Mineral Resources of the Northeastern U.S.: the BIG picture

The Inland Basin has two areas of mineral resources that produce very different mineral assemblages: the Precambrian Grenville rocks of the Adirondacks, and the Paleozoic sedimentary rocks that make up the bulk of the region. The Adirondacks produce most of the metallic minerals as well as important non-metallic minerals such as garnet and wollastonite. The sedimentary rocks to the southwest contain an abundance of non-metallic minerals, including slat, gypsum, beryl and tourmaline.

Region 2: Appalachian/Piedmont

The metallic and non-metallic mineral resources of the Appalachian/Piedmont originate from the Precambrian Grenville rocks, the Ordovician-age Ultramafic Belt, and the Rift Basin rocks formed in the Triassic and Jurassic. Metallic mineral resources include zinc, aluminum, copper and magnesium. Non-metallic minerals include talc, mica, kaolin and asbestos. There is also a wide variety of gemstones found in the region.

Region 3: Coastal Plain

Unlike the other regions of the Northeast, there are no igneous and metamorphic rocks in the Coastal Plain. The relatively young sediments of the Coastal Plain do not have the proper conditions to produce the variety of minerals found elsewhere. Gypsum and magnesium compounds are the only mineral resources currently being produced.

Region 4: Exotic Terrane

The addition of the exotic terranes to North America in the Paleozoic deformed the crust, providing excellent conditions for the formation of a broad spectrum of metamorphic minerals and granite pegmatites. Metallic minerals in the Exotic Terrane include pyrite, gold, lead, silver, and copper. Non-metallics include rare minerals derived from the pegmatites as well as metamorphic minerals that reflect the varying degrees of metamorphism across the region. The pegmatites are also the source of many of the region's fine-quality gemstones.