Marcellus Shale
- The Marcellus Shale, also known as the Devonian Marcellus formation, was formed approximately 380 million years ago during the middle Devonian age. The organic material decayed, forming methane and other natural gases. About 300 million years ago, the pressure of the gas caused fractures to form in the shale. These fractures run from the northeast to the southwest. According to research done by Dr. Terry Engelder of Penn State University, there are an estimated 489 trillion cubic feet of recoverable gas in the shale, enough to meet U.S. demand for about 19 years. About 75-80% of this recoverable gas is located in Pennsylvania. [Source: geology.com and pamarcellus.com]
