chapter 9-3, 4

Question 1

what are plates? what are lithospheric plates?

Answer 1

plates - separate sections of the lithosphere that fit together along cracks in the lithosphere. lithospheric plates - when earth’s crust and upper mantle are broken into sections

Question 2

how are plates moved?

Answer 2

The hot material deep in the mantle move upward, subduction sinks cooler denser plate down into the mantle

Question 3

describe the types of plate boundaries.

Answer 3

divergent: when two plates move apart from one another where seafloor spreading occurs
convergent: when two plates come together and collide. makes crust disappear
transform: when two plates slide past each other, either moving in opposite directions or in the same but at different speeds.

Question 4

what is upwarping?

Answer 4

plumes of hot rock rising from the mantle that causes crust to bend and fracture

Question 5

what is a subduction zone?

Answer 5

area where one plate descends under the upper plates

Question 6

explain the types of convergent boundaries.

Answer 6

Oceanic-continental boundary: when continental and oceanic plates converge together. Ocean floor plates sink under continental plates forming a deep sea trench
Oceanic-oceanic boundary: when two oceanic plates collide. the more dense plate slides under the less dense one, forming a subduction zone
Continental-continental boundary: when two continental plates collide. no subduction and forms mountain ranges. earthquakes common but no volcanoes

Question 7

what is a continental volcanic arc and volcanic island arc?

Answer 7

continental volcanic arc - newly formed magma rises toward the surface along these plate boundaries forming a row of volcanic mountains
volcanic island arc - deep sea trench is formed and new magma produced rises to from a row of volcanic islands that build up from the ocean floor

Question 8

explain the 3 ways heat is transferred

Answer 8

Radiation: trasnsfer of heat by electromagnetic waves, how heat reaches earth from the sun. no direct contact
Conduction: transfer of energy when molecules bump into one another, always in constant motion. Energy transferred until all molecules are moving at the same rate. Direct contact
Convection: transfer of heat because of density differences in air or liquid

Question 9

what is a convection current?

Answer 9

circular motion of a gas or liquid

Question 10

How do convection currents move plates?

Answer 10

air movements in atmosphere hot air rises and cool air sinks. heat is released in the mantle and flows slowly. hot solid rock rises

Question 11

what is slab-pull and ridge-push?

Answer 11

Slab-pull: when gravity pulls dense oceanic lithospheric down into the deep mantle at subduction zones
Ridge-push: where asthenosphere rises from the mantle causing lithosphere to rise that occurs at mid-ocean ridges