Australia: The Land Where Time Began

A biography of the Australian continent 

Columbia   aka Nuna, Hudsonland                                                                                                                                                               

Columbia is the name proposed for a postulated supercontinent, in the Palaeo-Mesoproterozoic, that pre-dated Rodinia (Rogers & Santosh, 2002), based on lithostratigraphic, tectonothermal, geochronological and palaeomagnetic data, from collisional orogens dating to 2.1-1.8 Ga, related to cratonic blocks around the world. These data indicate connections between South America and West Africa; Western Australia and South Africa; Laurentia and Baltica; Laurentia and Siberia; Laurentia and Central Australia; East Antarctica and Laurentia and North China and India.

It has been suggested that this supercontinent was formed by the welding of cratonic blocks dating from the Archaean to Palaeoproterozoic by global collisional belts of 2.1-1.8 Ga. The Transamazonian Orogeny and the Eburnean Orogeny had welded the cratonic blocks in South America and West Africa by 2.1-1.8 Ga. The Kaapvaal Craton and the Zimbabwe Craton had collided along the Limpopo Belt about 2.0 Ga. According to Guochun Zhao et al.,

'the cratonic blocks of Laurentia were sutured along the 1.9-1.8 Ga Trans-Hudson, Penokean, Talston-Thelon, Wopmay, Ungava, Torngat and Nagssugtoqidain Orogens; the Kola, Karelia, Volgo-Uralia and Sarmatia (Ukrainian) Cratons in Baltica (Eastern Europe) were joined by the 1.9-1.8 Ga Kola-Korelia, Svecofennian, Volhyn-Central Russian and Pachelma Orogens; the Anabar and Aldan Cratons in Siberia were connected by the 1.9-1.8 Ga Akitkan and Central Aldan Orogens; the East Antarctica and an unknown continental block were joined by the Transantarctic Mountain Orogen; the South and North Indian Blocks were amalgamated along the Central Indian Tectonic Zone. and the Eastern and Western Blocks of the North China Craton were welded together by the approximately 1.85 Ga Trans North China Orogen.'

It has been suggested that Columbia existed based on the evidence, that is consistent with its existence, such as the sedimentary and magmatic records of the Palaeoproterozoic and Mesoproterozoic. At about 2.0 Ga, Fluvio-deltaic deposits have been found in all the blocks of South America and West Africa, which are believes to have formed in a foreland basin during the final stage of the Transamazonian-Eburnian collisional event, of about 2.1-2.0 Ga, that led to the assembly of South America and West Africa.

A 1.8-1.3 Ga subduction-related magmatic belt continues from Arizona through Colorado, Michigan, South Greenland, Sweden and Finland, ending in Russia. The existence of a supercontinent in the Palaeo-Mesoproterozoic has been suggested to be supported by the presence of rocks that are similar, temporarily and petrologically, across thousands of kilometres between these continents. At 1.6-1.2 Ga, emplacement of anorthosite-mangorite-charnokite-rapakivi (AMCR) suites, and at 1.4-1.2 Ga, mafic dyke swarms, as well as the intrusion of kimberlite-lamproite-carbonatite suits that occur throughout much of the continent, are associated with accretion, attenuation and eventually breakup of the supercontinent.

Sources & Further reading

Review of global 2.1-1.8 Ga orogens: Implications for a pre-Rodinia supercontinent

Links

  1. Columbia
  2. Taking the Pulse of Planet Earth/Completing the Plate Tectonics Revolution
  3. Change of the Earth's Tectonic Plates in 650 Million Years
Author: M. H. Monroe
Email:  admin@austhrutime.com
Last Updated 27/03/2011 

 

Columbia
Rodinia
Pannotia
Pangaea
Gondwana

 

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                                                                                           Author: M.H.Monroe  Email: admin@austhrutime.com     Sources & Further reading