Syrtis Major Planum is a "dark spot" located in the boundary between the northern lowlands and southern highlands of Mars just west of the impact basin Isidis in the Syrtis Major quadrangle. It was discovered, on the basis of data from Mars Global Surveyor, to be a low-relief shield volcano, but was formerly believed to be a plain, and was then known as Syrtis Major Planitia. The dark color comes from the basaltic volcanic rock of the region and the relative lack of dust.
Holden is a 140 km wide crater situated within the Margaritifer Sinus quadrangle (MC-19) region of the planet Mars, located with the southern highlands. It is named after American astronomer Edward Singleton Holden. It is part of the Uzboi-Landon-Morava (ULM) system.
The Memnonia quadrangle is one of a series of 30 quadrangle maps of Mars used by the United States Geological Survey (USGS) Astrogeology Research Program. The Memnonia quadrangle is also referred to as MC-16.
Arabia Terra is a large upland region in the north of Mars that lies mostly in the Arabia quadrangle, but a small part is in the Mare Acidalium quadrangle. It is densely cratered and heavily eroded. This battered topography indicates great age, and Arabia Terra is presumed to be one of the oldest terrains on the planet. It covers as much as 4,500 km (2,800 mi) at its longest extent, centered roughly at 21°N6°E with its eastern and southern regions rising 4 km (13,000 ft) above the north-west. Alongside its many craters, canyons wind through the Arabia Terra, many emptying into the large northern lowlands of the planet, which borders Arabia Terra to the north.
An ejecta blanket is a generally symmetrical apron of ejecta that surrounds an impact crater; it is layered thickly at the crater's rim and thin to discontinuous at the blanket's outer edge. The impact cratering is one of the basic surface formation mechanisms of the solar system bodies and the formation and emplacement of ejecta blankets are the fundamental characteristics associated with impact cratering event. The ejecta materials are considered as the transported materials beyond the transient cavity formed during impact cratering regardless of the state of the target materials.
Isidis Planitia is a plain located within a giant impact basin on Mars, located partly in the Syrtis Major quadrangle and partly in the Amenthes quadrangle. At approximately 1,500 km (930 mi) in diameter, it is the third-largest obvious impact structure on the planet, after the Hellas and Argyre basins. Isidis was likely the last major basin to be formed on Mars, having formed approximately 3.9 billion years ago during the Noachian period. Due to dust coverage, it typically appears bright in telescopic views, and was mapped as a classical albedo feature, Isidis Regio, visible by telescope in the pre-spacecraft era.
The 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 analogous to the field of terrestrial geology. In planetary science, the term geology is used in its broadest sense to mean the study of the solid parts of planets and moons. The term incorporates aspects of geophysics, geochemistry, mineralogy, geodesy, and cartography. A neologism, areology, from the Greek word Arēs (Mars), sometimes appears as a synonym for Mars's geology in the popular media and works of science fiction. The term areology is also used by the Areological Society.
Nili Fossae is a group of large, concentric grabens on Mars, in the Syrtis Major quadrangle. They have been eroded and partly filled in by sediments and clay-rich ejecta from a nearby giant impact crater, the Isidis basin. It is at approximately 22°N, 75°E, and has an elevation of −0.6 km (−0.37 mi). Nili Fossae was on the list of potential landing sites of the Mars Science Laboratory, arriving in 2012, but was dropped before the final four sites were determined. Although not among the last finalists, in September 2015 it was selected as a potential landing site for the Mars 2020 rover, which will use the same design as Curiosity, but with a different payload focused on astrobiology. Nili Fossae is also considered ideal for future human exploration, with the prominent Gavin Crater at 21.43°N, 76.93°E considered the most likely landing zone in Nili Fossae.
Jezero is a crater on Mars in the Syrtis Major quadrangle, about 45.0 km (28.0 mi) in diameter. Thought to have once been flooded with water, the crater contains a fan-delta deposit rich in clays. The lake in the crater was present when valley networks were forming on Mars. Besides having a delta, the crater shows point bars and inverted channels. From a study of the delta and channels, it was concluded that the lake inside the crater probably formed during a period in which there was continual surface runoff.
The Syrtis Major quadrangle is one of a series of 30 quadrangle maps of Mars used by the United States Geological Survey (USGS) Astrogeology Research Program. The Syrtis Major quadrangle is also referred to as MC-13.
The Amazonis quadrangle is one of a series of 30 quadrangle maps of Mars used by the United States Geological Survey (USGS) Astrogeology Research Program. The Amazonis quadrangle is also referred to as MC-8.
The Mare Tyrrhenum quadrangle is one of a series of 30 quadrangle maps of Mars used by the United States Geological Survey (USGS) Astrogeology Research Program. This quadrangle is also referred to as MC-22. It contains parts of the regions Tyrrhena Terra, Hesperia Planum, and Terra Cimmeria.
The Phoenicis Lacus quadrangle is one of a series of 30 quadrangle maps of Mars used by the United States Geological Survey (USGS) Astrogeology Research Program. The Phoenicis Lacus quadrangle is also referred to as MC-17. Parts of Daedalia Planum, Sinai Planum, and Solis Planum are found in this quadrangle. Phoenicis Lacus is named after the phoenix which according to myth burns itself up every 500 years and then is reborn.
Pangboche is a young impact crater on Mars, in the Tharsis quadrangle near the summit of Olympus Mons. It was named after a village in Nepal. It measures 10 kilometer in diameter, and is at 17.47° N and 133.4° W.
Ritchey is a crater on Mars, located in the Coprates quadrangle at 28.8° South and 51° West. It measures 79 kilometers in diameter and was named after George W. Ritchey, an American astronomer (1864–1945). Ritchey lies south of Valles Marineris and north of Argyre Planitia, a large impact crater. There is strong evidence that it was once a lake.
The Noachian is a geologic system and early time period on the planet Mars characterized by high rates of meteorite and asteroid impacts and the possible presence of abundant surface water. The absolute age of the Noachian period is uncertain but probably corresponds to the lunar Pre-Nectarian to Early Imbrian periods of 4100 to 3700 million years ago, during the interval known as the Late Heavy Bombardment. Many of the large impact basins on the Moon and Mars formed at this time. The Noachian Period is roughly equivalent to the Earth's Hadean and early Archean eons when the first life forms likely arose.
Peace Vallis is an ancient stream valley on the northern rim of Gale Crater on the planet Mars. It is notable for its associated alluvial fan which lies near the Mars Science Laboratory Curiosity landing site. The valley and alluvial fan provide evidence for geologically recent (Amazonian-aged) fluvial activity and sustained water flow on Mars. Recent high-resolution orbital images of Peace Vallis and its watershed also suggest that at least one glacial episode affected Gale crater. All of this evidence has implications for the history of water on Mars and the planet's long-term habitability. Understanding Peace Vallis and its fan also provides geologic context for the rocks observed on the ground by the Curiosity rover.
In summer 1965, the first close-up images from Mars showed a cratered desert with no signs of water. However, over the decades, as more parts of the planet were imaged with better cameras on more sophisticated satellites, Mars showed evidence of past river valleys, lakes and present ice in glaciers and in the ground. It was discovered that the climate of Mars displays huge changes over geologic time because its axis is not stabilized by a large moon, as Earth's is. Also, some researchers maintain that surface liquid water could have existed for periods of time due to geothermal effects, chemical composition or asteroid impacts. This article describes some of the places that could have held large lakes.
Linear ridge networks are found in various places on Mars in and around craters. These features have also been called "polygonal ridge networks," "boxwork ridges", and "reticulate ridges." Ridges often appear as mostly straight segments that intersect in a lattice-like manner. They are hundreds of meters long, tens of meters high, and several meters wide. It is thought that impacts created fractures in the surface, these fractures later acted as channels for fluids. Fluids cemented the structures. With the passage of time, surrounding material was eroded away, thereby leaving hard ridges behind. It is reasonable to think that on Mars impacts broke the ground with cracks since faults are often formed in impact craters on Earth. One could guess that these ridge networks were dikes, but dikes would go more or less in the same direction, as compared to these ridges that have a large variety of orientations. Since the ridges occur in locations with clay, these formations could serve as a marker for clay which requires water for its formation. Water here could have supported past life in these locations. Clay may also preserve fossils or other traces of past life.
Northeast Syrtis is a region of Mars once considered by NASA as a landing site for the Mars 2020 rover mission. This landing site failed in the competition with Jezero crater, another landing site dozens of kilometers away from Northeast Syrtis. It is located in the northern hemisphere of Mars at coordinates 18°N,77°E in the northeastern part of the Syrtis Major volcanic province, within the ring structure of Isidis impact basin as well. This region contains diverse morphological features and minerals, indicating that water once flowed here. It may be an ancient habitable environment; microbes could have developed and thrived here.
