These coordinates will position you at the northern end of a unique geologic feature for which this conservation area is named. Stretching southward before you is a prominent area of steep sided rock outcroppings of ledges resulting from a volcanic event that occurred millions of years ago. Though the majority of Haverhill sits on bedrock of slate and sandstone, this area is predominantly hard, resistant granite called gneiss. Geologists have identified this granitic gneiss as an intrusive igneous rock. Erosional forces carved the gorge and spread boulders and rock material in a "boulder train" throughout the surrounding area.
A gorge is a narrow valley with steep, rocky walls located between hills or mountains. The term comes from the French word gorge, which means throat or neck. A gorge is often smaller than a canyon, although both words are used to describe deep, narrow valleys with a stream or river running along their bottom.
A number of natural forces form gorges. The most common is erosion due to streams or rivers. Streams carve through hard layers of rock, breaking down or eroding it. Sediment from the worn-away rock is then carried downstream. Over time, this erosion will form the steep walls of the gorge. The flooding of streams or rivers increases the speed and intensity of this erosion , creating deeper and wider gorges.
Geologic uplift also forms gorges. Geologic uplift is the upward movement of the Earth's surface. Geologic uplift is often associated with earthquakes and orogeny, the process of creating mountains. Erosion and geologic uplift often work together to create gorges.
The movement and melting of glaciers can also produce gorges. Glaciers cut deep valleys into the Earths surface. These rivers of ice can create huge canyons and sharp steep gorges. As glaciers melt, or retreat, these gorges and canyons are exposed.
In order to claim a find for this EarthCache you will need to answer the following questions and Email them to me. Do not post the answers on the log page!
1. Estimate the depth of the gorge at it's lowest point between the canyon walls, at approximately 100' south west from you ? 2. Explain in your own words what you think created this gorge here and in this orientation. 3. Optional: Post a picture of yourself or your GPS at GZ