Harry Hess significantly contributed to the plate tectonic theory through his research on ocean floor dynamics and the concept of seafloor spreading. In the early 1960s, he proposed that molten material from the Earth's mantle rises at mid-ocean ridges, creating new oceanic crust while older crust is pushed away. His ideas helped provide a mechanism for continental drift and supported the understanding that Earth's lithosphere is divided into tectonic plates that move over the asthenosphere. Hess's work laid crucial groundwork for the modern theory of plate tectonics.
Hess's and Wegener's theories are interconnected in their exploration of continental movement and plate tectonics. Alfred Wegener proposed the theory of continental drift, suggesting that continents were once joined and have since moved apart. Harry Hess later contributed to this understanding with his theory of seafloor spreading, which explained how new oceanic crust forms at mid-ocean ridges and pushes continents apart. Together, their ideas laid the foundation for the modern understanding of plate tectonics.
One key piece of evidence not included in support of Harry Hess's hypothesis of sea-floor spreading was the discovery of paleomagnetic data. While Hess's theory focused on the creation of new oceanic crust at mid-ocean ridges and the recycling of crust at subduction zones, the paleomagnetic records provided insights into the historical movement of continents and the magnetic orientation of rocks, which later supported the theory of plate tectonics. Other evidence, such as the age of oceanic crust and the distribution of fossils, played a more direct role in supporting his hypothesis.