Nilokeras Scopulus is a long escarpment (cliff) in the northern hemisphere of the planet Mars. It is located along the southeastern boundary of the Tempe Terra plateau and forms the northern valley wall (wallrock boundary) of the downstream portion of the immense Kasei Valles outflow channel system. The escarpment is 765 km long[ citation needed ] [1] and ranges from 1 to a little over 2 km (3300–6600 ft) in height. [2]
For most of its length, Nilokeras Scopulus lies between lat. 31° and 32° N. It trends west-east, extending from approximately long. 297° to 309° E. [1] The escarpment curves northward at the eastern edge of Tempe Terra where the northern segment of Kasei Valles debouches into Chryse and southwestern Acidalia Planitiae.
Nilokeras, which is Greek for "horn of the Nile," was the name given by astronomer E. M. Antoniadi in 1930 to a telescopic albedo feature and canal centered at lat. 30° N., long. 55° W. (See List of Martian canals.) Scopulus is a descriptor term used in planetary geology for an irregular escarpment or cliff. The International Astronomical Union (IAU) formally adopted the name Nilokeras Scopulus in 1976. [1] Scopulus is the Latin term for "crag" or cliff.
In geomorphology, an escarpment (usually shortened to scarp) is any steep, abrupt slope or cliff along the margin of a plateau, terrace, or other topographic bench. A scarp may be formed by tectonic, erosional, or depositional processes. [3] The term carries no implication of geologic origin.
Nilokeras Scopulus likely formed from a combination of faulting and erosion from flood waters that formed Kasei Valles. Recent geologic mapping of the Kasei Valles region [4] [5] indicates that the west-to-east flow of the Kasei Valles floods followed the existing structural trend of rift valleys in southern Tempe Terra. Thus, the proto-Nilokeras Scopulus was probably an east-west oriented fault scarp or fracture zone (or zone of weakness [6] ) that was eroded and further downcut by at least one (and possibly two) episodes of early catastrophic flooding from the northern Tharsis region. (See outflow channels.) These floods occurred in Hesperian time between about 3.6 and 3.4 billion years ago (Gya).
After initial flooding, the northern Kasei valley was covered by extensive late Hesperian-aged basaltic lava flows from Tharsis. Two final episode of flooding from the Echus Chasma region to the south occurred in Kasei Valles during Amazonian times (<1.8 Gya). The later floods carved the channels south of Nilokeras Scopulus and may not have strongly influenced development of the scarp.
During the course of its history, Nilokeras Scopulus has been subjected to glacial/periglacial processes and modified by groundwater sapping, slumping, collapse, and other mass wasting processes. Rocks making up the scarp face are Noachian or Early Hesperian in age (>3.6 Gya). They probably consist of ancient impact breccias and volcanic materials. Layered bedrock is visible at the top of the escarpment in some medium and high resolution spacecraft images, but the scarp face is largely covered by talus aprons and dust.
Valles Marineris is a system of canyons that runs along the Martian surface east of the Tharsis region. At more than 4,000 km (2,500 mi) long, 200 km (120 mi) wide and up to 7 km (23,000 ft) deep, Valles Marineris is one of the largest canyons of the Solar System, surpassed in length only by the rift valleys of the mid-ocean ridge system of Earth.
Tharsis is a vast volcanic plateau centered near the equator in the western hemisphere of Mars. The region is home to the largest volcanoes in the Solar System, including the three enormous shield volcanoes Arsia Mons, Pavonis Mons, and Ascraeus Mons, which are collectively known as the Tharsis Montes. The tallest volcano on the planet, Olympus Mons, is often associated with the Tharsis region but is actually located off the western edge of the plateau. The name Tharsis is the Greco-Latin transliteration of the biblical Tarshish, the land at the western extremity of the known world.
Vallis or valles is the Latin word for valley. It is used in planetary geology to name landform features on other planets.
Chryse Planitia is a smooth circular plain in the northern equatorial region of Mars close to the Tharsis region to the west, centered at 28.4°N 319.7°E. Chryse Planitia lies partially in the Lunae Palus quadrangle, partially in the Oxia Palus quadrangle, partially in the Mare Acidalium quadrangle. It is 1600 km or 994 mi in diameter and with a floor 2.5 km below the average planetary surface altitude, and has been suggested to be an ancient buried impact basin, thought this is contested. It has several features in common with lunar maria, such as wrinkle ridges. The density of impact craters in the 100 to 2,000 metres range is close to half the average for lunar maria.
Ganges Chasma is a deep canyon at the eastern end of the vast Valles Marineris system on Mars, an offshoot of Capri Chasma, and is in the Coprates quadrangle. It is named after the River Ganges in South Asia. Ganges Chasma is thought to have formed through a series of catastrophic discharges of water and CO2 from chaos terrains such as that preserved in Ganges Chaos at its southern margin. Most of the evidence for these discharges and the ensuing collapses is believed to have been washed away. Prior to developing an outlet that joined it to Capri Chasma and the connected outflow channels to its east, Ganges Chasma may at some point in the Noachian period have contained a lake which drained northward through partially subsurface pathways into Shalbatana Vallis.
Tempe Terra is a heavily cratered highland region in the northern hemisphere of the planet Mars. Located at the northeastern edge of the Tharsis volcanic province, Tempe Terra is notable for its high degree of crustal fracturing and deformation. The region also contains many small shield volcanoes, lava flows, and other volcanic structures.
Echus Chasma is a chasma in the Lunae Planum high plateau north of the Valles Marineris canyon system of Mars. It is in the Coprates quadrangle. Clay has been found within it, meaning that water once sat there for a time. It may have been one of the many lakes that have been advanced for the Martian past.
Tharsis Tholus is an intermediate-sized shield volcano located in the eastern Tharsis region of the planet Mars. The volcano was discovered by the Mariner 9 spacecraft in 1972 and originally given the informal name Volcano 7. In 1973, the International Astronomical Union (IAU) officially designated it Tharsis Tholus. In planetary geology, tholus is the term for a small domical mountain, usually a volcano.
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 Coprates quadrangle is one of a series of 30 quadrangle maps of Mars used by the United States Geological Survey (USGS) Astrogeology Research Program. The Coprates quadrangle is also referred to as MC-18. The Coprates quadrangle contains parts of many of the old classical regions of Mars: Sinai Planum, Solis Planum, Thaumasia Planum, Lunae Planum, Noachis Terra, and Xanthe Terra.
The Maja Valles are a large system of ancient outflow channels in the Lunae Palus quadrangle on Mars. Their location is 12.6° north latitude and 58.3° west longitude. The name is a Nepali word for "Mars". The Maja Valles begin at Juventae Chasma. Parts of the system have been partially buried by thin volcanic debris. The channels end at Chryse Planitia.
The Kasei Valles are a giant system of canyons in Mare Acidalium and Lunae Palus quadrangles on Mars, centered at 24.6° north latitude and 65.0° west longitude. They are 1,580 km (980 mi) long and were named for the word for "Mars" in Japanese. This is one of the largest outflow channel systems on Mars.
Outflow channels are extremely long, wide swathes of scoured ground on Mars. They extend many hundreds of kilometers in length and are typically greater than one kilometer in width. They are thought to have been carved by huge outburst floods.
Coprates Chasma is a huge canyon in the Coprates quadrangle of Mars, located at 13.4° south latitude and 61.4° west longitude, part of the Valles Marineris canyon system. It is 966 km (600 mi) long and was named after a classical albedo feature name. It was named from the classical Greek name for the Dez River in Persia.
Enipeus Vallis is a valley in the northern hemisphere of the planet Mars. It is centered at lat. 37°N, long. 267°E in the Arcadia quadrangle (MC-3) between the large volcano Alba Mons and the Tempe Terra plateau. The valley follows a gently sinuous, north-south path for a distance of about 357 km (222 mi). It is likely an ancient watercourse that formed during the early Hesperian period, around 3.7 billion years ago.
The Hesperian is a geologic system and time period on the planet Mars characterized by widespread volcanic activity and catastrophic flooding that carved immense outflow channels across the surface. The Hesperian is an intermediate and transitional period of Martian history. During the Hesperian, Mars changed from the wetter and perhaps warmer world of the Noachian to the dry, cold, and dusty planet seen today. The absolute age of the Hesperian Period is uncertain. The beginning of the period followed the end of the Late Heavy Bombardment and probably corresponds to the start of the lunar Late Imbrian period, around 3700 million years ago (Mya). The end of the Hesperian Period is much more uncertain and could range anywhere from 3200 to 2000 Mya, with 3000 Mya being frequently cited. The Hesperian Period is roughly coincident with the Earth's early Archean Eon.
The geological history of Mars follows the physical evolution of Mars as substantiated by observations, indirect and direct measurements, and various inference techniques. Methods dating back to 17th century techniques developed by Nicholas Steno, including the so-called law of superposition and stratigraphy, used to estimate the geological histories of Earth and the Moon, are being actively applied to the data available from several Martian observational and measurement resources. These include the landers, orbiting platforms, Earth-based observations, and Martian meteorites.
The Amazonian is a geologic system and time period on the planet Mars characterized by low rates of meteorite and asteroid impacts and by cold, hyperarid conditions broadly similar to those on Mars today. The transition from the preceding Hesperian period is somewhat poorly defined. The Amazonian is thought to have begun around 3 billion years ago, although error bars on this date are extremely large. The period is sometimes subdivided into the Early, Middle, and Late Amazonian. The Amazonian continues to the present day.
Galilaei is a large impact crater on Mars in the region known as Margaritifer Terra. The crater is in the southern part of the Oxia Palus quadrangle (MC-11) at 5.7°N 333.0°E. Galilaei is located north of Hydaspis Chaos in the area east of Tiu Valles and west of Ares Vallis. The crater was named after the Italian astronomer and physicist Galileo Galilei. Galilaei is one of the numerous large craters that formed during the Noachian Period, which ended around 3.7 billion years ago. The crater floor was modified by superficial geologic processes through Late Hesperian time, as mapped by Tanaka, K.L. and others.
The Thaumasia Plateau is a vast sloping volcanic plain in the western hemisphere of Mars, and is the most extensive component of the Tharsis Rise by area. Syria Planum, Solis Planum, Sinai Planum, and Thaumasia Planum are the constituent sectors of the plateau, which sits between 8 km and 4 km above the surrounding southern highlands. It is bounded by vestigial basement terrains that predate the formation of Tharsis. This area has been proposed to be a drainage basin that sourced the floodwaters forming the outflow channels surrounding Chryse Planitia.