U.S. Highway 89 Bryce Canyon to Grand Canyon
Road damage south of Page, Arizona will impact travel between Bryce Canyon and Grand Canyon National Parks. Click for a travel advisory and link to a map with suggested alternate routes: More »
Sunset Campground Construction
From April-July 2014, three new restroom facilities will be constructed in Sunset Campground. Visitors may experience construction noise and dust, as well as some campsite and restroom closures. 'Sunset Campground' webpage has additional information. More »
Bryce Point to Peekaboo Connector Trail Closure
Due to a large rockslide, the connecting trail from Bryce Point to Peekaboo Loop is closed. Trail will be reopened once repairs are made. The Peekaboo Loop is open, but must be accessed from Sunset or Sunrise Point.
Wall Street Section of Navajo Loop Closed
Due to dangerous conditions (falling rock and treacherous, icy switchbacks), the Wall Street section of the Navajo Loop Trail is CLOSED. It will reopen in Spring once freezing temperatures have subsided.
Backcountry Campsite Closures
Due to bear activity at select campsites in Bryce Canyon's backcountry, two backcountry campsites have been closed until further notice: Sheep Creek and Iron Spring.
Activity 3: Igneous Rocks
IN OR OUT? IGNEOUS ROCKS
Igneous rocks are formed by the cooling and hardening of melted rock material. Students will learn how rate of cooling affects what type of rock forms.
Students will be introduced to igneous rocks, how they form, what the different types are and how to identify them.
Students will be able to:
30 minute setup
The term igneous comes from the Latin ignis, meaning "fire". Igneous is used to describe rocks that crystallize out of hot molten material in the Earth called magma. When magma pushes up through Earth's crust to the surface, it is called lava. Both magma and lava cool and harden to form igneous rocks.
Intrusive vs. Extrusive
Intrusive rocks come from magma. They cool slowly deep in Earth's crust. When magma cools underground, the crust acts like a blanket, insulating it, keeping it warm longer. Because the magma cools slowly, crystals of different minerals have time to grow. The molecules in the magma have time to arrange themselves into crystal formations before the magma hardens. Intrusive rocks have large crystals that can be seen with the naked eye. A common example of an intrusive igneous rock is granite.
The mineral proportions of the rock are what allows geologists to classify rocks chemically. Depending on the proportion of light minerals to dark minerals, igneous rocks can be broken into four main types: felsic, intermediate, mafic and ultramafic. The following list gives more information about igneous chemical categories. This information is provided for you, the teacher, to better understand igneous rocks.
What type of igneous rocks were formed? How did cooling rate affect the size of crystals formed? Do you think this process really happens in magma? In lava?
For teachers interested in rock identification, the following is a suggestion of how you can set up a rock-ID activity. For information about how to identify igneous rocks, refer to the above definitions and the United States Geologic Survey's (USGS) web site for igneous rocks, http://wrgis.wr.usgs.gov/docs/parks/rxmin/rock.html.
For pictures of common rock-forming minerals, refer to http://wrgis.wr.usgs.gov/docs/parks/rxmin/mineral.html#feldspar.htm. Using this information and the rocks contained in the Rocks and Minerals Discovery Chest, pass around the rocks to small groups and have them identify the rocks based on texture, mineral content and chemical composition.
Included National Parks and other sites:
Black Canyon of the Gunnison
Utah Science Core:
2nd Grade Standard 6 Objective 1, 2, 3
Did You Know?
On a clear day, the visibility at Bryce Canyon National Park often exceeds 100 miles! This is due to our exceptional air quality, low humidity and high elevation. More...