chapter 10-1

Question 1

what is a volcano?

Answer 1

weak spot in the crust where magma from mantle rises to the surface

Question 2

what is magma?

Answer 2

mixture of partially melted mineral crystals, dissolved gases, and water

Question 3

what does magma depend on? how?

Answer 3

heat - Near solid rock is near its melting point
pressure - Deeper into earth’s interior, pressure rises
water content - Increasing water content of rock lowers rock’s melting point. Wet rock beneath the surface melts at a much lower temperature than dry rock of the same composition and pressure

Question 4

what is decompression melting?

Answer 4

when rock rises and melts due to reduced pressure. Rock melting point decreases as pressure drops

Question 5

what is divergent boundary volcanism?

Answer 5

plates apart; mantle rock rises to fill in the gap and decompression melting occurs. Magma erupts through center and forms rifts

Question 6

what is convergent boundary volcanism?

Answer 6

oceanic plates collide with another ocean plate and one goes under the other. Magma forms volcanoes and sometimes volcanic continental arc

Question 7

what is intraplate volcanism?

Answer 7

volcanic activity within a plate

Question 8

what is a mantle plume?

Answer 8

area where the magma is unusually hot and hot rock is forced upward toward the crust. Volcanoes form, sometimes rise above sea level, and form islands.

Question 9

what is a hot spot?

Answer 9

volcanic region that results from a mantle plume