Fissures to the north, and Apollinaris Mons, an isolated volcano situated in the center of the deposit.
 These eruptions may have caused meteorological events that influenced the surface of Mars. Terrestrial explosive volcanic eruptions are often likened to “dirty thunderstorms” due to their electrical activity, convective updrafts, and elevated water contents (from magmatic volatiles, interactions with water).<ref>Brown, R. J., Bonadonna, C. & Durant, A. J. A review of volcanic ash aggregation. Phys. Chem. Earth, Parts A/B/C. 45, 65–78 (2012).</ref>   This water can encase volcanic ash, leading to phenomena like volcanic hail, graupel, snow, and rain.<ref>Van Eaton, A. R. et al. Hail formation triggers rapid ash aggregation in volcanic plumes. Nat. Commun. 6, 1–7 (2015).</ref>
-Examples include the volcanic hail in the 2009 eruption of Redoubt Volcano in Alaska, <ref>Van Eaton, A. R. et al. Hail formation triggers rapid ash aggregation in volcanic plumes. Nat. Commun. 6, 1–7 (2015).</ref> and volcanically induced thunderstorms and rain showers following the 1991 Mount Pinatubo, Philippines eruption, <ref> .Oswalt, J. S., Nichols, W. & O’Hara, J. F. Meteorological observations of the 1991 Mount Pinatubo eruption. In Fire and Mud: Eruptions of Pinatubo, Philippines (eds Newhall, C. G. & Punongbayan, S.) 545–570 (University of Washington Press, Seattle, 1996).</ref>
+Examples include the volcanic hail in the 2009 eruption of Redoubt Volcano in Alaska,<ref>Van Eaton, A. R. et al. Hail formation triggers rapid ash aggregation in volcanic plumes. Nat. Commun. 6, 1–7 (2015).</ref>  and volcanically induced thunderstorms and rain showers following the 1991 Mount Pinatubo, Philippines eruption,<ref> .Oswalt, J. S., Nichols, W. & O’Hara, J. F. Meteorological observations of the 1991 Mount Pinatubo eruption. In Fire and Mud: Eruptions of Pinatubo, Philippines (eds Newhall, C. G. & Punongbayan, S.) 545–570 (University of Washington Press, Seattle, 1996).</ref>
 Since most ash particles are effective ice-forming nuclei, volcanic clouds and subsequent precipitation could have played a key role in shaping Mars’ surface by delivering ash-ice mixtures or ice layers covered in ash. This ash can insulate and preserve underlying ice.<ref>Durant, A. J., Shaw, R. A., Rose, W. I., Mi, Y. & Ernst, G. G. J. Ice nucleation and overseeding of ice in volcanic clouds. J. Geophys. Res. Atmospheres 113, 1–13 (2008).</ref>

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 Scientists are excited about a possible “oasis” of bulk ice in the equatorial region.  Having a source of ice near the equator could make it easier for future human exploration.  Landings near the equator are more efficient at the equator.  We know that Mars has much frozen ground, but at some distance from the equator.
 Explosive volcanic eruptions can propel large pulses of water vapor from the volcano to higher levels of the atmosphere.  These eruptions could  deposit  an ash-ice mixture, or a layer of ice covered in ash.  Under certain conditions the ice may be preserved for long periods.<ref>Ayris, P. M. & Delmelle, P. The immediate environmental effects of tephra emission. Bull. Volcanol. 74, 1905–1936 (2012).</ref>
 The Medusae Fossae Formation is surrounded by possible volcanic sources, including Olympus Mons and the Tharsis Montes to the east, the Elysium volcanoes and Cerberus Fissures to the north, and Apollinaris Mons, an isolated volcano situated in the center of the deposit.

@@ Line 55: / Line 55: @@
 Explosive volcanic eruptions can propel large pulses of water vapor from the volcano to higher levels of the atmosphere.  These eruptions could  deposit  an ash-ice mixture, or a layer of ice covered in ash.  Under certain conditions the ice may be preserved for long periods.<ref>Ayris, P. M. & Delmelle, P. The immediate environmental effects of tephra emission. Bull. Volcanol. 74, 1905–1936 (2012).</ref>
-he Medusae Fossae Formation is surrounded by possible volcanic sources, including Olympus Mons and the Tharsis Montes to the east, the Elysium volcanoes and Cerberus Fissures to the north, and Apollinaris Mons, an isolated volcano situated in the center of the deposit.
+The Medusae Fossae Formation is surrounded by possible volcanic sources, including Olympus Mons and the Tharsis Montes to the east, the Elysium volcanoes and Cerberus Fissures to the north, and Apollinaris Mons, an isolated volcano situated in the center of the deposit.
 These eruptions may have caused meteorological events that influenced the surface of Mars. Terrestrial explosive volcanic eruptions are often likened to “dirty thunderstorms” due to their electrical activity, convective updrafts, and elevated water contents (from magmatic volatiles, interactions with water).<ref>Brown, R. J., Bonadonna, C. & Durant, A. J. A review of volcanic ash aggregation. Phys. Chem. Earth, Parts A/B/C. 45, 65–78 (2012).</ref>   This water can encase volcanic ash, leading to phenomena like volcanic hail, graupel, snow, and rain.<ref>Van Eaton, A. R. et al. Hail formation triggers rapid ash aggregation in volcanic plumes. Nat. Commun. 6, 1–7 (2015).</ref>
- Examples include the volcanic hail in the 2009 eruption of Redoubt Volcano in Alaska, <ref>Van Eaton, A. R. et al. Hail formation triggers rapid ash aggregation in volcanic plumes. Nat. Commun. 6, 1–7 (2015).</ref> and volcanically induced thunderstorms and rain showers following the 1991 Mount Pinatubo, Philippines eruption, <ref> .Oswalt, J. S., Nichols, W. & O’Hara, J. F. Meteorological observations of the 1991 Mount Pinatubo eruption. In Fire and Mud: Eruptions of Pinatubo, Philippines (eds Newhall, C. G. & Punongbayan, S.) 545–570 (University of Washington Press, Seattle, 1996).</ref>
+Examples include the volcanic hail in the 2009 eruption of Redoubt Volcano in Alaska, <ref>Van Eaton, A. R. et al. Hail formation triggers rapid ash aggregation in volcanic plumes. Nat. Commun. 6, 1–7 (2015).</ref> and volcanically induced thunderstorms and rain showers following the 1991 Mount Pinatubo, Philippines eruption, <ref> .Oswalt, J. S., Nichols, W. & O’Hara, J. F. Meteorological observations of the 1991 Mount Pinatubo eruption. In Fire and Mud: Eruptions of Pinatubo, Philippines (eds Newhall, C. G. & Punongbayan, S.) 545–570 (University of Washington Press, Seattle, 1996).</ref>
 Since most ash particles are effective ice-forming nuclei, volcanic clouds and subsequent precipitation could have played a key role in shaping Mars’ surface by delivering ash-ice mixtures or ice layers covered in ash. This ash can insulate and preserve underlying ice.<ref>Durant, A. J., Shaw, R. A., Rose, W. I., Mi, Y. & Ernst, G. G. J. Ice nucleation and overseeding of ice in volcanic clouds. J. Geophys. Res. Atmospheres 113, 1–13 (2008).</ref>

@@ Line 54: / Line 54: @@
 Scientists are excited about a possible “oasis” of bulk ice in the equatorial region.  Having a source of ice near the equator could make it easier for future human exploration.  Landings near the equator are more efficient at the equator.  We know that Mars has much frozen ground, but at some distance from the equator.
 Explosive volcanic eruptions can propel large pulses of water vapor from the volcano to higher levels of the atmosphere.  These eruptions could  deposit  an ash-ice mixture, or a layer of ice covered in ash.  Under certain conditions the ice may be preserved for long periods.<ref>Ayris, P. M. & Delmelle, P. The immediate environmental effects of tephra emission. Bull. Volcanol. 74, 1905–1936 (2012).</ref>
-Eruptions from Apollinaris Mons lead to dispersal  ash and ice deposits forming around the Medussae Fossae Formation .  Eruptions from Syrtis Major can also deposit material here.
 The water detected by orbiting instruments could be found in many different materials.  Some are  (1) adsorbed water onto regolith particles.<ref>Feldman, W. C. et al. Global distribution of near-surface hydrogen on Mars. J. Geophys. Res.: Planets 109, E09006 (2004)</ref>  <ref>Malakhov, A. V. et al. Ice permafrost ‘“oases”’ close to Martian equator: planet neutron mapping based on data of FREND instrument onboard TGO orbiter of Russian-European ExoMars mission. Astron. Lett. 46, 407–421 (2020)</ref>, (2) water incorporated into the mineral’s crystal structure (i.e., hydrated minerals),<ref>Malakhov, A. V. et al. Ice permafrost ‘“oases”’ close to Martian equator: planet neutron mapping based on data of FREND instrument onboard TGO orbiter of Russian-European ExoMars mission. Astron. Lett. 46, 407–421 (2020)</ref>,(3) OH and H2O located in the structure of salt hydrates, <ref>Basilevsky, A. T. et al. Search for traces of chemically bound water in the martian surface layer based on HEND measurements onboard the 2001 Mars Odyssey spacecraft. Sol. Syst. Res. 37, 387–396 (2003).</ref> (4) small amounts of water ice in the pores between regolith particles,<ref>Malakhov, A. V. et al. Ice permafrost ‘“oases”’ close to Martian equator: planet neutron mapping based on data of FREND instrument onboard TGO orbiter of Russian-European ExoMars mission. Astron. Lett. 46, 407–421 (2020)</ref>, (5) hydrous alteration in an aqueous environment,<ref>Hood, D. R. et al. Contrasting regional soil alteration across the topographic dichotomy of Mars. Geophys. Res. Lett. 46, 13,668–13,677 (2019).</ref>  (6) sulfate hydration in the shallow subsurface,<ref>Karunatillake, S. et al. Sulfates hydrating bulk soil in the Martian low and middle latitudes. Geophys. Res. Lett. 41, 7987–7996 (2014)</ref>. (7) OH that is part of the structure of clays and trapped water between clay layers<ref>Feldman, W. C. et al. Global distribution of near-surface hydrogen on Mars. J. Geophys. Res.: Planets 109, E09006 (2004)</ref>   and/or (8) water interacting with cations located in the pores of zeolite mineral structure. <ref>Feldman, W. C. et al. Global distribution of near-surface hydrogen on Mars. J. Geophys. Res.: Planets 109, E09006 (2
 ).</ref> <ref>Hamid, S.S., Kerber, L. & Clarke, A.B. Precipitation induced by explosive volcanism on Mars and its implications for unexpected equatorial ice. Nat Commun 16, 8923 (2025). https://doi.org/10.1038/s41467-025-63518-8</ref>

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 File: ESP 051978 1720yardangslayers.jpg|Small yardangs
 </gallery>
 ==See also==

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 ==See also==
+*[[Amazonis quadrangle]]
 *[[Geography of Mars]]
 *[[High Resolution Imaging Science Experiment (HiRISE)]]

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 == Origin and age ==
 The origin of the formation is unknown, but many theories have been presented over the years.
 In 2020, a group of researchers headed by Peter Mouginis-Mark has hypothesized that the formation could have been formed from pumice rafts from the volcano [[Olympus Mons]].<ref>Scientists Float a New Theory on the Medusae Fossae Formation". Eos. 19 May 2020.</ref>  In 2012, a group headed by Laura Kerber hypothesized that it could have been formed from ash from the volcanoes Apollinaris Mons, Arsia Mons, and possibly Pavonis Mons.<ref>{{cite journal |doi=10.1016/j.icarus.2012.03.016 |title=The dispersal of pyroclasts from ancient explosive volcanoes on Mars: Implications for the friable layered deposits |journal=Icarus |volume=219 |issue=1 |pages=358–381 |year=2012 |last1=Kerber |first1=Laura |last2=Head |first2=James W. |last3=Madeleine |first3=Jean-Baptiste |last4=Forget |first4=François |last5=Wilson |first5=Lionel | }}</ref>

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 |url=https://www.nature.com/articles/s41467-018-05291-5/figures/1|journal=Nature Communications|language=en|</ref>
-The total area of the Medusae Fossae Formation is equal to 20% the size of the continental United States.<ref name="pmid30030425">{{cite journal |doi=10.1038/s41467-018-05291-5 |pmid=30030425 |pmc=6054634 |title=The Medusae Fossae Formation as the single largest source of dust on Mars |journal=Nature Communications |volume=9 |issue=1 |pages=2867 |year=2018 |last1=Ojha |first1=Lujendra |last2=Lewis |first2=Kevin |last3=Karunatillake |first3=Suniti |last4=Schmidt |first4=Mariek |bibcode=2018NatCo...9.2867O }}</ref>
+The total area of the Medusae Fossae Formation is equal to 20% the size of the continental United States.<ref name="pmid30030425"> |pmid=30030425 |pmc=6054634 |title=The Medusae Fossae Formation as the single largest source of dust on Mars |journal=Nature Communications |volume=9 |issue=1 |pages=2867 |year=2018 |last1=Ojha |first1=Lujendra |last2=Lewis |first2=Kevin |last3=Karunatillake |first3=Suniti |last4=Schmidt |first4=Mariek |</ref>
 The formation straddles what is called the  martian dichotomy|highland - lowland boundary near the Tharsis and Elysium volcanic areas, and extends across five quadrangles: [[Amazonis quadrangle|Amazonis]], [[Tharsis quadrangle|Tharsis]], [[Memnonia quadrangle|Memnonia]], [[Elysium quadrangle|Elysium]], and [[Aeolis quadrangle|Aeolis]].