What was unknown to scientists during Wegener’s time?

Answer 1

During Wegener's time, scientists were uncertain about several important concepts that are now well-established. Some of the things that were unknown to scientists during Wegener's time include:

1. Mechanism of continental drift: Although Alfred Wegener proposed the idea of continental drift, he couldn't provide a convincing mechanism for how it occurred. The theory of plate tectonics, which explains the movement of Earth's lithospheric plates, was not developed until several decades later.

2. Seafloor spreading: The process of seafloor spreading, where new crust is formed at mid-oceanic ridges and pushes older crust aside, was not known during Wegener's time. This process is a significant piece of evidence supporting the theory of plate tectonics.

3. Paleomagnetism: Paleomagnetism, the study of Earth's magnetic field recorded in rocks, was not well-understood during Wegener's time. It was only later discovered that the Earth's magnetic field has undergone polarity reversals and that rocks on either side of a spreading ridge display alternating magnetic polarities.

4. Subduction: The process of subduction, where one tectonic plate is forced beneath another and sinks into the mantle, was not known during Wegener's time. Subduction zones play a crucial role in the recycling of Earth's crust and the formation of volcanic arcs.

5. Mantle convection: The idea of convective currents in Earth's mantle, driving the movement of tectonic plates, was not established at the time. Scientists didn't have a solid understanding of the dynamics of Earth's interior and its relation to plate movements.

6. Dating techniques: Radiometric dating techniques, which are used to determine the age of rocks and fossils, were not available during Wegener's time. These dating methods later played a significant role in supporting the idea of continental drift and plate tectonics.

Overall, Wegener's contemporaries lacked several crucial pieces of knowledge that are now fundamental to our understanding of plate tectonics and Earth's geology.