marine science ch 2 test vocab

Subduction

The downward movement of a plate into the mantle that occurs in trenches

Continental drift

The movement of continental masses on the surface of the earth

mass

the weight of a substance

crust

the outermost layer of the earth

rift

a crack in the earth formed as pieces of the crust separate

basalt

the dark colored rock that forms the sea floor (oceanic crust)

granite

the light colored rock that forms most of the continental crust

plate tectonics

the process involved in the movement of large plates of the earth crust

sediment

loose material such as sand and mud that settles on the bottom (biogenesis or lithogenous)

mantle

the semi liquid region between the crust and core of the earth

sea floor spreading

the process by which new sea floor is formed as it moves away from spreading centers

density

the weight or mass of a given volume of a substance

mid ocean ridge

the continuous chain of volcanic submarine mountains that extend around the earth

pangaea

the single large landmass or supercontinent that broke up to form today’s continents

lithosphere

the crust and the top part of the mantle that covers the earths surface

trench

a narrow deep depression in the sea floor

magnetic anomalies

magnetic bands in the sea floor that run parallel to the mid ocean ridge

core

the innermost layer of the earth

island arcs

the curved chain of volcanic islands that form along a trench

asthenosphere

the rest of the upper mantle that includes slow swirling rocks that drives the movement of the lithosphere plates

hydrothermal vents

deep springs

seamounts

submarine volcanos

weathering

the process by which rocks and minerals break down at or near the earth’s surface due to chemical , physical and biological interactions

active margins

where plates are colliding ; lack a continental rise

passive margins

the trailing edge of plate movement ; wide continental shelves

passive margins

the trailing edge of plate movement ; wide continental shelves