Vocabulary Unit 6 - Rocks
1. Rock Cycle - the continuous process by which rocks are created, changed from one form to another,
destroyed, and then formed again
2. igneous rock - formed when magma or lava cools and hardens. Basalt and obsidian are igneous
3. intrusive igneous rock – formed from cooled and hardened magma inside the earth. These typically
have large crystals because they cool slowly
4. extrusive igneous rock - formed from cooled and hardened lava on the surface of the Earth.
5. metamorphic rock - formed under the surface of the earth from the change that occurs due to intense
heat and pressure - Gneiss and marble are examples of metamorphic rock
6. sedimentary rock - formed from particles of sand, shells, pebbles, and other fragments that
accumulates in layers and over a long period of time hardens into rock - Limestone is an example of
sedimentary rock
7. fossil - a remnant or trace of an organism from the past, such as a skeleton or leaf imprint, embedded
and preserved in the earth's crust
8. radiometric dating - a method of finding the age of items by determining the relative proportions of
particular radioactive isotopes present in a sample
9. The Law of Superposition - A general law stating that in any sequence of sediments or rocks that has
not been overturned, the youngest sediments or rocks are at the top of the sequence and the oldest are at
the bottom
10. pressure - the continuous physical force exerted on or against an object by something in contact
with it
11. magma - hot fluid or semi fluid material (molten rock) below or within the earth's crust
12. lava - molten rock that flows on the surface of the earth
13. stalagmite - deposits of minerals that form into cave structures that emerging from the ground and
stand up like a traffic cone
14. stalactite - deposits of minerals that form into cave structures that hang from the ceilings of caves
like icicles
15. amber - the fossilized resin from ancient trees
16. silica – a natural element found within the Earth’s crust. The amount of silica in magma determines
the speed of the lava. An increase in the amount of silica in lava, slows the lava down
17. trace fossil - a fossil of a footprint, trail, burrow, or other trace of an animal rather than of the animal
18. petrification - the process of turning some plant material into stone by infiltration with water
carrying mineral particles without changing the original shape
19. petrified wood - a fossil that forms when plant material is buried by sediment, dissolves over time,
and sediment replaces the original plant material
20. fossil fuels - a natural fuel such as coal or gas, formed in the geological past from the remains of
living organisms
21. Lithification – the process that turns sediment into rock

Vocabulary - Effingham County Schools

get an essay or any other
homework writing help
for a fair price!
check it here!