- 2.1: Early Earth
- Earth in its early stages was like a depiction of hell, scalding rock and choking fumes, due to accretion from cosmic debris. The surface was essentially a magma ocean, much too harsh of conditions for anything to survive. Some water and a very early atmosphere was present, and crustal rocks began to form. But the mantle was convecting and volcanism was intense. Large asteroids kept falling in, producing craters and an overall large-scale disturbance.
- 2.2: Structure of the Earth
- The structure of the earth has been classically divided into four major groups. The crust, the mantel, and the outer and inner cores have all been defined by their unique chemical properties based off of studies of volcanic and seismic activity as well as mass estimates of the earth that have been able to determine the densities of the different layers. The way these layers interact with each other has significant implications to volcanic, seismic, and electromagnetic activity.
- 2.3: Continental Drift
- Continental drift was first conceived by scholars and philosophers named Francis Bacon, George Buffon, and Alexander von Humboldt. As maps grew more accurate the landmasses began appeared as puzzle pieces. The continents once had fit together but had drifted apart after millions of years. The continents now far apart showed similar sediment, rock formation, and vegetation supporting the theory that they were one landmass in the past.
- 2.5: Types of Plate Boundaries
- Categorization of plate boundaries is based off of how two plates move relative to each other. There are essentially three types of plate boundaries, which are divergent, convergent, and transform.
Thumbnail: Diagram of the Earth. (CC-SA-BY 3.0; Kelvinsong).