Unit 4 Test Review: Plate Tectonics & Fossils

the crust and the upper mantle divided into plates

created from the heating and rising, cooling and sinking of molten rock in the mantle

long mountain chains at the sites of sea-floor spreading where new crust is being made

younger than rock further away

more dense than continental plate; slides under

less dense than oceanic plate

continents look like they fit together, same fossils and rocks found on different continents

found at subduction zones; deepest places in the ocean

when two plates move towards each other

when two plates pull apart

when two plates slide past each other

formed when other rocks change due to heat and pressure

formed when magma or lava cools

formed from sediments being deposited in layers, then compated and cemented together

trace, evidence, or remains of a once living thing

sedimentary rock layers

4.6 Billion Years Old

only under curtain environmental conditions

the age of an object in relation to another object

the age of a rock or fossil in years

a fossil that is widespread and existed in a known time span; used to date other rocks and fossils

the time it takes for half the atoms of a sample of radioactive element to decayto

a method to date rocks and fossils using radioactive elements

the idea that in undistrubed rock layers, the oldest rock is at the bottom and the youngest rock is at the top

formed when magma burns its way through rock layers then cools and hardens; always younger than the rock it cuts through

a break in the rock layers; causes rocks to shift

when rock layers are bent due to tectonic plate movement

when rock layers are missing due to erosion