Non-Mineral Resources of the Coastal Plain

Figure 7.11: Principal non-mineral resource-producing localities of the Coastal Plain. Figure adapted from 1998 United States Geological Survey State Mineral Information.

The primary non-mineral resources of the Coastal Plain are the layers of sand and gravel eroded from the Appalachian Mountains to the west (Figure 7.11). Greensand and diatomaceous earth were also at one time important resources. Since the region does not have solid rock and is composed entirely of layers of loose sediments, the Coastal Plain does not have the same kinds of resources that are abundant in the other regions.


Sand and gravel, eroded from the Appalachian Mountains to the west, are easily accessible, extremely abundant and useful natural resources in the Coastal Plain region. Due to the nature of the Coastal Plain, which is loose sediment and not rock, sand and gravel deposits are plentiful and easily mined. Sand and gravel are primarily used in construction, concrete and road fill. Industrial sand, mined in Cumberland County, Maryland, has a slightly different nature than ordinary sand and gravel. Important for its predominantly quartz content, industrial sand is used in sandblasting, filtering and in the manufacture of glass.

Greensand, containing the relatively common Coastal Plain mineral glauconite, is still used today as a soil conditioner and water softener. It also has potential for use in landfills and as a filter for heavy metals from industrial wastes. Diatomaceous earth from the Maryland Calvert Formation was at one time an important natural resource for Maryland (and the only place in the United States where it was mined). Made of the hard shells of microscopic marine organisms, known as diatoms, diatomaceous earth is used in filtering and as an abrasive. 


The soil of the Coastal Plain developed on the already loose, unconsolidated layers of sediment that make up the region. As there is no hard, cemented rock, soil forms much more easily and quickly in the Coastal Plain than in other regions of the Northeast. In most areas of the Coastal Plain, the soil for agriculture is an excellent mix between sand and clay, with the sand providing good drainage. Areas that are too clay rich have poor drainage due to the impermeable nature of clay. Depressions in the landscape or areas of slightly lower topography in the Coastal Plain often remain too wet and are not good areas for cultivation of crops.