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35-615: Like the Imbrium and Orientale Basins on the Moon, Caloris Basin is surrounded by an extensive and well-preserved ejecta blanket As on the Moon, where ejecta from the better preserved basins was used to construct a stratigraphy , the ejecta from the Caloris Basin also can be used as a marker horizon . This ejecta is recognizable to a distance of about one basin diameter in all directions. A stratigraphic and structural comparison between

70-628: A diameter of 1300 km and is divided into several different ranges; the Montes Carpatus to the south, the Montes Apenninus to the southeast, and the Montes Caucasus to the east. At their highest, the outer ring of mountains rise more than 5 km above the surface of Mare Imbrium. The ring mountains are not as well developed to the north and west, and it appears they were simply not raised as high in these regions by

105-591: A map of the Moon that names Mare Imbrium "Regio Magna Orientalis" (the Large Eastern Region). Michael van Langren 's 1645 map named it "Mare Austriacum" (the Austrian Sea). Mare Imbrium is visible to the naked eye from Earth. In the traditional ' Man in the Moon ' image seen on the Moon in Western folklore, Mare Imbrium forms the man's right eye. On 17 November 1970 at 03:47 Universal Time,

140-524: Is compositionally distinct from the Apollo and Luna landing sites. Mearcair Planitia Mearcair Planitia is a large plain on the planet Mercury . The name Mearcair is the Irish and Scottish Gaelic word for "Mercury", and the name was approved in 2017. It was first observed in detail by MESSENGER . It lies between the large crater Raditladi and the ancient Caloris basin. Mearcair Planitia

175-567: Is difficult to define individual secondary craters within the Van Eyck, but at a distance of about one basin diameter, numerous clusters and chains of moderately well preserved craters occur that are interpreted as far-flung Caloris secondary craters. These craters have been included in a separate facies of the Van Eyck Formation because of their regional stratigraphic significance. It is noteworthy that this lineated terrain occurs near

210-673: Is named after Odin Planitia, its "type area". It is also mapped in Mearcair Planitia , Stilbon Planitia , and Tir Planitia . The Van Eyck Formation, which is the most distinctive of the circum-Caloris stratigraphic units, was called the Caloris lineated terrain by Trask and Guest. It is named after the Van Eyck crater. The Van Eyck Formation has a lineated facies and a secondary-crater facies. The lineated facies extends from

245-581: Is one of four named plains that surround the Caloris basin (with Odin Planitia , Stilbon Planitia , and Tir Planitia ). All of these plains are classified as smooth , as opposed to intracrater plains which have rougher topography. They also contain areas where kilometer-scale knobs protrude above the plains, and these areas are called the Odin Formation . The Odin Formation is interpreted as

280-661: Is unknown, but it is somewhat similar to the gap on the east side of the Imbrium Basin, where the mountain ring cuts the edge of the Serenitatis Basin . On Mercury, however, we have no evidence for the presence of a preexisting basin east of Caloris. The Nervo Formation consists of rolling to locally hummocky plains that lie in inter massif depressions between the mountains formed by the Caloris Montes Formation. The plains generally lie within

315-614: Is very similar in morphology to and is considered the equivalent of the massif facies of the Montes Rook Formation around the Orientale Basin. The Caloris Montes is interpreted as basin rim deposits consisting of ejecta from deep within Caloris that is mixed with but generally overlies uplifted and highly fractured prebasin bedrock. A gap is present in the Caloris Montes toward the southeast; its origin

350-542: The Apennine Mountains . Commander David Scott and Lunar Module Pilot James Irwin spent three days on the surface of the Moon, including 18½ hours outside the spacecraft on lunar extra-vehicular activity . Command Module Pilot Alfred Worden remained in orbit and acquired hundreds of high-resolution photographs of Mare Imbrium (and other regions of the Moon) as well as other types of scientific data. The crew on

385-731: The Caloris Montes as much as about 1,000 km. It consists of long, hilly ridges and grooves that are subradial to the Caloris Basin and are extensively embayed by smooth plains. The inner boundary of the Van Eyck is generally coincident with the weak outer Caloris scarp. The Van Eyck is similar in morphology but somewhat more degraded than the Fra Mauro Formation around the Imbrium Basin on the Moon; secondary cratering and ballistic deposition of ejecta from Caloris undoubtedly played an important role in its emplacement. It

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420-405: The Caloris ejecta sequence, but its mode of origin is less clear than those of certain other Caloris formations. The unit may consist of late-arriving, blocky, coherent ejecta from deep within the Caloris cavity, later partly buried by smooth plains. Odin locally mantles intercrater plains, lineated plains, and intermediate plains materials to a distance of 1,100 km from the Caloris Basin scarp. It

455-528: The Imbrium impact. The middle ring of mountains forms the Montes Alpes and Montes Archimedes . The innermost ring, with a diameter of 650 km, is defined by Montes Recti , Montes Teneriffe , and possibly Montes Spitzbergen . Much of this ring is submerged under the mare's basalt, resulting in only isolated peaks remaining in some areas, such as Mons Pico and Mons La Hire . Numerous estimates of

490-553: The Moon because molten lava pooled in the craters and formed a relatively smooth surface. Mare Imbrium is not as flat as it would have originally been when it first formed as a result of later events that have altered its surface. Mare Imbrium formed when a proto-planet from the asteroid belt collided with the Moon during the Late Heavy Bombardment . The impact is dated to approximately 3922 ± 12 million years ago, based on radiometric dating techniques. Ejecta from

525-417: The Moon's entire lithosphere . At the region of the Moon's surface exactly opposite Imbrium Basin, there is a region of chaotic terrain (the crater Van de Graaff ) which is thought to have been formed when the seismic waves of the impact were focused there after travelling through the Moon's interior. Mare Imbrium is about 750 miles (1,210 km) wide. A mass concentration (mascon), or gravitational high,

560-422: The Moon's surface by large projectiles blasted out of the basin at low angles, causing them to skim across the lunar surface ploughing out these features. The sculpture pattern was first identified by Grove Karl Gilbert in 1893. Furthermore, a Moon-wide pattern of faults which run both radial to and concentric to the Imbrium basin were thought to have been formed by the Imbrium impact; the event literally shattered

595-569: The Odin appears similar to that of the thinner, more distal parts of Alpes Formation of the Imbrium Basin on the Moon. The Odin, like the Alpes, occurs in broad lobes such as those in Odin Planitia beyond the main basin scarp. The Odin also mantles the intercrater plains ancient crater materials out to a distance of 1200 km from the main Caloris scarp. The Odin Formation is interpreted as part of

630-472: The Orientale and Caloris Basins has been made by McCauley. McCauley and others proposed a formal rock stratigraphy for the Caloris Basin. This stratigraphy is patterned after that used in and around the Orientale Basin on the Moon. Crater degradation chronologies, such as the one modified from Trask, and correlations between plains units on the basis of crater frequency may aid in tying much of the remainder of

665-507: The Soviet spacecraft Luna 17 made a soft landing in the mare, at latitude 38.28 N, and longitude 35.00 W. Luna 17 carried Lunokhod 1 , the first robotic rover to be deployed on the Moon or any extraterrestrial body. Lunokhod 1, a remote-controlled rover, was successfully deployed and undertook a mission lasting several months. In 1971, the crewed Apollo 15 mission landed in the southeastern region of Mare Imbrium, between Hadley Rille and

700-504: The Yutu rover 7 hours and 24 minutes later. Chang'e 3 mission attempted to perform the first direct measurement of the structure and depth of the lunar soil down to a depth of 30 m (98 ft), and investigate the lunar crust structure down to several hundred meters deep. The rover's ground penetrating radar found evidence of at least nine distinct rock layers , indicating that the area had surprisingly complex geological processes and

735-702: The annulus of rugged terrain marked by the Caloris Montes Formation and locally appear to drape and overlie some of the more low-lying massifs. The Nervo bears some resemblance to the Apennine Bench Formation around the Imbrium Basin; its closest counterpart in Orientale is the knobby facies of the Montes Rook Formation . The Nervo Formation was originally designated the intermontane plains by Trask and Guest and has been interpreted by them as fallback ejecta, an interpretation that seems to explain its distribution pattern and relative roughness as well as

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770-427: The collision of a proto-planet during the Late Heavy Bombardment . Basaltic lava later flooded the giant crater to form the flat volcanic plain seen today. The basin's age has been estimated using uranium–lead dating methods to approximately 3.9 billion years ago, and the diameter of the impactor has been estimated to be 250 ± 25 km. The Moon's maria (plural of mare ) have fewer features than other areas of

805-410: The depth of the mare material have been made using various methods. These include analyses of gravity, seismic, and radar data; studies of craters partially filled with basalt and those that have completely penetrated the mare; and comparisons of lunar basins filled with mare deposits to unfilled basins. These studies have yielded depth estimates ranging from 2 km to 5 km in the central part of

840-407: The fact that it is generally perched above the smooth plains that encompass Caloris. The Nervo formation is named after Nervo crater. The Odin Formation, which was originally called the hummocky plains by Trask and Guest, was described by them as consisting of low, closely spaced to scattered smooth hills about 0.3 to 1 km across and from tens of meters to a few hundred meters high. In some places

875-442: The foot of the Caloris Montes, whereas similar units of the Imbrium Basin on the Moon occur farther from the basin rim. Such a difference in extent is to be expected because mercurian gravity is two and a half times greater than lunar gravity, and ejecta would fall closer to its source than ejecta from a similar-size basin on the Moon. Over much of its outcrop, it appears to be veneered by a thin plains unit that has filled hollows in

910-518: The hills are aligned concentrically with the rim to the Caloris Basin, and the plains appear corrugated. The area between the hills is similar in appearance to the smooth plains; in some areas the Odin Formation may be partly flooded by smooth plains materials, but for mapping convenience this area has been included in the Odin Formation. The extent of the Odin Formation was expanded by Fassett et al. and Denevi et al. The distribution pattern of

945-401: The impact covers large areas of the near side of the Moon. With a diameter of 1145 km, Mare Imbrium is second only to Oceanus Procellarum in size among the maria, and it is the largest mare associated with an impact basin. The Imbrium Basin is surrounded by three concentric rings of mountains, uplifted by the colossal impact event that excavated it. The outermost ring of mountains has

980-503: The mare may be "The Shrine of Hecate "; Plutarch records that the Ancient Greeks gave this name to the largest of the "hollows and deeps" on the Moon, believing it to be the place where the souls of the deceased were tormented. Ewen A. Whitaker argues that this likely refers to Mare Imbrium, "the largest regular-shaped dark area unbroken by bright patches" that can be seen with the naked eye. Around 1600, William Gilbert made

1015-437: The mare. It is thought that the original crater left by the Imbrium impact was as much as 100 km deep, but that the floor of the basin bounced back upwards immediately afterwards. Surrounding the Imbrium Basin is a region blanketed by ejecta from the impact, extending roughly 800 km outward. Also encircling the basin is a pattern of radial grooves called the "Imbrium Sculpture", which have been interpreted as furrows cut in

1050-510: The rille wall. On 17 March 2013, an object hit the lunar surface in Mare Imbrium and exploded in a flash of apparent magnitude 4. The resulting crater was 18 meters wide. This was the brightest impact recorded since NASA's lunar impact team began monitoring in 2005. Chang'e 3 landed on 14 December 2013 on Mare Imbrium, about 40 km south of the 6 km diameter Laplace F crater, at 44.1260°N 19.5014°W. The lander deployed

1085-458: The rim of Caloris Basin outward: The Caloris Montes Formation, which was informally called the Caloris mountains terrain by Trask and Guest, consists of a jumbled array of smooth-appearing but highly segmented mountain massifs that rise 1-2 km above the surrounding terrain. These massifs mark the crestline of the most prominent scarp or ring of the Caloris Basin and grade outward into smaller blocks and lineated terrain. The Caloris Montes Formation

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1120-429: The surface explored the area using the first lunar rover and returned to Earth with 77 kilograms (170 lb) of lunar surface material. Samples were collected from Mons Hadley Delta , believed to be a fault block of pre-Imbrian ( Nectarian or Pre-Nectarian ) lunar crust, including the " Genesis Rock ." This was also the only Apollo mission to visit a lunar rille, and to observe outcrops of lunar bedrock visible in

1155-578: The surface of Mercury to the Caloris event. Unlike the Imbrium-related stratigraphy of Shoemaker and Hackman, the stratigraphy devised for Mercury is a rock rather than a time stratigraphy. It recognizes the existence of an orderly, in essence isochronous sequence of mappable units around Caloris that are similar in character to those recognized around the better preserved impact basins of the Moon such as Orientale, Imbrium, and Nectaris . The four formations are described in order of occurrence from

1190-608: The surface. The plains unit in these areas has generally been infilled with the Van Eyck Formation, although it may, in part, be smooth plains material. Imbrium Basin Mare Imbrium / ˈ ɪ m b r i ə m / ( Latin imbrium , the " Sea of Showers " or " Sea of Rains ") is a vast lava plain within the Imbrium Basin on the Moon and is one of the larger craters in the Solar System . The Imbrium Basin formed from

1225-451: Was identified in the center of Mare Imbrium from Doppler tracking of the five Lunar Orbiter spacecraft in 1968. The Imbrium mascon is the largest on the Moon. It was confirmed and mapped at higher resolution with later orbiters such as Lunar Prospector and GRAIL . Like most of the other maria on the Moon, Mare Imbrium was named by Giovanni Riccioli , whose 1651 nomenclature system has become standardized. The earliest known name for

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