I.   INTRODUCTION

                   

This brief primer is a collection of basic accepted facts from the study of earth's prehistoric geological evolution. It is meant for popular use — it is not an academic or definitive document. The need for a simple summary arises because, although this material is often referenced in all kinds of pedagogical and popular literature, it does not appear in the school curriculum of any subject at any stage. Most individuals therefore have only an approximate idea of geological names, time-frames, and factors affecting earth's history. The information is publicly available, and that is the source for this summary; but there is often no occasion when these individuals might review it in a succinct outline.

All of the information in this extract is taken from Wikipedia articles. As such, the primer does not present new concepts, but mostly outlines information widely accepted as established and supportable by scientific observation. Specific references are not given, as practically any significant name or phrase entered into Wikipedia's search-bar will bring up a relevant source. Wikipedia by its nature is not infallible or completely unerring, but it is a reference much relied upon generally.

The many stories of earth's four-billion-year life are fascinating and even unlikely. But they are all supported by diligent study of information revealed by rocks, sediments and ice. Delving into these narratives is informative in its own right. But also, in a time when various groups actively apply themselves to influencing mass opinion for various ends, it is essential to be rooted in objective realities. Perhaps this slim primer can serve as an incentive or road-map for further exploration.