Thermal Waters & Geologic Provinces
computer exercisehandout exercisesuggested grade levels: 9-12
view Idaho achievement standards for this lesson

Overview:
This lesson plan is designed to inform students about Thermal Waters & Geologic Provinces.
All geothermal waters originate as meteoric waters at the surface, by percolation of rain and snow meltwater into shallow aquifers and then into a geothermal aquifer. Geothermal heating is due to one or a combination of the following three factors:
i) groundwater can be heated during deep circulation through rocks that are hotter than normal due to the geothermal temperature gradient in the earth's crust. This temperature gradient normally means that rocks get about 1.5 - 2oC warmer per kilometer of depth, but can be substantially higher in volcanically and tectonically active areas;
ii) groundwater can be heated by exposure to magmatic heat sources in volcanically-active areas, such as occurs in Yellowstone Park;
iii) rocks rich in uranium, thorium, and/or potassium are heated by the energy liberated during radioactive decay of these elements, thereby providing a source of heat to ground water circulating through them.

Procedure:
Take a look at the maps of geothermal springs and thermal wells in Figure 5. Turn the various layers off or on so as to clearly view the locations of springs and wells across the state, and their locations relative to Idaho's geologic provinces. Print the handout below.

Handouts/Activities:
These are links to access the handouts and printable materials.
geol4.pdf | cad map: figure 5

Handout Sample:
Using the information on these and preceding maps, answer the following:

1. Which of the following rocks tend to have more potassium: sandstone or carbonate? more uranium and thorium: felsic igneous rocks or mafic igneous rocks?
2. Which geologic province contains most of the thermal springs in Idaho?

Related Lesson Topics:
Geology: Geology Topics

Lesson Plan provided by Vita Taube, 2000
Idaho Achievement Standards (as of 7/2001) met by completing this activity:
351.04
352.01
357.01.02