![]() ![]() Part of the problem was that he had no convincing mechanism for how the continents might move. ![]() Reactions to Wegener’s theory were almost uniformly hostile. In 1915 Wegener completed ‘Die Entstehung der Kontinente und Ozeane’ (‘The Origin of Continents and Oceans’), the fourth and final expanded edition of which was published in 1929. Wegener first presented this hypothesis of Continental Drift on 6th January, 1912, and he also speculated on sea-floor spreading and the role of the mid-ocean ridges, though he did not pursue these ideas further. Pangaea subsequently rifted apart and the segments began drifting away from each other. Wegener hypothesised that about 300 million years ago the continents had formed a single mass, which he called ‘Urkontinent‘, now more widely known as ‘Pangaea’ (‘All Earth’). Wegener also found that the fossils commonly indicated a palaeoclimate different from that of their present location: for example, fossils of tropical plants, such as ferns and cycads, are found on the arctic island of Spitsbergen to the north of Norway. The Paraná traps in Brazil and Etendeka flood basalts in Namibia and southwest Angola are part of the same Large Igneous Province. The Appalachian mountains of eastern North America could be matched with the Scottish Highlands. Wegener found that geological features on the separated continents appeared to match. Wegener also noticed the close fit between the coastlines of Africa and South America at the continental shelf level and he began to wonder whether the continents had once been joined. At the time it was believed that land bridges had once joined the continents, which had since sunk beneath the oceans. Wegener was fascinated and began to look for other instances of similar fossil organisms separated by oceans. In 1911 Alfred Wegener, astronomer, meteorologist and Greenland explorer, was browsing in the university library at Marburg in Germany when he ran across a paper that listed identical plants and animals found as fossils on opposite sides of the Atlantic. It all started with a trip to the University Library … Kathy Kavanagh outlines the life, times and ideas of Alfred Wegener… ![]()
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |