PLATE TECTONICS

What produced the change from the hothouse to the ice house Earth in the last ~60 million years? What caused earlier ice ages and huge swinges in sea level that covered so much of the continents with marine sediments? The possible answers, from weathering of rocks during periods of enhanced mountain building to changes in the rate of CO2 release at mid-ocean ridges, all involve plate tectonics. We review the development of the plate tectonic theory, including role Columbia researchers played in making the break-throughs that first confirmed the theory. We will discuss ideas about what might control plate motions on Earth as well as what we know about different kinds of tectonics on other planets. Researchers working on cutting-edge observations and models relating tectonics and climate will be invited to air their views to the class.