by Nancy Carruthers

8TH-GRADE INTEGRATED SCIENCE
Standard 3, Objective 2 -
describe the nature of the changes
that rocks undergo over long periods
of time.
Standard 3, Objective 4 -
compare rapid and gradual changes
to Earth's surface.

In the second of our continuing series illustrating how relevant geologic information in Survey Notes articles can be used in the classroom, this “Teacher’s Corner” highlights articles in the September 2006 Survey Notes (pdf) that discuss aspects of the igneous and metamorphic geology of Utah.

Utah’s igneous activity has produced rocks and landforms of many shapes, sizes, and compositions, from the basaltic lava flows of southwestern Utah to the granitic intrusions found at Granite Peak Mountain.

9TH-GRADE EARTH SYSTEMS
Standard 3, Objective 2 -
describe the processes within the
Earth that result in plate motion and
relate it to changes in other Earth
systems.

In the article “New Age for the Santa Clara (Snow Canyon State Park) Basalt Flow,” learn how geologists unravel clues to Utah’s volcanic past by studying evidence found in the present, and explore the complex processes associated with studying and dating igneous rocks.

In the article “Granite Peak Mountain - A Geologic Mystery Revealed,” learn how geologists collaborate with other research scientists to produce a geologic map of the mountain range and gain knowledge about the geologic history of the area, which includes igneous intrusions, mountain-building events, and regional metamorphism (that often accompanies massive intrusions).

In the GeoSights' article “Spectacular Towering Cliffs at Castle Rock Campground, Sevier County,” learn about the geologic history that includes volcanic eruptions, ash and lava flows, and collapsing calderas.

This issue of Survey Notes provides a variety of discussion topics that can be incorporated into the 8th-grade Integrated Science and 9th-grade Earth Systems curricula.

For more information on basalt flows and dating rocks, see the following publications:

The Geology of Snow Canyon State Park, Washington County, Utah (pdf)
Public Information Series 13

How Do Geologists Know How Old a Rock Is?

Inverted Topography in the St. George Area of Washington County
Use the information in this article to discuss erosion and landform development and why basaltic lava flows ended up on the top of bluffs and mesas, creating some of Utah’s most interesting geologic features.

Possible Discussion Points

Why does magma solidify underground in some places (like at Granite Peak Mountain) but rise to the surface to emerge as lava in other places (like at Snow Canyon State Park)? Explain the difference between intrusive and extrusive igneous rocks.

Geologic studies constantly reveal new data. What were the original age ranges estimated to be for the granite and metamorphic rocks at Granite Peak Mountain? What are the ages of these rocks now thought to be, and what scientific methods were used to help narrow in on the ages?

How are metamorphic rocks formed?

What type of volcanoes produced the lava flows in the Snow Canyon State Park area? (mostly cinder cones).

What type of volcano produced the volcanic tuff at Castle Rock? (composite, or stratovolcano).