rock
a solid material made of minerals that forms the Earth's crust
mineral
a naturally occurring, inorganic solid that has a crystal structure and a definite chemical composition
igneous rock
rock that forms when molten rock cools and hardens
intrusive
a type of igneous rock that generally contains large crystals and forms when magma cools slowly beneath Earth's surface.
extrusive
fine-grained igneous rock that forms when magma cools quickly at or near Earth's surface
magma
molten rock beneath the earth's surface
lava
magma that reaches Earth's surface
sedimentary rock
rock that forms when sediments are compacted and cemented together
cementation
process in which dissolved materials crystallize and glue and sediments together
compaction
process that forms sedimentary rocks from sediments compressed by the weight of the rock layers above them
rock cycle
the process by which one rock type changes into another; between igneous, sedimentary, and metamorphic rocks.
metamorphic
Rocks changed by intense heat or extreme pressure
foliated
describes metamorphic rocks whose grains are arranged in parallel layers or bands.
deposition
process in which sediment is laid down in new locations
erosion
the process of moving sediment from one place to another
delta
flat, low-lying triangular shaped land built up from silt carried downstream by a river and deposited at its mouth
mechanical weathering
the process of physically breaking down rock.
chemical weathering
a process that changes the composition of rocks
sediments
loose materials such as rock fragments, mineral grains, and bits of shell that have been moved by wind, water, ice, or gravity
geology
The scientific study of the origin, history, composition, and structure of the earth.