Castle Rock:
This volcanic neck or volcanic plug is part of the Pacific Ring of Fire. These types of volcanic plugs can cause explosive eruptions, but if it is preserved, the surrounding rock erodes away creating a vertical rock outcropping. Castle Rock is one of the top ten Canadian Volcanoes with recent seismic activity. The last time this volcano was active was during the Pleistocene period which was between 11,700 years ago and 2.5 million years ago. Castle rock is part of the Northern Cordilleran Volcanic Province. This belt of volcanoes extends roughly north-northwest from northwestern British Columbia and the Alaska Panhandle through Yukon to the Southeast Fairbanks Census Area of far eastern Alaska, in a corridor hundreds of kilometers wide.
It is the most recently defined volcanic province in the Western Cordillera. It has formed due to extensional cracking of the North American continent—similar to other on-land extensional volcanic zones, including the Basin and Range Province and the East African Rift. Although taking its name from the Western Cordillera, this term is a geologic grouping rather than a geographic one. The south most part of the NCVP has more, and larger, volcanoes than does the rest of the NCVP; further north it is less clearly delineated, describing a large arch that sways westward through central Yukon. The Northern Cordilleran Volcanic Province is part of an area of intensive earthquake and volcanic activity around the Pacific Ocean called the Pacific Ring of Fire. However, the Northern Cordilleran Volcanic Province is commonly interpreted to be part of a gap in the Pacific Ring of Fire between the Cascade Volcanic Arc further south and the Aleutian Arc further north. But the Northern Cordilleran Volcanic Province is recognized to include over 100 independent volcanoes that have been active in the past 1.8 million years. At least three of them have erupted in the past 360 years, making it the most active volcanic area in Canada.
Volcanic plug:
A volcanic plug, also called a volcanic neck or lava neck, is a volcanic object created when magma hardens within a vent on an active volcano. When present, a plug can cause an extreme build-up of pressure if rising volatile-charged magma is trapped beneath it, and this can sometimes lead to an explosive eruption.
Notice:
Keep in mind that the Top of the World Highway is a remote northern highway, and be prepared for long distances in between services, tight turns, and washboard conditions in the rain. Fuel is available in either Chicken or Tok. For the drive from Dawson City to Tok allow yourself a minimum of seven hours. The top of the world highway is open during May - September (for exact dates call the information center in Dawson City).
**Logging requirements**
DO NOT POST ANSWERS IN YOUR LOG.
Send the following answers to me via email.
- The text "GC61TQQ Castle Rock" on the first line
- What color is castle rock?
- How tall is it?
- Which direction do the majority of the cracks within the rock go? (i.e. perpendicular, parallel, and so on)
- Which direction does this outcrop head? (i.e. north/south, east/west, and so on)
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