What Is the Marcellus Shale?

The Marcellus shale is a large, underground land formation that extends across much of the eastern portion of the United States. Trapped within the rock are valuable energy resources, such as gas or coal, which in previous years, have been difficult to access. Interest in the land formation is peaking due to new technologies that make reaching these trapped resources easier. As with any beneficial energy extraction process, there are significant environmental concerns.

The large volume of sedimentary rock, known as the Marcellus shale, covers much of the underground portion of Appalachian basin. It lies beneath sections of Ohio, West Virginia, New York, New Jersey, and Pennsylvania with depths reaching around 7,000 feet (2,133 meters) in certain areas. The Marcellus formation is composed of fine grain clay minerals, fragments of quartz, and calcite. There may be as much as 516 trillion cubic feet (14.6 trillion cubic meters) of natural gas trapped within the vertical joints of the rock formation.

Interest in the shale is growing because there is enough natural gas trapped within the rock to supply the eastern seaboard of the United States with energy for 14 years. New technology and the construction of the Millennium Pipeline have made the gas trapped inside the Marcellus shale accessible. Energy companies are also inventing new processes, such as fracturing, to access the gas trapped within the rock. The process of fracturing forces water and chemicals into the rock, placing it under pressure and causing it to split apart. Companies can then reach the gas reserves using more traditional methods of vertical and horizontal drilling.

There are significant environmental concerns surrounding the extraction and transport of natural gas from the Marcellus shale. Protecting the natural habitat for plants and animals is a concern as ecosystems may be destroyed where new drilling sites are constructed. In addition, the chemicals used in the fracturing process may harm the environment by seeping into water supplies. Certain studies have shown that fracturing can cause small to medium-sized earthquakes, which may damage local communities.

State and local governments in the Marcellus shale region work diligently to minimize environmental concerns and maximize the benefits of natural gas extraction. As a result, cities and states in the region enjoy increased revenues in the form of various taxes. There is an increase in available employment in states where drilling is possible, and land owners benefit through the sale or leasing of land rights.