The Manicouagan Crater
http://www.space.gc.ca/asc/eng/sciences/planetary_geology.asp
Craters can be found in many places on the surface of the Earth, and on other planets in our solar system. In the simplest sense, they are a circular hole carved out when a smaller, fast moving object collides with it. This collision transfers huge amounts of kinetic energy that is absorbed into the immediate area because of the conservation of energy (Melosh, 1989).

      Diagram
http://deepimpact.jpl.nasa.gov/science/cratering.html
The cratering takes place in three major parts. The first is the compression stage. Here, the impactor makes initial contact with the other and begins the excavation. The energy is now converted into heat, but melting has not yet begun. The collision causes the shock (or compression) wave to be sent out in all directions.

The second part is the excavation stage. It is important to note that the site of the shock wave does not originate from the surface where the impact takes place. It starts from a point below, where the object first breaks through. It is because of this that the compressional wave travels back up, sending material out of the crater (ejecta). This material is sent out of the crater to form a blanket surrounding the crater and possibly areas near by. This is also where we can find the lip of the crater rolling back causing the overturning of the beds at impact sites.

The final stage is the modification stage and is less drastic as the material settles and most of the dynamics are over. Now, the newly formed sediments will settle in the crater. This is also the time where the center of the crater sometimes rebounds back and causes a peak in the middle. This can be caused by both excavated and; or the rebound of the crust after the initial impact from the object (Wiggins, 2006).

Index
Introduction
Background
Model Setup
Model Results
Discussion
References