The Mawson Continent (or Mawson Block, Mawson Craton) was a continent that may have formed around about 1730 Ma (1,730 million years ago). It included the

Gawler craton The Gawler Craton covers approximately 440,000 square kilometres of central South Australia. Its Precambrian crystalline basement crustal block was cratonised ca. 1550–1450 Ma. Prior to 1550 Ma the craton comprised a number of active Protero ...

of southern Australia and correlated terrains in

Antarctica Antarctica () is Earth's southernmost and least-populated continent. Situated almost entirely south of the Antarctic Circle and surrounded by the Southern Ocean (also known as the Antarctic Ocean), it contains the geographic South Pole. ...

. Since very little of the historical continent is exposed, the full extent is conjectural.

Gawler–Adélie Craton

The Gawler craton and

Terre Adélie craton ''S'il suffisait d'aimer'' (English: "if only love could be enough") is the sixteenth studio album by Canadian singer Celine Dion, and her eleventh French-language album. It was released by Sony Music on 31 August 1998. The album was mainly writ ...

share late

Archean The Archean ( , also spelled Archaean or Archæan), in older sources sometimes called the Archaeozoic, is the second of the four geologic eons of Earth's history of Earth, history, preceded by the Hadean Eon and followed by the Proterozoic and t ...

and early

Proterozoic The Proterozoic ( ) is the third of the four geologic eons of Earth's history, spanning the time interval from 2500 to 538.8 Mya, and is the longest eon of Earth's geologic time scale. It is preceded by the Archean and followed by the Phanerozo ...

tectono-thermal events, and may be considered to be a single terrain from the Archean until rifting in the

Cretaceous The Cretaceous ( ) is a geological period that lasted from about 143.1 to 66 mya (unit), million years ago (Mya). It is the third and final period of the Mesozoic Era (geology), Era, as well as the longest. At around 77.1 million years, it is the ...

. There are correlatable timelines between the Gawler–Adélie Craton, Curnamona Province and North Australian Craton around 2500–2430 Ma, 2000 Ma, 1865–1850 Ma, 1730–1690 Ma and 1600–1550 Ma. It is therefore plausible that throughout the

Paleoproterozoic The Paleoproterozoic Era (also spelled Palaeoproterozoic) is the first of the three sub-divisions ( eras) of the Proterozoic eon, and also the longest era of the Earth's geological history, spanning from (2.5–1.6 Ga). It is further sub ...

the Gawler– Adélie Craton and North Australian Craton were joined into a single continental terrain.

Formation of Mawson Continent

The Mawson Continent seems to have formed during the

Kimban orogeny The Kimban orogeny, also termed the Strangways orogeny, affected the Gawler craton in what is now Australia between 1.73 and 1.69 billion years ago in the Proterozoic. As the most widespread orogenic event in the craton's evolution, the Kimban o ...

of around 1730–1690 Ma when the Gawler–Adélie Craton combined with the crust of the

Miller Range The Miller Range () is a mountain range extending south from Nimrod Glacier for along the western edge of the Marsh Glacier in Antarctica. Name The range is named for J.H. "Bob", now Sir Joseph Holmes Miller, a member of the New Zealand p ...

of the

Transantarctic Mountains The Transantarctic Mountains (abbreviated TAM) comprise a mountain range of uplifted rock (primarily sedimentary) in Antarctica which extends, with some interruptions, across the continent from Cape Adare in northern Victoria Land to Coats L ...

. Later, around 1600–1550 Ma, the Coompana Block and its Antarctic extension was joined to the continent. The extent of the Mawson Continent is uncertain since Australia is now widely covered by

Neoproterozoic The Neoproterozoic Era is the last of the three geologic eras of the Proterozoic geologic eon, eon, spanning from 1 billion to 538.8 million years ago, and is the last era of the Precambrian "supereon". It is preceded by the Mesoproterozoic era an ...

Phanerozoic The Phanerozoic is the current and the latest of the four eon (geology), geologic eons in the Earth's geologic time scale, covering the time period from 538.8 million years ago to the present. It is the eon during which abundant animal and ...

rocks and Antarctica is almost entirely covered by ice and snow.

Extent of the continent

The Gawler craton, Terre Adélie craton, Miller Range and

Shackleton Range The Shackleton Range () is a mountain range in Antarctica that rises to and extends in an east–west direction for about between the Slessor and Recovery Glaciers. Surveys The Commonwealth Trans-Antarctic Expedition (CTAE), which in 1956 s ...

have few tectono-thermal events in common, apart from tectonism around 1700 Ma. Airborne and satellite magnetic geophysical data suggest that the Gawler-Adélie cratons differ in fundamental ways from the Miller Range and other parts of the

East Antarctic Shield The East Antarctic Shield or Craton is a cratonic rock body that covers 10.2 million square kilometers or roughly 73% of the continent of Antarctica. The shield is almost entirely buried by the East Antarctic Ice Sheet that has an average thicknes ...

. There is evidence that suggests that the Miller Range terrain was accreted to the Gawler–Adélie Craton during the 1730–1690 Ma Kimban–Nimrod Orogeny, with a suture zone that may be at or near the location of the Nimrod Group. Australia and Antarctica separated between 85 Ma and 30 Ma. Tectonics in the Southern Terrane of the Shackleton Range during the

were similar to that of the Mawson Continent, which may mean that this continent extends over the Eastern Antarctic Shield and includes the Shackleton Range. However, the correlations between the Mawson Continent and Shackleton Range do not prove the Shackleton Range was part of the continent, since there could have been rifting or accretion events during the

Mesoproterozoic The Mesoproterozoic Era is a geologic era that occurred from . The Mesoproterozoic was the first era of Earth's history for which a fairly definitive geological record survives. Continents existed during the preceding era (the Paleoproterozoic ...

Gawler–Adélie Craton

Formation of Mawson Continent

Extent of the continent

Notes

References

Sources