America's Volcanic Past -
New Hampshire

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Volcanic Highlights and Features:
[This list is just a sample of various New Hampshire volcanic features or events and is by no means inclusive.]

• New Hampshire
• New Hampshire Regions
• New Hampshire - Brief Geologic History
• New Hampshire's Volcanic Rocks
• New Hampshire's Gold
• Flume Gorge State Park
• Franconia Notch State Park
• Mt. Kearsarge
• Rollins State Park
• White Mountains
• Winslow State Park

The Granite State:²
Granite is the official state rock of New Hampshire. Granite is the traditional rock in New Hampshire. It gave New Hampshire it's Nickname of "The Granite State." New Hampshire once had a large industry surrounding the quarrying of granite. Beryl is the official state mineral of New Hampshire. Beryl is a gemstone commonly found in the granite rocks abundant in the state. Beryl Crystals are a yellow-green and yellow colors. Smoky quartz is the official state gem of New Hampshire. Smoky Quartz is a common mineral also found in many types of rocks, including granite. It is also know as cairngorm.

New Hampshire's Volcanic Rocks:¹
Volcanic rocks, not abundant in the state, are only found associated with the granitic rocks of the southern White Mountains. About 50 percent of the state is underlain by metamorphic rocks which are in part derived from the recrystallization of rocks which were of volcanic origin. The remainder of the rocks of the state are granitic or related rocks. (See more White Mountains below)

New Hampshire's Gold:¹
Gold, in anomalous amounts, is not only associated with granitic rocks, but also with rocks such as serpentinite at the other end of the igneous spectrum. Gold is commonly associated with volcanic rocks, especially those characterized by the analogs of granitic rocks, rhyolite for example.

Flume Gorge:⁶
Nearly 200 million years ago in Jurassic times, the Conway granite that forms the walls of the Flume was deeply buried molten rock. As it cooled the granite was broken by closely spaced vertical fractures which lay nearly parallel in a northeasterly direction. Sometime after the fractures were formed, small dikes of basalt were forced up along the fractures. The basalt came from deep within the earth as a fluid material, and because of pressure, was able to force the Conway granite aside. The basalt crystallized quickly against the relatively cold granite. Because of this quick cooling, the basalt is a fine grained rock. Had this material ever reached the surface, it would have become lava flows. Erosion quickly lowered the earth's surface and exposed the dikes. As the overlying rock was worn away, pressure was relieved and horizontal cracks developed which allowed water to get into the rock layers. The basalt dikes eroded faster than the surrounding Conway granite, creating a deepening valley where the gorge is now. The gorge was covered by glaciers during the Ice Age, but the ice sheet did not greatly change the surface. It partially filled the valley with glacial debris and removed soil and weathered rock from the vicinity. After the Ice Age, Flume Brook began to flow through the valley again. The highly fractured granite and basalt have been eroded by frost action as well as by the brook's water. As you walk through the Flume, you may see remnants of the main basalt dike on the floor of the gorge and small branches along the canyon walls. The process of erosion is still occurring in the Flume.

Old Man of the Mountain:⁶
The Old Man of the Mountain, nicknamed the Great Stone Face or Profile (immortalized by Nathaniel Hawthorne and Daniel Webster), is located in Franconia Notch State Park. The Old Man of the Mountain is scenically set 1,200' above Profile Lake. The Profile is a natural rock formation that was formed by a series of geologic happenings that began an estimated 200 million years ago. Hovering majestically 1,200 feet above Profile Lake, the Old Man is made of five separate granite ledges arranged horizontally to form a man's profile. From chin to forehead, the Profile measures about 40 feet and is 25 feet wide. The Old Man of the Mountain is the State Symbol for New Hampshire and was chosen as representation for the New Hampshire Quarter.

Mt. Kearsarge:⁶
Located in Warner and Wilmot, New Hampshire, 2,937-foot Mt. Kearsarge, one of the oldest mountains in the state, is the home of both Winslow and Rollins state parks. Because of its easy accessibility from the parks and outstanding summit vistas, Mt. Kearsarge is a popular family hiking destination. Views include nearby Sunapee, Ragged and Cardigan mountains and more distant Mt. Monadnock and Ascutney. On very clear days views extend to the White Mountains, the Green Mountains of Vermont, the Atlantic Ocean and Boston. The exposed granite summit is a good place to see evidence of past glacial activity. During the glacial period more than 25,000 years ago, a great ice sheet more than a mile thick moved over Kearsarge and much of New Hampshire. Glacial striations, grooves cut in rock by the movement of glacial ice, can be seen on the summit, as well as on ledge outcroppings in the Winslow picnic area. In addition, large boulders called glacial erratics, can be seen from the trails. The mass of ice was powerful enough to move the boulders which were left behind when the ice sheet retreated. The bare summit is the result of a 1796 forest fire which burned the vegetation and exposed the soil to wind and water erosion.

Old Man of the Mountain:⁶
The Old Man of the Mountain, nicknamed the Great Stone Face or Profile (immortalized by Nathaniel Hawthorne and Daniel Webster), is located in Franconia Notch State Park. The Old Man of the Mountain is scenically set 1,200' above Profile Lake. The Profile is a natural rock formation that was formed by a series of geologic happenings that began an estimated 200 million years ago. Hovering majestically 1,200 feet above Profile Lake, the Old Man is made of five separate granite ledges arranged horizontally to form a man's profile. From chin to forehead, the Profile measures about 40 feet and is 25 feet wide. The Old Man of the Mountain is the State Symbol for New Hampshire and was chosen as representation for the New Hampshire Quarter.

Rollins State Park:⁶
Located in Warner and Wilmot, New Hampshire, 2,937-foot Mt. Kearsarge, one of the oldest mountains in the state, is the home of both Winslow and Rollins state parks. The exposed granite summit is a good place to see evidence of past glacial activity. [See Mt. Kearsarge above]

White Mountain's Volcanic Rocks:¹
Volcanic rocks, not abundant in the state, are only found associated with the granitic rocks of the southern White Mountains. About 50 percent of the state is underlain by metamorphic rocks which are in part derived from the recrystallization of rocks which were of volcanic origin. The remainder of the rocks of the state are granitic or related rocks

White Mountains of New Hampshire:³
Many of the rocks in these areas were formed by eruptions or by intrusion of magma into the Earth's crust many millions of years ago.

More White Mountains:⁴
The White Mountain igneous province consists of plutons, ring complexes, and volcanics emplaced along a NNE trend across New England. Four petrographic associations are recognized: (1) alkali syenite-quartz syenite-granite; (2) subaluminous biotite granite; (3) gabbro-diorite-monzonite and; (4) syenite-nepheline syenite. The igneous activity is largely confined to two periods, 200-165 million years ago and 130-110 million years ago. These two major periods of igneous activity are related to the opening of the North Atlantic Ocean.

Winslow State Park:⁶
Located in Warner and Wilmot, New Hampshire, 2,937-foot Mt. Kearsarge, one of the oldest mountains in the state, is the home of both Winslow and Rollins state parks. The exposed granite summit is a good place to see evidence of past glacial activity. [See Mt. Kearsarge above]

Excerpts from:

1) Gold in New Hampshire, 1993, Environmental Fact Sheet CO-1, New Hampshire Department of Environmental Services Website, July 2001
2) New Hampshire Department of Environmental Services Website, July 2001
3) Brantley, 1994, Volcanoes of the United States: USGS General Interest Publication
4) Creasy and Fitzgerald, Bedrock Geology of the Eastern White Mountain Batholith, North Conway Area, New Hampshire
5) USGS/NPS Geology in the Parks Website, August 2001
6) New Hampshire State Parks Website, 2002

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