10.4 The Geology of Mars
4 min read•june 12, 2024
Mars, the Red Planet, has captivated explorers for decades. From 's groundbreaking orbit to Curiosity's ongoing mission, each probe has unveiled Mars' secrets. These missions have revealed massive volcanoes, deep canyons, and tantalizing hints of past water.
Mars' geology tells a tale of a world both alien and familiar. Its surface features, from to sprawling valleys, showcase a complex history. While Mars lacks , it boasts the solar system's largest volcano and canyon, dwarfing Earth's counterparts.
Mars Exploration and Geology
Key Mars exploration missions
Top images from around the web for Key Mars exploration missions
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Viking Archives - Universe Today View original
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Viking Archives - Universe Today View original
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Top images from around the web for Key Mars exploration missions
Viking Archives - Universe Today View original
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Viking mission Archives - Universe Today View original
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Viking Archives - Universe Today View original
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Viking Archives - Universe Today View original
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- Mariner 9 (1971-1972)
- First spacecraft to successfully orbit another planet
- Discovered massive Martian volcanoes (), extensive canyons (), and evidence of past water erosion
- and 2 (1976)
- Conducted first successful landings on Mars' surface
- Analyzed soil composition and searched for signs of life but results were inconclusive
- (1997-2006)
- Mapped the entire Martian surface in high detail
- Discovered evidence of recent water activity (gullies) and remnants of a global magnetic field
- Mars Exploration Rovers: and (2004-2010, 2004-2018)
- Investigated Martian geology at multiple sites
- Found clear evidence of past water activity (sedimentary rocks, hematite spherules)
- (2006-present)
- Provides highest-resolution images of Mars' surface and spectral data
- Monitors Martian weather patterns, climate cycles, and surface changes
- Mars Science Laboratory: (2012-present)
- Investigates Martian climate, geology, and potential for past microbial life
- Discovered evidence of ancient habitable environments () with conditions favorable for microbial life
Insights from Martian meteorites
- , , and (SNC meteorites)
- Igneous rocks ejected from Mars by large impact events
- Provide valuable insights into Martian magmatism, mantle composition, and differentiation history
- (ALH84001)
- Ancient Martian meteorite (4.09 billion years old) discovered in Antarctica
- Contains disputed evidence of possible microfossils and organic compounds
- (NWA 7034) and paired meteorites
- Martian breccia containing diverse fragments of Martian crust
- Offers a broad sampling of Martian crustal materials and evidence of past water-rock interactions
Diverse surface features of Mars
- Polar caps
- Composed of layered deposits of water ice and carbon dioxide ice (dry ice)
- Exhibit seasonal changes in size due to sublimation and deposition of ice
- Valleys and channels
- Outflow channels: Formed by catastrophic water floods from subsurface sources ()
- Valley networks: Formed by sustained water flow in Mars' ancient past ()
- Plains and lowlands
- Northern lowlands: Smooth, sparsely cratered, and possibly shaped by ancient oceans
- : Largest impact basin on Mars, spanning over 2,000 km in diameter
- Highlands and mountains
- Southern highlands: Heavily cratered and geologically older than northern lowlands
- region: Extensive volcanic plateau hosting the largest volcanoes in the solar system (Olympus Mons, )
Mars vs Earth: Volcanoes and canyons
- Volcanoes
- Olympus Mons: Largest known volcano in the solar system
- Shield volcano similar in shape to Hawaii's Mauna Loa but much larger (height: 22 km, base diameter: 624 km)
- Tharsis Montes: Three large shield volcanoes (, , and )
- Comparable in morphology to Earth's shield volcanoes but with significantly larger sizes and heights
- Olympus Mons: Largest known volcano in the solar system
- Canyons
- Valles Marineris: Largest canyon system in the solar system
- Extends over 4,000 km in length, up to 200 km in width, and up to 7 km in depth
- Formed by a combination of tectonic rifting and water erosion, similar to the formation of Earth's Grand Canyon but on a much larger scale
- Valles Marineris: Largest canyon system in the solar system
Current environmental conditions on Mars
- Atmospheric composition
- 95.3% carbon dioxide, 2.7% nitrogen, 1.6% argon, with traces of oxygen and water vapor
- Low atmospheric pressure (about 1% of Earth's) and cold average temperature (-63℃)
- Water on Mars
- Water ice is present in the polar ice caps and in subsurface deposits ()
- Liquid water is unlikely to persist on the surface due to low atmospheric pressure
- Radiation and oxidizing soil
- Lack of a global magnetic field and thin atmosphere allows high levels of cosmic and solar radiation to reach the surface
- Oxidizing compounds in Martian soil () can be toxic to life as we know it
- Implications for potential life
- Current surface conditions are challenging for life as we know it due to low temperatures, low pressure, radiation, and oxidizing soil
- Subsurface environments, such as underground aquifers or geothermal regions, may be more habitable
- Past Martian environments were likely more conducive to life, as evidenced by the widespread presence of ancient water-related features (valley networks, lake basins)
Geological processes shaping Mars
- Plate tectonics: Unlike Earth, Mars lacks active plate tectonics, which has significant implications for its geological evolution
- : Extensive volcanic activity has shaped Mars' surface, particularly in the Tharsis region
- : The heavily cratered surface of Mars, especially in the southern highlands, reflects its long history of meteorite impacts
- : Wind-driven erosion and deposition have significantly modified the Martian landscape, creating features like dunes and dust storms
- : Ancient water-related activities have left their mark on Mars, forming valleys, channels, and sedimentary deposits
Key Terms to Review (33)
Aeolian Processes: Aeolian processes refer to the geological and geomorphological activities driven by wind. These processes shape the surface of a planet or moon through the erosion, transportation, and deposition of sediments, creating distinctive landforms and features.
Allan Hills 84001: Allan Hills 84001 (ALH84001) is a Martian meteorite that was discovered in the Allan Hills region of Antarctica in 1984. It is one of the oldest known meteorites to have originated from Mars and has been the subject of intense scientific study due to its potential implications for the possibility of past life on Mars.
Arsia Mons: Arsia Mons is a massive shield volcano located in the Tharsis region of Mars. It is one of the largest volcanoes in the solar system, with a height of over 18 kilometers (11 miles) and a base diameter of more than 300 kilometers (190 miles). Arsia Mons is part of the Tharsis Montes, a group of three large shield volcanoes on Mars.
Ascraeus Mons: Ascraeus Mons is a large shield volcano located in the Tharsis region of Mars. It is one of the three major volcanoes that make up the Tharsis Montes, a group of massive shield volcanoes on the planet's surface.
Chassignites: Chassignites are a type of Martian meteorite that originated from the planet Mars. They are named after the town of Chassigny in France, where the first specimen of this meteorite type was discovered in 1815. Chassignites provide valuable insights into the geology and composition of the Martian crust and mantle.
Curiosity Rover: The Curiosity Rover is a car-sized Mars rover designed to explore the Gale Crater on Mars as part of NASA's Mars Science Laboratory mission. It was launched in 2011 and landed on Mars in 2012, with the primary goals of studying the planet's geology and climate, and assessing whether past environmental conditions could have supported microbial life.
Fluvial Processes: Fluvial processes refer to the geological and geomorphological activities associated with rivers and streams. These processes shape the landscape through the erosion, transport, and deposition of sediments, ultimately influencing the formation and evolution of various landforms.
Hellas Basin: The Hellas Basin is a large impact crater located on the southern hemisphere of Mars. It is the largest confirmed impact basin on the planet and one of the most prominent geological features, with significant implications for the geology and evolution of Mars.
Impact Cratering: Impact cratering is the process by which a large meteoroid, asteroid, comet, or other celestial object collides with and leaves a crater on the surface of a planet, moon, or other solid body. This is a fundamental geological process that has shaped the surfaces of many planetary bodies throughout the solar system, including Earth, Mars, and the Moon.
Kasei Valles: Kasei Valles is a vast outflow channel system on the surface of Mars, located in the Tharsis region of the planet. It is one of the largest and most prominent fluvial features on the Martian surface, formed by catastrophic flooding events in the planet's distant past.
Mariner 9: Mariner 9 was an American robotic spacecraft that was the first to orbit another planet, Mars, in 1971. It played a crucial role in advancing our understanding of the geology and atmospheric processes of the Red Planet.
Mars Global Surveyor: The Mars Global Surveyor was a NASA spacecraft that orbited Mars from 1997 to 2006, conducting a comprehensive study of the planet's surface, atmosphere, and magnetic field. It was the first successful Mars orbiter mission since the failure of the Mars Observer in 1993 and played a crucial role in advancing our understanding of the geology and climate of the Red Planet.
Mars Reconnaissance Orbiter: The Mars Reconnaissance Orbiter (MRO) is a NASA spacecraft that has been orbiting Mars since 2006. Its primary mission is to study the geology, climate, and atmosphere of Mars in unprecedented detail, providing valuable insights into the planet's history and potential for supporting life.
Nakhlites: Nakhlites are a group of rare Martian meteorites that provide valuable insights into the geology and evolution of Mars. These meteorites are named after the town of Nakhla in Egypt, where the first specimen was discovered in 1911.
Nanedi Valles: Nanedi Valles is a system of deep, meandering valleys located on the surface of Mars. These valleys are believed to have been formed by the flow of liquid water over an extended period of time, providing important insights into the geological history and past climate conditions of the planet.
Northwest Africa 7034: Northwest Africa 7034 (NWA 7034) is a unique Martian meteorite that provides valuable insights into the geology and history of the planet Mars. It is the first known Martian meteorite that closely resembles the composition and characteristics of the Martian surface as observed by various spacecraft missions.
Olympus Mons: Olympus Mons is a massive shield volcano located on the planet Mars, known for being the largest volcano in the solar system. This remarkable geological feature is closely tied to the composition, structure, and evolution of planets, particularly in the context of the Martian surface and the broader understanding of planetary geology.
Opportunity: Opportunity refers to a chance or favorable set of circumstances that allows for the exploration, investigation, or discovery of something. In the context of planetary geology, the term 'Opportunity' is specifically associated with the Mars Exploration Rover mission, which provided a unique opportunity to study the geology and environment of the planet Mars in great detail.
Pavonis Mons: Pavonis Mons is one of the three major shield volcanoes located on the Tharsis bulge of Mars. It is a large, gently sloping volcano that is part of the Tharsis Montes, a group of three aligned shield volcanoes on the planet.
Perchlorates: Perchlorates are a class of chemical compounds containing the perchlorate ion (ClO4-). They are known to be present on the surface of Mars and have important implications for the geology and potential habitability of the planet.
Permafrost: Permafrost is a layer of soil, rock, or sediment that remains frozen for at least two consecutive years, typically found in polar and high-altitude regions. It is a crucial component of the Earth's cryosphere and plays a significant role in the geology and climate of these environments, particularly in the context of the planet Mars.
Plate Tectonics: Plate tectonics is the scientific theory that describes the large-scale motion of the Earth's lithosphere, which is divided into several rigid plates that move independently over the more fluid asthenosphere. This concept is fundamental to understanding the global perspective, the structure of Earth's crust, the evolution of life and climate, and the geology of other terrestrial planets in our solar system.
Polar Ice Caps: Polar ice caps are the permanent, year-round covers of ice that exist at the northernmost and southernmost regions of the Earth. These expansive frozen landmasses play a crucial role in the planet's climate, reflecting solar radiation and regulating global temperatures.
Regolith: Regolith is the layer of loose, unconsolidated rock and dust that covers the surface of a planetary body, such as the Moon, Mercury, or Mars. It is the result of the continuous breakdown and weathering of the underlying bedrock through various geological processes.
Shergottites: Shergottites are a type of Martian meteorite that originated from the surface of Mars. These meteorites provide valuable insights into the geology and geochemistry of the Red Planet, offering a rare opportunity to study the composition and evolution of the Martian crust and mantle.
Spirit: In the context of planetary geology, the term 'spirit' refers to a robotic rover designed and launched by NASA to explore the surface of Mars. These rovers are equipped with advanced scientific instruments and cameras to study the Martian environment and geology in great detail.
Tharsis: Tharsis is a vast volcanic region located in the western hemisphere of Mars, known for its massive shield volcanoes and extensive lava flows. It is a prominent feature of the Martian surface that has significantly influenced the planet's geological and atmospheric evolution.
Tharsis Montes: Tharsis Montes is a vast volcanic region located in the western hemisphere of Mars, characterized by a cluster of large shield volcanoes. It is one of the most prominent geological features on the Martian surface and has significantly influenced the planet's geology and evolution.
Valles Marineris: Valles Marineris is a vast system of canyons located on the planet Mars, stretching across the Martian surface for over 4,000 kilometers. It is considered one of the most significant geological features on Mars and provides valuable insights into the planet's composition, structure, and geological history.
Viking 1: Viking 1 was the first successful interplanetary spacecraft to land on the surface of Mars. It was part of NASA's Viking program, which aimed to study the Martian environment and search for signs of life on the planet.
Viking 2: Viking 2 was the second successful robotic spacecraft mission to Mars, launched in 1975 as part of the Viking program. It was designed to study the Martian surface, atmosphere, and potential for life, building on the discoveries of its predecessor, Viking 1.
Volcanism: Volcanism refers to the processes and phenomena associated with the eruption of molten rock, called magma, from the interior of a planetary body onto its surface. This term is central to understanding the composition, structure, and evolution of planets within our solar system.
Yellowknife Bay: Yellowknife Bay is a geological feature on the planet Mars that has been extensively studied by the Curiosity rover as part of NASA's Mars Science Laboratory mission. It is a significant site in the search for evidence of past or present life on Mars due to its unique geological characteristics and potential for harboring habitable environments.