Coordinates | 4°13′S137°14′E / 4.21°S 137.23°E |
---|---|
Length | 35.24 km (21.90 mi) |
Naming | Adopted by the IAU on September 26, 2012, after the Peace River in British Columbia and Alberta, Canada. [1] |
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 (Bradbury Landing). The valley and alluvial fan provide evidence for geologically recent (Amazonian-aged) fluvial activity [2] [3] and sustained water flow [4] on Mars. Recent high-resolution orbital images of Peace Vallis and its watershed also suggest that at least one glacial episode affected Gale crater. [5] All of this evidence has implications for the history of water on Mars and the planet's long-term habitability. [6] Understanding Peace Vallis and its fan also provides geologic context for the rocks observed on the ground by the Curiosity rover. [7]
The valley is centered at 4°13′S137°14′E / 4.21°S 137.23°E [1] in the northeastern Aeolis quadrangle of Mars and drains approximately 1,500 square kilometers (580 sq mi) of the northern rim of Gale Crater. [8] While the stream was active, surface water and groundwater drained to the south into a low-lying plain in the northern interior of the crater (Aeolis Palus) where the stream valley debouched into a large alluvial fan (Peace Vallis fan).
Gale Crater itself is a 154-kilometer (96 mi)-diameter impact crater that straddles the martian hemispheric dichotomy between the heavily cratered southern highlands and the lower elevation plains (Elysium Planitia) to the north. Gale Crater is noteworthy for its enigmatic 5-kilometer (3.1 mi)-high crescent-shaped central mound, Aeolis Mons (known informally as Mt. Sharp). The crater is late Noachian or Early Hesperian in age (approximately 3.65 to 3.55 billion years old). [9]
The northern rim of Gale Crater is heavily eroded and hosts a number of geomorphic features indicating the effects of flowing water. These include valleys, gullies, and canyons; sinuous ridges interpreted to be inverted channels; and alluvial fan-like mesas. [10] Peace Vallis and its alluvial fan is the largest and best studied of these fluvial features in northern Gale Crater.
Peace Vallis is named after the Peace River in Alberta and British Columbia, Canada. The name was adopted by the International Astronomical Union (IAU) on September 26, 2012. Vallis is the Latin word for valley. [1]
Peace Vallis is a valley network characterized by a branching (dendritic) pattern of tributary valleys that resembles river drainage basins on Earth. They are common on the older heavily cratered regions of Mars. Most planetary scientists agree that valley networks were formed by flowing water, but the source of the water is still debated. [11] Some argue that rainfall on a warm and wet early mars produced them. [12] Others have suggested they were produced by mass wasting, [13] spring sapping, [14] or from snowmelt [15] on an ancient Mars whose climate was dry and cold much like today's.
The Peace Vallis drainage basin (or catchment) covers an area of about 1,500 km2 (579 mi2). This area sits 1,300 m (4,265 ft) [5] above the crater floor and consists of gently sloping plains interspersed with hills roughly 100 to 350 m (328 to 1,148 ft) high. These irregular hills are mostly mantled with debris that appear to be some combination of aeolian deposits and colluvium. [16] Erosion of the watershed surface has produced a mottled scoured appearance, suggesting mobilization and transport of sediments into topographic lows.
Compared with most terrestrial valleys carved by rainfall, the drainage density (stream length per unit area) of Peace Vallis and its tributaries is very low. There is a lack of highly integrated fluvial channels, [17] and the areas between the tributary valleys (interfluves) are undissected by smaller valleys or gullies. The drainage density of the Peace Vallis system has been estimated to be 0.15 km–1. [16] In contrast, drainage densities of rivers on Earth range from 2 to 30 km–1. [18] Factors that control drainage density include slope, rock type (which determines infiltration capacity) [19] and climate (mainly precipitation). The low drainage density of Peace Vallis suggests an environment of relatively gentle slopes, very low (or infrequent) precipitation, permeable soils or bedrock, or some combination of the three. [20]
The valleys are U-shaped in topographic profile, with widths ranging from 80 to 900 meters (262 to 2,950 feet) and a mean of 300 meters (984 feet). The main or trunk valley is about 32 km (20 miles) long. [16]
Curiosity rover landed near the end of the Peace Vallis fan. Peace Vallis fan covers 80 km2 (31 sq mi) and obtained water from an area of 730 km2 (280 sq mi). Peace Vallis enters Gale Crater through a 15 km-wide (9.3 mi) gap in its rim. Calculations suggest that the fan has an average thickness of 9 m (30 ft). Numerous inverted channels are visible on the western surface of the fan. Runoff through Peace Vallis that made the fan is estimated to be between 600 and 6,000 m (0.37 and 3.73 mi); therefore a hydrologic cycle probably lasted at least thousands of years. The water that flowed in Peace Vallis is believed to be from precipitation, possibly in the form of snow. [16]
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.
Eberswalde, formerly known as Holden NE, is a partially buried impact crater in Margaritifer Terra, Mars. Eberswalde crater lies just to the north of Holden, a large crater that may have been a lake. The 65.3-km-diameter crater, centered at 24°S, 33°W, is named after the German town of the same name, in accordance with the International Astronomical Union's rules for planetary nomenclature. It was one of the final four proposed landing sites for the Mars rover Mars Science Laboratory mission. This extraterrestrial geological feature lies situated within the Margaritifer Sinus quadrangle (MC-19) region of Mars. Although not chosen, it was considered a potential landing site for the Mars 2020 Perseverance rover, and in the second Mars 2020 Landing Site Workshop it survived the cut and was among the top eight sites still in the running.
Gale is a crater, and probable dry lake, at 5.4°S 137.8°E in the northwestern part of the Aeolis quadrangle on Mars. It is 154 km (96 mi) in diameter and estimated to be about 3.5–3.8 billion years old. The crater was named after Walter Frederick Gale, an amateur astronomer from Sydney, Australia, who observed Mars in the late 19th century. Mount Sharp is a mountain in the center of Gale and rises 5.5 km (18,000 ft) high. Aeolis Palus is the plain between the northern wall of Gale and the northern foothills of Aeolis Mons. Peace Vallis, a nearby outflow channel, 'flows' down from the hills to the Aeolis Palus below and seems to have been carved by flowing water. Several lines of evidence suggest that a lake existed inside Gale shortly after the formation of the crater.
The Lunae Palus quadrangle is one of a series of 30 quadrangle maps of Mars used by the United States Geological Survey (USGS) Astrogeology Research Program. The quadrangle is also referred to as MC-10. Lunae Planum and parts of Xanthe Terra and Chryse Planitia are found in the Lunae Palus quadrangle. The Lunae Palus quadrangle contains many ancient river valleys.
The Aeolis quadrangle is one of a series of 30 quadrangle maps of Mars used by the United States Geological Survey (USGS) Astrogeology Research Program. The Aeolis quadrangle is also referred to as MC-23 . The Aeolis quadrangle covers 180° to 225° W and 0° to 30° south on Mars, and contains parts of the regions Elysium Planitia and Terra Cimmeria. A small part of the Medusae Fossae Formation lies in this quadrangle.
The Margaritifer Sinus quadrangle is one of a series of 30 quadrangle maps of Mars used by the United States Geological Survey (USGS) Astrogeology Research Program. The Margaritifer Sinus quadrangle is also referred to as MC-19. The Margaritifer Sinus quadrangle covers the area from 0° to 45° west longitude and 0° to 30° south latitude on Mars. Margaritifer Sinus quadrangle contains Margaritifer Terra and parts of Xanthe Terra, Noachis Terra, Arabia Terra, and Meridiani Planum.
Aeolis Mensae is a tableland feature in the northwest Aeolis quadrangle of Mars. Its location is centered at 2.9° south latitude and 219.6° west longitude, in the transition zone between the Martian highlands and lowlands. It is 820 kilometres (510 mi) long and was named after a classical albedo feature (Aeolis). The constituent mensae can be as long as 70 kilometres (43 mi) and as tall as 2 kilometres (1.2 mi). It is notable for being the origin of an abnormal concentration of methane detected by Curiosity in 2019, although its geology has attracted scientific attention since at least a decade before this event. Aeolis Mensae is also the first region in Mars where submarine cyclic steps, an erosion feature that gives evidence of an ancient ocean, were identified.
The composition of Mars covers the branch of the geology of Mars that describes the make-up of the planet Mars.
Mount Sharp, officially Aeolis Mons, is a mountain on Mars. It forms the central peak within Gale crater and is located around 5.08°S 137.85°E, rising 5.5 km (18,000 ft) high from the valley floor. Its ID in the United States Geological Survey's Gazetteer of Planetary Nomenclature is 15000.
Aeolis Palus is a plain between the northern wall of Gale crater and the northern foothills of Aeolis Mons on Mars. It is located at 4.47°S 137.42°E.
Bradbury Landing is the August 6, 2012, landing site within Gale crater on planet Mars of the Mars Science Laboratory (MSL) Curiosity rover. On August 22, 2012, on what would have been his 92nd birthday, NASA named the site for author Ray Bradbury, who had died on June 5, 2012. The coordinates of the landing site on Mars are: 4.5895°S 137.4417°E.
Jake Matijevic is a pyramidal rock on the surface of Aeolis Palus, between Peace Vallis and Aeolis Mons, in Gale crater on the planet Mars. The approximate site coordinates are: 4.59°S 137.44°E.
Hottah is a rock outcrop on the surface of Aeolis Palus, between Peace Vallis and Aeolis Mons, in Gale crater on the planet Mars.
Rocknest is a sand patch on the surface of Aeolis Palus, between Peace Vallis and Aeolis Mons, in Gale crater on the planet Mars. The patch was encountered by the Curiosity rover on the way from Bradbury Landing to Glenelg Intrigue on September 28, 2012. The approximate site coordinates are: 4.59°S 137.44°E.
Link is a rock outcrop on the surface of Aeolis Palus, between Peace Vallis and Aeolis Mons, in Gale crater on the planet Mars. The outcrop was encountered by the Curiosity rover on the way from Bradbury Landing to Glenelg Intrigue on September 2, 2012, and was named after a significant rock formation in the Northwest Territories of Canada. The "approximate" site coordinates are: 4.59°S 137.44°E.
Goulburn, also known as Goulburn Scour, is a rock outcrop on the surface of Aeolis Palus, between Peace Vallis and Aeolis Mons, in Gale crater on the planet Mars. The outcrop was encountered by the Curiosity rover on landing at the Bradbury Landing on August 6, 2012 and is named after a two-billion year-old sequence of rocks in Northern Canada. The "approximate" site coordinates are: 4.59°S 137.44°E.
Rocknest 3 is a rock on the surface of Aeolis Palus, between Peace Vallis and Aeolis Mons, in Gale crater on the planet Mars. The approximate site coordinates are: 4.59°S 137.44°E.
Tintina is a rock on the surface of Aeolis Palus, between Peace Vallis and Aeolis Mons, in Gale crater on the planet Mars. The approximate site coordinates are: 4.59°S 137.44°E.
Yellowknife Bay is a geologic formation in Gale Crater on the planet Mars. NASA's Mars Science Laboratory rover, named Curiosity, arrived at the low lying depression on December 17, 2012, 125 sols, or Martian days, into its 668-sol planned mission on the planet. Primary mission goals of the Mars Science Laboratory were to assess the potential habitability of the planet and whether or not the Martian environment is, or has ever been, capable of supporting life.
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.