What is the Marcellus Shale?
The Marcellus Shale, also referred to as the Marcellus Formation, is a Middle Devonian-age black, low density, carbonaceous (organic rich) shale that occurs in the subsurface beneath much of Ohio, West Virginia, Pennsylvania and New York. Small areas of Maryland, Kentucky, Tennessee, and Virginia are also underlain by the Marcellus Shale. See the map of the Marcellus Shale at right.
Throughout most of its extent, the Marcellus is nearly a mile or more below the surface. The map at right shows the depth of the Marcellus Shale. These great depths make the Marcellus Formation a very expensive target. Successful wells must yield large volumes of “natural gas” (a public relations industry term for ‘methane’) to pay for the drilling costs that can easily exceed a million dollars for a traditional vertical well and much more for a horizontal well with hydraulic fracturing.
For more on the issues and impacts of horizontal hydrofracking proposed for New York State, click here.