Final answer:
The Dutch cartographer who proposed the idea of continental separation in 1596 is not identified in available sources; however, Alfred Wegener is credited with the theory of continental drift in 1915, leading to the concept of the supercontinent Pangaea and later the development of plate tectonics.
Step-by-step explanation:
The Dutch cartographer who suggested that the continents were once joined and subsequently separated in 1596 was not mentioned in the sources provided. However, it is well-documented that the theory of continental drift was first seriously proposed by German meteorologist and astronomer Alfred Wegener in 1915.
Wegener provided evidence such as the fit of South America and Africa, as well as fossil records and paleoclimate data to support his theory of Pangaea, a supercontinent where all the continents were once joined. Although Wegener's theory was not immediately accepted and he struggled to explain the mechanism behind the drifting continents, his idea laid the groundwork for the development of the modern theory of plate tectonics in the 1960s.