Plate Tectonic - Volcanoes (5)
Do rocks produced
by volcanoes provide clues about that volcanic eruption?
Look at a map and locate where the rocks came from in
California. Describe the rocks in the area provided below. After learning about
the type of eruption that caused the volcano, can you interpret if there is a
difference in rock type between a violent eruption and a quiet eruption?
- GILROY, CALIFORNIA - This ancient lava flow
erupted with a powerful blast. Lava cascaded down the slopes of the growing
- CLEARLAKE, CALIFORNIA - The cinders swished from
the volcano, causing extensive deposits, (scoria). Flows of lava cooled
quickly to form thick bands of obsidian.
- BLACK BUTTES, CALIFORNIA - Lava slowly moved
from the crater of the volcano. A thick layer of basalt was deposited.
- MONO CRATERS, CALIFORNIA - the volcano
"coughed" violently, gas trapped in the molten rock formed
- INYO MOUNTAINS, CALIFORNIA - The magma chamber
was cooling, but suddenly the volcano erupted formed a rock called andesite
CONCLUSION: Are there characteristics of volcanic
rocks that indicate what type of eruption produces them?
Is there enough data here to really tell? Explain