earth's geology vocab

Question 1

asthenosphere

Answer 1

region of the mantle where rocks become ductile, having little strength, and are easily deformed. It lies at a depth of 100 to 350 km below the surface

Question 2

continental drift

Answer 2

slow movement of continents across the face of the earth

Question 3

convergent boundary

Answer 3

the zone where plates meet as they move toward each other

Question 4

core

Answer 4

the spherical mass, largely metallic iron, at the center of the earth

Question 5

crust

Answer 5

the outermost and thinnest of the Earth’s compositional layers, which consists of rocky matter that is less dense than the rocks of the mantle below

Question 6

divergent boundary

Answer 6

a fracture in the lithosphere where two plates move apart

Question 7

igneous rock

Answer 7

describes stones formed from cooling magma

Question 8

inner core

Answer 8

the central, solid portion of the earths core

Question 9

island arc

Answer 9

a curved belt of volcanoes that forms above a subduction zone

Question 10

lithosphere

Answer 10

the outer 100 km of the solid earth, where rocks are harder and more rigid than those in the plastic asthenosphere

Question 11

mantle

Answer 11

the thick shell of dense, rocky matter that surrounds the core

Question 12

metamorphic rock

Answer 12

describes stone that has undergone a change after being exposed to extreme heat or pressure

Question 13

mineral

Answer 13

a naturally occurring, inorganic, crystalline solid with definite physical and chemical characteristics

Question 14

outer core

Answer 14

the outer portion of the earth’s core, which is molten

Question 15

paleomagnetism

Answer 15

remnant magnetism in ancient rock recording the direction of the magnetic poles at some time in the past

Question 16

plate tectonics

Answer 16

the special branch of tectonics that deals with the processes by which the lithosphere is moved laterally over the asthenosphere

Question 17

rift

Answer 17

depression along the center of a spreading center

Question 18

sedimentary rock

Answer 18

any rock formed by chemical precipitation or by sedimentation and cementation of mineral grains transported to a site of deposition by water, wind, ice, or gravity

Question 19

suture

Answer 19

an area on the earths surface where two continental plates collide, and neither is subducted

Question 20

transform boundary

Answer 20

a fracture in the lithosphere along which two plates slide past each other

Question 21

trench

Answer 21

point on the earth where a plate is subducted underneath another

Question 22

triple junction

Answer 22

a crack that forms as magma from the earth mantle pushes upward on the crust