What Sedimentary Rocks Are in Keene, New Hampshire?

Keene, N.H.

• Keene is a historic city surrounded by the Monadnock Region, a hotspot for outdoor sports, including swimming, hiking, skiing and skating. It also is home to Keene State, a local college that regularly hosts the New Hampshire Phantoms, a professional soccer team. Through a variety of high-tech businesses, Keene employs more than 44,000 workers in industries such as production of medical equipment and ball bearings. Other businesses in the area have clientele in Europe and the Far East.

The Devonian Period

• The majority of the United States' sedimentary rock began to form in the Devonian Period, which lasted from 417 to 354 million years before the 21st century. At this time, the area that makes up Keene was part of a supercontinent that included modern-day North America and Europe. Modern-day Siberia was the only other landmass on Earth. In the past, life in this area was primarily plants under a meter tall, small land-dwelling vertebrates and tiny winged insects. The oldest example of sedimentary rock, the Rhynie Chert, came from the Devonian Period and was found in Scotland.

Sedimentary Rock in Keene

• In the past, sedimentary rock covered Keene and the rest of New Hampshire. The rocks were created by the slow but steady collisions of African and North American tectonic plates. The same forces that created sedimentary rock eventually would destroy them. The continual pressure from the plates overwhelmed the structural integrity of sedimentary rocks and converted them into metamorphic rocks. Some of these rocks were further crushed into igneous rocks. The vast majority of sedimentary rocks that survived these forces have weathered away by erosion. Still, some rocks did survive these destructive forces, proved by fossils recovered from New Hampshire. Marine invertebrates are the primary fossils found in New Hampshire. For the most part, they come from the western part of the state.

Other Keene Rocks

• The majority of the rock in the Keene area is of the Littleton Formation class, an extremely erosion-resistant type of metamorphic rock. Despite being called the Granite State, the vast majority of rock found in Keene and the rest of New Hampshire is not granite. This nickname originates from the massive exportation of rock from New Hampshire for building projects in surrounding New England cities, such as Washington, D.C., New York and Boston. New Hampshire also holds a high concentration of valuable minerals.