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.

Boris Choubert mainly dedicated himself to three geological fields, of which he significantly advanced the first two:[2] Evoked several times between 1596 and 1908, the continental drift concept was chiefly developed and advocated by the German meteorologist Alfred Wegener between 1912 et 1929, on the basis of different criteria, morphological (the nesting of continent shapes, like the Horn of Brazil and the Gulf of Guinea), stratigraphic (stratigraphic continuity between Africa and South America, and complementarity of Paleozoic cratons), paleoclimatic (similarity of Paleozoic striated pebbles of South Africa and South America) and paleontological (same fauna and flora during the Paleozoic era).

Working on rocks from Gabon, Congo and Brazil, Boris Choubert confirmed the findings of du Toit and in turn became a fervent supporter of continental drift.

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.

Thirty years later, Edward Bullard and co-authors published a paper[10] in which a reconstruction similar to Choubert's was achieved with the help of a computer, through the numerical minimisation of distances between continental blocks.