page_title: Boris Choubert
section_title: Reconstruction of the pre-Atlantic paleocontinent
hierarchical_section_title: Boris Choubert / Boris Choubert and continental drift / Reconstruction of the pre-Atlantic paleocontinent
caption_attribution_description: Français&#160;: Reconstruction par Boris Choubert du supercontinent Amérique-Groenland-Europe-Afrique (1935). English: Boris Choubert's fit of America, Greenland, Europe and Africa continents (1935).
context_page_description: Boris Choubert or Schuberth was a French geologist. An adept of Wegener's theory, he was the first to precisely reconstruct the layout of the continental masses of Africa, America, Europe and Greenland prior to the fragmentation of Pangaea, thirty years before the article generally credited for this discovery.
context_section_description: Boris Choubert published in 1935 a reconstruction of the relative positions of America, Africa and Europe before the Triassic. This reconstitution was much more precise than the previous proposals by Wegener and du Toit, essentially because Choubert, instead of using coastlines, based his reconstitution on the 1000-m isobath, a much better representation of the limits of continental blocks.
  That excellent fit was more convincing a proof of continental drift than previous attempts, which left a large gap between Africa and South America. For his reconstruction Boris Choubert dared for the first time the idea that the Iberian Peninsula suffered, after the Triassic, a rotation with respect to the rest of Europe. He also swept the Mid-Atlantic Ridge problem by explaining that it formed posteriorly to Atlantic Ocean opening. The Caribbean Sea does not fit as well as the rest but, as it is known today, it was seriously affected by Cenozoic tectonics.
  Boris Choubert drew the theory farther than Wegener, who had only considered post-Triassic continental drift. By reconstructing the Paleozoic mountain ranges across the Atlantic (Caledonian range, Hercynian range et Appalachians), he made clear that they were formed by the compression of sediments that had been accumulated between three Precambrian cratons (Canadian Shield and Fennoscandian Shield at north, Gondwana at south). Withdrawing those ranges he concluded that the three cratons had made a single continent at the end of the Precambrian, which was later fragmented during the Paleozoic. Hence he realized that continental drift is a general process, which has affected the Earth all along its geological history.
caption: Boris Choubert's reconstruction of the America-Greenland-Europe-Africa supercontinent (1935).
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