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Gondwanaland |
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Gondwanaland (gŏnd'wä`nəlănd'): see continental drift continental drift, geological theory that the relative positions of the continents on the earth's surface have changed considerably through geologic time. Though first proposed by American geologist Frank Bursley Taylor in a lecture in 1908, the first detailed theory
..... Click the link for more information. . Gondwanaor GondwanalandHypothetical former supercontinent in the Southern Hemisphere, which included modern South America, Africa, southern Europe, India, Australia, and much of the Middle East and Antarctica. The concept that the continents were at one time joined was first set forth in detail by Alfred Wegener in 1912. He envisioned a single great landmass, Pangea, which supposedly began to separate early in the Jurassic Period (approximately 200 million to 146 million years ago). Subsequent workers distinguished between a southern landmass, Gondwana, and Laurasia to the north. See also continental drift. Gondwanaland [gän′dwän·ə‚land] (geology) Gondwanaland (named after the historical region in middle India), a hypothetical continent that, in the opinion of many scientists, existed in the southern hemisphere in the Paleozoic era and partially in the Mesozoic era. It included a large part of contemporary South America (to the east of the Andes), Africa (without the Atlas Mountains), the island of Madagascar, Arabia, the Indian peninsula (south of the Himalayas), Australia (to the west of the mountain ranges in the east), and possibly a large portion of Antarctica. The proponents of Gondwanaland’s existence feel that in the Proterozoic era and the Upper Carboniferous period, extensive glaciation developed on the continent. Traces of Upper Carboniferous glaciation are evident in Central and South Africa, in the southern part of South America, and in India and Australia. During the Carboniferous and Permian periods, unique flora of the temperate and cold belts developed in Gondwanaland. This flora was characterized by an abundance of glossopteres and equisetums. Gondwanaland began to break up in the Mesozoic era and by the end of the Cretaceous period and the beginning of the Paleogene epoch, the modern continents and their regions had separated. Many geologists feel that the breakup of Gondwanaland was a consequence of the horizontal separation of its modern parts, a fact confirmed by the data of paleomagnetism. However, instead of separation some scientists have proposed the collapse of individual areas of Gondwanaland that previously were situated on the site of the present-day Indian and southern Atlantic oceans. REFERENCESMazarovich, A. N. Osnovy regional’noi geologii materikov. Part 2: luzhnye materiki, okeany i obshchie zakonomernosti razvitiia struktury zemnoi kory. [Moscow] 1952.Gignoux, M. Stratigraficheskaia geologiia. Moscow, 1952. (Translated from French.) Problemy peremeshcheniia materikov. Moscow, 1963. (Collection of articles; translated from English and German.) Problemy paleoklimatologii. Trudy simpoziuma. Moscow, 1968. (Translated from English.) Want to thank TFD for its existence? Tell a friend about us, add a link to this page, add the site to iGoogle, or visit the webmaster's page for free fun content. |
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