Lesson 3 // Plate Tectonics

Plate Tectonics (Click here for a complete overview and other lessons on plate tectonics.)
Further Reference Microsoft Encarta 99 – Find: Animation – Plate Tectonics

Objective:

The student will define plate tectonics. The student will explain how the Himalaya Mountains were formed.

Guided Practice:

1. Review the location of Nepal. Point out on the map of Nepal where the Himalaya Mountains are located.
2. Review the layers of the earth (crust, mantle, core). Compare the earth to either an apple or an egg with the skin/shell like the crust, the fruit/white like the mantle, and the seeds/yolk like the core.
3. Read the information on plate tectonics and the formation of the Himalaya Mountains either orally to the class or have each student read it independently.

Independent Practice:

1. The students will answer the comprehension questions that correspond to the reading.
2. The students will locate Kathmandu and Mount Everest on the map of Nepal. Then color the map using different colors for the mountain regions. Be sure to have the students include a map title and a compass rose.

Optional Extensions:

1. The students will answer the comprehension questions that correspond to the reading.
2. The student will define: plate tectonics, continental drift, crust, mantle, and core.

Optional Extensions:

1. Have the students create a map of what the world looked like before the plates started to move.
2. Have the student create a map of what the world will look like a million years from now. Have the student include a paragraph explanation of their map.
3. Have the student research (using the Internet) fossil discoveries on different continents to see if there are any similarities.
4. Have the students define the terms lithosphere and asthenosphere. Then have them compare these terms to the crust, mantle, and core of the earth.

Reading and Questions:

The country of Nepal is not only home to eight of the ten highest mountains in the world, but it is also home to the youngest mountain range on the earth. The Himalaya mountain range was formed more than 45 million years ago. Scientists attribute the formation of these great mountains to the theory of plate tectonics.

In 1912, a German scientist named Alfred Wegener first postulated the theory of continental drift. Mr. Wegener noted after studying the world map that the continents resemble that of a jigsaw puzzle, and thus he stated that the world must have been one land mass at one time. Through extensive study of the earth's surface and fossil records, geologists have renamed continental drift to the theory of plate tectonics.

According to the theory of plate tectonics, the earth is divided into nine large plates. These plates rest on top of the molten rock below the surface of the earth (which can be up to 60-miles deep). Instead of remaining in the same place, these plates are in constant motion, either pushed or pulled by the matter below the crust. Volcanoes, earthquakes, and mountain ranges all occur due to plate tectonics.

The country of Nepal is located on the Eurasian Plate, while the country of India is located on the Indian Plate. The Indian Plate separated from the large landmass (called Gondwanaland) approximately 60 million years. This plate moved at an approximate rate of 8 to10 inches a year and began colliding into the Eurasian Plate. When these two plates collided, the land started to crumple and rise, causing the Himalaya mountain range.

The plates are still moving to this day at a rate of approximately two inches per year! Because of this movement, many geologists believe that the Himalayan Mountains are rising as well.

THE GEOLOGY OF EVEREST

Everest is composed of three distinct layers of rock:

1) The bottom layer, extending upwards to 24,500ft, consists of a light-colored gneiss, most of which is permanently covered with snow and ice.

2) The middle layer is metamorphosed shale containing granite intrusions and bands of material like quartzite which formed from sandstone through heating and recrystallization. Easily eroded, this layer contains rugged cliffs and fantastic pinnacles.

3) Layer three begins at 27,500 feet, the first 500 feet of which consists of yellow limestone known as the Yellow Band. This feature actually slices through Everest at an angle and is most pronounced on the North Face. (On the south side, it's visible around 24,000ft.) Above the Yellow Band is more limestone but here the color is dark grey; it can be seen most prominently in the First and Second Steps of the Northeast Ridge.

1. Explain what the term plate tectonics means.
2. How did the Himalaya Mountains form?
3. According to the Theory of Plate tectonics, what will happen to the Himalaya Mountains and why?
4. Define: continental drift, crust, mantle, and core. Draw a picture of the earth showing the crust, mantle, and core.
5. Describe the three distinct layers of rock that Everest if composed of.

References:

1. Lisa A. Rossbacher, Recent Revolutions in Geology, Franklin Watts, New York, 1986, chapter 1.
2. Lisa Choegyal, Insight Guides Nepal, Langenscheidt Publishers Inc., New York, 11378, p. 31-33.

3. Geology facts excerpted from "Everest, The Mountaineering History" by Walt Unsworth

AZ State Standard - 6SC-E5. Explain how earth processes seen today, including erosion, movement of lithoshoeric plates, and changes in atmospheric composition, are similar to those that occurred in the past.

AZ State Standard - SS3 E4 Demonstrate understanding of the characteristics, purposes and use of geographic tools to located and analyze information about people, places and environments, with emphasis on:

PO 1 ways to display geographic information and characteristics and purposes of maps, globes, aerial photographs, charts and satellite images.

PO 2 constructing and interpreting maps, charts and geographic databases using geographic information.

PO 3 drawing an accurate map after being given a description of a place.

PO 4 identifying and locating physical and cultural features in their own and nearby communities in the United States, and in regions of the world, and the relationship between them.