What do we really know about seafloor spreading and how ocean crust is generated at the Earth’s mid-ocean ridges? What actually is the ‘Moho’ seismic horizon beneath the ocean floor, long taken as the boundary between crust and the mantle? Is the ocean crust as simple and regular as the conventional plate tectonics model would have us believe? Whereas conventional plate tectonic theory provides a beautifully simple explanation for the formation of ocean crust by seafloor spreading, ongoing research is making fascinating new observations that the standard model cannot explain. Why can we find mantle rocks on the seafloor at mid-ocean ridges? What might this mean for what we understand about water, carbon, even life on Earth?

The research being done today provides a wonderful case study of the scientific method in action: how new observations are leading us to re-examine the basic assumptions underlying plate tectonic theory, and to very different hypotheses for one of the most fundamental geological processes on the planet.

This web site aims to provide resources as a case study to help teachers convey the challenges and wonder of modern science in action; here how researchers are working at and beyond the final frontier of the Earth’s deep oceans to re-examine our basic understanding of how the planet works. Materials available for free download here are specifically designed to assist those teaching Geology in UK schools at A-, AS- and GCSE level – where this topic is a named item on the curriculum – but are also for suitable for teachers of Geography and Science, in the UK and worldwide.