Volcanoes

Chapter 7 Study Guide – VOLCANOES
Unit: Earthquakes and Volcanoes

Galapagos Geology

1. What is a hot spot and how does it create volcanic islands?

A hot spot is an area wherematerial from deep within the mantle raises then melts, forming magma. Some hot spots are in the middle of plates far from any plate boundaries. A hot spot in the ocean floor can gradually form a seriesof volcanic mountains, like the Hawaiian Islands.

2. What is the relationship between hot spots and mantle plumes? You should be able to compare and contrast these.

3. Explain the history of theGalapagos, including how they were formed, where they are located (specifically), which islands are youngest and oldest, how old are they.

They are located in 1,000 Km West off Ecuador(Pacific Ocean, North West of South America)
Longitude 90°W; Latitude 0° 00''


4. Be able to explain the relationships between the South American, Nazca, Pacific, and Cocos plates.

5. Whattype of volcanoes, magma, and lava flows make up the majority of the Galapagos?

6. How are each of the following formed?

Spatter cones: A spatter cone is formed of molten lava ejected from a ventsomewhat like taffy. Expanding gases in the lava fountains tear the liquid rock into irregular gobs that fall back to earth, forming a heap around the vent. The still partly liquid rock splashes downand over the sides of the developing mound is called spatter. Because spatter is not fully solid when it lands, the individual deposits are very irregular in shape and weld together as they cool, andin this way particularly differ from cinder and ash. Spatter cones are typical of volcanoes with highly fluid magma, such as those found in the Hawaiian Islands.

Tuff cones: They are formed bymagma-water eruptions (phreatomagmatic eruptions).
They have steep sides (>25 degrees), and crater floors which lie above ground level

Lava tubes:

Parasitic cones

7. Describe the Sierra...