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Rodinia
In geology, Rodinia (from the Russian "Родина", ''ródina'', meaning "The Motherland")〔Li, Z. X.; Bogdanova, S. V.; Collins, A. S.; Davidson, A.; B. De Waele, R. E. Ernst, I. C. W. Fitzsimons, R. A. Fuck, D. P. Gladkochub, J. Jacobs, K. E. Karlstrom, S. Lul, L.M. Natapov, V. Pease, S. A. Pisarevsky, K. Thrane and V. Vernikovsky (2008). "Assembly, configuration, and break-up history of Rodinia: A synthesis". ''Precambrian Research'' 160: 179–210〕〔(Статья о Родинии на портале образовательных ресурсов )〕 is the name of a hypothetical supercontinent, a continent which contained most or all of Earth's landmass. The name was coined by McMenamin & McMenamin in 1990. According to plate tectonic reconstructions, Rodinia existed between 1.1 billion and 750 million years ago, in the Neoproterozoic Era. It is one of two models for the configuration and history of the continental crust in the latter part of Precambrian times. The other is Paleopangea.〔Piper, J. D. A. (2010). "Paleopangea in Meso-Neoproterozoic times: the paleomagnetic evidence and implications to continental integrity, supercontinent from and Eocambrian break-up". ''Journal of Geodynamics'' 50: 191–223〕 Rodinia is postulated to have formed at ~1.0 Ga by accretion and collision of fragments produced by breakup of a hypothetical older supercontinent, Columbia, assembled by global-scale 2.0–1.8 Ga collisional events. Rodinia has entered popular consciousness as one of the two great supercontinents of earth history, the other being Pangaea.
Rodinia is hypothesized to have broken up in the Neoproterozoic with its continental fragments re-assembled to form Pannotia 600–550 million years ago. In contrast with Pannotia, little is known yet about the exact configuration and geodynamic history of Rodinia. Paleomagnetic evidence provides some clues to the paleolatitude of individual pieces of the Earth's crust, but not to their longitude, which geologists have pieced together by comparing similar geologic features, often now widely dispersed.
J.D.A. Piper has raised serious doubt that Rodinia ever existed as a transient supercontinent subject to progressive break-up in the latter part of Proterozoic times because the palaeomagnetic poles from the continental crust assigned to this time conform to a single path between 800 and 600 million years ago and latterly to a near-static position between 750 and 600 million years.〔Piper, J.D.A. (2013), ''A planetary perspective on Earth evolution: Lid Tectonics before Plate Tectonics,'' Tectonophysics, 589, pp. 44–56〕 This latter solution predicts that break-up was confined to the Ediacaran Period and produced the dramatic environmental changes that characterised the transition between Precambrian and Phanerozoic times.
The extreme cooling of the global climate around 700 million years ago (the so-called Snowball Earth of the Cryogenian Period) and the rapid evolution of primitive life during the subsequent Ediacaran and Cambrian periods are thought to have been triggered by the breaking up of Rodinia or to a slowing down of tectonic processes.〔
==Geodynamics==
抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』
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