Continental Drift and Sea-Floor Spreading

Abstract

The outlines of the continents had suggested from an early date that they had become separated from each other during geological time. The location that they occupy today is no longer the one they once had. Several groups of related arguments led to the continental drift theory. The theory was not adopted immediately because it provided no explanation for the driving force behind the mechanism. Subsequently, however, physical data connected with the magnetism of rocks caused geophysicists to reconsider the drift theory. Simultaneously, a mechanism was proposed to explain the process: as the oceans open the continents separate. Today, ‘continental drift’ and ‘sea-floor spreading’ represent two sides of the same coin: together they form a theory which accounts for many of the facts set out in the preceding chapters.