Argyre Planitia
Encyclopedia
Argyre Planitia is a plain located in the Argyre impact basin in the southern highlands of Mars
. Its name comes from a map produced by Giovanni Schiaparelli
in 1877; it refers to Argyre
, a mythical island of silver
in Greek mythology.
Argyre lies between -35 and -61 deg S and 27 and 62 deg W, centered at 49.7°N 316.0°W. The basin is approximately 1120 miles (1800 kilometers) wide, believed to be the second-largest impact basin on Mars after Hellas Planitia
, and drops 3.2 miles (5.2 kilometers) below the surrounding plains.
The basin was possibly formed by a giant impact during a Heavy Bombardment Period of the early Solar System
, approximately 3.9 billion years ago, and may be one of the best preserved ancient impact basins from that hypothetical event. Argyre is surrounded by rugged massif
s which form concentric and radial patterns around the basin. Several mountain ranges are present, including Charitum
and Nereidum Montes
.
Four large Noachian epoch channels lie radial to the basin. Three of these channels (Surius Valles, Dzígai Valles, and Palacopas Valles) flowed into Argyre from the south and east through the rim mountains. The fourth, Uzboi Vallis
, appears to have flowed out from the basin's north rim to the Chryse
region and may have drained a lake
of melting ice within the basin. A smaller outflow channel named Nia Valles is relatively fresh-looking, and probably formed during the early Amazonian after the major fluvial and lacustrine episodes had finished.
The original basin floor is buried with friable, partially deflated layered material that may be lake sediment
. No inner rings are visible, however isolated massifs within the basin may be remnants of an inner ring.
The crater Galle
, located on the east rim of Argyre at 51°S, 31°W, strongly resembles a smiley
face.
Mars
Mars is the fourth planet from the Sun in the Solar System. The planet is named after the Roman god of war, Mars. It is often described as the "Red Planet", as the iron oxide prevalent on its surface gives it a reddish appearance...
. Its name comes from a map produced by Giovanni Schiaparelli
Giovanni Schiaparelli
Giovanni Virginio Schiaparelli was an Italian astronomer and science historian. He studied at the University of Turin and Berlin Observatory. In 1859-1860 he worked in Pulkovo Observatory and then worked for over forty years at Brera Observatory...
in 1877; it refers to Argyre
Argyre
In Greek and Roman mythology, Argyre was a mythical island of silver, located in the east. The name comes from the Greek argyros ....
, a mythical island of silver
Silver
Silver is a metallic chemical element with the chemical symbol Ag and atomic number 47. A soft, white, lustrous transition metal, it has the highest electrical conductivity of any element and the highest thermal conductivity of any metal...
in Greek mythology.
Argyre lies between -35 and -61 deg S and 27 and 62 deg W, centered at 49.7°N 316.0°W. The basin is approximately 1120 miles (1800 kilometers) wide, believed to be the second-largest impact basin on Mars after Hellas Planitia
Hellas Planitia
Hellas Planitia, also known as the Hellas Impact Basin, is a huge, roughly circular impact basin located in the southern hemisphere of the planet Mars. It is the second or third largest impact crater and the largest visible impact crater known in the Solar System...
, and drops 3.2 miles (5.2 kilometers) below the surrounding plains.
The basin was possibly formed by a giant impact during a Heavy Bombardment Period of the early Solar System
Solar System
The Solar System consists of the Sun and the astronomical objects gravitationally bound in orbit around it, all of which formed from the collapse of a giant molecular cloud approximately 4.6 billion years ago. The vast majority of the system's mass is in the Sun...
, approximately 3.9 billion years ago, and may be one of the best preserved ancient impact basins from that hypothetical event. Argyre is surrounded by rugged massif
Massif
In geology, a massif is a section of a planet's crust that is demarcated by faults or flexures. In the movement of the crust, a massif tends to retain its internal structure while being displaced as a whole...
s which form concentric and radial patterns around the basin. Several mountain ranges are present, including Charitum
Charitum Montes
Charitum Montes is a large group of mountains in the Argyre quadrangle of Mars, located at 58.3° south latitude and 40.2° west longitude. It is 850 km across and was named after a classical albedo feature name.- Gullies :...
and Nereidum Montes
Nereidum Montes
The Nereidum Montes is a mountain range on Mars. It stretches 3,677 km, northeast of Argyre Planitia.There is a crater at 45.1°S, 55.0°W on the Nereidum Montes that is similar to Galle in that it also has a smiley face pattern on the crater. However, it is much smaller than Galle itself.- Gullies...
.
Four large Noachian epoch channels lie radial to the basin. Three of these channels (Surius Valles, Dzígai Valles, and Palacopas Valles) flowed into Argyre from the south and east through the rim mountains. The fourth, Uzboi Vallis
Uzboi Vallis
Uzboi Vallis is a valley on Mars. It is named after a dry river valley in USSR, now in Turkmenistan.The valley begins on the northern rim of the Argyre basin, and cuts through several craters, before ending at Holden crater....
, appears to have flowed out from the basin's north rim to the Chryse
Chryse Planitia
Chryse Planitia is a smooth circular plain in the northern equatorial region of Mars close to the Tharsis region to the west, centered at . Chryse Planitia lies partially in the Lunae Palus quadrangle and partially in the Oxia Palus quadrangle...
region and may have drained a lake
Lake
A lake is a body of relatively still fresh or salt water of considerable size, localized in a basin, that is surrounded by land. Lakes are inland and not part of the ocean and therefore are distinct from lagoons, and are larger and deeper than ponds. Lakes can be contrasted with rivers or streams,...
of melting ice within the basin. A smaller outflow channel named Nia Valles is relatively fresh-looking, and probably formed during the early Amazonian after the major fluvial and lacustrine episodes had finished.
The original basin floor is buried with friable, partially deflated layered material that may be lake sediment
Sediment
Sediment is naturally occurring material that is broken down by processes of weathering and erosion, and is subsequently transported by the action of fluids such as wind, water, or ice, and/or by the force of gravity acting on the particle itself....
. No inner rings are visible, however isolated massifs within the basin may be remnants of an inner ring.
Galle (Martian crater)
Galle is a crater on Mars. It is located on the eastern rim of the huge impact basin Argyre Planitia. It is named after the astronomer Johann Gottfried Galle....
, located on the east rim of Argyre at 51°S, 31°W, strongly resembles a smiley
Smiley
A smiley, smiley face, or happy face, is a stylized representation of a smiling human face, commonly occurring in popular culture. It is commonly represented as a yellow circle with two black dots representing eyes and a black arc representing the mouth...
face.