It will never be quite the same again

New Hampshire's sole geo-site is Flume Gorge, New Hampshire, and that is where we went today, on a cloudy day. We began at the Visitor's Center and watched a 20 minute film on Franconia Notch; the highway runs through this valley between the White Mountains. In the film the narrator made a point that many of these natural features are created by erosion and that erosion continues today, so what we see today will be different tomorrow because on ongoing erosion. Hence, it will never be quite the same again.

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 gradually lowered the earth's surface and exposed the dikes. As the overlying rock was worn away, pressure was relieved and horizontal cracks developed, allowing 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 brook water. Erosion is still occurring - and what we saw today will never be quite the same again!

Frederick and moose at the Visitor's Center.

There are many glacial erratics in the area and on the trail to the Flume. Some are quite large, weighing over 300 tons. During the glacial period, over 25,000 years ago, a great ice sheet more than a mile thick moved over this area. The mass of ice was so powerful it moved both large and small boulders. As the ice sheet retreated these boulders were left behind.

Below the gorge, the Pemigewasset River flows. It will merge with the Merrimack River and enter the Atlantic Ocean at Newburyport, MA. 

Over time, the rushing water of the Flume Brook has exposed this large outcropping of rock. Table Rock is a section of Conway granite that is 500 feet long and 75 feet wide. 

Inside the Flume that Spock found fascinating.

Even though the Flume/gorge walkway is slippery when wet, Spock and Frederick were able to steady each other.

Spock liked this basalt rock that is still in the gorge.

At the top of the Flume is Avalanche Falls. The 45-foot waterfall creates a roaring sound as the Flume Brook enters the gorge. The falls were formed during a great storm in 1883. 

Another, smaller, eroded basalt dike.

Just some pretty fall leaves on the rocks.

Selfie at Avalanche Falls.

We thought that this tree, that looks like it is growing out of the rock, looked like a giraffe.

Liberty Gorge, a beautiful cascading mountain stream that flows through the narrow valley.

The Pool is a deep basin in the Pemigewasset River. It was formed at the end of the Ice Age, 14,000 years ago, by a silt-laden stream flowing from the glacier. The Pool is 40 feet deep and 150 feet in diameter and is surrounded by cliffs 130 feet high. A cascade rushes into it over fragments of granite that have fallen from the cliffs above. 

The Sentinel Bridge crosses the Pemigewasset River. Here it is at center right, with some lovely fall color.

Frederick at the Sentinel Bridge.

There are several reasons why bridges were covered.

1. Protect wooden structure from the weather
2. Help get livestock over the bridge - they thought it looked like a barn and were willing to enter it when they might have been frightened to cross a raging river.
3. Keep rain off roadway to eliminate slipperiness since the bridge deck was often oiled and would be slippery when wet
4. Covered "ugly" trusses
5. Provide shelter in bad weather
6. Actually strengthen the bridge
7. Keep snow off the bridge surface
8. Nowadays - attract tourists     

I also learned that reason #7 was not the most important, in fact, in the winter someone would have to be hired to "snow pave" the covered bridge because people traveled by sleigh and the runners needed the snow to cross the bridge.

The Pemigewasset River flowing to the Sentinel Bridge.

On the high cliff above the Pemi River, the Sentinel Pine tree stood for centuries. With a circumference of 16 feet and nearly 175 feet high, the tree was one of the largest in the state. The hurricane of 1938 uprooted the giant pine whose trunk now bridges the river and forms the base for the covered bridge. I think you can just see it at the base of the bridge.

A little further down the road from the Flume is another natural attraction called The Basin. After we viewed the Flume and hiked the trail we drove to The Basin where we ate our lunch before exploring the Pemigewasset Trail and The Basin.

Along the trail is a formation that is called the Baby Flume.

At the base of the beautiful waterfall is The Basin, a granite pothole 20 feet in diameter. It is believed to have been eroded 25,000 years ago while the North American ice sheet was melting. The Basin has been smoothed by small stones and sand, whirled around by the Pemigewasset River. 

Below the Basin is a water-eroded rock formation called the Old Man's Foot. At first I couldn't see it until Frederick pointed it out to me. Think BIG - the rounded rock in the middle is the heel; the ankle and leg extends to the right, sloping down; the arch of the foot is to the left of the rounded rock with the rest of the foot extending down to the left from the arch; the toes are under the water. See it?

Just a pretty little water fall next to a pool with fall leaves.

I love the way the leaves line up behind the rocks in the flowing stream.