The early history of Earth covers such vast stretches of time that years, centuries, and even millennia become virtually meaningless. Instead, paleontologists and scientists who study geochronology divide time into periods and eras.

The current view of science is that Earth is around 4.6 billion years old, and the first four billion years of its development are known as the Precambrian period. For the first billion years or so, there was no life in Earth. Then the first single-celled life-forms, early bacteria and algae, began to emerge. It’s unclear where they came from or even if they originated on this planet at all, but this gradual development continued until around four billion years ago when suddenly (in geological terms) more complex forms of life began to emerge.

Scientists call this time of an explosion of new forms of life the Paleozoic Era, and it stretched from around 541-250 million years ago (Mya). In the oceans and then on land, new creatures and plants began to appear in bewildering variety, and by the end of this period, life on Earth had diversified into a myriad of complex forms that filled virtually every habitat and niche available in the seas and on the planet’s only continent, Pangea.

Among the most interesting of the prehistoric eras is the Permian age, the most extreme period in the planet’s history. It spanned 47 million years, beginning with an ice age, warming, and ending with the most cataclysmic volcanic episode in the planet’s history. The great bulk of all life on the Earth was almost immediately snuffed out, barely crawling back over the following 10 to 30 million years, and it set the stage for the “Age of Dinosaurs”.

What is termed by some as the “Pennsylvanian” or “Carboniferous” period prepared the emergence of the Permian age. Named for the abundance of rocks from the period found in the state of Pennsylvania, many prefer the term “Silesian” or “Carboniferous” era. In the preceding “Mississippian era”, warm, shallow seas disappeared causing serious upheaval to marine life in a tendency toward glaciation.

“Significant glaciation” marks the beginning of the Carboniferous immediately preceding the Permian. Carboniferous glaciation began in the late Ordovician Period long before. The eventual Andean-Saharan glaciation, a minor ice age, occurred later in the Silurian Age. These were all remnants of the “Snowball Earth” period of the Cryogenian. The resultant sea level drop as the Carboniferous ice age set in produced conditions much like that of today, with ice on both poles, wet tropics near the equator and temperate regions in between. Despite similar conditions, the Carboniferous lacked the output of greenhouse gases produced by humans.

Fragments of plates collided as continents were still fusing into the supercontinent Pangea. During glaciation, “latitudinal climactic belts were widespread”. Permian rocks have been found on all the continents and some have been displaced “considerable distances from their original latitudes” in the Mesozoic and Cenozoic eras that followed the Permian".