The Tormented Valley
The Tormented Valley is an easy EarthCache that can be done from the train or the Klondike Highway.
Earthcaches have no "box" to find. Rather, with this earthcache, you discover something about the geology of Skagway For more information, see earthcache.org.
The Tormented Valley contains large areas having an almost "lunar" appearance, making this one of the most unique eco-systems in North America. Within this lunar landscape are some interesting geological formations.
Fractures beneath the surface of the North American Plate are commonly filled and expanded by intruding molten magma. Trapped within a solid crust, this magna cools slowly until it is hard, becoming a huge body of granite called a pluton. Uplift drives these plutons upwards. Millions of years of weathering and erosion eat away at the miles of material on top of the plutons, eventually exposing them as the massive granitic mountains north of Skagway.
At these coordinates you can see an example of a portion of a pluton. A magma chamber deep within the earth cooled slowly, forming this pluton. Through uplift and erosion, the pluton is now exposed to the sky as a uniform mass of granite.
Logging Tasks: (Required)
Please send your answers via geocaching message center (preferred) or email.
- What rock type is this pluton (igneous, sedimentary, or metamorphic)?
- What is another name for a pluton?
- Take a look at the rocks in this area. Besides grey, what are some other colors of the granite?
- Please post IN YOUR FOUND IT LOG a picture of you, your GPS, your group, a limb, your geo-pet as you are passing through the tormented valley.