Volcanic cones are among the simplest volcanic landforms. They are built by ejecta from a volcanic vent, piling up around the vent in the shape of a cone with a central crater. Volcanic cones are of different types, depending upon the nature and size of the fragments ejected during the eruption. Types of volcanic cones include stratocones, spatter cones, tuff cones, and cinder cones.
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.
Ascraeus Mons is a large shield volcano located in the Tharsis region of the planet Mars. It is the northernmost and tallest of three shield volcanoes collectively known as the Tharsis Montes.
Alba Mons is a volcano located in the northern Tharsis region of the planet Mars. It is the biggest volcano on Mars in terms of surface area, with volcanic flow fields that extend for at least 1,350 km (840 mi) from its summit. Although the volcano has a span comparable to that of the United States, it reaches an elevation of only 6.8 km (22,000 ft) at its highest point. This is about one-third the height of Olympus Mons, the tallest volcano on the planet. The flanks of Alba Mons have very gentle slopes. The average slope along the volcano's northern flank is 0.5°, which is over five times lower than the slopes on the other large Tharsis volcanoes. In broad profile, Alba Mons resembles a vast but barely raised welt on the planet's surface. It is a unique volcanic structure with no counterpart on Earth or elsewhere on Mars.
Elysium, located in the Elysium and Cebrenia quadrangles, is the second largest volcanic region on Mars, after Tharsis. The region includes the volcanoes Hecates Tholus, Elysium Mons and Albor Tholus. The province is centered roughly on Elysium Mons at 24.7°N 150°E. Elysium Planitia is a broad plain to the south of Elysium, centered at 3.0°N 154.7°E. Another large volcano, Apollinaris Mons, lies south of Elysium Planitia and is not part of the province. Besides having large volcanoes, Elysium has several areas with long trenches, called fossa or fossae (plural) on Mars. They include the Cerberus Fossae, Elysium Fossae, Galaxias Fossae, Hephaestus Fossae, Hyblaeus Fossae, Stygis Fossae and Zephyrus Fossae.
The Cerberus Fossae are a series of semi-parallel fissures on Mars formed by faults which pulled the crust apart in the Cerberus region. They are 1235 km across and centered at 11.28 °N and 166.37 °E. Their northernmost latitude is 16.16 °N and their southernmost latitude 6.23 °N. Their easternmost and westernmost longitudes are 174.72 °E and 154.43 °E, respectively. They can be seen in the Elysium quadrangle.
A cinder cone is a steep conical hill of loose pyroclastic fragments, such as volcanic clinkers, volcanic ash, or scoria that has been built around a volcanic vent. The pyroclastic fragments are formed by explosive eruptions or lava fountains from a single, typically cylindrical, vent. As the gas-charged lava is blown violently into the air, it breaks into small fragments that solidify and fall as either cinders, clinkers, or scoria around the vent to form a cone that often is symmetrical; with slopes between 30 and 40°; and a nearly circular ground plan. Most cinder cones have a bowl-shaped crater at the summit.
Volcanism on Io, a moon of Jupiter, is represented by the presence of volcanoes, volcanic pits and lava flows on the moon's surface. Its volcanic activity was discovered in 1979 by Voyager 1 imaging scientist Linda Morabito. Observations of Io by passing spacecraft and Earth-based astronomers have revealed more than 150 active volcanoes. Up to 400 such volcanoes are predicted to exist based on these observations. Io's volcanism makes the satellite one of only five known currently volcanically or cryovolcanically active worlds in the Solar System
Volcanic activity, or volcanism, has played a significant role in the geologic evolution of Mars. Scientists have known since the Mariner 9 mission in 1972 that volcanic features cover large portions of the Martian surface. These features include extensive lava flows, vast lava plains, and the largest known volcanoes in the Solar System. Martian volcanic features range in age from Noachian to late Amazonian, indicating that the planet has been volcanically active throughout its history, and some speculate it probably still is so today. Both Earth and Mars are large, differentiated planets built from similar chondritic materials. Many of the same magmatic processes that occur on Earth also occurred on Mars, and both planets are similar enough compositionally that the same names can be applied to their igneous rocks and minerals.
The Medusae Fossae Formation is a large geological formation of probable volcanic origin on the planet Mars. It is named for the Medusa of Greek mythology. "Fossae" is Latin for "trenches". The formation is a collection of soft, easily eroded deposits that extends discontinuously for more than 5,000 km along the equator of Mars. Its roughly-shaped regions extend from just south of Olympus Mons to Apollinaris Patera, with a smaller additional region closer to Gale Crater.
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 Tharsis quadrangle is one of a series of 30 quadrangle maps of Mars used by the United States Geological Survey (USGS) Astrogeology Research Program. The Tharsis quadrangle is also referred to as MC-9 . The name Tharsis refers to a land mentioned in the Bible. It may be at the location of the old town of Tartessus at the mouth of Guadalquivir.
The Ceraunius Fossae are a set of fractures in the northern Tharsis region of Mars. They lie directly south of the large volcano Alba Mons and consist of numerous parallel faults and tension cracks that deform the ancient highland crust. In places, younger lava flows cover the fractured terrain, dividing it into several large patches or islands. They are found in the Tharsis quadrangle.
The Ulysses Fossae are a group of troughs in the Tharsis quadrangle of Mars at 10.06° north latitude and 123.07° west longitude. They were named after an albedo feature name. The area contains pitted cones called Ulysses Colles which were interpreted to be possible Martian equivalents to terrestrial cinder cones.
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 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.
Elysium Planitia, located in the Elysium and Aeolis quadrangles, is a broad plain that straddles the equator of Mars, centered at 3.0°N 154.7°E. It lies to the south of the volcanic province of Elysium, the second largest volcanic region on the planet, after Tharsis. Elysium contains the major volcanoes Elysium Mons, Albor Tholus and Hecates Tholus. Another more ancient shield volcano, Apollinaris Mons, is situated just to the south of eastern Elysium Planitia. Within the plains, Cerberus Fossae is the only Mars location with recent volcanic eruptions. Lava flows dated no older than 0.2 million years from the present have been found, and evidence has been found that volcanic activity may have occurred as recently as 53,000 years ago. Such activity could have provided the environment, in terms of energy and chemicals, needed to support life forms.
The Chaac-Camaxtli region is a volcanic region on Jupiter's moon Io, located from approximately 5 to 20°N and 130 to 160°W in its anti-Jovian hemisphere. It consists mainly of the hummocky bright plains that occupy the surface. This area is defined on the west by Chaac Patera, and on the east by Camaxtli Patera. At least 10 distinct volcanic centers are located in the region, making it a volcanically active region on Io's surface. Most of the volcanism here is expressed as paterae, which range in size from circular to elliptical. A patera is defined by the International Astronomical Union as "irregular or complex craters with scalloped edges." The largest volcanic structure here is the Chaac Patera. The paterae found in the Chaac-Camaxtli region are Chaac, Balder Patera, Grannos, Ababinili, Ruaumoko, Steropes, Camaxtli, Tien Mu, Utu, and Mentu.
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.
Volcanism on the Moon is represented by the presence of volcanoes, pyroclastic deposits and vast lava plains on the lunar surface. The volcanoes are typically in the form of small domes and cones that form large volcanic complexes and isolated edifices. Calderas, large-scale collapse features generally formed late in a volcanic eruptive episode, are exceptionally rare on the Moon. Lunar pyroclastic deposits are the result of lava fountain eruptions from volatile-laden basaltic magmas rapidly ascending from deep mantle sources and erupting as a spray of magma, forming tiny glass beads. However, pyroclastic deposits formed by less common non-basaltic explosive eruptions are also thought to exist on the Moon. Lunar lava plains cover large swaths of the Moon's surface and consist mainly of voluminous basaltic flows. They contain a number of volcanic features related to the cooling of lava, including lava tubes, rilles and wrinkle ridges.
