Infomods Forty years ago, scientists developed a theory that explains everything from the movement of creation of the mid-ocean ridge, to the presence of earthquakes and volcanoes, to the movement of entire continents. Learn about the theory of plate tectonics. (Plate tectonic graphics adapted from Tasa Graphics) The global mid-ocean ridge is a volcanic mountain range more than 60,000 kilometers long. It is the site where the oceanic crust of the Earth is created. Learn about the place where lava erupts and seafloor spreading occurs. Thousands of meters below the ocean surface, chimneys spew plumes of scalding black fluid. Learn about how these black smokers form, the chemistry of the plumes, and their effects on the surrounding water. The environment around hydrothermal vents is extremely hostile. There is no light, the pressure is 250 times what we experience on earth, and the vent plumes contain toxic chemicals. However, vents host an assortment of amazing animals. Learn about the tubeworms, crabs, and other creatures that thrive around vents. Scroll through the timeline to learn about some of the most important events in Earth’s history. Learn about the Earth’s structure, from core to crust. From Polynesian seafarers to modern day explorations, learn about key events in history that greatly advanced the field of oceanography. Definitions for geological and oceanographic terms used throughout the web site (Extracted and modified from Tasa Graphics Earth Dictionary)