Glaciers on Mars
Encyclopedia
Glaciers formed much of the observable surface in large areas of Mars. Most of the area in high latitudes, especially the Ismenius Lacus quadrangle
, is believed to still contain enormous amounts of water ice. Recent evidence has led many planetary scientists to believe that water ice still exists in the form of glaciers that are covered with a thin layer of insulating rock. In March 2010, scientists released the results of a radar study of an area called Deuteronilus Mensae
that found widespread evidence of ice lying beneath a few meters of rock debris. Glaciers are believed to be associated with Fretted terrain
, many volcanoes, and even some craters.
Ridges of debris on the surface of the glaciers show the direction of ice movement. The surface of some glaciers has a rough texture due to sublimation of buried ice. The ice goes directly into a gas (this process is called sublimation) and leaves behind an empty space. Overlying material then collapses into the void. Various sized pits and holes result. Glaciers are not pure ice; they contain dirt and rocks. At times, they will dump their load of materials into ridges. Such ridges are called moraines. Some places on Mars have groups of ridges that are twisted around; this may have been due to more movement after the ridges were put into place. Sometimes chunks of ice fall from the glacier and get buried in the land surface. When they melt and more or less round hole remains. On Earth we call these features kettles or kettle holes. Mendon Ponds Park
in upstate NY has preserved several of these kettles. One picture below from HiRISE
shows possible kettles in Moreux Crater
.
Some of the glacial-like features were revealed by NASA's Viking orbiters in the 1970s. Since that time glacial-like features have been studied by more and more advanced instruments. Much better data has been received from Mars Global Surveyor
, Mars Odyssey, Mars Express
, and Mars Reconnaissance Orbiter
.
’s Shallow Radar instrument penetrated the rocky debris flows that lie in the mid-latitude regions of both hemispheres. An examination of the radar echoes pointed to ice, and lots of it. The radar echoes received back by MRO indicated that radio waves passed through the overlying debris material and reflected off a deeper surface below without losing much strength — the expected signal for thick ice covered by a thin layer of debris. The radar echoes also showed no signs of significant rock debris within the glaciers, suggesting that they are relatively pure water ice.
Ice on the surface of Mars today would immediately sublimate (or change directly into the gas phase). The rocky debris covering the ice is likely what has allowed it to survive below the surface for millions of years.
contains dozens to hundreds of concentric ridges that are caused by the movements of sometimes hundreds of meter thick accumulations of ice in craters. Lineated valley fill
are lines of ridges in valleys. These lines may have developed as other glaciers moved down valleys. Some of these glaciers seem to come from material sitting around mesas and buttes. Lobate debris aprons is the name given to these glaciers. All of these features that are believed to contain large amounts of ice are found in the mid-latitudes in both the Northern and Southern hemispheres. These areas are sometimes called Fretted terrain
because it is sometimes winkled. Many of these features are found in the Northern hemisphere in parts of a boundary called the Martian dichotomy
. The Martian dichotomy is mostly found between 0 to 70 E longitudes. Near this area are regions that are named from ancient names: Deuteronilus Mensae
, Protonilus Mensae
, and Nilosyrtis Mensae
.
Many supposed glaciers have been observed on some of large Martian volcanoes. Researchers have described glacial deposits on Hecates Tholus
, Arsia Mons
, Pavonis Mons
, and Olympus Mons
.
Pictures below show various features that appear to be connected with the existence of glaciers.
Ismenius Lacus quadrangle
The Ismenius Lacus quadrangle is one of a series of 30 quadrangle maps of Mars used by the United States Geological Survey Astrogeology Research Program. The quadrangle is located in the northwestern portion of Mars’ eastern hemisphere and covers 0° to 60° east longitude and 30° to 65° north...
, is believed to still contain enormous amounts of water ice. Recent evidence has led many planetary scientists to believe that water ice still exists in the form of glaciers that are covered with a thin layer of insulating rock. In March 2010, scientists released the results of a radar study of an area called Deuteronilus Mensae
Deuteronilus Mensae
Deuteronilus Mensae is a region on Mars 937 km across and centered at . It covers 344° -325° West and 40°-48° North. Deuteronilus region lies just to the north of Arabia Terra and is included in the Ismenius Lacus quadrangle. It is along the dichotomy boundary, that is between the old,...
that found widespread evidence of ice lying beneath a few meters of rock debris. Glaciers are believed to be associated with Fretted terrain
Fretted terrain
Fretted terrain is a type of surface feature common to certain areas of Mars and discovered in Mariner 9 images. It lies between two different types of terrain...
, many volcanoes, and even some craters.
Ridges of debris on the surface of the glaciers show the direction of ice movement. The surface of some glaciers has a rough texture due to sublimation of buried ice. The ice goes directly into a gas (this process is called sublimation) and leaves behind an empty space. Overlying material then collapses into the void. Various sized pits and holes result. Glaciers are not pure ice; they contain dirt and rocks. At times, they will dump their load of materials into ridges. Such ridges are called moraines. Some places on Mars have groups of ridges that are twisted around; this may have been due to more movement after the ridges were put into place. Sometimes chunks of ice fall from the glacier and get buried in the land surface. When they melt and more or less round hole remains. On Earth we call these features kettles or kettle holes. Mendon Ponds Park
Mendon Ponds Park
Mendon Ponds Park is a county park located southeast of Rochester, New York, within the suburban towns of Mendon and Pittsford. At over 2500 acres , it is the largest park in Monroe County...
in upstate NY has preserved several of these kettles. One picture below from HiRISE
HiRISE
High Resolution Imaging Science Experiment is a camera on board the Mars Reconnaissance Orbiter. The 65 kg , $40 million instrument was built under the direction of the University of Arizona's Lunar and Planetary Laboratory by Ball Aerospace & Technologies Corp....
shows possible kettles in Moreux Crater
Moreux Crater
Moreux Crater is a crater in the Ismenius Lacus quadrangle on Mars with a diameter of 138 km. It is located at 42.1° north latitude and 315.6° west longitude It was named after Theophile Moreux, a French astronomer and meteorologist ....
.
Water source for future colonists
Mars has vast glaciers hidden under a layer of rocky debris over wide areas in the mid-latitudes. These glaciers could be large reservoir of life-supporting water on the planet for simple life forms and for future colonists of the Red Planet. Research by John Holt, of the University of Texas at Austin, and others found that one of the features examined is three times larger than the city of Los Angeles and up to one-half-mile thick, and there are many more.Some of the glacial-like features were revealed by NASA's Viking orbiters in the 1970s. Since that time glacial-like features have been studied by more and more advanced instruments. Much better data has been received from Mars Global Surveyor
Mars Global Surveyor
The Mars Global Surveyor was a US spacecraft developed by NASA's Jet Propulsion Laboratory and launched November 1996. It began the United States's return to Mars after a 10-year absence. It completed its primary mission in January 2001 and was in its third extended mission phase when, on 2...
, Mars Odyssey, Mars Express
Mars Express
Mars Express is a space exploration mission being conducted by the European Space Agency . The Mars Express mission is exploring the planet Mars, and is the first planetary mission attempted by the agency. "Express" originally referred to the speed and efficiency with which the spacecraft was...
, and Mars Reconnaissance Orbiter
Mars Reconnaissance Orbiter
Mars Reconnaissance Orbiter is a NASA multipurpose spacecraft designed to conduct reconnaissance and Exploration of Mars from orbit...
.
Radar finds ice
For decades scientists speculated that many features on Mars could be glaciers. Studies with NASA's Mars Reconnaissance OrbiterMars Reconnaissance Orbiter
Mars Reconnaissance Orbiter is a NASA multipurpose spacecraft designed to conduct reconnaissance and Exploration of Mars from orbit...
’s Shallow Radar instrument penetrated the rocky debris flows that lie in the mid-latitude regions of both hemispheres. An examination of the radar echoes pointed to ice, and lots of it. The radar echoes received back by MRO indicated that radio waves passed through the overlying debris material and reflected off a deeper surface below without losing much strength — the expected signal for thick ice covered by a thin layer of debris. The radar echoes also showed no signs of significant rock debris within the glaciers, suggesting that they are relatively pure water ice.
Climate Changes
It is now widely believed that ice accumulated when Mars' orbital tilt was much different than it is now (the axis the planet spins on has considerable "wobble," meaning its angle changes over time). A few million years ago, the tilt of the axis of Mars was 45 degrees instead of its present 25 degrees. Its’ tilt, also called obliquity, varies greatly because its two tiny moons cannot stabilize it, like our relatively large moon does to the Earth. At high tilt, the ice caps at the poles disappear, the atmosphere thickens, and the moisture in the atmosphere goes up. These conditions cause snow and frost to appear on the surface. Some of the moisture would have coated dust grains until the grains would be too heavy to be held up in the atmosphere; they would then fall and accumulate on the surface. Just plain snow would have also added to the mix.Ice on the surface of Mars today would immediately sublimate (or change directly into the gas phase). The rocky debris covering the ice is likely what has allowed it to survive below the surface for millions of years.
Concentric crater fill, Lineated valley fill, and Lobate debris aprons
Several types of landforms have been identified as probably dirt and rock debris covering huge deposits of ice. Concentric crater fillConcentric crater fill
Concentric crater fill is when the floor of a crater is mostly covered with a large number of parallel ridges. It is common in the mid-latitudes of Mars, and is widely believed to be caused by glacial movement...
contains dozens to hundreds of concentric ridges that are caused by the movements of sometimes hundreds of meter thick accumulations of ice in craters. Lineated valley fill
Lineated valley fill
Lineated valley fill , also called lineated floor deposit, is a feature of the floors of some channels on Mars, exhibiting ridges and grooves that seem to flow around obstacles. Shadow measurements show that at least some of the ridges are several metres high. LVF is believed to be ice-rich. ...
are lines of ridges in valleys. These lines may have developed as other glaciers moved down valleys. Some of these glaciers seem to come from material sitting around mesas and buttes. Lobate debris aprons is the name given to these glaciers. All of these features that are believed to contain large amounts of ice are found in the mid-latitudes in both the Northern and Southern hemispheres. These areas are sometimes called Fretted terrain
Fretted terrain
Fretted terrain is a type of surface feature common to certain areas of Mars and discovered in Mariner 9 images. It lies between two different types of terrain...
because it is sometimes winkled. Many of these features are found in the Northern hemisphere in parts of a boundary called the Martian dichotomy
Martian dichotomy
The most conspicuous feature of Martian surface geology is a sharp contrast, known as the Martian dichotomy, between the rugged southern highlands and the relatively smooth northern basins. The two hemispheres differ in elevation by 1 to 3 km...
. The Martian dichotomy is mostly found between 0 to 70 E longitudes. Near this area are regions that are named from ancient names: Deuteronilus Mensae
Deuteronilus Mensae
Deuteronilus Mensae is a region on Mars 937 km across and centered at . It covers 344° -325° West and 40°-48° North. Deuteronilus region lies just to the north of Arabia Terra and is included in the Ismenius Lacus quadrangle. It is along the dichotomy boundary, that is between the old,...
, Protonilus Mensae
Protonilus Mensae
Protonilus Mensae is an area of Mars in the Ismenius Lacus quadrangle. It is centered on the coordinates of 43.86° N and 49.4° E. Its western and eastern longitudes are 37° E and 59.7° E. North and south latitudes are 47.06° N and 39.87° N. Protonilus Mensae is between Deuteronilus Mensae and...
, and Nilosyrtis Mensae
Nilosyrtis Mensae
Nilosyrtis Mensae is an area of Mars in the Casius quadrangle. It is centered on the coodinates of 36.87° N and 67.9° E. Its western and eastern longitudes are 51.1° E and 74.4° E. North and south latitudes are 36.87° N and 29.61° N. Nilosyrtis Mensae is just to the east of Protonilus Mensae...
.
Tongue-shaped glaciers and glaciers on volcanoes
Some of the glaciers flow down mountains and are shaped by obstacles and valleys; they make a sort of tongue shape.Many supposed glaciers have been observed on some of large Martian volcanoes. Researchers have described glacial deposits on Hecates Tholus
Hecates Tholus
Hecates Tholus is a Martian volcano, notable for results from the European Space Agency's Mars Express mission which indicate a major eruption took place 350 million years ago. The eruption created a caldera 10 km in diameter. It has been suggested that glacial deposits later partly filled the...
, Arsia Mons
Arsia Mons
Arsia Mons is the southernmost of three volcanos on the Tharsis bulge near the equator of the planet Mars. To its north is Pavonis Mons, and north of that is Ascraeus Mons. The tallest mountain in the solar system, Olympus Mons, is to its northwest...
, Pavonis Mons
Pavonis Mons
Pavonis Mons is a large shield volcano located in the Tharsis region of the planet Mars. It is the middle member of a chain of three volcanic mountains that straddle the Martian equator between longitudes 235°E and 259°E. The volcano was discovered by the Mariner 9 spacecraft in 1971 and was...
, and Olympus Mons
Olympus Mons
Olympus Mons is a large volcanic mountain on the planet Mars. At a height of almost , it is one of the tallest mountains in the Solar System, three times as tall as Mount Everest and more than twice the height of Mauna Kea the tallest mountain on Earth. Olympus Mons is the youngest of the large...
.
Pictures below show various features that appear to be connected with the existence of glaciers.
See also
- Water on MarsWater on MarsWater on Mars is a psychedelic rock and electronic music group from Quebec City, Québec, Canada. The music trio is led by Philippe Navarro, guitarist, vocalist, arranger, producer, principal lyricist, and music composer....
- Climate of MarsClimate of MarsThe climate of Mars has been an issue of scientific curiosity for centuries, not least because Mars is the only terrestrial planet whose surface can be directly observed in detail from the Earth....
- Geology of MarsGeology of MarsThe geology of Mars is the scientific study of the surface, crust, and interior of the planet Mars. It emphasizes the composition, structure, history, and physical processes that shape the planet. It is fully analogous to the field of terrestrial geology. In planetary science, the term geology is...
- Fretted terrainFretted terrainFretted terrain is a type of surface feature common to certain areas of Mars and discovered in Mariner 9 images. It lies between two different types of terrain...
- Lineated valley fillLineated valley fillLineated valley fill , also called lineated floor deposit, is a feature of the floors of some channels on Mars, exhibiting ridges and grooves that seem to flow around obstacles. Shadow measurements show that at least some of the ridges are several metres high. LVF is believed to be ice-rich. ...
- Martian dichotomyMartian dichotomyThe most conspicuous feature of Martian surface geology is a sharp contrast, known as the Martian dichotomy, between the rugged southern highlands and the relatively smooth northern basins. The two hemispheres differ in elevation by 1 to 3 km...
- Deuteronilus MensaeDeuteronilus MensaeDeuteronilus Mensae is a region on Mars 937 km across and centered at . It covers 344° -325° West and 40°-48° North. Deuteronilus region lies just to the north of Arabia Terra and is included in the Ismenius Lacus quadrangle. It is along the dichotomy boundary, that is between the old,...
- Protonilus MensaeProtonilus MensaeProtonilus Mensae is an area of Mars in the Ismenius Lacus quadrangle. It is centered on the coordinates of 43.86° N and 49.4° E. Its western and eastern longitudes are 37° E and 59.7° E. North and south latitudes are 47.06° N and 39.87° N. Protonilus Mensae is between Deuteronilus Mensae and...
- Nilosyrtis MensaeNilosyrtis MensaeNilosyrtis Mensae is an area of Mars in the Casius quadrangle. It is centered on the coodinates of 36.87° N and 67.9° E. Its western and eastern longitudes are 51.1° E and 74.4° E. North and south latitudes are 36.87° N and 29.61° N. Nilosyrtis Mensae is just to the east of Protonilus Mensae...
- Ismenius Lacus quadrangleIsmenius Lacus quadrangleThe Ismenius Lacus quadrangle is one of a series of 30 quadrangle maps of Mars used by the United States Geological Survey Astrogeology Research Program. The quadrangle is located in the northwestern portion of Mars’ eastern hemisphere and covers 0° to 60° east longitude and 30° to 65° north...
- GlacierGlacierA glacier is a large persistent body of ice that forms where the accumulation of snow exceeds its ablation over many years, often centuries. At least 0.1 km² in area and 50 m thick, but often much larger, a glacier slowly deforms and flows due to stresses induced by its weight...