Wednesday, July 2, 2014

Geologic Time Scale

A geologic time scale is given here in order to help discussions
that will follow in my future posts.

For a more complete and much more detailed version, as well as one that is to scale, the link is HERE
It is from the Geological Society of America and is their 2012, version 4.0.

It is important to realize that the Precambrian accounts for about 7/8 of all geologic time. A way to visualize this is consider that if your  entire arm (from shoulder to wrist) and your hand represent all of geologic time, the Precambrian would extend from the shoulder to the wrist. The rest of geologic time is represented by your hand. 

A handy way to remember the sequence of the names of the periods of the geologic time scale involves the following mnemonic devices (by using the first letter of each period name in its respective position in the sequence):

For the Paleozoic:  "Certain old stones delight my paleontology professor."

For the Mesozoic and Cenozoic: "The jungle cat prowls nightly, quietly."

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