Loading Search Form
Please Wait
Experience Matters
Marcellus Shale
What is it?
The Marcellus shale is an organic-rich black shale that was deposited in an oxygen-deficient marine environment during Middle Devonian time (~390 million years ago). Long known to be a source rock for many conventional oil and gas reservoirs in the Appalachian basin, it is now being explored as an unconventional reservoir. The formal name for this rock unit is the Marcellus Formation.
Where is it found?
The Marcellus shale is prevalent throughout much of the Appalachian basin and most of Pennsylvania, although its depth and thickness are variable.
Where do I get the best information?
www.dcnr.state.pa.us/topogeo/oilandgas/marcellus_shale.aspx