I'm interested in geology topics but it's all too much for me! So here you'll find some interesting Colorado sightseeing notes with a geologic viewpoint that I'll try to add
    For example... The eons, eras, periods & epochs(!) of the Geologic Time Chart can be too detailed and overwhelming. In contrast, I found this simpler illustrated chart to help me learning the periods!
    A couple of periods make 'sense' to me. (1) Around 250 mya earth's greatest mass extinction (The Great Dying) occurred. 90% of the Permian species disappeared from the fossil record. The new period was the 1st of 3 in the Mesozoic Era. Named the Triassic Period, it was the beginning of the Age of Dinosaurs. (2) Then 65 mya the impact of an asteroid created another mass extinction. This last period was the Cretaceous and marks the end of the Mesozoic Era (and dinosaurs!).
    I wonder what worldwide events explain the naming of so many other periods in the geologic time scale?