Artists Bluff is located within Franconia Notch State Park and offers amazing views looking south over the lake and towards the center of Franconia Notch. The notch is dominated by Cannon Mountain to the west and Mount Lafayette to the east. Franconia Notch was home to the Old Man of the Mountain, which collapsed in 2003 and was and still is a symbol of New Hampshire. The Old Man of the Mountain became famous because of Daniel Webster who once wrote, "Men hang out their signs indicative of their respective trades; shoemakers hang out a gigantic shoe; jewelers a monster watch, and the dentist hangs out a gold tooth; but up in the Mountains of New Hampshire, God Almighty has hung out a sign to show that there He makes men".
Franconia Notch was shaped extensively by the glaciers. Beginning approximately 3 million years ago, the Earth entered an Ice Age. The Laurentide Ice Sheet formed and moved south into New England from Canada. Even as recently as roughly 12,000 years ago the White Mountains were covered by a sheet of ice which was more than a mile thick! While the glaciers are no longer here, they did leave behind evidence. The shape of the valley is often a big clue. Rivers will carve out a v-shaped valley. Often glaciers take easiest path when they flow downslope and as they flow down the existing valleys, they will widen the floor and oversteepen the walls. After the glacier retreats, it leaves behind a U-shaped valley. There are also glacial erratics which are defined as glacially deposited rock differing from the type of rock native to the area on which it rests. As glaciers move, they will pick up material such as rocks and soil and transport them for long distances. When rocks are dropped (usually due to glacier retreating), the rocks are often far from their origin. By studying glacial erratics, it can tell us a lot about how the glaciers travelled.
Northern New Hampshire's bedrock geology is a fascinating mix of ancient rocks. If you look on the map above, Artist's Bluff is located slightly southeast of Littleton. As you can see, a wide variety of rocks can be found in this part of the state. One important rock group is the Highlandcroft and Oliverian Plutonic Succession. These rocks formed deep underground and include granite, which is light-colored and speckled with minerals like quartz and feldspar. They have a coarse-grained texture, meaning you can see the individual mineral grains with the naked eye. Another significant rock group is the White Mountain Plutonic Volcanic Succession. These rocks formed from volcanic activity and include rocks like rhyolite and tuff. Rhyolite is often light gray to pinkish and has a fine-grained texture, feeling smooth to the touch. Tuff, on the other hand, is made up of volcanic ash and can be quite soft and crumbly. In addition to these, there are Silurian rocks in northern New Hampshire, including schist, quartzite, and granofels. Schist often has wavy layers and a shiny appearance due to its mica minerals. Quartzite is very hard and is made up almost entirely of quartz grains, giving it a glassy and sparkling look. Granofels is a hard rock formed from existing rocks being heated and changed, and it can be recognized by its altered appearance.
Identifying these rocks in the region involves looking at their color, texture, and the minerals present. Granite and rhyolite are light-colored and coarse- or fine-grained, while schist, quartzite, and granofels have distinct textures and unique mineral compositions. By examining these features, geologists can piece together the ancient geological history of northern New Hampshire.
Logging Requirements:
- At the posted coordinates, examine the large cube shaped boulder. Describe the color, texture, and grain size.
- Next, examine the bedrock which you are standing on. Describe the color, texture, and grain size.
- Based on your observations, is this boulder a glacial erratic?
- Using the description as a guide, identify the rock. Next, using the bedrock geology map found on the cache page, where do you think the boulder likely originated from?
- Upload a photo taken from Artists Bluff. You do not need to be in the photo, though it is strongly encouraged.