The Great Continental Train Wreck
North America and Europe collided head-on.
This continental smashup resulted in the raising of the Appalachian Range. Steady erosion of these bare, newly uplifted mountains yielded great volumes of sediment, which were deposited in vast lowlands and shallow seas nearby.
In the process, the mud—that organic road kill on the seabed—became buried under incalculable millions of tons of debris and minerals. The site of modern-day Pittsburgh, geologists estimate, was entombed under 16,000 feet of sediment. Down below it was literally…
A Geological Pressure Cooker
Under extreme temperature and pressure created by the sheer weight of the sediment, the mud began to cook.
As this hodgepodge stewed beneath the earth, the organic matter—the green slime—began to break down. Small pores, like air bubbles, formed in the hot mud. Think of Swiss cheese, except instead of air, the bubbles were filled with methane.
In other words, natural gas.
Another few eons passed and the sediment compressed into rock—black shale. But the pores, or bubbles if you prefer, remained.
And so did the natural gas trapped inside the pores. You could say it just sat there waiting—for hundreds of millions of years.