Chapter 8 Flashcards
Volcanoes are made of ______ rocks
igneous
The term volcano originally came from the name for _______
a Roman God
A volcano begins to form when magma fores its way to the surface and breaks through, forming a hole or
vent
Where does pillow lava form?
underwater
A mudslide caused by a volcano is called a ___
lahar
List the size of particles from solid emission in order of smallest to largest
ash > cinder > bomb
Which organisms are the base or first step of the food chain around black smokers deep within the ocean?
bacteria
Which structure type is the most common for volcanoes?
stratovolcano
How would a typical young-earth creation geologist’s view the formation of volcanoes?
Most volcanoes formed during or shortly after the Flood
What are the three ways to describe the activity level of a volcano?
- active
- extinct
3 dormant
What is the name of the large volcano that we learned about in Washington?
Mt. Saint Helens
The VEI of a volcano’s eruption is based on what?
- The amount of tephra produced
- the height of the eruption cloud
- a descriptive estimate of the explosion
Vertical is to dike as horizontal is to ____________
sill
Batholiths and laccoliths are both types of _________
plutons
A hydrothermal circuit is best seen in
the eruption of a geyser
A spring that periodically ejects large quantities of hot water and steam is known as a ____________
geyser
A _____ is a depositional mountain built up by molten rock that has risen to the earth’s surface through a vent.
volcano
The depression found at the top of most volcanic cones is called a __________
crater
A _________ is a vent in the ground through which hot gases escape.
fumarole
Flood ________ are thick layers of igneous rock covering large portions of the earth. They are thought to have formed when huge quantities of magma were released through cracks in the earth’s crust.
basalts
The internal energy of the earth, particularly evident in areas where hot springs are geysers exist, is sometimes harnessed for man’s use. This is called __________ energy.
geothermal
Explain the relationship between the amount of silica that is found in a type of magma and its viscosity.
There are three different classifications of magma that are based on the percentage of silica they contain. Those with the lowest amount of silica are the least viscous. That is, they flow more easily than those higher in silica content.
Why are so many volcanoes found in ares of tectonic activity?
Where plates are being subducted, great amounts of magma are being created. The mid-ocean rifts created by sea-floor spreading also allow magma to rise to the surface.
Why is the term stratovolcano appropriate for the volcano structure type that it applies to?
These volcanoes intermittently release both lava and pyroclastic materials. The lava and tephra form layers or strata.
What does the term geothermal gradient refer to?
The term geothermal gradient refers to the way the temperature within the earth increases continuously with its depth.
Why do geysers and hot springs produce distinctive mineral deposits?
Hot groundwater is very effective at dissolving minerals in the rocks that it flows through. The hot water cools when it reaches the surface, causing the minerals to precipitate.
