As mentioned above, the post-drift studies provided considerable information that was not available at the time Wegener put forth his concept of continental drift.
Particularly, the mapping of the ocean floor and palaeomagnetic studies of rocks from oceanic regions revealed the following facts:
- It was realised that all along the mid- oceanic ridges, volcanic eruptions are common and they bring huge amounts of lava to the surface in this area.
- Rocks closer to the mid-oceanic ridges have normal polarity and are the youngest. The age of the rocks increases as one moves away from the crest.
- The ocean crust rocks are much younger than the continental rocks. The age of rocks in the oceanic crust is nowhere more than 200 million years old. Some of the continental rock formations are as old as 3,200 million years.
- Hess (1961) to propose his hypothesis, known as the “sea floor spreading”.
